tools/ucl/src/n2b_d.c

   1 /* n2b_d.c -- implementation of the NRV2B decompression algorithm
   2
   3    This file is part of the UCL data compression library.
   4
   5    Copyright (C) 1996-2002 Markus Franz Xaver Johannes Oberhumer
   6    All Rights Reserved.
   7
   8    The UCL library is free software; you can redistribute it and/or
   9    modify it under the terms of the GNU General Public License as
  10    published by the Free Software Foundation; either version 2 of
  11    the License, or (at your option) any later version.
  12
  13    The UCL library is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with the UCL library; see the file COPYING.
  20    If not, write to the Free Software Foundation, Inc.,
  21    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  22
  23    Markus F.X.J. Oberhumer
  24    <markus@oberhumer.com>
  25    http://www.oberhumer.com/opensource/ucl/
  26  */
  27
  28
  29 /***********************************************************************
  30 // actual implementation used by a recursive #include
  31 ************************************************************************/
  32
  33 #ifdef getbit
  34
  35 #ifdef SAFE
  36 #define fail(x,r)   if (x) { *dst_len = olen; return r; }
  37 #else
  38 #define fail(x,r)
  39 #endif
  40
  41 {
  42     ucl_uint32 bb = 0;
  43 #ifdef TEST_OVERLAP
  44     ucl_uint ilen = src_off, olen = 0, last_m_off = 1;
  45 #else
  46     ucl_uint ilen = 0, olen = 0, last_m_off = 1;
  47 #endif
  48 #ifdef SAFE
  49     const ucl_uint oend = *dst_len;
  50 #endif
  51     UCL_UNUSED(wrkmem);
  52
  53 #ifdef TEST_OVERLAP
  54     src_len += src_off;
  55     fail(oend >= src_len, UCL_E_OVERLAP_OVERRUN);
  56 #endif
  57
  58     for (;;)
  59     {
  60         ucl_uint m_off, m_len;
  61
  62         while (getbit(bb))
  63         {
  64             fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
  65             fail(olen >= oend, UCL_E_OUTPUT_OVERRUN);
  66 #ifdef TEST_OVERLAP
  67             fail(olen > ilen, UCL_E_OVERLAP_OVERRUN);
  68             olen++; ilen++;
  69 #else
  70             dst[olen++] = src[ilen++];
  71 #endif
  72         }
  73         m_off = 1;
  74         do {
  75             m_off = m_off*2 + getbit(bb);
  76             fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
  77             fail(m_off > UCL_UINT32_C(0xffffff) + 3, UCL_E_LOOKBEHIND_OVERRUN);
  78         } while (!getbit(bb));
  79         if (m_off == 2)
  80         {
  81             m_off = last_m_off;
  82         }
  83         else
  84         {
  85             fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
  86             m_off = (m_off-3)*256 + src[ilen++];
  87             if (m_off == UCL_UINT32_C(0xffffffff))
  88                 break;
  89             last_m_off = ++m_off;
  90         }
  91         m_len = getbit(bb);
  92         m_len = m_len*2 + getbit(bb);
  93         if (m_len == 0)
  94         {
  95             m_len++;
  96             do {
  97                 m_len = m_len*2 + getbit(bb);
  98                 fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
  99                 fail(m_len >= oend, UCL_E_OUTPUT_OVERRUN);
 100             } while (!getbit(bb));
 101             m_len += 2;
 102         }
 103         m_len += (m_off > 0xd00);
 104         fail(olen + m_len > oend, UCL_E_OUTPUT_OVERRUN);
 105         fail(m_off > olen, UCL_E_LOOKBEHIND_OVERRUN);
 106 #ifdef TEST_OVERLAP
 107         olen += m_len + 1;
 108         fail(olen > ilen, UCL_E_OVERLAP_OVERRUN);
 109 #else
 110         {
 111             const ucl_byte *m_pos;
 112             m_pos = dst + olen - m_off;
 113             dst[olen++] = *m_pos++;
 114             do dst[olen++] = *m_pos++; while (--m_len > 0);
 115         }
 116 #endif
 117     }
 118     *dst_len = olen;
 119     return ilen == src_len ? UCL_E_OK : (ilen < src_len ? UCL_E_INPUT_NOT_CONSUMED : UCL_E_INPUT_OVERRUN);
 120 }
 121
 122 #undef fail
 123
 124 #endif /* getbit */
 125
 126
 127 /***********************************************************************
 128 // decompressor entries for the different bit-buffer sizes
 129 ************************************************************************/
 130
 131 #ifndef getbit
 132
 133 #include <ucl/ucl.h>
 134 #include "ucl_conf.h"
 135 #include "getbit.h"
 136
 137
 138 UCL_PUBLIC(int)
 139 ucl_nrv2b_decompress_8          ( const ucl_bytep src, ucl_uint  src_len,
 140                                         ucl_bytep dst, ucl_uintp dst_len,
 141                                         ucl_voidp wrkmem )
 142 {
 143 #define getbit(bb)      getbit_8(bb,src,ilen)
 144 #include "n2b_d.c"
 145 #undef getbit
 146 }
 147
 148
 149 UCL_PUBLIC(int)
 150 ucl_nrv2b_decompress_le16       ( const ucl_bytep src, ucl_uint  src_len,
 151                                         ucl_bytep dst, ucl_uintp dst_len,
 152                                         ucl_voidp wrkmem )
 153 {
 154 #define getbit(bb)      getbit_le16(bb,src,ilen)
 155 #include "n2b_d.c"
 156 #undef getbit
 157 }
 158
 159
 160 UCL_PUBLIC(int)
 161 ucl_nrv2b_decompress_le32       ( const ucl_bytep src, ucl_uint  src_len,
 162                                         ucl_bytep dst, ucl_uintp dst_len,
 163                                         ucl_voidp wrkmem )
 164 {
 165     unsigned bc = 0;
 166 #define getbit(bb)      getbit_le32(bb,bc,src,ilen)
 167 #include "n2b_d.c"
 168 #undef getbit
 169 }
 170
 171
 172 #endif /* !getbit */
 173
 174
 175 /*
 176 vi:ts=4:et
 177 */
 178