tools/ucl/src/n2d_d.c

   1 /* n2d_d.c -- implementation of the NRV2D 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         for (;;)
  75         {
  76             m_off = m_off*2 + getbit(bb);
  77             fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
  78             fail(m_off > UCL_UINT32_C(0xffffff) + 3, UCL_E_LOOKBEHIND_OVERRUN);
  79             if (getbit(bb)) break;
  80             m_off = (m_off-1)*2 + getbit(bb);
  81         }
  82         if (m_off == 2)
  83         {
  84             m_off = last_m_off;
  85             m_len = getbit(bb);
  86         }
  87         else
  88         {
  89             fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
  90             m_off = (m_off-3)*256 + src[ilen++];
  91             if (m_off == UCL_UINT32_C(0xffffffff))
  92                 break;
  93             m_len = (m_off ^ UCL_UINT32_C(0xffffffff)) & 1;
  94             m_off >>= 1;
  95             last_m_off = ++m_off;
  96         }
  97         m_len = m_len*2 + getbit(bb);
  98         if (m_len == 0)
  99         {
 100             m_len++;
 101             do {
 102                 m_len = m_len*2 + getbit(bb);
 103                 fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
 104                 fail(m_len >= oend, UCL_E_OUTPUT_OVERRUN);
 105             } while (!getbit(bb));
 106             m_len += 2;
 107         }
 108         m_len += (m_off > 0x500);
 109         fail(olen + m_len > oend, UCL_E_OUTPUT_OVERRUN);
 110         fail(m_off > olen, UCL_E_LOOKBEHIND_OVERRUN);
 111 #ifdef TEST_OVERLAP
 112         olen += m_len + 1;
 113         fail(olen > ilen, UCL_E_OVERLAP_OVERRUN);
 114 #else
 115         {
 116             const ucl_byte *m_pos;
 117             m_pos = dst + olen - m_off;
 118             dst[olen++] = *m_pos++;
 119             do dst[olen++] = *m_pos++; while (--m_len > 0);
 120         }
 121 #endif
 122     }
 123     *dst_len = olen;
 124     return ilen == src_len ? UCL_E_OK : (ilen < src_len ? UCL_E_INPUT_NOT_CONSUMED : UCL_E_INPUT_OVERRUN);
 125 }
 126
 127 #undef fail
 128
 129 #endif /* getbit */
 130
 131
 132 /***********************************************************************
 133 // decompressor entries for the different bit-buffer sizes
 134 ************************************************************************/
 135
 136 #ifndef getbit
 137
 138 #include <ucl/ucl.h>
 139 #include "ucl_conf.h"
 140 #include "getbit.h"
 141
 142
 143 UCL_PUBLIC(int)
 144 ucl_nrv2d_decompress_8          ( const ucl_bytep src, ucl_uint  src_len,
 145                                         ucl_bytep dst, ucl_uintp dst_len,
 146                                         ucl_voidp wrkmem )
 147 {
 148 #define getbit(bb)      getbit_8(bb,src,ilen)
 149 #include "n2d_d.c"
 150 #undef getbit
 151 }
 152
 153
 154 UCL_PUBLIC(int)
 155 ucl_nrv2d_decompress_le16       ( const ucl_bytep src, ucl_uint  src_len,
 156                                         ucl_bytep dst, ucl_uintp dst_len,
 157                                         ucl_voidp wrkmem )
 158 {
 159 #define getbit(bb)      getbit_le16(bb,src,ilen)
 160 #include "n2d_d.c"
 161 #undef getbit
 162 }
 163
 164
 165 UCL_PUBLIC(int)
 166 ucl_nrv2d_decompress_le32       ( const ucl_bytep src, ucl_uint  src_len,
 167                                         ucl_bytep dst, ucl_uintp dst_len,
 168                                         ucl_voidp wrkmem )
 169 {
 170     unsigned bc = 0;
 171 #define getbit(bb)      getbit_le32(bb,bc,src,ilen)
 172 #include "n2d_d.c"
 173 #undef getbit
 174 }
 175
 176
 177 #endif /* !getbit */
 178
 179
 180 /*
 181 vi:ts=4:et
 182 */
 183