text: /* n2b_d.c -- implementation of the NRV2B decompression algorithm
  
     This file is part of the UCL data compression library.
  
     Copyright (C) 1996-2004 Markus Franz Xaver Johannes Oberhumer
     All Rights Reserved.
  
     The UCL library is free software; you can redistribute it and/or
     modify it under the terms of the GNU General Public License as
     published by the Free Software Foundation; either version 2 of
     the License, or (at your option) any later version.
  
     The UCL library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
  
     You should have received a copy of the GNU General Public License
     along with the UCL library; see the file COPYING.
     If not, write to the Free Software Foundation, Inc.,
     59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  
     Markus F.X.J. Oberhumer
     <markus@oberhumer.com>
     http://www.oberhumer.com/opensource/ucl/
   */
  
  
  /***********************************************************************
  // actual implementation used by a recursive #include
  ************************************************************************/
  
  #ifdef getbit
  
  #ifdef SAFE
  #define fail(x,r)   if (x) { *dst_len = olen; return r; }
  #else
  #define fail(x,r)
  #endif
  
  {
      ucl_uint32 bb = 0;
  #ifdef TEST_OVERLAP
      ucl_uint ilen = src_off, olen = 0, last_m_off = 1;
  #else
      ucl_uint ilen = 0, olen = 0, last_m_off = 1;
  #endif
  #ifdef SAFE
      const ucl_uint oend = *dst_len;
  #endif
      ACC_UNUSED(wrkmem);
  
  #ifdef TEST_OVERLAP
      src_len += src_off;
      fail(oend >= src_len, UCL_E_OVERLAP_OVERRUN);
  #endif
  
      for (;;)
      {
          ucl_uint m_off, m_len;
  
          while (getbit(bb))
          {
              fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
              fail(olen >= oend, UCL_E_OUTPUT_OVERRUN);
  #ifdef TEST_OVERLAP
              fail(olen > ilen, UCL_E_OVERLAP_OVERRUN);
              olen++; ilen++;
  #else
              dst[olen++] = src[ilen++];
  #endif
          }
          m_off = 1;
          do {
              m_off = m_off*2 + getbit(bb);
              fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
              fail(m_off > UCL_UINT32_C(0xffffff) + 3, UCL_E_LOOKBEHIND_OVERRUN);
          } while (!getbit(bb));
          if (m_off == 2)
          {
              m_off = last_m_off;
          }
          else
          {
              fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
              m_off = (m_off-3)*256 + src[ilen++];
              if (m_off == UCL_UINT32_C(0xffffffff))
                  break;
              last_m_off = ++m_off;
          }
          m_len = getbit(bb);
          m_len = m_len*2 + getbit(bb);
          if (m_len == 0)
          {
              m_len++;
              do {
                  m_len = m_len*2 + getbit(bb);
                  fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
                  fail(m_len >= oend, UCL_E_OUTPUT_OVERRUN);
              } while (!getbit(bb));
              m_len += 2;
          }
          m_len += (m_off > 0xd00);
          fail(olen + m_len > oend, UCL_E_OUTPUT_OVERRUN);
          fail(m_off > olen, UCL_E_LOOKBEHIND_OVERRUN);
  #ifdef TEST_OVERLAP
          olen += m_len + 1;
          fail(olen > ilen, UCL_E_OVERLAP_OVERRUN);
  #else
          {
              const ucl_bytep m_pos;
              m_pos = dst + olen - m_off;
              dst[olen++] = *m_pos++;
              do dst[olen++] = *m_pos++; while (--m_len > 0);
          }
  #endif
      }
      *dst_len = olen;
      return ilen == src_len ? UCL_E_OK : (ilen < src_len ? UCL_E_INPUT_NOT_CONSUMED : UCL_E_INPUT_OVERRUN);
  }
  
  #undef fail
  
  #endif /* getbit */
  
  
  /***********************************************************************
  // decompressor entries for the different bit-buffer sizes
  ************************************************************************/
  
  #ifndef getbit
  
  #include "ucl_conf.h"
  #include <ucl/ucl.h>
  #include "getbit.h"
  
  
  UCL_PUBLIC(int)
  ucl_nrv2b_decompress_8          ( const ucl_bytep src, ucl_uint  src_len,
                                          ucl_bytep dst, ucl_uintp dst_len,
                                          ucl_voidp wrkmem )
  {
  #define getbit(bb)      getbit_8(bb,src,ilen)
  #include "n2b_d.c"
  #undef getbit
  }
  
  
  UCL_PUBLIC(int)
  ucl_nrv2b_decompress_le16       ( const ucl_bytep src, ucl_uint  src_len,
                                          ucl_bytep dst, ucl_uintp dst_len,
                                          ucl_voidp wrkmem )
  {
  #define getbit(bb)      getbit_le16(bb,src,ilen)
  #include "n2b_d.c"
  #undef getbit
  }
  
  
  UCL_PUBLIC(int)
  ucl_nrv2b_decompress_le32       ( const ucl_bytep src, ucl_uint  src_len,
                                          ucl_bytep dst, ucl_uintp dst_len,
                                          ucl_voidp wrkmem )
  {
      unsigned bc = 0;
  #define getbit(bb)      getbit_le32(bb,bc,src,ilen)
  #include "n2b_d.c"
  #undef getbit
  }
  
  
  #endif /* !getbit */
  
  
  /*
  vi:ts=4:et
  */
  
  