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  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) 1996-2004 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.     ACC_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_bytep 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_conf.h"
  139. #include <ucl/ucl.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.  
  184.