text: /* minigzip.c -- simulate gzip using the zlib compression library
   * Copyright (C) 1995-2002 Jean-loup Gailly.
   * For conditions of distribution and use, see copyright notice in zlib.h
   */
  
  /*
   * minigzip is a minimal implementation of the gzip utility. This is
   * only an example of using zlib and isn't meant to replace the
   * full-featured gzip. No attempt is made to deal with file systems
   * limiting names to 14 or 8+3 characters, etc... Error checking is
   * very limited. So use minigzip only for testing; use gzip for the
   * real thing. On MSDOS, use only on file names without extension
   * or in pipe mode.
   */
  
  /* @(#) $Id: minigzip.c,v 1.1.1.1 2005/04/24 21:39:42 giles Exp $ */
  
  #include <stdio.h>
  #include "zlib.h"
  
  #ifdef STDC
  #  include <string.h>
  #  include <stdlib.h>
  #else
     extern void exit  OF((int));
  #endif
  
  #ifdef USE_MMAP
  #  include <sys/types.h>
  #  include <sys/mman.h>
  #  include <sys/stat.h>
  #endif
  
  #if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
  #  include <fcntl.h>
  #  include <io.h>
  #  define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
  #else
  #  define SET_BINARY_MODE(file)
  #endif
  
  #ifdef VMS
  #  define unlink delete
  #  define GZ_SUFFIX "-gz"
  #endif
  #ifdef RISCOS
  #  define unlink remove
  #  define GZ_SUFFIX "-gz"
  #  define fileno(file) file->__file
  #endif
  #if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
  #  include <unix.h> /* for fileno */
  #endif
  
  #ifndef WIN32 /* unlink already in stdio.h for WIN32 */
    extern int unlink OF((const char *));
  #endif
  
  #ifndef GZ_SUFFIX
  #  define GZ_SUFFIX ".gz"
  #endif
  #define SUFFIX_LEN (sizeof(GZ_SUFFIX)-1)
  
  #define BUFLEN      16384
  #define MAX_NAME_LEN 1024
  
  #ifdef MAXSEG_64K
  #  define local static
     /* Needed for systems with limitation on stack size. */
  #else
  #  define local
  #endif
  
  char *prog;
  
  void error            OF((const char *msg));
  void gz_compress      OF((FILE   *in, gzFile out));
  #ifdef USE_MMAP
  int  gz_compress_mmap OF((FILE   *in, gzFile out));
  #endif
  void gz_uncompress    OF((gzFile in, FILE   *out));
  void file_compress    OF((char  *file, char *mode));
  void file_uncompress  OF((char  *file));
  int  main             OF((int argc, char *argv[]));
  
  /* ===========================================================================
   * Display error message and exit
   */
  void error(msg)
      const char *msg;
  {
      fprintf(stderr, "%s: %s\n", prog, msg);
      exit(1);
  }
  
  /* ===========================================================================
   * Compress input to output then close both files.
   */
  
  void gz_compress(in, out)
      FILE   *in;
      gzFile out;
  {
      local char buf[BUFLEN];
      int len;
      int err;
  
  #ifdef USE_MMAP
      /* Try first compressing with mmap. If mmap fails (minigzip used in a
       * pipe), use the normal fread loop.
       */
      if (gz_compress_mmap(in, out) == Z_OK) return;
  #endif
      for (;;) {
          len = (int)fread(buf, 1, sizeof(buf), in);
          if (ferror(in)) {
              perror("fread");
              exit(1);
          }
          if (len == 0) break;
  
          if (gzwrite(out, buf, (unsigned)len) != len) error(gzerror(out, &err));
      }
      fclose(in);
      if (gzclose(out) != Z_OK) error("failed gzclose");
  }
  
  #ifdef USE_MMAP /* MMAP version, Miguel Albrecht <malbrech@eso.org> */
  
  /* Try compressing the input file at once using mmap. Return Z_OK if
   * if success, Z_ERRNO otherwise.
   */
  int gz_compress_mmap(in, out)
      FILE   *in;
      gzFile out;
  {
      int len;
      int err;
      int ifd = fileno(in);
      caddr_t buf;    /* mmap'ed buffer for the entire input file */
      off_t buf_len;  /* length of the input file */
      struct stat sb;
  
      /* Determine the size of the file, needed for mmap: */
      if (fstat(ifd, &sb) < 0) return Z_ERRNO;
      buf_len = sb.st_size;
      if (buf_len <= 0) return Z_ERRNO;
  
      /* Now do the actual mmap: */
      buf = mmap((caddr_t) 0, buf_len, PROT_READ, MAP_SHARED, ifd, (off_t)0);
      if (buf == (caddr_t)(-1)) return Z_ERRNO;
  
      /* Compress the whole file at once: */
      len = gzwrite(out, (char *)buf, (unsigned)buf_len);
  
      if (len != (int)buf_len) error(gzerror(out, &err));
  
      munmap(buf, buf_len);
      fclose(in);
      if (gzclose(out) != Z_OK) error("failed gzclose");
      return Z_OK;
  }
  #endif /* USE_MMAP */
  
  /* ===========================================================================
   * Uncompress input to output then close both files.
   */
  void gz_uncompress(in, out)
      gzFile in;
      FILE   *out;
  {
      local char buf[BUFLEN];
      int len;
      int err;
  
      for (;;) {
          len = gzread(in, buf, sizeof(buf));
          if (len < 0) error (gzerror(in, &err));
          if (len == 0) break;
  
          if ((int)fwrite(buf, 1, (unsigned)len, out) != len) {
              error("failed fwrite");
          }
      }
      if (fclose(out)) error("failed fclose");
  
      if (gzclose(in) != Z_OK) error("failed gzclose");
  }
  
  
  /* ===========================================================================
   * Compress the given file: create a corresponding .gz file and remove the
   * original.
   */
  void file_compress(file, mode)
      char  *file;
      char  *mode;
  {
      local char outfile[MAX_NAME_LEN];
      FILE  *in;
      gzFile out;
  
      strcpy(outfile, file);
      strcat(outfile, GZ_SUFFIX);
  
      in = fopen(file, "rb");
      if (in == NULL) {
          perror(file);
          exit(1);
      }
      out = gzopen(outfile, mode);
      if (out == NULL) {
          fprintf(stderr, "%s: can't gzopen %s\n", prog, outfile);
          exit(1);
      }
      gz_compress(in, out);
  
      unlink(file);
  }
  
  
  /* ===========================================================================
   * Uncompress the given file and remove the original.
   */
  void file_uncompress(file)
      char  *file;
  {
      local char buf[MAX_NAME_LEN];
      char *infile, *outfile;
      FILE  *out;
      gzFile in;
      uInt len = (uInt)strlen(file);
  
      strcpy(buf, file);
  
      if (len > SUFFIX_LEN && strcmp(file+len-SUFFIX_LEN, GZ_SUFFIX) == 0) {
          infile = file;
          outfile = buf;
          outfile[len-3] = '\0';
      } else {
          outfile = file;
          infile = buf;
          strcat(infile, GZ_SUFFIX);
      }
      in = gzopen(infile, "rb");
      if (in == NULL) {
          fprintf(stderr, "%s: can't gzopen %s\n", prog, infile);
          exit(1);
      }
      out = fopen(outfile, "wb");
      if (out == NULL) {
          perror(file);
          exit(1);
      }
  
      gz_uncompress(in, out);
  
      unlink(infile);
  }
  
  
  /* ===========================================================================
   * Usage:  minigzip [-d] [-f] [-h] [-r] [-1 to -9] [files...]
   *   -d : decompress
   *   -f : compress with Z_FILTERED
   *   -h : compress with Z_HUFFMAN_ONLY
   *   -r : compress with Z_RLE
   *   -1 to -9 : compression level
   */
  
  int main(argc, argv)
      int argc;
      char *argv[];
  {
      int uncompr = 0;
      gzFile file;
      char outmode[20];
  
      strcpy(outmode, "wb6 ");
  
      prog = argv[0];
      argc--, argv++;
  
      while (argc > 0) {
        if (strcmp(*argv, "-d") == 0)
          uncompr = 1;
        else if (strcmp(*argv, "-f") == 0)
          outmode[3] = 'f';
        else if (strcmp(*argv, "-h") == 0)
          outmode[3] = 'h';
        else if (strcmp(*argv, "-r") == 0)
          outmode[3] = 'R';
        else if ((*argv)[0] == '-' && (*argv)[1] >= '1' && (*argv)[1] <= '9' &&
                 (*argv)[2] == 0)
          outmode[2] = (*argv)[1];
        else
          break;
        argc--, argv++;
      }
      if (argc == 0) {
          SET_BINARY_MODE(stdin);
          SET_BINARY_MODE(stdout);
          if (uncompr) {
              file = gzdopen(fileno(stdin), "rb");
              if (file == NULL) error("can't gzdopen stdin");
              gz_uncompress(file, stdout);
          } else {
              file = gzdopen(fileno(stdout), outmode);
              if (file == NULL) error("can't gzdopen stdout");
              gz_compress(stdin, file);
          }
      } else {
          do {
              if (uncompr) {
                  file_uncompress(*argv);
              } else {
                  file_compress(*argv, outmode);
              }
          } while (argv++, --argc);
      }
      return 0;
  }
  