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-rw-r--r--tools/ucl/src/n2b_d.c178
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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
138UCL_PUBLIC(int)
139ucl_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
149UCL_PUBLIC(int)
150ucl_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
160UCL_PUBLIC(int)
161ucl_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/*
176vi:ts=4:et
177*/
178