Commit message: [libpng16] Silently truncate over-length PLTE chunk while reading.
CVE: CVE-2015-8126
CWE: CWE-120
Vulnerability description: Multiple buffer overflows in the (1) png_set_PLTE and (2) png_get_PLTE functions in libpng before 1.0.64, 1.1.x and 1.2.x before 1.2.54, 1.3.x and 1.4.x before 1.4.17, 1.5.x before 1.5.24, and 1.6.x before 1.6.19 allow remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact via a small bit-depth value in an IHDR (aka image header) chunk in a PNG image.

Project: libpng
File: pngrutil.c

png_get_int_32)(png_const_bytep buf)
{
   png_uint_32 uval = png_get_uint_32(buf);
   if ((uval & 0x80000000) == 0) /* non-negative */
      return uval;

   uval = (uval ^ 0xffffffff) + 1;  /* 2's complement: -x = ~x+1 */
   if ((uval & 0x80000000) == 0) /* no overflow */
       return -(png_int_32)uval;
   /* The following has to be safe; this function only gets called on PNG data
    * and if we get here that data is invalid.  0 is the most safe value and
    * if not then an attacker would surely just generate a PNG with 0 instead.
    */
   return 0;
}

Project: libpng
File: pngset.c

png_set_chunk_cache_max (png_structrp png_ptr, png_uint_32 user_chunk_cache_max)
{
   if (png_ptr != NULL)
      png_ptr->user_chunk_cache_max = user_chunk_cache_max;
}

Project: libpng
File: pngset.c

png_set_sCAL_s(png_const_structrp png_ptr, png_inforp info_ptr,
    int unit, png_const_charp swidth, png_const_charp sheight)
{
   png_size_t lengthw = 0, lengthh = 0;

   png_debug1(1, "in %s storage function", "sCAL");

   if (png_ptr == NULL || info_ptr == NULL)
      return;

   /* Double check the unit (should never get here with an invalid
    * unit unless this is an API call.)
    */
   if (unit != 1 && unit != 2)
      png_error(png_ptr, "Invalid sCAL unit");

   if (swidth == NULL || (lengthw = strlen(swidth)) == 0 ||
       swidth[0] == 45 /* '-' */ || !png_check_fp_string(swidth, lengthw))
      png_error(png_ptr, "Invalid sCAL width");

   if (sheight == NULL || (lengthh = strlen(sheight)) == 0 ||
       sheight[0] == 45 /* '-' */ || !png_check_fp_string(sheight, lengthh))
      png_error(png_ptr, "Invalid sCAL height");

   info_ptr->scal_unit = (png_byte)unit;

   ++lengthw;

   png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthw);

   info_ptr->scal_s_width = png_voidcast(png_charp,
      png_malloc_warn(png_ptr, lengthw));

   if (info_ptr->scal_s_width == NULL)
   {
      png_warning(png_ptr, "Memory allocation failed while processing sCAL");

      return;
   }

   memcpy(info_ptr->scal_s_width, swidth, lengthw);

   ++lengthh;

   png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthh);

   info_ptr->scal_s_height = png_voidcast(png_charp,
      png_malloc_warn(png_ptr, lengthh));

   if (info_ptr->scal_s_height == NULL)
   {
      png_free (png_ptr, info_ptr->scal_s_width);
      info_ptr->scal_s_width = NULL;

      png_warning(png_ptr, "Memory allocation failed while processing sCAL");

      return;
   }

   memcpy(info_ptr->scal_s_height, sheight, lengthh);

   info_ptr->valid |= PNG_INFO_sCAL;
   info_ptr->free_me |= PNG_FREE_SCAL;
}

Project: libpng
File: pngset.c

png_set_user_limits (png_structrp png_ptr, png_uint_32 user_width_max,
    png_uint_32 user_height_max)
{
   /* Images with dimensions larger than these limits will be
    * rejected by png_set_IHDR().  To accept any PNG datastream
    * regardless of dimensions, set both limits to 0x7ffffff.
    */
   if (png_ptr == NULL)
      return;

   png_ptr->user_width_max = user_width_max;
   png_ptr->user_height_max = user_height_max;
}

Project: libpng
File: pngset.c

png_set_IHDR(png_const_structrp png_ptr, png_inforp info_ptr,
    png_uint_32 width, png_uint_32 height, int bit_depth,
    int color_type, int interlace_type, int compression_type,
    int filter_type)
{
   png_debug1(1, "in %s storage function", "IHDR");

   if (png_ptr == NULL || info_ptr == NULL)
      return;

   info_ptr->width = width;
   info_ptr->height = height;
   info_ptr->bit_depth = (png_byte)bit_depth;
   info_ptr->color_type = (png_byte)color_type;
   info_ptr->compression_type = (png_byte)compression_type;
   info_ptr->filter_type = (png_byte)filter_type;
   info_ptr->interlace_type = (png_byte)interlace_type;

   png_check_IHDR (png_ptr, info_ptr->width, info_ptr->height,
       info_ptr->bit_depth, info_ptr->color_type, info_ptr->interlace_type,
       info_ptr->compression_type, info_ptr->filter_type);

   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      info_ptr->channels = 1;

   else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
      info_ptr->channels = 3;

   else
      info_ptr->channels = 1;

   if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
      info_ptr->channels++;

   info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);

   info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, width);
}

Project: libpng
File: pngset.c

png_set_cHRM_XYZ(png_const_structrp png_ptr, png_inforp info_ptr, double red_X,
    double red_Y, double red_Z, double green_X, double green_Y, double green_Z,
    double blue_X, double blue_Y, double blue_Z)
{
   png_set_cHRM_XYZ_fixed(png_ptr, info_ptr,
      png_fixed(png_ptr, red_X, "cHRM Red X"),
      png_fixed(png_ptr, red_Y, "cHRM Red Y"),
      png_fixed(png_ptr, red_Z, "cHRM Red Z"),
      png_fixed(png_ptr, green_X, "cHRM Red X"),
      png_fixed(png_ptr, green_Y, "cHRM Red Y"),
      png_fixed(png_ptr, green_Z, "cHRM Red Z"),
      png_fixed(png_ptr, blue_X, "cHRM Red X"),
      png_fixed(png_ptr, blue_Y, "cHRM Red Y"),
      png_fixed(png_ptr, blue_Z, "cHRM Red Z"));
}

Project: libpng
File: pngset.c

png_set_sBIT(png_const_structrp png_ptr, png_inforp info_ptr,
    png_const_color_8p sig_bit)
{
   png_debug1(1, "in %s storage function", "sBIT");

   if (png_ptr == NULL || info_ptr == NULL || sig_bit == NULL)
      return;

   info_ptr->sig_bit = *sig_bit;
   info_ptr->valid |= PNG_INFO_sBIT;
}

Project: libpng
File: pngset.c

png_set_invalid(png_const_structrp png_ptr, png_inforp info_ptr, int mask)
{
   if (png_ptr != NULL && info_ptr != NULL)
      info_ptr->valid &= ~mask;
}

Project: libpng
File: pngrutil.c

png_get_uint_16)(png_const_bytep buf)
{
   /* ANSI-C requires an int value to accomodate at least 16 bits so this
    * works and allows the compiler not to worry about possible narrowing
    * on 32-bit systems.  (Pre-ANSI systems did not make integers smaller
    * than 16 bits either.)
    */
   unsigned int val =
       ((unsigned int)(*buf) << 8) +
       ((unsigned int)(*(buf + 1)));

   return (png_uint_16)val;
}

Project: libpng
File: pngset.c

png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
    png_const_textp text_ptr, int num_text)
{
   int i;

   png_debug1(1, "in %lx storage function", png_ptr == NULL ? 0xabadca11U :
      (unsigned long)png_ptr->chunk_name);

   if (png_ptr == NULL || info_ptr == NULL || num_text <= 0 || text_ptr == NULL)
      return(0);

   /* Make sure we have enough space in the "text" array in info_struct
    * to hold all of the incoming text_ptr objects.  This compare can't overflow
    * because max_text >= num_text (anyway, subtract of two positive integers
    * can't overflow in any case.)
    */
   if (num_text > info_ptr->max_text - info_ptr->num_text)
   {
      int old_num_text = info_ptr->num_text;
      int max_text;
      png_textp new_text = NULL;

      /* Calculate an appropriate max_text, checking for overflow. */
      max_text = old_num_text;
      if (num_text <= INT_MAX - max_text)
      {
         max_text += num_text;

         /* Round up to a multiple of 8 */
         if (max_text < INT_MAX-8)
            max_text = (max_text + 8) & ~0x7;

         else
            max_text = INT_MAX;

         /* Now allocate a new array and copy the old members in; this does all
          * the overflow checks.
          */
         new_text = png_voidcast(png_textp,png_realloc_array(png_ptr,
            info_ptr->text, old_num_text, max_text-old_num_text,
            sizeof *new_text));
      }

      if (new_text == NULL)
      {
         png_chunk_report(png_ptr, "too many text chunks",
            PNG_CHUNK_WRITE_ERROR);

         return 1;
      }

      png_free(png_ptr, info_ptr->text);

      info_ptr->text = new_text;
      info_ptr->free_me |= PNG_FREE_TEXT;
      info_ptr->max_text = max_text;
      /* num_text is adjusted below as the entries are copied in */

      png_debug1(3, "allocated %d entries for info_ptr->text", max_text);
   }

   for (i = 0; i < num_text; i++)
   {
      size_t text_length, key_len;
      size_t lang_len, lang_key_len;
      png_textp textp = &(info_ptr->text[info_ptr->num_text]);

      if (text_ptr[i].key == NULL)
          continue;

      if (text_ptr[i].compression < PNG_TEXT_COMPRESSION_NONE ||
          text_ptr[i].compression >= PNG_TEXT_COMPRESSION_LAST)
      {
         png_chunk_report(png_ptr, "text compression mode is out of range",
            PNG_CHUNK_WRITE_ERROR);
         continue;
      }

      key_len = strlen(text_ptr[i].key);

      if (text_ptr[i].compression <= 0)
      {
         lang_len = 0;
         lang_key_len = 0;
      }

      else
#  ifdef PNG_iTXt_SUPPORTED
      {
         /* Set iTXt data */

         if (text_ptr[i].lang != NULL)
            lang_len = strlen(text_ptr[i].lang);

         else
            lang_len = 0;

         if (text_ptr[i].lang_key != NULL)
            lang_key_len = strlen(text_ptr[i].lang_key);

         else
            lang_key_len = 0;
      }
#  else /* iTXt */
      {
         png_chunk_report(png_ptr, "iTXt chunk not supported",
            PNG_CHUNK_WRITE_ERROR);
         continue;
      }
#  endif

      if (text_ptr[i].text == NULL || text_ptr[i].text[0] == '\0')
      {
         text_length = 0;
#  ifdef PNG_iTXt_SUPPORTED
         if (text_ptr[i].compression > 0)
            textp->compression = PNG_ITXT_COMPRESSION_NONE;

         else
#  endif
            textp->compression = PNG_TEXT_COMPRESSION_NONE;
      }

      else
      {
         text_length = strlen(text_ptr[i].text);
         textp->compression = text_ptr[i].compression;
      }

      textp->key = png_voidcast(png_charp,png_malloc_base(png_ptr,
          key_len + text_length + lang_len + lang_key_len + 4));

      if (textp->key == NULL)
      {
         png_chunk_report(png_ptr, "text chunk: out of memory",
               PNG_CHUNK_WRITE_ERROR);

         return 1;
      }

      png_debug2(2, "Allocated %lu bytes at %p in png_set_text",
          (unsigned long)(png_uint_32)
          (key_len + lang_len + lang_key_len + text_length + 4),
          textp->key);

      memcpy(textp->key, text_ptr[i].key, key_len);
      *(textp->key + key_len) = '\0';

      if (text_ptr[i].compression > 0)
      {
         textp->lang = textp->key + key_len + 1;
         memcpy(textp->lang, text_ptr[i].lang, lang_len);
         *(textp->lang + lang_len) = '\0';
         textp->lang_key = textp->lang + lang_len + 1;
         memcpy(textp->lang_key, text_ptr[i].lang_key, lang_key_len);
         *(textp->lang_key + lang_key_len) = '\0';
         textp->text = textp->lang_key + lang_key_len + 1;
      }

      else
      {
         textp->lang=NULL;
         textp->lang_key=NULL;
         textp->text = textp->key + key_len + 1;
      }

      if (text_length != 0)
         memcpy(textp->text, text_ptr[i].text, text_length);

      *(textp->text + text_length) = '\0';

#  ifdef PNG_iTXt_SUPPORTED
      if (textp->compression > 0)
      {
         textp->text_length = 0;
         textp->itxt_length = text_length;
      }

      else
#  endif
      {
         textp->text_length = text_length;
         textp->itxt_length = 0;
      }

      info_ptr->num_text++;
      png_debug1(3, "transferred text chunk %d", info_ptr->num_text);
   }

   return(0);
}

Project: libpng
File: pngset.c

png_set_oFFs(png_const_structrp png_ptr, png_inforp info_ptr,
    png_int_32 offset_x, png_int_32 offset_y, int unit_type)
{
   png_debug1(1, "in %s storage function", "oFFs");

   if (png_ptr == NULL || info_ptr == NULL)
      return;

   info_ptr->x_offset = offset_x;
   info_ptr->y_offset = offset_y;
   info_ptr->offset_unit_type = (png_byte)unit_type;
   info_ptr->valid |= PNG_INFO_oFFs;
}

Project: libpng
File: pngset.c

png_set_rows(png_const_structrp png_ptr, png_inforp info_ptr,
    png_bytepp row_pointers)
{
   png_debug1(1, "in %s storage function", "rows");

   if (png_ptr == NULL || info_ptr == NULL)
      return;

   if (info_ptr->row_pointers != NULL &&
       (info_ptr->row_pointers != row_pointers))
      png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);

   info_ptr->row_pointers = row_pointers;

   if (row_pointers != NULL)
      info_ptr->valid |= PNG_INFO_IDAT;
}

Project: libpng
File: pngrutil.c

png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
{
   png_const_charp errmsg = NULL;
   png_bytep       buffer;
   png_uint_32     keyword_length;

   png_debug(1, "in png_handle_zTXt");

#ifdef PNG_USER_LIMITS_SUPPORTED
   if (png_ptr->user_chunk_cache_max != 0)
   {
      if (png_ptr->user_chunk_cache_max == 1)
      {
         png_crc_finish(png_ptr, length);
         return;
      }

      if (--png_ptr->user_chunk_cache_max == 1)
      {
         png_crc_finish(png_ptr, length);
         png_chunk_benign_error(png_ptr, "no space in chunk cache");
         return;
      }
   }
#endif

   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
      png_chunk_error(png_ptr, "missing IHDR");

   if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
      png_ptr->mode |= PNG_AFTER_IDAT;

   buffer = png_read_buffer(png_ptr, length, 2/*silent*/);

   if (buffer == NULL)
   {
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "out of memory");
      return;
   }

   png_crc_read(png_ptr, buffer, length);

   if (png_crc_finish(png_ptr, 0) != 0)
      return;

   /* TODO: also check that the keyword contents match the spec! */
   for (keyword_length = 0;
      keyword_length < length && buffer[keyword_length] != 0;
      ++keyword_length)
      /* Empty loop to find end of name */ ;

   if (keyword_length > 79 || keyword_length < 1)
      errmsg = "bad keyword";

   /* zTXt must have some LZ data after the keyword, although it may expand to
    * zero bytes; we need a '\0' at the end of the keyword, the compression type
    * then the LZ data:
    */
   else if (keyword_length + 3 > length)
      errmsg = "truncated";

   else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE)
      errmsg = "unknown compression type";

   else
   {
      png_alloc_size_t uncompressed_length = PNG_SIZE_MAX;

      /* TODO: at present png_decompress_chunk imposes a single application
       * level memory limit, this should be split to different values for iCCP
       * and text chunks.
       */
      if (png_decompress_chunk(png_ptr, length, keyword_length+2,
         &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
      {
         png_text text;

         /* It worked; png_ptr->read_buffer now looks like a tEXt chunk except
          * for the extra compression type byte and the fact that it isn't
          * necessarily '\0' terminated.
          */
         buffer = png_ptr->read_buffer;
         buffer[uncompressed_length+(keyword_length+2)] = 0;

         text.compression = PNG_TEXT_COMPRESSION_zTXt;
         text.key = (png_charp)buffer;
         text.text = (png_charp)(buffer + keyword_length+2);
         text.text_length = uncompressed_length;
         text.itxt_length = 0;
         text.lang = NULL;
         text.lang_key = NULL;

         if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
            errmsg = "insufficient memory";
      }

      else
         errmsg = png_ptr->zstream.msg;
   }

   if (errmsg != NULL)
      png_chunk_benign_error(png_ptr, errmsg);
}

Project: libpng
File: pngrutil.c

png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
{
   png_bytep buffer;
   png_size_t i;
   int state;

   png_debug(1, "in png_handle_sCAL");

   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
      png_chunk_error(png_ptr, "missing IHDR");

   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
   {
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "out of place");
      return;
   }

   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0)
   {
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "duplicate");
      return;
   }

   /* Need unit type, width, \0, height: minimum 4 bytes */
   else if (length < 4)
   {
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "invalid");
      return;
   }

   png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
      length + 1);

   buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);

   if (buffer == NULL)
   {
      png_chunk_benign_error(png_ptr, "out of memory");
      png_crc_finish(png_ptr, length);
      return;
   }

   png_crc_read(png_ptr, buffer, length);
   buffer[length] = 0; /* Null terminate the last string */

   if (png_crc_finish(png_ptr, 0) != 0)
      return;

   /* Validate the unit. */
   if (buffer[0] != 1 && buffer[0] != 2)
   {
      png_chunk_benign_error(png_ptr, "invalid unit");
      return;
   }

   /* Validate the ASCII numbers, need two ASCII numbers separated by
    * a '\0' and they need to fit exactly in the chunk data.
    */
   i = 1;
   state = 0;

   if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 ||
       i >= length || buffer[i++] != 0)
      png_chunk_benign_error(png_ptr, "bad width format");

   else if (PNG_FP_IS_POSITIVE(state) == 0)
      png_chunk_benign_error(png_ptr, "non-positive width");

   else
   {
      png_size_t heighti = i;

      state = 0;
      if (png_check_fp_number((png_const_charp)buffer, length,
          &state, &i) == 0 || i != length)
         png_chunk_benign_error(png_ptr, "bad height format");

      else if (PNG_FP_IS_POSITIVE(state) == 0)
         png_chunk_benign_error(png_ptr, "non-positive height");

      else
         /* This is the (only) success case. */
         png_set_sCAL_s(png_ptr, info_ptr, buffer[0],
            (png_charp)buffer+1, (png_charp)buffer+heighti);
   }
}

Project: libpng
File: pngset.c

png_set_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
    png_const_timep mod_time)
{
   png_debug1(1, "in %s storage function", "tIME");

   if (png_ptr == NULL || info_ptr == NULL || mod_time == NULL ||
       (png_ptr->mode & PNG_WROTE_tIME) != 0)
      return;

   if (mod_time->month == 0   || mod_time->month > 12  ||
       mod_time->day   == 0   || mod_time->day   > 31  ||
       mod_time->hour  > 23   || mod_time->minute > 59 ||
       mod_time->second > 60)
   {
      png_warning(png_ptr, "Ignoring invalid time value");

      return;
   }

   info_ptr->mod_time = *mod_time;
   info_ptr->valid |= PNG_INFO_tIME;
}

Project: libpng
File: pngset.c

png_set_chunk_malloc_max (png_structrp png_ptr,
    png_alloc_size_t user_chunk_malloc_max)
{
   if (png_ptr != NULL)
      png_ptr->user_chunk_malloc_max = user_chunk_malloc_max;
}

Project: libpng
File: pngset.c

png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
    int chunk, int location)
{
   /* This API is pretty pointless in 1.6.0 because the location can be set
    * before the call to png_set_unknown_chunks.
    *
    * TODO: add a png_app_warning in 1.7
    */
   if (png_ptr != NULL && info_ptr != NULL && chunk >= 0 &&
      chunk < info_ptr->unknown_chunks_num)
   {
      if ((location & (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT)) == 0)
      {
         png_app_error(png_ptr, "invalid unknown chunk location");
         /* Fake out the pre 1.6.0 behavior: */
         if ((location & PNG_HAVE_IDAT) != 0) /* undocumented! */
            location = PNG_AFTER_IDAT;

         else
            location = PNG_HAVE_IHDR; /* also undocumented */
      }

      info_ptr->unknown_chunks[chunk].location =
         check_location(png_ptr, location);
   }
}

Project: libpng
File: pngset.c

add_one_chunk(png_bytep list, unsigned int count, png_const_bytep add, int keep)
{
   unsigned int i;

   /* Utility function: update the 'keep' state of a chunk if it is already in
    * the list, otherwise add it to the list.
    */
   for (i=0; i<count; ++i, list += 5)
   {
      if (memcmp(list, add, 4) == 0)
      {
         list[4] = (png_byte)keep;

         return count;
      }
   }

   if (keep != PNG_HANDLE_CHUNK_AS_DEFAULT)
   {
      ++count;
      memcpy(list, add, 4);
      list[4] = (png_byte)keep;
   }

   return count;
}

Project: libpng
File: pngset.c

png_set_benign_errors(png_structrp png_ptr, int allowed)
{
   png_debug(1, "in png_set_benign_errors");

   /* If allowed is 1, png_benign_error() is treated as a warning.
    *
    * If allowed is 0, png_benign_error() is treated as an error (which
    * is the default behavior if png_set_benign_errors() is not called).
    */

   if (allowed != 0)
      png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN |
         PNG_FLAG_APP_WARNINGS_WARN | PNG_FLAG_APP_ERRORS_WARN;

   else
      png_ptr->flags &= ~(PNG_FLAG_BENIGN_ERRORS_WARN |
         PNG_FLAG_APP_WARNINGS_WARN | PNG_FLAG_APP_ERRORS_WARN);
}

Project: libpng
File: pngset.c

png_set_gAMA_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
    png_fixed_point file_gamma)
{
   png_debug1(1, "in %s storage function", "gAMA");

   if (png_ptr == NULL || info_ptr == NULL)
      return;

   png_colorspace_set_gamma(png_ptr, &info_ptr->colorspace, file_gamma);
   png_colorspace_sync_info(png_ptr, info_ptr);
}

Project: libpng
File: pngrutil.c

png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
   png_const_bytep prev_row)
{
   png_size_t i;
   png_bytep rp = row;
   png_const_bytep pp = prev_row;
   unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
   png_size_t istop = row_info->rowbytes - bpp;

   for (i = 0; i < bpp; i++)
   {
      *rp = (png_byte)(((int)(*rp) +
         ((int)(*pp++) / 2 )) & 0xff);

      rp++;
   }

   for (i = 0; i < istop; i++)
   {
      *rp = (png_byte)(((int)(*rp) +
         (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);

      rp++;
   }
}

Project: libpng
File: pngset.c

png_set_sCAL_fixed(png_const_structrp png_ptr, png_inforp info_ptr, int unit,
    png_fixed_point width, png_fixed_point height)
{
   png_debug1(1, "in %s storage function", "sCAL");

   /* Check the arguments. */
   if (width <= 0)
      png_warning(png_ptr, "Invalid sCAL width ignored");

   else if (height <= 0)
      png_warning(png_ptr, "Invalid sCAL height ignored");

   else
   {
      /* Convert 'width' and 'height' to ASCII. */
      char swidth[PNG_sCAL_MAX_DIGITS+1];
      char sheight[PNG_sCAL_MAX_DIGITS+1];

      png_ascii_from_fixed(png_ptr, swidth, (sizeof swidth), width);
      png_ascii_from_fixed(png_ptr, sheight, (sizeof sheight), height);

      png_set_sCAL_s(png_ptr, info_ptr, unit, swidth, sheight);
   }
}

Project: libpng
File: pngset.c

png_set_tRNS(png_structrp png_ptr, png_inforp info_ptr,
    png_const_bytep trans_alpha, int num_trans, png_const_color_16p trans_color)
{
   png_debug1(1, "in %s storage function", "tRNS");

   if (png_ptr == NULL || info_ptr == NULL)

      return;

   if (trans_alpha != NULL)
   {
       /* It may not actually be necessary to set png_ptr->trans_alpha here;
        * we do it for backward compatibility with the way the png_handle_tRNS
        * function used to do the allocation.
        *
        * 1.6.0: The above statement is incorrect; png_handle_tRNS effectively
        * relies on png_set_tRNS storing the information in png_struct
        * (otherwise it won't be there for the code in pngrtran.c).
        */

       png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);

       /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1 */
       png_ptr->trans_alpha = info_ptr->trans_alpha = png_voidcast(png_bytep,
         png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH));

       if (num_trans > 0 && num_trans <= PNG_MAX_PALETTE_LENGTH)
          memcpy(info_ptr->trans_alpha, trans_alpha, (png_size_t)num_trans);
   }

   if (trans_color != NULL)
   {
#ifdef PNG_WARNINGS_SUPPORTED
      if (info_ptr->bit_depth < 16)
      {
         int sample_max = (1 << info_ptr->bit_depth) - 1;

         if ((info_ptr->color_type == PNG_COLOR_TYPE_GRAY &&
             trans_color->gray > sample_max) ||
             (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
             (trans_color->red > sample_max ||
             trans_color->green > sample_max ||
             trans_color->blue > sample_max)))
            png_warning(png_ptr,
               "tRNS chunk has out-of-range samples for bit_depth");
      }
#endif

      info_ptr->trans_color = *trans_color;

      if (num_trans == 0)
         num_trans = 1;
   }

   info_ptr->num_trans = (png_uint_16)num_trans;

   if (num_trans != 0)
   {
      info_ptr->valid |= PNG_INFO_tRNS;
      info_ptr->free_me |= PNG_FREE_TRNS;
   }
}

Project: libpng
File: pngrutil.c

png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
/* Note: this does not properly handle chunks that are > 64K under DOS */
{
   png_bytep entry_start, buffer;
   png_sPLT_t new_palette;
   png_sPLT_entryp pp;
   png_uint_32 data_length;
   int entry_size, i;
   png_uint_32 skip = 0;
   png_uint_32 dl;
   png_size_t max_dl;

   png_debug(1, "in png_handle_sPLT");

#ifdef PNG_USER_LIMITS_SUPPORTED
   if (png_ptr->user_chunk_cache_max != 0)
   {
      if (png_ptr->user_chunk_cache_max == 1)
      {
         png_crc_finish(png_ptr, length);
         return;
      }

      if (--png_ptr->user_chunk_cache_max == 1)
      {
         png_warning(png_ptr, "No space in chunk cache for sPLT");
         png_crc_finish(png_ptr, length);
         return;
      }
   }
#endif

   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
      png_chunk_error(png_ptr, "missing IHDR");

   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
   {
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "out of place");
      return;
   }

#ifdef PNG_MAX_MALLOC_64K
   if (length > 65535U)
   {
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "too large to fit in memory");
      return;
   }
#endif

   buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
   if (buffer == NULL)
   {
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "out of memory");
      return;
   }


   /* WARNING: this may break if size_t is less than 32 bits; it is assumed
    * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
    * potential breakage point if the types in pngconf.h aren't exactly right.
    */
   png_crc_read(png_ptr, buffer, length);

   if (png_crc_finish(png_ptr, skip) != 0)
      return;

   buffer[length] = 0;

   for (entry_start = buffer; *entry_start; entry_start++)
      /* Empty loop to find end of name */ ;

   ++entry_start;

   /* A sample depth should follow the separator, and we should be on it  */
   if (entry_start > buffer + length - 2)
   {
      png_warning(png_ptr, "malformed sPLT chunk");
      return;
   }

   new_palette.depth = *entry_start++;
   entry_size = (new_palette.depth == 8 ? 6 : 10);
   /* This must fit in a png_uint_32 because it is derived from the original
    * chunk data length.
    */
   data_length = length - (png_uint_32)(entry_start - buffer);

   /* Integrity-check the data length */
   if ((data_length % entry_size) != 0)
   {
      png_warning(png_ptr, "sPLT chunk has bad length");
      return;
   }

   dl = (png_int_32)(data_length / entry_size);
   max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry));

   if (dl > max_dl)
   {
      png_warning(png_ptr, "sPLT chunk too long");
      return;
   }

   new_palette.nentries = (png_int_32)(data_length / entry_size);

   new_palette.entries = (png_sPLT_entryp)png_malloc_warn(
       png_ptr, new_palette.nentries * (sizeof (png_sPLT_entry)));

   if (new_palette.entries == NULL)
   {
      png_warning(png_ptr, "sPLT chunk requires too much memory");
      return;
   }

#ifdef PNG_POINTER_INDEXING_SUPPORTED
   for (i = 0; i < new_palette.nentries; i++)
   {
      pp = new_palette.entries + i;

      if (new_palette.depth == 8)
      {
         pp->red = *entry_start++;
         pp->green = *entry_start++;
         pp->blue = *entry_start++;
         pp->alpha = *entry_start++;
      }

      else
      {
         pp->red   = png_get_uint_16(entry_start); entry_start += 2;
         pp->green = png_get_uint_16(entry_start); entry_start += 2;
         pp->blue  = png_get_uint_16(entry_start); entry_start += 2;
         pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
      }

      pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
   }
#else
   pp = new_palette.entries;

   for (i = 0; i < new_palette.nentries; i++)
   {

      if (new_palette.depth == 8)
      {
         pp[i].red   = *entry_start++;
         pp[i].green = *entry_start++;
         pp[i].blue  = *entry_start++;
         pp[i].alpha = *entry_start++;
      }

      else
      {
         pp[i].red   = png_get_uint_16(entry_start); entry_start += 2;
         pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
         pp[i].blue  = png_get_uint_16(entry_start); entry_start += 2;
         pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
      }

      pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
   }
#endif

   /* Discard all chunk data except the name and stash that */
   new_palette.name = (png_charp)buffer;

   png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);

   png_free(png_ptr, new_palette.entries);
}

Project: libpng
File: pngset.c

png_set_read_user_chunk_fn(png_structrp png_ptr, png_voidp user_chunk_ptr,
    png_user_chunk_ptr read_user_chunk_fn)
{
   png_debug(1, "in png_set_read_user_chunk_fn");

   if (png_ptr == NULL)
      return;

   png_ptr->read_user_chunk_fn = read_user_chunk_fn;
   png_ptr->user_chunk_ptr = user_chunk_ptr;
}

Project: libpng
File: pngset.c

png_set_text(png_const_structrp png_ptr, png_inforp info_ptr,
    png_const_textp text_ptr, int num_text)
{
   int ret;
   ret = png_set_text_2(png_ptr, info_ptr, text_ptr, num_text);

   if (ret != 0)
      png_error(png_ptr, "Insufficient memory to store text");
}

Project: libpng
File: pngrutil.c

png_read_sig(png_structrp png_ptr, png_inforp info_ptr)
{
   png_size_t num_checked, num_to_check;

   /* Exit if the user application does not expect a signature. */
   if (png_ptr->sig_bytes >= 8)
      return;

   num_checked = png_ptr->sig_bytes;
   num_to_check = 8 - num_checked;

#ifdef PNG_IO_STATE_SUPPORTED
   png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
#endif

   /* The signature must be serialized in a single I/O call. */
   png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
   png_ptr->sig_bytes = 8;

   if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check) != 0)
   {
      if (num_checked < 4 &&
          png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
         png_error(png_ptr, "Not a PNG file");
      else
         png_error(png_ptr, "PNG file corrupted by ASCII conversion");
   }
   if (num_checked < 3)
      png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
}

Project: libpng
File: pngset.c

png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr,
    png_const_colorp palette, int num_palette)
{

   png_uint_32 max_palette_length;

   png_debug1(1, "in %s storage function", "PLTE");

   if (png_ptr == NULL || info_ptr == NULL)
      return;

   max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
      (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;

   if (num_palette < 0 || num_palette > (int) max_palette_length)
   {
      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
         png_error(png_ptr, "Invalid palette length");

      else
      {
         png_warning(png_ptr, "Invalid palette length");

         return;
      }
   }

   if ((num_palette > 0 && palette == NULL) ||
      (num_palette == 0
#        ifdef PNG_MNG_FEATURES_SUPPORTED
            && (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0
#        endif
      ))
   {
      png_error(png_ptr, "Invalid palette");
   }

   /* It may not actually be necessary to set png_ptr->palette here;
    * we do it for backward compatibility with the way the png_handle_tRNS
    * function used to do the allocation.
    *
    * 1.6.0: the above statement appears to be incorrect; something has to set
    * the palette inside png_struct on read.
    */
   png_free_data(png_ptr, info_ptr, PNG_FREE_PLTE, 0);

   /* Changed in libpng-1.2.1 to allocate PNG_MAX_PALETTE_LENGTH instead
    * of num_palette entries, in case of an invalid PNG file or incorrect
    * call to png_set_PLTE() with too-large sample values.
    */
   png_ptr->palette = png_voidcast(png_colorp, png_calloc(png_ptr,
       PNG_MAX_PALETTE_LENGTH * (sizeof (png_color))));

   if (num_palette > 0)
      memcpy(png_ptr->palette, palette, num_palette * (sizeof (png_color)));
   info_ptr->palette = png_ptr->palette;
   info_ptr->num_palette = png_ptr->num_palette = (png_uint_16)num_palette;

   info_ptr->free_me |= PNG_FREE_PLTE;

   info_ptr->valid |= PNG_INFO_PLTE;
}

Project: libpng
File: pngrutil.c

png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
   png_uint_32 transformations /* Because these may affect the byte layout */)
{
   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
   /* Offset to next interlace block */
   static PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};

   png_debug(1, "in png_do_read_interlace");
   if (row != NULL && row_info != NULL)
   {
      png_uint_32 final_width;

      final_width = row_info->width * png_pass_inc[pass];

      switch (row_info->pixel_depth)
      {
         case 1:
         {
            png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3);
            png_bytep dp = row + (png_size_t)((final_width - 1) >> 3);
            int sshift, dshift;
            int s_start, s_end, s_inc;
            int jstop = png_pass_inc[pass];
            png_byte v;
            png_uint_32 i;
            int j;

#ifdef PNG_READ_PACKSWAP_SUPPORTED
            if ((transformations & PNG_PACKSWAP) != 0)
            {
                sshift = (int)((row_info->width + 7) & 0x07);
                dshift = (int)((final_width + 7) & 0x07);
                s_start = 7;
                s_end = 0;
                s_inc = -1;
            }

            else
#endif
            {
                sshift = 7 - (int)((row_info->width + 7) & 0x07);
                dshift = 7 - (int)((final_width + 7) & 0x07);
                s_start = 0;
                s_end = 7;
                s_inc = 1;
            }

            for (i = 0; i < row_info->width; i++)
            {
               v = (png_byte)((*sp >> sshift) & 0x01);
               for (j = 0; j < jstop; j++)
               {
                  unsigned int tmp = *dp & (0x7f7f >> (7 - dshift));
                  tmp |= v << dshift;
                  *dp = (png_byte)(tmp & 0xff);

                  if (dshift == s_end)
                  {
                     dshift = s_start;
                     dp--;
                  }

                  else
                     dshift += s_inc;
               }

               if (sshift == s_end)
               {
                  sshift = s_start;
                  sp--;
               }

               else
                  sshift += s_inc;
            }
            break;
         }

         case 2:
         {
            png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
            png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
            int sshift, dshift;
            int s_start, s_end, s_inc;
            int jstop = png_pass_inc[pass];
            png_uint_32 i;

#ifdef PNG_READ_PACKSWAP_SUPPORTED
            if ((transformations & PNG_PACKSWAP) != 0)
            {
               sshift = (int)(((row_info->width + 3) & 0x03) << 1);
               dshift = (int)(((final_width + 3) & 0x03) << 1);
               s_start = 6;
               s_end = 0;
               s_inc = -2;
            }

            else
#endif
            {
               sshift = (int)((3 - ((row_info->width + 3) & 0x03)) << 1);
               dshift = (int)((3 - ((final_width + 3) & 0x03)) << 1);
               s_start = 0;
               s_end = 6;
               s_inc = 2;
            }

            for (i = 0; i < row_info->width; i++)
            {
               png_byte v;
               int j;

               v = (png_byte)((*sp >> sshift) & 0x03);
               for (j = 0; j < jstop; j++)
               {
                  unsigned int tmp = *dp & (0x3f3f >> (6 - dshift));
                  tmp |= v << dshift;
                  *dp = (png_byte)(tmp & 0xff);

                  if (dshift == s_end)
                  {
                     dshift = s_start;
                     dp--;
                  }

                  else
                     dshift += s_inc;
               }

               if (sshift == s_end)
               {
                  sshift = s_start;
                  sp--;
               }

               else
                  sshift += s_inc;
            }
            break;
         }

         case 4:
         {
            png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1);
            png_bytep dp = row + (png_size_t)((final_width - 1) >> 1);
            int sshift, dshift;
            int s_start, s_end, s_inc;
            png_uint_32 i;
            int jstop = png_pass_inc[pass];

#ifdef PNG_READ_PACKSWAP_SUPPORTED
            if ((transformations & PNG_PACKSWAP) != 0)
            {
               sshift = (int)(((row_info->width + 1) & 0x01) << 2);
               dshift = (int)(((final_width + 1) & 0x01) << 2);
               s_start = 4;
               s_end = 0;
               s_inc = -4;
            }

            else
#endif
            {
               sshift = (int)((1 - ((row_info->width + 1) & 0x01)) << 2);
               dshift = (int)((1 - ((final_width + 1) & 0x01)) << 2);
               s_start = 0;
               s_end = 4;
               s_inc = 4;
            }

            for (i = 0; i < row_info->width; i++)
            {
               png_byte v = (png_byte)((*sp >> sshift) & 0x0f);
               int j;

               for (j = 0; j < jstop; j++)
               {
                  unsigned int tmp = *dp & (0xf0f >> (4 - dshift));
                  tmp |= v << dshift;
                  *dp = (png_byte)(tmp & 0xff);

                  if (dshift == s_end)
                  {
                     dshift = s_start;
                     dp--;
                  }

                  else
                     dshift += s_inc;
               }

               if (sshift == s_end)
               {
                  sshift = s_start;
                  sp--;
               }

               else
                  sshift += s_inc;
            }
            break;
         }

         default:
         {
            png_size_t pixel_bytes = (row_info->pixel_depth >> 3);

            png_bytep sp = row + (png_size_t)(row_info->width - 1)
                * pixel_bytes;

            png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes;

            int jstop = png_pass_inc[pass];
            png_uint_32 i;

            for (i = 0; i < row_info->width; i++)
            {
               png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */
               int j;

               memcpy(v, sp, pixel_bytes);

               for (j = 0; j < jstop; j++)
               {
                  memcpy(dp, v, pixel_bytes);
                  dp -= pixel_bytes;
               }

               sp -= pixel_bytes;
            }
            break;
         }
      }

      row_info->width = final_width;
      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
   }
#ifndef PNG_READ_PACKSWAP_SUPPORTED
   PNG_UNUSED(transformations)  /* Silence compiler warning */
#endif
}

Project: libpng
File: pngset.c

png_set_sCAL(png_const_structrp png_ptr, png_inforp info_ptr, int unit,
    double width, double height)
{
   png_debug1(1, "in %s storage function", "sCAL");

   /* Check the arguments. */
   if (width <= 0)
      png_warning(png_ptr, "Invalid sCAL width ignored");

   else if (height <= 0)
      png_warning(png_ptr, "Invalid sCAL height ignored");

   else
   {
      /* Convert 'width' and 'height' to ASCII. */
      char swidth[PNG_sCAL_MAX_DIGITS+1];
      char sheight[PNG_sCAL_MAX_DIGITS+1];

      png_ascii_from_fp(png_ptr, swidth, (sizeof swidth), width,
         PNG_sCAL_PRECISION);
      png_ascii_from_fp(png_ptr, sheight, (sizeof sheight), height,
         PNG_sCAL_PRECISION);

      png_set_sCAL_s(png_ptr, info_ptr, unit, swidth, sheight);
   }
}

Project: libpng
File: pngset.c

png_set_unknown_chunks(png_const_structrp png_ptr,
   png_inforp info_ptr, png_const_unknown_chunkp unknowns, int num_unknowns)
{
   png_unknown_chunkp np;

   if (png_ptr == NULL || info_ptr == NULL || num_unknowns <= 0 ||
       unknowns == NULL)
      return;

   /* Check for the failure cases where support has been disabled at compile
    * time.  This code is hardly ever compiled - it's here because
    * STORE_UNKNOWN_CHUNKS is set by both read and write code (compiling in this
    * code) but may be meaningless if the read or write handling of unknown
    * chunks is not compiled in.
    */
#  if !defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) && \
      defined(PNG_READ_SUPPORTED)
      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
      {
         png_app_error(png_ptr, "no unknown chunk support on read");

         return;
      }
#  endif
#  if !defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED) && \
      defined(PNG_WRITE_SUPPORTED)
      if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
      {
         png_app_error(png_ptr, "no unknown chunk support on write");

         return;
      }
#  endif

   /* Prior to 1.6.0 this code used png_malloc_warn; however, this meant that
    * unknown critical chunks could be lost with just a warning resulting in
    * undefined behavior.  Now png_chunk_report is used to provide behavior
    * appropriate to read or write.
    */
   np = png_voidcast(png_unknown_chunkp, png_realloc_array(png_ptr,
         info_ptr->unknown_chunks, info_ptr->unknown_chunks_num, num_unknowns,
         sizeof *np));

   if (np == NULL)
   {
      png_chunk_report(png_ptr, "too many unknown chunks",
         PNG_CHUNK_WRITE_ERROR);

      return;
   }

   png_free(png_ptr, info_ptr->unknown_chunks);
   info_ptr->unknown_chunks = np; /* safe because it is initialized */
   info_ptr->free_me |= PNG_FREE_UNKN;

   np += info_ptr->unknown_chunks_num;

   /* Increment unknown_chunks_num each time round the loop to protect the
    * just-allocated chunk data.
    */
   for (; num_unknowns > 0; --num_unknowns, ++unknowns)
   {
      memcpy(np->name, unknowns->name, (sizeof np->name));
      np->name[(sizeof np->name)-1] = '\0';
      np->location = check_location(png_ptr, unknowns->location);

      if (unknowns->size == 0)
      {
         np->data = NULL;
         np->size = 0;
      }

      else
      {
         np->data = png_voidcast(png_bytep,
            png_malloc_base(png_ptr, unknowns->size));

         if (np->data == NULL)
         {
            png_chunk_report(png_ptr, "unknown chunk: out of memory",
               PNG_CHUNK_WRITE_ERROR);
            /* But just skip storing the unknown chunk */
            continue;
         }

         memcpy(np->data, unknowns->data, unknowns->size);
         np->size = unknowns->size;
      }

      /* These increments are skipped on out-of-memory for the data - the
       * unknown chunk entry gets overwritten if the png_chunk_report returns.
       * This is correct in the read case (the chunk is just dropped.)
       */
      ++np;
      ++(info_ptr->unknown_chunks_num);
   }
}

Project: libpng
File: pngrutil.c

png_check_chunk_name(png_structrp png_ptr, png_uint_32 chunk_name)
{
   int i;

   png_debug(1, "in png_check_chunk_name");

   for (i=1; i<=4; ++i)
   {
      int c = chunk_name & 0xff;

      if (c < 65 || c > 122 || (c > 90 && c < 97))
         png_chunk_error(png_ptr, "invalid chunk type");

      chunk_name >>= 8;
   }
}

Project: libpng
File: pngset.c

png_set_pHYs(png_const_structrp png_ptr, png_inforp info_ptr,
    png_uint_32 res_x, png_uint_32 res_y, int unit_type)
{
   png_debug1(1, "in %s storage function", "pHYs");

   if (png_ptr == NULL || info_ptr == NULL)
      return;

   info_ptr->x_pixels_per_unit = res_x;
   info_ptr->y_pixels_per_unit = res_y;
   info_ptr->phys_unit_type = (png_byte)unit_type;
   info_ptr->valid |= PNG_INFO_pHYs;
}

Project: libpng
File: pngset.c

png_set_cHRM_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
    png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x,
    png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y,
    png_fixed_point blue_x, png_fixed_point blue_y)
{
   png_xy xy;

   png_debug1(1, "in %s storage function", "cHRM fixed");

   if (png_ptr == NULL || info_ptr == NULL)
      return;

   xy.redx = red_x;
   xy.redy = red_y;
   xy.greenx = green_x;
   xy.greeny = green_y;
   xy.bluex = blue_x;
   xy.bluey = blue_y;
   xy.whitex = white_x;
   xy.whitey = white_y;

   if (png_colorspace_set_chromaticities(png_ptr, &info_ptr->colorspace, &xy,
       2/* override with app values*/) != 0)
      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;

   png_colorspace_sync_info(png_ptr, info_ptr);
}

Project: libpng
File: pngset.c

png_set_compression_buffer_size(png_structrp png_ptr, png_size_t size)
{
    if (png_ptr == NULL)
       return;

    if (size == 0 || size > PNG_UINT_31_MAX)
       png_error(png_ptr, "invalid compression buffer size");

#  ifdef PNG_SEQUENTIAL_READ_SUPPORTED
      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
      {
         png_ptr->IDAT_read_size = (png_uint_32)size; /* checked above */
         return;
      }
#  endif

#  ifdef PNG_WRITE_SUPPORTED
      if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
      {
         if (png_ptr->zowner != 0)
         {
            png_warning(png_ptr,
              "Compression buffer size cannot be changed because it is in use");

            return;
         }

#ifndef __COVERITY__
         /* Some compilers complain that this is always false.  However, it
          * can be true when integer overflow happens.
          */
         if (size > ZLIB_IO_MAX)
         {
            png_warning(png_ptr,
               "Compression buffer size limited to system maximum");
            size = ZLIB_IO_MAX; /* must fit */
         }
#endif

         if (size < 6)
         {
            /* Deflate will potentially go into an infinite loop on a SYNC_FLUSH
             * if this is permitted.
             */
            png_warning(png_ptr,
               "Compression buffer size cannot be reduced below 6");

            return;
         }

         if (png_ptr->zbuffer_size != size)
         {
            png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
            png_ptr->zbuffer_size = (uInt)size;
         }
      }
#  endif
}

Project: libpng
File: pngrutil.c

png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
{
   unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
   png_const_bytep sp = png_ptr->row_buf + 1;
   png_alloc_size_t row_width = png_ptr->width;
   unsigned int pass = png_ptr->pass;
   png_bytep end_ptr = 0;
   png_byte end_byte = 0;
   unsigned int end_mask;

   png_debug(1, "in png_combine_row");

   /* Added in 1.5.6: it should not be possible to enter this routine until at
    * least one row has been read from the PNG data and transformed.
    */
   if (pixel_depth == 0)
      png_error(png_ptr, "internal row logic error");

   /* Added in 1.5.4: the pixel depth should match the information returned by
    * any call to png_read_update_info at this point.  Do not continue if we got
    * this wrong.
    */
   if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
          PNG_ROWBYTES(pixel_depth, row_width))
      png_error(png_ptr, "internal row size calculation error");

   /* Don't expect this to ever happen: */
   if (row_width == 0)
      png_error(png_ptr, "internal row width error");

   /* Preserve the last byte in cases where only part of it will be overwritten,
    * the multiply below may overflow, we don't care because ANSI-C guarantees
    * we get the low bits.
    */
   end_mask = (pixel_depth * row_width) & 7;
   if (end_mask != 0)
   {
      /* end_ptr == NULL is a flag to say do nothing */
      end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
      end_byte = *end_ptr;
#     ifdef PNG_READ_PACKSWAP_SUPPORTED
      if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
         /* little-endian byte */
         end_mask = 0xff << end_mask;

      else /* big-endian byte */
#     endif
      end_mask = 0xff >> end_mask;
      /* end_mask is now the bits to *keep* from the destination row */
   }

   /* For non-interlaced images this reduces to a memcpy(). A memcpy()
    * will also happen if interlacing isn't supported or if the application
    * does not call png_set_interlace_handling().  In the latter cases the
    * caller just gets a sequence of the unexpanded rows from each interlace
    * pass.
    */
#ifdef PNG_READ_INTERLACING_SUPPORTED
   if (png_ptr->interlaced != 0 &&
       (png_ptr->transformations & PNG_INTERLACE) != 0 &&
       pass < 6 && (display == 0 ||
       /* The following copies everything for 'display' on passes 0, 2 and 4. */
       (display == 1 && (pass & 1) != 0)))
   {
      /* Narrow images may have no bits in a pass; the caller should handle
       * this, but this test is cheap:
       */
      if (row_width <= PNG_PASS_START_COL(pass))
         return;

      if (pixel_depth < 8)
      {
         /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
          * into 32 bits, then a single loop over the bytes using the four byte
          * values in the 32-bit mask can be used.  For the 'display' option the
          * expanded mask may also not require any masking within a byte.  To
          * make this work the PACKSWAP option must be taken into account - it
          * simply requires the pixels to be reversed in each byte.
          *
          * The 'regular' case requires a mask for each of the first 6 passes,
          * the 'display' case does a copy for the even passes in the range
          * 0..6.  This has already been handled in the test above.
          *
          * The masks are arranged as four bytes with the first byte to use in
          * the lowest bits (little-endian) regardless of the order (PACKSWAP or
          * not) of the pixels in each byte.
          *
          * NOTE: the whole of this logic depends on the caller of this function
          * only calling it on rows appropriate to the pass.  This function only
          * understands the 'x' logic; the 'y' logic is handled by the caller.
          *
          * The following defines allow generation of compile time constant bit
          * masks for each pixel depth and each possibility of swapped or not
          * swapped bytes.  Pass 'p' is in the range 0..6; 'x', a pixel index,
          * is in the range 0..7; and the result is 1 if the pixel is to be
          * copied in the pass, 0 if not.  'S' is for the sparkle method, 'B'
          * for the block method.
          *
          * With some compilers a compile time expression of the general form:
          *
          *    (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
          *
          * Produces warnings with values of 'shift' in the range 33 to 63
          * because the right hand side of the ?: expression is evaluated by
          * the compiler even though it isn't used.  Microsoft Visual C (various
          * versions) and the Intel C compiler are known to do this.  To avoid
          * this the following macros are used in 1.5.6.  This is a temporary
          * solution to avoid destabilizing the code during the release process.
          */
#        if PNG_USE_COMPILE_TIME_MASKS
#           define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
#           define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
#        else
#           define PNG_LSR(x,s) ((x)>>(s))
#           define PNG_LSL(x,s) ((x)<<(s))
#        endif
#        define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
           PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
#        define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
           PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)

         /* Return a mask for pass 'p' pixel 'x' at depth 'd'.  The mask is
          * little endian - the first pixel is at bit 0 - however the extra
          * parameter 's' can be set to cause the mask position to be swapped
          * within each byte, to match the PNG format.  This is done by XOR of
          * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
          */
#        define PIXEL_MASK(p,x,d,s) \
            (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))

         /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
          */
#        define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
#        define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)

         /* Combine 8 of these to get the full mask.  For the 1-bpp and 2-bpp
          * cases the result needs replicating, for the 4-bpp case the above
          * generates a full 32 bits.
          */
#        define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))

#        define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
            S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
            S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)

#        define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
            B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
            B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)

#if PNG_USE_COMPILE_TIME_MASKS
         /* Utility macros to construct all the masks for a depth/swap
          * combination.  The 's' parameter says whether the format is PNG
          * (big endian bytes) or not.  Only the three odd-numbered passes are
          * required for the display/block algorithm.
          */
#        define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
            S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }

#        define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }

#        define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))

         /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
          * then pass:
          */
         static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] =
         {
            /* Little-endian byte masks for PACKSWAP */
            { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
            /* Normal (big-endian byte) masks - PNG format */
            { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
         };

         /* display_mask has only three entries for the odd passes, so index by
          * pass>>1.
          */
         static PNG_CONST png_uint_32 display_mask[2][3][3] =
         {
            /* Little-endian byte masks for PACKSWAP */
            { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
            /* Normal (big-endian byte) masks - PNG format */
            { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
         };

#        define MASK(pass,depth,display,png)\
            ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
               row_mask[png][DEPTH_INDEX(depth)][pass])

#else /* !PNG_USE_COMPILE_TIME_MASKS */
         /* This is the runtime alternative: it seems unlikely that this will
          * ever be either smaller or faster than the compile time approach.
          */
#        define MASK(pass,depth,display,png)\
            ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
#endif /* !USE_COMPILE_TIME_MASKS */

         /* Use the appropriate mask to copy the required bits.  In some cases
          * the byte mask will be 0 or 0xff; optimize these cases.  row_width is
          * the number of pixels, but the code copies bytes, so it is necessary
          * to special case the end.
          */
         png_uint_32 pixels_per_byte = 8 / pixel_depth;
         png_uint_32 mask;

#        ifdef PNG_READ_PACKSWAP_SUPPORTED
         if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
            mask = MASK(pass, pixel_depth, display, 0);

         else
#        endif
         mask = MASK(pass, pixel_depth, display, 1);

         for (;;)
         {
            png_uint_32 m;

            /* It doesn't matter in the following if png_uint_32 has more than
             * 32 bits because the high bits always match those in m<<24; it is,
             * however, essential to use OR here, not +, because of this.
             */
            m = mask;
            mask = (m >> 8) | (m << 24); /* rotate right to good compilers */
            m &= 0xff;

            if (m != 0) /* something to copy */
            {
               if (m != 0xff)
                  *dp = (png_byte)((*dp & ~m) | (*sp & m));
               else
                  *dp = *sp;
            }

            /* NOTE: this may overwrite the last byte with garbage if the image
             * is not an exact number of bytes wide; libpng has always done
             * this.
             */
            if (row_width <= pixels_per_byte)
               break; /* May need to restore part of the last byte */

            row_width -= pixels_per_byte;
            ++dp;
            ++sp;
         }
      }

      else /* pixel_depth >= 8 */
      {
         unsigned int bytes_to_copy, bytes_to_jump;

         /* Validate the depth - it must be a multiple of 8 */
         if (pixel_depth & 7)
            png_error(png_ptr, "invalid user transform pixel depth");

         pixel_depth >>= 3; /* now in bytes */
         row_width *= pixel_depth;

         /* Regardless of pass number the Adam 7 interlace always results in a
          * fixed number of pixels to copy then to skip.  There may be a
          * different number of pixels to skip at the start though.
          */
         {
            unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth;

            row_width -= offset;
            dp += offset;
            sp += offset;
         }

         /* Work out the bytes to copy. */
         if (display != 0)
         {
            /* When doing the 'block' algorithm the pixel in the pass gets
             * replicated to adjacent pixels.  This is why the even (0,2,4,6)
             * passes are skipped above - the entire expanded row is copied.
             */
            bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth;

            /* But don't allow this number to exceed the actual row width. */
            if (bytes_to_copy > row_width)
               bytes_to_copy = (unsigned int)/*SAFE*/row_width;
         }

         else /* normal row; Adam7 only ever gives us one pixel to copy. */
            bytes_to_copy = pixel_depth;

         /* In Adam7 there is a constant offset between where the pixels go. */
         bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth;

         /* And simply copy these bytes.  Some optimization is possible here,
          * depending on the value of 'bytes_to_copy'.  Special case the low
          * byte counts, which we know to be frequent.
          *
          * Notice that these cases all 'return' rather than 'break' - this
          * avoids an unnecessary test on whether to restore the last byte
          * below.
          */
         switch (bytes_to_copy)
         {
            case 1:
               for (;;)
               {
                  *dp = *sp;

                  if (row_width <= bytes_to_jump)
                     return;

                  dp += bytes_to_jump;
                  sp += bytes_to_jump;
                  row_width -= bytes_to_jump;
               }

            case 2:
               /* There is a possibility of a partial copy at the end here; this
                * slows the code down somewhat.
                */
               do
               {
                  dp[0] = sp[0], dp[1] = sp[1];

                  if (row_width <= bytes_to_jump)
                     return;

                  sp += bytes_to_jump;
                  dp += bytes_to_jump;
                  row_width -= bytes_to_jump;
               }
               while (row_width > 1);

               /* And there can only be one byte left at this point: */
               *dp = *sp;
               return;

            case 3:
               /* This can only be the RGB case, so each copy is exactly one
                * pixel and it is not necessary to check for a partial copy.
                */
               for (;;)
               {
                  dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2];

                  if (row_width <= bytes_to_jump)
                     return;

                  sp += bytes_to_jump;
                  dp += bytes_to_jump;
                  row_width -= bytes_to_jump;
               }

            default:
#if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
               /* Check for double byte alignment and, if possible, use a
                * 16-bit copy.  Don't attempt this for narrow images - ones that
                * are less than an interlace panel wide.  Don't attempt it for
                * wide bytes_to_copy either - use the memcpy there.
                */
               if (bytes_to_copy < 16 /*else use memcpy*/ &&
                   png_isaligned(dp, png_uint_16) &&
                   png_isaligned(sp, png_uint_16) &&
                   bytes_to_copy % (sizeof (png_uint_16)) == 0 &&
                   bytes_to_jump % (sizeof (png_uint_16)) == 0)
               {
                  /* Everything is aligned for png_uint_16 copies, but try for
                   * png_uint_32 first.
                   */
                  if (png_isaligned(dp, png_uint_32) != 0 &&
                      png_isaligned(sp, png_uint_32) != 0 &&
                      bytes_to_copy % (sizeof (png_uint_32)) == 0 &&
                      bytes_to_jump % (sizeof (png_uint_32)) == 0)
                  {
                     png_uint_32p dp32 = png_aligncast(png_uint_32p,dp);
                     png_const_uint_32p sp32 = png_aligncastconst(
                         png_const_uint_32p, sp);
                     size_t skip = (bytes_to_jump-bytes_to_copy) /
                         (sizeof (png_uint_32));

                     do
                     {
                        size_t c = bytes_to_copy;
                        do
                        {
                           *dp32++ = *sp32++;
                           c -= (sizeof (png_uint_32));
                        }
                        while (c > 0);

                        if (row_width <= bytes_to_jump)
                           return;

                        dp32 += skip;
                        sp32 += skip;
                        row_width -= bytes_to_jump;
                     }
                     while (bytes_to_copy <= row_width);

                     /* Get to here when the row_width truncates the final copy.
                      * There will be 1-3 bytes left to copy, so don't try the
                      * 16-bit loop below.
                      */
                     dp = (png_bytep)dp32;
                     sp = (png_const_bytep)sp32;
                     do
                        *dp++ = *sp++;
                     while (--row_width > 0);
                     return;
                  }

                  /* Else do it in 16-bit quantities, but only if the size is
                   * not too large.
                   */
                  else
                  {
                     png_uint_16p dp16 = png_aligncast(png_uint_16p, dp);
                     png_const_uint_16p sp16 = png_aligncastconst(
                        png_const_uint_16p, sp);
                     size_t skip = (bytes_to_jump-bytes_to_copy) /
                        (sizeof (png_uint_16));

                     do
                     {
                        size_t c = bytes_to_copy;
                        do
                        {
                           *dp16++ = *sp16++;
                           c -= (sizeof (png_uint_16));
                        }
                        while (c > 0);

                        if (row_width <= bytes_to_jump)
                           return;

                        dp16 += skip;
                        sp16 += skip;
                        row_width -= bytes_to_jump;
                     }
                     while (bytes_to_copy <= row_width);

                     /* End of row - 1 byte left, bytes_to_copy > row_width: */
                     dp = (png_bytep)dp16;
                     sp = (png_const_bytep)sp16;
                     do
                        *dp++ = *sp++;
                     while (--row_width > 0);
                     return;
                  }
               }
#endif /* ALIGN_TYPE code */

               /* The true default - use a memcpy: */
               for (;;)
               {
                  memcpy(dp, sp, bytes_to_copy);

                  if (row_width <= bytes_to_jump)
                     return;

                  sp += bytes_to_jump;
                  dp += bytes_to_jump;
                  row_width -= bytes_to_jump;
                  if (bytes_to_copy > row_width)
                     bytes_to_copy = (unsigned int)/*SAFE*/row_width;
               }
         }

         /* NOT REACHED*/
      } /* pixel_depth >= 8 */

      /* Here if pixel_depth < 8 to check 'end_ptr' below. */
   }
   else
#endif /* READ_INTERLACING */

   /* If here then the switch above wasn't used so just memcpy the whole row
    * from the temporary row buffer (notice that this overwrites the end of the
    * destination row if it is a partial byte.)
    */
   memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width));

   /* Restore the overwritten bits from the last byte if necessary. */
   if (end_ptr != NULL)
      *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
}

Project: libpng
File: pngrutil.c

png_read_filter_row_up(png_row_infop row_info, png_bytep row,
   png_const_bytep prev_row)
{
   png_size_t i;
   png_size_t istop = row_info->rowbytes;
   png_bytep rp = row;
   png_const_bytep pp = prev_row;

   for (i = 0; i < istop; i++)
   {
      *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
      rp++;
   }
}

Project: libpng
File: pngrutil.c

png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
{
   if (png_ptr->zowner != 0)
   {
      char msg[64];

      PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner);
      /* So the message that results is "<chunk> using zstream"; this is an
       * internal error, but is very useful for debugging.  i18n requirements
       * are minimal.
       */
      (void)png_safecat(msg, (sizeof msg), 4, " using zstream");
#if PNG_RELEASE_BUILD
      png_chunk_warning(png_ptr, msg);
      png_ptr->zowner = 0;
#else
      png_chunk_error(png_ptr, msg);
#endif
   }

   /* Implementation note: unlike 'png_deflate_claim' this internal function
    * does not take the size of the data as an argument.  Some efficiency could
    * be gained by using this when it is known *if* the zlib stream itself does
    * not record the number; however, this is an illusion: the original writer
    * of the PNG may have selected a lower window size, and we really must
    * follow that because, for systems with with limited capabilities, we
    * would otherwise reject the application's attempts to use a smaller window
    * size (zlib doesn't have an interface to say "this or lower"!).
    *
    * inflateReset2 was added to zlib 1.2.4; before this the window could not be
    * reset, therefore it is necessary to always allocate the maximum window
    * size with earlier zlibs just in case later compressed chunks need it.
    */
   {
      int ret; /* zlib return code */
#if PNG_ZLIB_VERNUM >= 0x1240

# if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW)
      int window_bits;

      if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) ==
          PNG_OPTION_ON)
         window_bits = 15;

      else
         window_bits = 0;
# else
#   define window_bits 0
# endif
#endif

      /* Set this for safety, just in case the previous owner left pointers to
       * memory allocations.
       */
      png_ptr->zstream.next_in = NULL;
      png_ptr->zstream.avail_in = 0;
      png_ptr->zstream.next_out = NULL;
      png_ptr->zstream.avail_out = 0;

      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
      {
#if PNG_ZLIB_VERNUM < 0x1240
         ret = inflateReset(&png_ptr->zstream);
#else
         ret = inflateReset2(&png_ptr->zstream, window_bits);
#endif
      }

      else
      {
#if PNG_ZLIB_VERNUM < 0x1240
         ret = inflateInit(&png_ptr->zstream);
#else
         ret = inflateInit2(&png_ptr->zstream, window_bits);
#endif

         if (ret == Z_OK)
            png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
      }

      if (ret == Z_OK)
         png_ptr->zowner = owner;

      else
         png_zstream_error(png_ptr, ret);

      return ret;
   }

#ifdef window_bits
# undef window_bits
#endif
}

Project: libpng
File: pngset.c

check_location(png_const_structrp png_ptr, int location)
{
   location &= (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT);

   /* New in 1.6.0; copy the location and check it.  This is an API
    * change; previously the app had to use the
    * png_set_unknown_chunk_location API below for each chunk.
    */
   if (location == 0 && (png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
   {
      /* Write struct, so unknown chunks come from the app */
      png_app_warning(png_ptr,
         "png_set_unknown_chunks now expects a valid location");
      /* Use the old behavior */
      location = (png_byte)(png_ptr->mode &
         (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT));
   }

   /* This need not be an internal error - if the app calls
    * png_set_unknown_chunks on a read pointer it must get the location right.
    */
   if (location == 0)
      png_error(png_ptr, "invalid location in png_set_unknown_chunks");

   /* Now reduce the location to the top-most set bit by removing each least
    * significant bit in turn.
    */
   while (location != (location & -location))
      location &= ~(location & -location);

   /* The cast is safe because 'location' is a bit mask and only the low four
    * bits are significant.
    */
   return (png_byte)location;
}

Project: libpng
File: pngset.c

png_set_bKGD(png_const_structrp png_ptr, png_inforp info_ptr,
    png_const_color_16p background)
{
   png_debug1(1, "in %s storage function", "bKGD");

   if (png_ptr == NULL || info_ptr == NULL || background == NULL)
      return;

   info_ptr->background = *background;
   info_ptr->valid |= PNG_INFO_bKGD;
}

Project: libpng
File: pngset.c

png_set_check_for_invalid_index(png_structrp png_ptr, int allowed)
{
   png_debug(1, "in png_set_check_for_invalid_index");

   if (allowed > 0)
      png_ptr->num_palette_max = 0;

   else
      png_ptr->num_palette_max = -1;
}

Project: libpng
File: pngset.c

png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
    png_const_bytep chunk_list, int num_chunks_in)
{
   png_bytep new_list;
   unsigned int num_chunks, old_num_chunks;

   if (png_ptr == NULL)
      return;

   if (keep < 0 || keep >= PNG_HANDLE_CHUNK_LAST)
   {
      png_app_error(png_ptr, "png_set_keep_unknown_chunks: invalid keep");

      return;
   }

   if (num_chunks_in <= 0)
   {
      png_ptr->unknown_default = keep;

      /* '0' means just set the flags, so stop here */
      if (num_chunks_in == 0)
        return;
   }

   if (num_chunks_in < 0)
   {
      /* Ignore all unknown chunks and all chunks recognized by
       * libpng except for IHDR, PLTE, tRNS, IDAT, and IEND
       */
      static PNG_CONST png_byte chunks_to_ignore[] = {
         98,  75,  71,  68, '\0',  /* bKGD */
         99,  72,  82,  77, '\0',  /* cHRM */
        103,  65,  77,  65, '\0',  /* gAMA */
        104,  73,  83,  84, '\0',  /* hIST */
        105,  67,  67,  80, '\0',  /* iCCP */
        105,  84,  88, 116, '\0',  /* iTXt */
        111,  70,  70, 115, '\0',  /* oFFs */
        112,  67,  65,  76, '\0',  /* pCAL */
        112,  72,  89, 115, '\0',  /* pHYs */
        115,  66,  73,  84, '\0',  /* sBIT */
        115,  67,  65,  76, '\0',  /* sCAL */
        115,  80,  76,  84, '\0',  /* sPLT */
        115,  84,  69,  82, '\0',  /* sTER */
        115,  82,  71,  66, '\0',  /* sRGB */
        116,  69,  88, 116, '\0',  /* tEXt */
        116,  73,  77,  69, '\0',  /* tIME */
        122,  84,  88, 116, '\0'   /* zTXt */
      };

      chunk_list = chunks_to_ignore;
      num_chunks = (unsigned int)/*SAFE*/(sizeof chunks_to_ignore)/5U;
   }

   else /* num_chunks_in > 0 */
   {
      if (chunk_list == NULL)
      {
         /* Prior to 1.6.0 this was silently ignored, now it is an app_error
          * which can be switched off.
          */
         png_app_error(png_ptr, "png_set_keep_unknown_chunks: no chunk list");

         return;
      }

      num_chunks = num_chunks_in;
   }

   old_num_chunks = png_ptr->num_chunk_list;
   if (png_ptr->chunk_list == NULL)
      old_num_chunks = 0;

   /* Since num_chunks is always restricted to UINT_MAX/5 this can't overflow.
    */
   if (num_chunks + old_num_chunks > UINT_MAX/5)
   {
      png_app_error(png_ptr, "png_set_keep_unknown_chunks: too many chunks");

      return;
   }

   /* If these chunks are being reset to the default then no more memory is
    * required because add_one_chunk above doesn't extend the list if the 'keep'
    * parameter is the default.
    */
   if (keep != 0)
   {
      new_list = png_voidcast(png_bytep, png_malloc(png_ptr,
          5 * (num_chunks + old_num_chunks)));

      if (old_num_chunks > 0)
         memcpy(new_list, png_ptr->chunk_list, 5*old_num_chunks);
   }

   else if (old_num_chunks > 0)
      new_list = png_ptr->chunk_list;

   else
      new_list = NULL;

   /* Add the new chunks together with each one's handling code.  If the chunk
    * already exists the code is updated, otherwise the chunk is added to the
    * end.  (In libpng 1.6.0 order no longer matters because this code enforces
    * the earlier convention that the last setting is the one that is used.)
    */
   if (new_list != NULL)
   {
      png_const_bytep inlist;
      png_bytep outlist;
      unsigned int i;

      for (i=0; i<num_chunks; ++i)
      {
         old_num_chunks = add_one_chunk(new_list, old_num_chunks,
            chunk_list+5*i, keep);
      }

      /* Now remove any spurious 'default' entries. */
      num_chunks = 0;
      for (i=0, inlist=outlist=new_list; i<old_num_chunks; ++i, inlist += 5)
      {
         if (inlist[4])
         {
            if (outlist != inlist)
               memcpy(outlist, inlist, 5);
            outlist += 5;
            ++num_chunks;
         }
      }

      /* This means the application has removed all the specialized handling. */
      if (num_chunks == 0)
      {
         if (png_ptr->chunk_list != new_list)
            png_free(png_ptr, new_list);

         new_list = NULL;
      }
   }

   else
      num_chunks = 0;

   png_ptr->num_chunk_list = num_chunks;

   if (png_ptr->chunk_list != new_list)
   {
      if (png_ptr->chunk_list != NULL)
         png_free(png_ptr, png_ptr->chunk_list);

      png_ptr->chunk_list = new_list;
   }
}

Project: libpng
File: pngrutil.c

png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
{
   unsigned int truelen;
   png_byte buf[6];
   png_color_16 background;

   png_debug(1, "in png_handle_bKGD");

   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
      png_chunk_error(png_ptr, "missing IHDR");

   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
       (png_ptr->mode & PNG_HAVE_PLTE) == 0))
   {
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "out of place");
      return;
   }

   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
   {
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "duplicate");
      return;
   }

   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      truelen = 1;

   else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
      truelen = 6;

   else
      truelen = 2;

   if (length != truelen)
   {
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "invalid");
      return;
   }

   png_crc_read(png_ptr, buf, truelen);

   if (png_crc_finish(png_ptr, 0) != 0)
      return;

   /* We convert the index value into RGB components so that we can allow
    * arbitrary RGB values for background when we have transparency, and
    * so it is easy to determine the RGB values of the background color
    * from the info_ptr struct.
    */
   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
   {
      background.index = buf[0];

      if (info_ptr != NULL && info_ptr->num_palette != 0)
      {
         if (buf[0] >= info_ptr->num_palette)
         {
            png_chunk_benign_error(png_ptr, "invalid index");
            return;
         }

         background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
         background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
         background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
      }

      else
         background.red = background.green = background.blue = 0;

      background.gray = 0;
   }

   else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */
   {
      background.index = 0;
      background.red =
      background.green =
      background.blue =
      background.gray = png_get_uint_16(buf);
   }

   else
   {
      background.index = 0;
      background.red = png_get_uint_16(buf);
      background.green = png_get_uint_16(buf + 2);
      background.blue = png_get_uint_16(buf + 4);
      background.gray = 0;
   }

   png_set_bKGD(png_ptr, info_ptr, &background);
}

Project: libpng
File: pngrutil.c

png_read_start_row(png_structrp png_ptr)
{
   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */

   /* Start of interlace block */
   static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};

   /* Offset to next interlace block */
   static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};

   /* Start of interlace block in the y direction */
   static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};

   /* Offset to next interlace block in the y direction */
   static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};

   int max_pixel_depth;
   png_size_t row_bytes;

   png_debug(1, "in png_read_start_row");

#ifdef PNG_READ_TRANSFORMS_SUPPORTED
   png_init_read_transformations(png_ptr);
#endif
   if (png_ptr->interlaced != 0)
   {
      if ((png_ptr->transformations & PNG_INTERLACE) == 0)
         png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
             png_pass_ystart[0]) / png_pass_yinc[0];

      else
         png_ptr->num_rows = png_ptr->height;

      png_ptr->iwidth = (png_ptr->width +
          png_pass_inc[png_ptr->pass] - 1 -
          png_pass_start[png_ptr->pass]) /
          png_pass_inc[png_ptr->pass];
   }

   else
   {
      png_ptr->num_rows = png_ptr->height;
      png_ptr->iwidth = png_ptr->width;
   }

   max_pixel_depth = png_ptr->pixel_depth;

   /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
    * calculations to calculate the final pixel depth, then
    * png_do_read_transforms actually does the transforms.  This means that the
    * code which effectively calculates this value is actually repeated in three
    * separate places.  They must all match.  Innocent changes to the order of
    * transformations can and will break libpng in a way that causes memory
    * overwrites.
    *
    * TODO: fix this.
    */
#ifdef PNG_READ_PACK_SUPPORTED
   if ((png_ptr->transformations & PNG_PACK) != 0 && png_ptr->bit_depth < 8)
      max_pixel_depth = 8;
#endif

#ifdef PNG_READ_EXPAND_SUPPORTED
   if ((png_ptr->transformations & PNG_EXPAND) != 0)
   {
      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      {
         if (png_ptr->num_trans != 0)
            max_pixel_depth = 32;

         else
            max_pixel_depth = 24;
      }

      else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
      {
         if (max_pixel_depth < 8)
            max_pixel_depth = 8;

         if (png_ptr->num_trans != 0)
            max_pixel_depth *= 2;
      }

      else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
      {
         if (png_ptr->num_trans != 0)
         {
            max_pixel_depth *= 4;
            max_pixel_depth /= 3;
         }
      }
   }
#endif

#ifdef PNG_READ_EXPAND_16_SUPPORTED
   if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
   {
#  ifdef PNG_READ_EXPAND_SUPPORTED
      /* In fact it is an error if it isn't supported, but checking is
       * the safe way.
       */
      if ((png_ptr->transformations & PNG_EXPAND) != 0)
      {
         if (png_ptr->bit_depth < 16)
            max_pixel_depth *= 2;
      }
      else
#  endif
      png_ptr->transformations &= ~PNG_EXPAND_16;
   }
#endif

#ifdef PNG_READ_FILLER_SUPPORTED
   if ((png_ptr->transformations & (PNG_FILLER)) != 0)
   {
      if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
      {
         if (max_pixel_depth <= 8)
            max_pixel_depth = 16;

         else
            max_pixel_depth = 32;
      }

      else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB ||
         png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      {
         if (max_pixel_depth <= 32)
            max_pixel_depth = 32;

         else
            max_pixel_depth = 64;
      }
   }
#endif

#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
   {
      if (
#ifdef PNG_READ_EXPAND_SUPPORTED
          (png_ptr->num_trans != 0 &&
          (png_ptr->transformations & PNG_EXPAND) != 0) ||
#endif
#ifdef PNG_READ_FILLER_SUPPORTED
          (png_ptr->transformations & (PNG_FILLER)) != 0 ||
#endif
          png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
      {
         if (max_pixel_depth <= 16)
            max_pixel_depth = 32;

         else
            max_pixel_depth = 64;
      }

      else
      {
         if (max_pixel_depth <= 8)
         {
            if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
               max_pixel_depth = 32;

            else
               max_pixel_depth = 24;
         }

         else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
            max_pixel_depth = 64;

         else
            max_pixel_depth = 48;
      }
   }
#endif

#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
   {
      int user_pixel_depth = png_ptr->user_transform_depth *
         png_ptr->user_transform_channels;

      if (user_pixel_depth > max_pixel_depth)
         max_pixel_depth = user_pixel_depth;
   }
#endif

   /* This value is stored in png_struct and double checked in the row read
    * code.
    */
   png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
   png_ptr->transformed_pixel_depth = 0; /* calculated on demand */

   /* Align the width on the next larger 8 pixels.  Mainly used
    * for interlacing
    */
   row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
   /* Calculate the maximum bytes needed, adding a byte and a pixel
    * for safety's sake
    */
   row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
       1 + ((max_pixel_depth + 7) >> 3);

#ifdef PNG_MAX_MALLOC_64K
   if (row_bytes > (png_uint_32)65536L)
      png_error(png_ptr, "This image requires a row greater than 64KB");
#endif

   if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
   {
     png_free(png_ptr, png_ptr->big_row_buf);
     png_free(png_ptr, png_ptr->big_prev_row);

     if (png_ptr->interlaced != 0)
        png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
            row_bytes + 48);

     else
        png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);

     png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);

#ifdef PNG_ALIGNED_MEMORY_SUPPORTED
     /* Use 16-byte aligned memory for row_buf with at least 16 bytes
      * of padding before and after row_buf; treat prev_row similarly.
      * NOTE: the alignment is to the start of the pixels, one beyond the start
      * of the buffer, because of the filter byte.  Prior to libpng 1.5.6 this
      * was incorrect; the filter byte was aligned, which had the exact
      * opposite effect of that intended.
      */
     {
        png_bytep temp = png_ptr->big_row_buf + 32;
        int extra = (int)((temp - (png_bytep)0) & 0x0f);
        png_ptr->row_buf = temp - extra - 1/*filter byte*/;

        temp = png_ptr->big_prev_row + 32;
        extra = (int)((temp - (png_bytep)0) & 0x0f);
        png_ptr->prev_row = temp - extra - 1/*filter byte*/;
     }

#else
     /* Use 31 bytes of padding before and 17 bytes after row_buf. */
     png_ptr->row_buf = png_ptr->big_row_buf + 31;
     png_ptr->prev_row = png_ptr->big_prev_row + 31;
#endif
     png_ptr->old_big_row_buf_size = row_bytes + 48;
   }

#ifdef PNG_MAX_MALLOC_64K
   if (png_ptr->rowbytes > 65535)
      png_error(png_ptr, "This image requires a row greater than 64KB");

#endif
   if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
      png_error(png_ptr, "Row has too many bytes to allocate in memory");

   memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);

   png_debug1(3, "width = %u,", png_ptr->width);
   png_debug1(3, "height = %u,", png_ptr->height);
   png_debug1(3, "iwidth = %u,", png_ptr->iwidth);
   png_debug1(3, "num_rows = %u,", png_ptr->num_rows);
   png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
   png_debug1(3, "irowbytes = %lu",
       (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);

   /* The sequential reader needs a buffer for IDAT, but the progressive reader
    * does not, so free the read buffer now regardless; the sequential reader
    * reallocates it on demand.
    */
   if (png_ptr->read_buffer != 0)
   {
      png_bytep buffer = png_ptr->read_buffer;

      png_ptr->read_buffer_size = 0;
      png_ptr->read_buffer = NULL;
      png_free(png_ptr, buffer);
   }

   /* Finally claim the zstream for the inflate of the IDAT data, use the bits
    * value from the stream (note that this will result in a fatal error if the
    * IDAT stream has a bogus deflate header window_bits value, but this should
    * not be happening any longer!)
    */
   if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK)
      png_error(png_ptr, png_ptr->zstream.msg);

   png_ptr->flags |= PNG_FLAG_ROW_INIT;
}

Project: libpng
File: pngrutil.c

png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
   png_const_bytep prev_row)
{
   png_bytep rp_end = row + row_info->rowbytes;
   int a, c;

   /* First pixel/byte */
   c = *prev_row++;
   a = *row + c;
   *row++ = (png_byte)a;

   /* Remainder */
   while (row < rp_end)
   {
      int b, pa, pb, pc, p;

      a &= 0xff; /* From previous iteration or start */
      b = *prev_row++;

      p = b - c;
      pc = a - c;

#ifdef PNG_USE_ABS
      pa = abs(p);
      pb = abs(pc);
      pc = abs(p + pc);
#else
      pa = p < 0 ? -p : p;
      pb = pc < 0 ? -pc : pc;
      pc = (p + pc) < 0 ? -(p + pc) : p + pc;
#endif

      /* Find the best predictor, the least of pa, pb, pc favoring the earlier
       * ones in the case of a tie.
       */
      if (pb < pa) pa = pb, a = b;
      if (pc < pa) a = c;

      /* Calculate the current pixel in a, and move the previous row pixel to c
       * for the next time round the loop
       */
      c = b;
      a += *row;
      *row++ = (png_byte)a;
   }
}

Project: libpng
File: pngrutil.c

png_decompress_chunk(png_structrp png_ptr,
   png_uint_32 chunklength, png_uint_32 prefix_size,
   png_alloc_size_t *newlength /* must be initialized to the maximum! */,
   int terminate /*add a '\0' to the end of the uncompressed data*/)
{
   /* TODO: implement different limits for different types of chunk.
    *
    * The caller supplies *newlength set to the maximum length of the
    * uncompressed data, but this routine allocates space for the prefix and
    * maybe a '\0' terminator too.  We have to assume that 'prefix_size' is
    * limited only by the maximum chunk size.
    */
   png_alloc_size_t limit = PNG_SIZE_MAX;

# ifdef PNG_SET_USER_LIMITS_SUPPORTED
   if (png_ptr->user_chunk_malloc_max > 0 &&
       png_ptr->user_chunk_malloc_max < limit)
      limit = png_ptr->user_chunk_malloc_max;
# elif PNG_USER_CHUNK_MALLOC_MAX > 0
   if (PNG_USER_CHUNK_MALLOC_MAX < limit)
      limit = PNG_USER_CHUNK_MALLOC_MAX;
# endif

   if (limit >= prefix_size + (terminate != 0))
   {
      int ret;

      limit -= prefix_size + (terminate != 0);

      if (limit < *newlength)
         *newlength = limit;

      /* Now try to claim the stream. */
      ret = png_inflate_claim(png_ptr, png_ptr->chunk_name);

      if (ret == Z_OK)
      {
         png_uint_32 lzsize = chunklength - prefix_size;

         ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
            /* input: */ png_ptr->read_buffer + prefix_size, &lzsize,
            /* output: */ NULL, newlength);

         if (ret == Z_STREAM_END)
         {
            /* Use 'inflateReset' here, not 'inflateReset2' because this
             * preserves the previously decided window size (otherwise it would
             * be necessary to store the previous window size.)  In practice
             * this doesn't matter anyway, because png_inflate will call inflate
             * with Z_FINISH in almost all cases, so the window will not be
             * maintained.
             */
            if (inflateReset(&png_ptr->zstream) == Z_OK)
            {
               /* Because of the limit checks above we know that the new,
                * expanded, size will fit in a size_t (let alone an
                * png_alloc_size_t).  Use png_malloc_base here to avoid an
                * extra OOM message.
                */
               png_alloc_size_t new_size = *newlength;
               png_alloc_size_t buffer_size = prefix_size + new_size +
                  (terminate != 0);
               png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr,
                  buffer_size));

               if (text != NULL)
               {
                  ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
                     png_ptr->read_buffer + prefix_size, &lzsize,
                     text + prefix_size, newlength);

                  if (ret == Z_STREAM_END)
                  {
                     if (new_size == *newlength)
                     {
                        if (terminate != 0)
                           text[prefix_size + *newlength] = 0;

                        if (prefix_size > 0)
                           memcpy(text, png_ptr->read_buffer, prefix_size);

                        {
                           png_bytep old_ptr = png_ptr->read_buffer;

                           png_ptr->read_buffer = text;
                           png_ptr->read_buffer_size = buffer_size;
                           text = old_ptr; /* freed below */
                        }
                     }

                     else
                     {
                        /* The size changed on the second read, there can be no
                         * guarantee that anything is correct at this point.
                         * The 'msg' pointer has been set to "unexpected end of
                         * LZ stream", which is fine, but return an error code
                         * that the caller won't accept.
                         */
                        ret = PNG_UNEXPECTED_ZLIB_RETURN;
                     }
                  }

                  else if (ret == Z_OK)
                     ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */

                  /* Free the text pointer (this is the old read_buffer on
                   * success)
                   */
                  png_free(png_ptr, text);

                  /* This really is very benign, but it's still an error because
                   * the extra space may otherwise be used as a Trojan Horse.
                   */
                  if (ret == Z_STREAM_END &&
                     chunklength - prefix_size != lzsize)
                     png_chunk_benign_error(png_ptr, "extra compressed data");
               }

               else
               {
                  /* Out of memory allocating the buffer */
                  ret = Z_MEM_ERROR;
                  png_zstream_error(png_ptr, Z_MEM_ERROR);
               }
            }

            else
            {
               /* inflateReset failed, store the error message */
               png_zstream_error(png_ptr, ret);

               if (ret == Z_STREAM_END)
                  ret = PNG_UNEXPECTED_ZLIB_RETURN;
            }
         }

         else if (ret == Z_OK)
            ret = PNG_UNEXPECTED_ZLIB_RETURN;

         /* Release the claimed stream */
         png_ptr->zowner = 0;
      }

      else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */
         ret = PNG_UNEXPECTED_ZLIB_RETURN;

      return ret;
   }

   else
   {
      /* Application/configuration limits exceeded */
      png_zstream_error(png_ptr, Z_MEM_ERROR);
      return Z_MEM_ERROR;
   }
}

Project: libpng
File: pngrutil.c

png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn)
{
   png_bytep buffer = png_ptr->read_buffer;

   if (buffer != NULL && new_size > png_ptr->read_buffer_size)
   {
      png_ptr->read_buffer = NULL;
      png_ptr->read_buffer = NULL;
      png_ptr->read_buffer_size = 0;
      png_free(png_ptr, buffer);
      buffer = NULL;
   }

   if (buffer == NULL)
   {
      buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size));

      if (buffer != NULL)
      {
         png_ptr->read_buffer = buffer;
         png_ptr->read_buffer_size = new_size;
      }

      else if (warn < 2) /* else silent */
      {
         if (warn != 0)
             png_chunk_warning(png_ptr, "insufficient memory to read chunk");

         else
             png_chunk_error(png_ptr, "insufficient memory to read chunk");
      }
   }

   return buffer;
}

Project: libpng
File: pngset.c

png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
    png_const_charp purpose, png_int_32 X0, png_int_32 X1, int type,
    int nparams, png_const_charp units, png_charpp params)
{
   png_size_t length;
   int i;

   png_debug1(1, "in %s storage function", "pCAL");

   if (png_ptr == NULL || info_ptr == NULL || purpose == NULL || units == NULL
       || (nparams > 0 && params == NULL))
      return;

   length = strlen(purpose) + 1;
   png_debug1(3, "allocating purpose for info (%lu bytes)",
       (unsigned long)length);

   /* TODO: validate format of calibration name and unit name */

   /* Check that the type matches the specification. */
   if (type < 0 || type > 3)
      png_error(png_ptr, "Invalid pCAL equation type");

   if (nparams < 0 || nparams > 255)
      png_error(png_ptr, "Invalid pCAL parameter count");

   /* Validate params[nparams] */
   for (i=0; i<nparams; ++i)
   {
      if (params[i] == NULL ||
          !png_check_fp_string(params[i], strlen(params[i])))
         png_error(png_ptr, "Invalid format for pCAL parameter");
   }

   info_ptr->pcal_purpose = png_voidcast(png_charp,
       png_malloc_warn(png_ptr, length));

   if (info_ptr->pcal_purpose == NULL)
   {
      png_warning(png_ptr, "Insufficient memory for pCAL purpose");

      return;
   }

   memcpy(info_ptr->pcal_purpose, purpose, length);

   png_debug(3, "storing X0, X1, type, and nparams in info");
   info_ptr->pcal_X0 = X0;
   info_ptr->pcal_X1 = X1;
   info_ptr->pcal_type = (png_byte)type;
   info_ptr->pcal_nparams = (png_byte)nparams;

   length = strlen(units) + 1;
   png_debug1(3, "allocating units for info (%lu bytes)",
     (unsigned long)length);

   info_ptr->pcal_units = png_voidcast(png_charp,
      png_malloc_warn(png_ptr, length));

   if (info_ptr->pcal_units == NULL)
   {
      png_warning(png_ptr, "Insufficient memory for pCAL units");

      return;
   }

   memcpy(info_ptr->pcal_units, units, length);

   info_ptr->pcal_params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
       (png_size_t)((nparams + 1) * (sizeof (png_charp)))));

   if (info_ptr->pcal_params == NULL)
   {
      png_warning(png_ptr, "Insufficient memory for pCAL params");

      return;
   }

   memset(info_ptr->pcal_params, 0, (nparams + 1) * (sizeof (png_charp)));

   for (i = 0; i < nparams; i++)
   {
      length = strlen(params[i]) + 1;
      png_debug2(3, "allocating parameter %d for info (%lu bytes)", i,
          (unsigned long)length);

      info_ptr->pcal_params[i] = (png_charp)png_malloc_warn(png_ptr, length);

      if (info_ptr->pcal_params[i] == NULL)
      {
         png_warning(png_ptr, "Insufficient memory for pCAL parameter");

         return;
      }

      memcpy(info_ptr->pcal_params[i], params[i], length);
   }

   info_ptr->valid |= PNG_INFO_pCAL;
   info_ptr->free_me |= PNG_FREE_PCAL;
}

Project: libpng
File: pngset.c

png_set_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
    png_fixed_point int_red_X, png_fixed_point int_red_Y,
    png_fixed_point int_red_Z, png_fixed_point int_green_X,
    png_fixed_point int_green_Y, png_fixed_point int_green_Z,
    png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
    png_fixed_point int_blue_Z)
{
   png_XYZ XYZ;

   png_debug1(1, "in %s storage function", "cHRM XYZ fixed");

   if (png_ptr == NULL || info_ptr == NULL)
      return;

   XYZ.red_X = int_red_X;
   XYZ.red_Y = int_red_Y;
   XYZ.red_Z = int_red_Z;
   XYZ.green_X = int_green_X;
   XYZ.green_Y = int_green_Y;
   XYZ.green_Z = int_green_Z;
   XYZ.blue_X = int_blue_X;
   XYZ.blue_Y = int_blue_Y;
   XYZ.blue_Z = int_blue_Z;

   if (png_colorspace_set_endpoints(png_ptr, &info_ptr->colorspace,
       &XYZ, 2) != 0)
      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;

   png_colorspace_sync_info(png_ptr, info_ptr);
}

Project: libpng
File: pngrutil.c

png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size,
   png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size,
   int finish)
{
   if (png_ptr->zowner == png_ptr->chunk_name)
   {
      int ret;

      /* next_in and avail_in must have been initialized by the caller. */
      png_ptr->zstream.next_out = next_out;
      png_ptr->zstream.avail_out = 0; /* set in the loop */

      do
      {
         if (png_ptr->zstream.avail_in == 0)
         {
            if (read_size > *chunk_bytes)
               read_size = (uInt)*chunk_bytes;
            *chunk_bytes -= read_size;

            if (read_size > 0)
               png_crc_read(png_ptr, read_buffer, read_size);

            png_ptr->zstream.next_in = read_buffer;
            png_ptr->zstream.avail_in = read_size;
         }

         if (png_ptr->zstream.avail_out == 0)
         {
            uInt avail = ZLIB_IO_MAX;
            if (avail > *out_size)
               avail = (uInt)*out_size;
            *out_size -= avail;

            png_ptr->zstream.avail_out = avail;
         }

         /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
          * the available output is produced; this allows reading of truncated
          * streams.
          */
         ret = inflate(&png_ptr->zstream,
            *chunk_bytes > 0 ? Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH));
      }
      while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0));

      *out_size += png_ptr->zstream.avail_out;
      png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */

      /* Ensure the error message pointer is always set: */
      png_zstream_error(png_ptr, ret);
      return ret;
   }

   else
   {
      png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
      return Z_STREAM_ERROR;
   }
}

Project: libpng
File: pngrutil.c

png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish,
    /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr,
    /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr)
{
   if (png_ptr->zowner == owner) /* Else not claimed */
   {
      int ret;
      png_alloc_size_t avail_out = *output_size_ptr;
      png_uint_32 avail_in = *input_size_ptr;

      /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
       * can't even necessarily handle 65536 bytes) because the type uInt is
       * "16 bits or more".  Consequently it is necessary to chunk the input to
       * zlib.  This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
       * maximum value that can be stored in a uInt.)  It is possible to set
       * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
       * a performance advantage, because it reduces the amount of data accessed
       * at each step and that may give the OS more time to page it in.
       */
      png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
      /* avail_in and avail_out are set below from 'size' */
      png_ptr->zstream.avail_in = 0;
      png_ptr->zstream.avail_out = 0;

      /* Read directly into the output if it is available (this is set to
       * a local buffer below if output is NULL).
       */
      if (output != NULL)
         png_ptr->zstream.next_out = output;

      do
      {
         uInt avail;
         Byte local_buffer[PNG_INFLATE_BUF_SIZE];

         /* zlib INPUT BUFFER */
         /* The setting of 'avail_in' used to be outside the loop; by setting it
          * inside it is possible to chunk the input to zlib and simply rely on
          * zlib to advance the 'next_in' pointer.  This allows arbitrary
          * amounts of data to be passed through zlib at the unavoidable cost of
          * requiring a window save (memcpy of up to 32768 output bytes)
          * every ZLIB_IO_MAX input bytes.
          */
         avail_in += png_ptr->zstream.avail_in; /* not consumed last time */

         avail = ZLIB_IO_MAX;

         if (avail_in < avail)
            avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */

         avail_in -= avail;
         png_ptr->zstream.avail_in = avail;

         /* zlib OUTPUT BUFFER */
         avail_out += png_ptr->zstream.avail_out; /* not written last time */

         avail = ZLIB_IO_MAX; /* maximum zlib can process */

         if (output == NULL)
         {
            /* Reset the output buffer each time round if output is NULL and
             * make available the full buffer, up to 'remaining_space'
             */
            png_ptr->zstream.next_out = local_buffer;
            if ((sizeof local_buffer) < avail)
               avail = (sizeof local_buffer);
         }

         if (avail_out < avail)
            avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */

         png_ptr->zstream.avail_out = avail;
         avail_out -= avail;

         /* zlib inflate call */
         /* In fact 'avail_out' may be 0 at this point, that happens at the end
          * of the read when the final LZ end code was not passed at the end of
          * the previous chunk of input data.  Tell zlib if we have reached the
          * end of the output buffer.
          */
         ret = inflate(&png_ptr->zstream, avail_out > 0 ? Z_NO_FLUSH :
             (finish ? Z_FINISH : Z_SYNC_FLUSH));
      } while (ret == Z_OK);

      /* For safety kill the local buffer pointer now */
      if (output == NULL)
         png_ptr->zstream.next_out = NULL;

      /* Claw back the 'size' and 'remaining_space' byte counts. */
      avail_in += png_ptr->zstream.avail_in;
      avail_out += png_ptr->zstream.avail_out;

      /* Update the input and output sizes; the updated values are the amount
       * consumed or written, effectively the inverse of what zlib uses.
       */
      if (avail_out > 0)
         *output_size_ptr -= avail_out;

      if (avail_in > 0)
         *input_size_ptr -= avail_in;

      /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
      png_zstream_error(png_ptr, ret);
      return ret;
   }

   else
   {
      /* This is a bad internal error.  The recovery assigns to the zstream msg
       * pointer, which is not owned by the caller, but this is safe; it's only
       * used on errors!
       */
      png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
      return Z_STREAM_ERROR;
   }
}

Project: libpng
File: pngset.c

png_set_sRGB_gAMA_and_cHRM(png_const_structrp png_ptr, png_inforp info_ptr,
    int srgb_intent)
{
   png_debug1(1, "in %s storage function", "sRGB_gAMA_and_cHRM");

   if (png_ptr == NULL || info_ptr == NULL)
      return;

   if (png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace,
       srgb_intent) != 0)
   {
      /* This causes the gAMA and cHRM to be written too */
      info_ptr->colorspace.flags |=
         PNG_COLORSPACE_FROM_gAMA|PNG_COLORSPACE_FROM_cHRM;
   }

   png_colorspace_sync_info(png_ptr, info_ptr);
}

Project: libpng
File: pngset.c

png_set_cHRM(png_const_structrp png_ptr, png_inforp info_ptr,
    double white_x, double white_y, double red_x, double red_y,
    double green_x, double green_y, double blue_x, double blue_y)
{
   png_set_cHRM_fixed(png_ptr, info_ptr,
      png_fixed(png_ptr, white_x, "cHRM White X"),
      png_fixed(png_ptr, white_y, "cHRM White Y"),
      png_fixed(png_ptr, red_x, "cHRM Red X"),
      png_fixed(png_ptr, red_y, "cHRM Red Y"),
      png_fixed(png_ptr, green_x, "cHRM Green X"),
      png_fixed(png_ptr, green_y, "cHRM Green Y"),
      png_fixed(png_ptr, blue_x, "cHRM Blue X"),
      png_fixed(png_ptr, blue_y, "cHRM Blue Y"));
}

Project: libpng
File: pngrutil.c

png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
{
   png_alloc_size_t limit = PNG_SIZE_MAX;

   if (png_ptr->unknown_chunk.data != NULL)
   {
      png_free(png_ptr, png_ptr->unknown_chunk.data);
      png_ptr->unknown_chunk.data = NULL;
   }

#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
   if (png_ptr->user_chunk_malloc_max > 0 &&
       png_ptr->user_chunk_malloc_max < limit)
      limit = png_ptr->user_chunk_malloc_max;

#  elif PNG_USER_CHUNK_MALLOC_MAX > 0
   if (PNG_USER_CHUNK_MALLOC_MAX < limit)
      limit = PNG_USER_CHUNK_MALLOC_MAX;
#  endif

   if (length <= limit)
   {
      PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
      /* The following is safe because of the PNG_SIZE_MAX init above */
      png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/;
      /* 'mode' is a flag array, only the bottom four bits matter here */
      png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/;

      if (length == 0)
         png_ptr->unknown_chunk.data = NULL;

      else
      {
         /* Do a 'warn' here - it is handled below. */
         png_ptr->unknown_chunk.data = png_voidcast(png_bytep,
            png_malloc_warn(png_ptr, length));
      }
   }

   if (png_ptr->unknown_chunk.data == NULL && length > 0)
   {
      /* This is benign because we clean up correctly */
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits");
      return 0;
   }

   else
   {
      if (length > 0)
         png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
      png_crc_finish(png_ptr, 0);
      return 1;
   }
}

Project: libpng
File: pngset.c

png_permit_mng_features (png_structrp png_ptr, png_uint_32 mng_features)
{
   png_debug(1, "in png_permit_mng_features");

   if (png_ptr == NULL)
      return 0;

   png_ptr->mng_features_permitted = mng_features & PNG_ALL_MNG_FEATURES;

   return png_ptr->mng_features_permitted;
}

Project: libpng
File: pngset.c

png_set_hIST(png_const_structrp png_ptr, png_inforp info_ptr,
    png_const_uint_16p hist)
{
   int i;

   png_debug1(1, "in %s storage function", "hIST");

   if (png_ptr == NULL || info_ptr == NULL)
      return;

   if (info_ptr->num_palette == 0 || info_ptr->num_palette
       > PNG_MAX_PALETTE_LENGTH)
   {
      png_warning(png_ptr,
          "Invalid palette size, hIST allocation skipped");

      return;
   }

   png_free_data(png_ptr, info_ptr, PNG_FREE_HIST, 0);

   /* Changed from info->num_palette to PNG_MAX_PALETTE_LENGTH in
    * version 1.2.1
    */
   info_ptr->hist = png_voidcast(png_uint_16p, png_malloc_warn(png_ptr,
       PNG_MAX_PALETTE_LENGTH * (sizeof (png_uint_16))));

   if (info_ptr->hist == NULL)
   {
      png_warning(png_ptr, "Insufficient memory for hIST chunk data");

      return;
   }

   info_ptr->free_me |= PNG_FREE_HIST;

   for (i = 0; i < info_ptr->num_palette; i++)
      info_ptr->hist[i] = hist[i];

   info_ptr->valid |= PNG_INFO_hIST;
}

Project: libpng
File: pngrutil.c

png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
{
   png_int_32 X0, X1;
   png_byte type, nparams;
   png_bytep buffer, buf, units, endptr;
   png_charpp params;
   int i;

   png_debug(1, "in png_handle_pCAL");

   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
      png_chunk_error(png_ptr, "missing IHDR");

   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
   {
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "out of place");
      return;
   }

   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0)
   {
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "duplicate");
      return;
   }

   png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
       length + 1);

   buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);

   if (buffer == NULL)
   {
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "out of memory");
      return;
   }

   png_crc_read(png_ptr, buffer, length);

   if (png_crc_finish(png_ptr, 0) != 0)
      return;

   buffer[length] = 0; /* Null terminate the last string */

   png_debug(3, "Finding end of pCAL purpose string");
   for (buf = buffer; *buf; buf++)
      /* Empty loop */ ;

   endptr = buffer + length;

   /* We need to have at least 12 bytes after the purpose string
    * in order to get the parameter information.
    */
   if (endptr <= buf + 12)
   {
      png_chunk_benign_error(png_ptr, "invalid");
      return;
   }

   png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
   X0 = png_get_int_32((png_bytep)buf+1);
   X1 = png_get_int_32((png_bytep)buf+5);
   type = buf[9];
   nparams = buf[10];
   units = buf + 11;

   png_debug(3, "Checking pCAL equation type and number of parameters");
   /* Check that we have the right number of parameters for known
    * equation types.
    */
   if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
       (type == PNG_EQUATION_BASE_E && nparams != 3) ||
       (type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
       (type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
   {
      png_chunk_benign_error(png_ptr, "invalid parameter count");
      return;
   }

   else if (type >= PNG_EQUATION_LAST)
   {
      png_chunk_benign_error(png_ptr, "unrecognized equation type");
   }

   for (buf = units; *buf; buf++)
      /* Empty loop to move past the units string. */ ;

   png_debug(3, "Allocating pCAL parameters array");

   params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
       nparams * (sizeof (png_charp))));

   if (params == NULL)
   {
      png_chunk_benign_error(png_ptr, "out of memory");
      return;
   }

   /* Get pointers to the start of each parameter string. */
   for (i = 0; i < nparams; i++)
   {
      buf++; /* Skip the null string terminator from previous parameter. */

      png_debug1(3, "Reading pCAL parameter %d", i);

      for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++)
         /* Empty loop to move past each parameter string */ ;

      /* Make sure we haven't run out of data yet */
      if (buf > endptr)
      {
         png_free(png_ptr, params);
         png_chunk_benign_error(png_ptr, "invalid data");
         return;
      }
   }

   png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams,
      (png_charp)units, params);

   png_free(png_ptr, params);
}

Project: libpng
File: pngrutil.c

png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
   png_const_bytep prev_row)
{
   png_size_t i;
   png_size_t istop = row_info->rowbytes;
   unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
   png_bytep rp = row + bpp;

   PNG_UNUSED(prev_row)

   for (i = bpp; i < istop; i++)
   {
      *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
      rp++;
   }
}

Project: libpng
File: pngset.c

png_set_sRGB(png_const_structrp png_ptr, png_inforp info_ptr, int srgb_intent)
{
   png_debug1(1, "in %s storage function", "sRGB");

   if (png_ptr == NULL || info_ptr == NULL)
      return;

   (void)png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace, srgb_intent);
   png_colorspace_sync_info(png_ptr, info_ptr);
}

Project: libpng
File: pngrutil.c

png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
   png_const_bytep prev_row)
{
   int bpp = (row_info->pixel_depth + 7) >> 3;
   png_bytep rp_end = row + bpp;

   /* Process the first pixel in the row completely (this is the same as 'up'
    * because there is only one candidate predictor for the first row).
    */
   while (row < rp_end)
   {
      int a = *row + *prev_row++;
      *row++ = (png_byte)a;
   }

   /* Remainder */
   rp_end += row_info->rowbytes - bpp;

   while (row < rp_end)
   {
      int a, b, c, pa, pb, pc, p;

      c = *(prev_row - bpp);
      a = *(row - bpp);
      b = *prev_row++;

      p = b - c;
      pc = a - c;

#ifdef PNG_USE_ABS
      pa = abs(p);
      pb = abs(pc);
      pc = abs(p + pc);
#else
      pa = p < 0 ? -p : p;
      pb = pc < 0 ? -pc : pc;
      pc = (p + pc) < 0 ? -(p + pc) : p + pc;
#endif

      if (pb < pa) pa = pb, a = b;
      if (pc < pa) a = c;

      a += *row;
      *row++ = (png_byte)a;
   }
}

Project: libpng
File: pngrutil.c

png_read_IDAT_data(png_structrp png_ptr, png_bytep output,
   png_alloc_size_t avail_out)
{
   /* Loop reading IDATs and decompressing the result into output[avail_out] */
   png_ptr->zstream.next_out = output;
   png_ptr->zstream.avail_out = 0; /* safety: set below */

   if (output == NULL)
      avail_out = 0;

   do
   {
      int ret;
      png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];

      if (png_ptr->zstream.avail_in == 0)
      {
         uInt avail_in;
         png_bytep buffer;

         while (png_ptr->idat_size == 0)
         {
            png_crc_finish(png_ptr, 0);

            png_ptr->idat_size = png_read_chunk_header(png_ptr);
            /* This is an error even in the 'check' case because the code just
             * consumed a non-IDAT header.
             */
            if (png_ptr->chunk_name != png_IDAT)
               png_error(png_ptr, "Not enough image data");
         }

         avail_in = png_ptr->IDAT_read_size;

         if (avail_in > png_ptr->idat_size)
            avail_in = (uInt)png_ptr->idat_size;

         /* A PNG with a gradually increasing IDAT size will defeat this attempt
          * to minimize memory usage by causing lots of re-allocs, but
          * realistically doing IDAT_read_size re-allocs is not likely to be a
          * big problem.
          */
         buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/);

         png_crc_read(png_ptr, buffer, avail_in);
         png_ptr->idat_size -= avail_in;

         png_ptr->zstream.next_in = buffer;
         png_ptr->zstream.avail_in = avail_in;
      }

      /* And set up the output side. */
      if (output != NULL) /* standard read */
      {
         uInt out = ZLIB_IO_MAX;

         if (out > avail_out)
            out = (uInt)avail_out;

         avail_out -= out;
         png_ptr->zstream.avail_out = out;
      }

      else /* after last row, checking for end */
      {
         png_ptr->zstream.next_out = tmpbuf;
         png_ptr->zstream.avail_out = (sizeof tmpbuf);
      }

      /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
       * process.  If the LZ stream is truncated the sequential reader will
       * terminally damage the stream, above, by reading the chunk header of the
       * following chunk (it then exits with png_error).
       *
       * TODO: deal more elegantly with truncated IDAT lists.
       */
      ret = inflate(&png_ptr->zstream, Z_NO_FLUSH);

      /* Take the unconsumed output back. */
      if (output != NULL)
         avail_out += png_ptr->zstream.avail_out;

      else /* avail_out counts the extra bytes */
         avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out;

      png_ptr->zstream.avail_out = 0;

      if (ret == Z_STREAM_END)
      {
         /* Do this for safety; we won't read any more into this row. */
         png_ptr->zstream.next_out = NULL;

         png_ptr->mode |= PNG_AFTER_IDAT;
         png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;

         if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0)
            png_chunk_benign_error(png_ptr, "Extra compressed data");
         break;
      }

      if (ret != Z_OK)
      {
         png_zstream_error(png_ptr, ret);

         if (output != NULL)
            png_chunk_error(png_ptr, png_ptr->zstream.msg);

         else /* checking */
         {
            png_chunk_benign_error(png_ptr, png_ptr->zstream.msg);
            return;
         }
      }
   } while (avail_out > 0);

   if (avail_out > 0)
   {
      /* The stream ended before the image; this is the same as too few IDATs so
       * should be handled the same way.
       */
      if (output != NULL)
         png_error(png_ptr, "Not enough image data");

      else /* the deflate stream contained extra data */
         png_chunk_benign_error(png_ptr, "Too much image data");
   }
}

Project: libpng
File: pngset.c

png_set_gAMA(png_const_structrp png_ptr, png_inforp info_ptr, double file_gamma)
{
   png_set_gAMA_fixed(png_ptr, info_ptr, png_fixed(png_ptr, file_gamma,
       "png_set_gAMA"));
}

Project: libpng
File: pngset.c

png_set_sPLT(png_const_structrp png_ptr,
    png_inforp info_ptr, png_const_sPLT_tp entries, int nentries)
/*
 *  entries        - array of png_sPLT_t structures
 *                   to be added to the list of palettes
 *                   in the info structure.
 *
 *  nentries       - number of palette structures to be
 *                   added.
 */
{
   png_sPLT_tp np;

   if (png_ptr == NULL || info_ptr == NULL || nentries <= 0 || entries == NULL)
      return;

   /* Use the internal realloc function, which checks for all the possible
    * overflows.  Notice that the parameters are (int) and (size_t)
    */
   np = png_voidcast(png_sPLT_tp,png_realloc_array(png_ptr,
      info_ptr->splt_palettes, info_ptr->splt_palettes_num, nentries,
      sizeof *np));

   if (np == NULL)
   {
      /* Out of memory or too many chunks */
      png_chunk_report(png_ptr, "too many sPLT chunks", PNG_CHUNK_WRITE_ERROR);

      return;
   }

   png_free(png_ptr, info_ptr->splt_palettes);
   info_ptr->splt_palettes = np;
   info_ptr->free_me |= PNG_FREE_SPLT;

   np += info_ptr->splt_palettes_num;

   do
   {
      png_size_t length;

      /* Skip invalid input entries */
      if (entries->name == NULL || entries->entries == NULL)
      {
         /* png_handle_sPLT doesn't do this, so this is an app error */
         png_app_error(png_ptr, "png_set_sPLT: invalid sPLT");
         /* Just skip the invalid entry */
         continue;
      }

      np->depth = entries->depth;

      /* In the event of out-of-memory just return - there's no point keeping
       * on trying to add sPLT chunks.
       */
      length = strlen(entries->name) + 1;
      np->name = png_voidcast(png_charp, png_malloc_base(png_ptr, length));

      if (np->name == NULL)
         break;

      memcpy(np->name, entries->name, length);

      /* IMPORTANT: we have memory now that won't get freed if something else
       * goes wrong; this code must free it.  png_malloc_array produces no
       * warnings; use a png_chunk_report (below) if there is an error.
       */
      np->entries = png_voidcast(png_sPLT_entryp, png_malloc_array(png_ptr,
          entries->nentries, sizeof (png_sPLT_entry)));

      if (np->entries == NULL)
      {
         png_free(png_ptr, np->name);
         np->name = NULL;
         break;
      }

      np->nentries = entries->nentries;
      /* This multiply can't overflow because png_malloc_array has already
       * checked it when doing the allocation.
       */
      memcpy(np->entries, entries->entries,
         entries->nentries * sizeof (png_sPLT_entry));

      /* Note that 'continue' skips the advance of the out pointer and out
       * count, so an invalid entry is not added.
       */
      info_ptr->valid |= PNG_INFO_sPLT;
      ++(info_ptr->splt_palettes_num);
      ++np;
   }
   while (++entries, --nentries);

   if (nentries > 0)
      png_chunk_report(png_ptr, "sPLT out of memory", PNG_CHUNK_WRITE_ERROR);
}

Project: libpng
File: pngset.c

png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
    png_const_charp name, int compression_type,
    png_const_bytep profile, png_uint_32 proflen)
{
   png_charp new_iccp_name;
   png_bytep new_iccp_profile;
   png_size_t length;

   png_debug1(1, "in %s storage function", "iCCP");

   if (png_ptr == NULL || info_ptr == NULL || name == NULL || profile == NULL)
      return;

   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
      png_app_error(png_ptr, "Invalid iCCP compression method");

   /* Set the colorspace first because this validates the profile; do not
    * override previously set app cHRM or gAMA here (because likely as not the
    * application knows better than libpng what the correct values are.)  Pass
    * the info_ptr color_type field to png_colorspace_set_ICC because in the
    * write case it has not yet been stored in png_ptr.
    */
   {
      int result = png_colorspace_set_ICC(png_ptr, &info_ptr->colorspace, name,
         proflen, profile, info_ptr->color_type);

      png_colorspace_sync_info(png_ptr, info_ptr);

      /* Don't do any of the copying if the profile was bad, or inconsistent. */
      if (result == 0)
         return;

      /* But do write the gAMA and cHRM chunks from the profile. */
      info_ptr->colorspace.flags |=
         PNG_COLORSPACE_FROM_gAMA|PNG_COLORSPACE_FROM_cHRM;
   }

   length = strlen(name)+1;
   new_iccp_name = png_voidcast(png_charp, png_malloc_warn(png_ptr, length));

   if (new_iccp_name == NULL)
   {
      png_benign_error(png_ptr, "Insufficient memory to process iCCP chunk");

      return;
   }

   memcpy(new_iccp_name, name, length);
   new_iccp_profile = png_voidcast(png_bytep,
      png_malloc_warn(png_ptr, proflen));

   if (new_iccp_profile == NULL)
   {
      png_free(png_ptr, new_iccp_name);
      png_benign_error(png_ptr,
          "Insufficient memory to process iCCP profile");

      return;
   }

   memcpy(new_iccp_profile, profile, proflen);

   png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, 0);

   info_ptr->iccp_proflen = proflen;
   info_ptr->iccp_name = new_iccp_name;
   info_ptr->iccp_profile = new_iccp_profile;
   info_ptr->free_me |= PNG_FREE_ICCP;
   info_ptr->valid |= PNG_INFO_iCCP;
}

Project: libpng
File: pngrutil.c

png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
/* Note: this does not properly handle profiles that are > 64K under DOS */
{
   png_const_charp errmsg = NULL; /* error message output, or no error */
   int finished = 0; /* crc checked */

   png_debug(1, "in png_handle_iCCP");

   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
      png_chunk_error(png_ptr, "missing IHDR");

   else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
   {
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "out of place");
      return;
   }

   /* Consistent with all the above colorspace handling an obviously *invalid*
    * chunk is just ignored, so does not invalidate the color space.  An
    * alternative is to set the 'invalid' flags at the start of this routine
    * and only clear them in they were not set before and all the tests pass.
    * The minimum 'deflate' stream is assumed to be just the 2 byte header and
    * 4 byte checksum.  The keyword must be at least one character and there is
    * a terminator (0) byte and the compression method.
    */
   if (length < 9)
   {
      png_crc_finish(png_ptr, length);
      png_chunk_benign_error(png_ptr, "too short");
      return;
   }

   /* If a colorspace error has already been output skip this chunk */
   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
   {
      png_crc_finish(png_ptr, length);
      return;
   }

   /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
    * this.
    */
   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0)
   {
      uInt read_length, keyword_length;
      char keyword[81];

      /* Find the keyword; the keyword plus separator and compression method
       * bytes can be at most 81 characters long.
       */
      read_length = 81; /* maximum */
      if (read_length > length)
         read_length = (uInt)length;

      png_crc_read(png_ptr, (png_bytep)keyword, read_length);
      length -= read_length;

      keyword_length = 0;
      while (keyword_length < 80 && keyword_length < read_length &&
         keyword[keyword_length] != 0)
         ++keyword_length;

      /* TODO: make the keyword checking common */
      if (keyword_length >= 1 && keyword_length <= 79)
      {
         /* We only understand '0' compression - deflate - so if we get a
          * different value we can't safely decode the chunk.
          */
         if (keyword_length+1 < read_length &&
            keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE)
         {
            read_length -= keyword_length+2;

            if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK)
            {
               Byte profile_header[132];
               Byte local_buffer[PNG_INFLATE_BUF_SIZE];
               png_alloc_size_t size = (sizeof profile_header);

               png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2);
               png_ptr->zstream.avail_in = read_length;
               (void)png_inflate_read(png_ptr, local_buffer,
                  (sizeof local_buffer), &length, profile_header, &size,
                  0/*finish: don't, because the output is too small*/);

               if (size == 0)
               {
                  /* We have the ICC profile header; do the basic header checks.
                   */
                  const png_uint_32 profile_length =
                     png_get_uint_32(profile_header);

                  if (png_icc_check_length(png_ptr, &png_ptr->colorspace,
                     keyword, profile_length) != 0)
                  {
                     /* The length is apparently ok, so we can check the 132
                      * byte header.
                      */
                     if (png_icc_check_header(png_ptr, &png_ptr->colorspace,
                        keyword, profile_length, profile_header,
                        png_ptr->color_type) != 0)
                     {
                        /* Now read the tag table; a variable size buffer is
                         * needed at this point, allocate one for the whole
                         * profile.  The header check has already validated
                         * that none of these stuff will overflow.
                         */
                        const png_uint_32 tag_count = png_get_uint_32(
                           profile_header+128);
                        png_bytep profile = png_read_buffer(png_ptr,
                           profile_length, 2/*silent*/);

                        if (profile != NULL)
                        {
                           memcpy(profile, profile_header,
                              (sizeof profile_header));

                           size = 12 * tag_count;

                           (void)png_inflate_read(png_ptr, local_buffer,
                              (sizeof local_buffer), &length,
                              profile + (sizeof profile_header), &size, 0);

                           /* Still expect a buffer error because we expect
                            * there to be some tag data!
                            */
                           if (size == 0)
                           {
                              if (png_icc_check_tag_table(png_ptr,
                                 &png_ptr->colorspace, keyword, profile_length,
                                 profile) != 0)
                              {
                                 /* The profile has been validated for basic
                                  * security issues, so read the whole thing in.
                                  */
                                 size = profile_length - (sizeof profile_header)
                                    - 12 * tag_count;

                                 (void)png_inflate_read(png_ptr, local_buffer,
                                    (sizeof local_buffer), &length,
                                    profile + (sizeof profile_header) +
                                    12 * tag_count, &size, 1/*finish*/);

                                 if (length > 0 && !(png_ptr->flags &
                                       PNG_FLAG_BENIGN_ERRORS_WARN))
                                    errmsg = "extra compressed data";

                                 /* But otherwise allow extra data: */
                                 else if (size == 0)
                                 {
                                    if (length > 0)
                                    {
                                       /* This can be handled completely, so
                                        * keep going.
                                        */
                                       png_chunk_warning(png_ptr,
                                          "extra compressed data");
                                    }

                                    png_crc_finish(png_ptr, length);
                                    finished = 1;

#                                   ifdef PNG_sRGB_SUPPORTED
                                    /* Check for a match against sRGB */
                                    png_icc_set_sRGB(png_ptr,
                                       &png_ptr->colorspace, profile,
                                       png_ptr->zstream.adler);
#                                   endif

                                    /* Steal the profile for info_ptr. */
                                    if (info_ptr != NULL)
                                    {
                                       png_free_data(png_ptr, info_ptr,
                                          PNG_FREE_ICCP, 0);

                                       info_ptr->iccp_name = png_voidcast(char*,
                                          png_malloc_base(png_ptr,
                                          keyword_length+1));
                                       if (info_ptr->iccp_name != NULL)
                                       {
                                          memcpy(info_ptr->iccp_name, keyword,
                                             keyword_length+1);
                                          info_ptr->iccp_proflen =
                                             profile_length;
                                          info_ptr->iccp_profile = profile;
                                          png_ptr->read_buffer = NULL; /*steal*/
                                          info_ptr->free_me |= PNG_FREE_ICCP;
                                          info_ptr->valid |= PNG_INFO_iCCP;
                                       }

                                       else
                                       {
                                          png_ptr->colorspace.flags |=
                                             PNG_COLORSPACE_INVALID;
                                          errmsg = "out of memory";
                                       }
                                    }

                                    /* else the profile remains in the read
                                     * buffer which gets reused for subsequent
                                     * chunks.
                                     */

                                    if (info_ptr != NULL)
                                       png_colorspace_sync(png_ptr, info_ptr);

                                    if (errmsg == NULL)
                                    {
                                       png_ptr->zowner = 0;
                                       return;
                                    }
                                 }

                                 else if (size > 0)
                                    errmsg = "truncated";

#ifndef __COVERITY__
                                 else
                                    errmsg = png_ptr->zstream.msg;
#endif
                              }

                              /* else png_icc_check_tag_table output an error */
                           }

                           else /* profile truncated */
                              errmsg = png_ptr->zstream.msg;
                        }

                        else
                           errmsg = "out of memory";
                     }

                     /* else png_icc_check_header output an error */
                  }

                  /* else png_icc_check_length output an error */
               }

               else /* profile truncated */
                  errmsg = png_ptr->zstream.msg;

               /* Release the stream */
               png_ptr->zowner = 0;
            }

            else /* png_inflate_claim failed */
               errmsg = png_ptr->zstream.msg;
         }

         else
            errmsg = "bad compression method"; /* or missing */
      }

      else
         errmsg = "bad keyword";
   }

   else
      errmsg = "too many profiles";

   /* Failure: the reason is in 'errmsg' */
   if (finished == 0)
      png_crc_finish(png_ptr, length);

   png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
   png_colorspace_sync(png_ptr, info_ptr);
   if (errmsg != NULL) /* else already output */
      png_chunk_benign_error(png_ptr, errmsg);
}