w32tex
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Decompressor.cpp
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1 /* GRAPHITE2 LICENSING
2 
3  Copyright 2015, SIL International
4  All rights reserved.
5 
6  This library is free software; you can redistribute it and/or modify
7  it under the terms of the GNU Lesser General Public License as published
8  by the Free Software Foundation; either version 2.1 of License, or
9  (at your option) any later version.
10 
11  This program is distributed in the hope that it will be useful,
12  but WITHOUT ANY WARRANTY; without even the implied warranty of
13  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  Lesser General Public License for more details.
15 
16  You should also have received a copy of the GNU Lesser General Public
17  License along with this library in the file named "LICENSE".
18  If not, write to the Free Software Foundation, 51 Franklin Street,
19  Suite 500, Boston, MA 02110-1335, USA or visit their web page on the
20  internet at http://www.fsf.org/licenses/lgpl.html.
21 
22 Alternatively, the contents of this file may be used under the terms of the
23 Mozilla Public License (http://mozilla.org/MPL) or the GNU General Public
24 License, as published by the Free Software Foundation, either version 2
25 of the License or (at your option) any later version.
26 */
27 #include <cassert>
28 
29 #include "inc/Decompressor.h"
30 #include "inc/Compression.h"
31 
32 using namespace lz4;
33 
34 namespace {
35 
36 inline
37 u32 read_literal(u8 const * &s, u8 const * const e, u32 l) {
38  if (l == 15 && s != e)
39  {
40  u8 b = 0;
41  do { l += b = *s++; } while(b==0xff && s != e);
42  }
43  return l;
44 }
45 
46 bool read_sequence(u8 const * &src, u8 const * const end, u8 const * &literal,
47  u32 & literal_len, u32 & match_len, u32 & match_dist)
48 {
49  u8 const token = *src++;
50 
51  literal_len = read_literal(src, end, token >> 4);
52  literal = src;
53  src += literal_len;
54 
55  // Normal exit for end of stream, wrap arround check and parital match check.
56  if (src > end - sizeof(u16) || src < literal)
57  return false;
58 
59  match_dist = *src++;
60  match_dist |= *src++ << 8;
61  match_len = read_literal(src, end, token & 0xf) + MINMATCH;
62 
63  // Malformed stream check.
64  return src <= end-MINCODA;
65 }
66 
67 }
68 
69 int lz4::decompress(void const *in, size_t in_size, void *out, size_t out_size)
70 {
71  if (out_size <= in_size || in_size < MINSRCSIZE)
72  return -1;
73 
74  u8 const * src = static_cast<u8 const *>(in),
75  * literal = 0,
76  * const src_end = src + in_size;
77 
78  u8 * dst = static_cast<u8*>(out),
79  * const dst_end = dst + out_size;
80 
81  // Check the in and out size hasn't wrapped around.
82  if (src >= src_end || dst >= dst_end)
83  return -1;
84 
85  u32 literal_len = 0,
86  match_len = 0,
87  match_dist = 0;
88 
89  while (read_sequence(src, src_end, literal, literal_len, match_len,
90  match_dist))
91  {
92  if (literal_len != 0)
93  {
94  // Copy in literal. At this point the a minimal literal + minminal
95  // match plus the coda (1 + 2 + 5) must be 8 bytes or more allowing
96  // us to remain within the src buffer for an overrun_copy on
97  // machines upto 64 bits.
98  if (align(literal_len) > out_size)
99  return -1;
100  dst = overrun_copy(dst, literal, literal_len);
101  out_size -= literal_len;
102  }
103 
104  // Copy, possibly repeating, match from earlier in the
105  // decoded output.
106  u8 const * const pcpy = dst - match_dist;
107  if (pcpy < static_cast<u8*>(out)
108  || match_len > unsigned(out_size - LASTLITERALS)
109  // Wrap around checks:
110  || out_size < LASTLITERALS || pcpy >= dst)
111  return -1;
112  if (dst > pcpy+sizeof(unsigned long)
113  && align(match_len) <= out_size)
114  dst = overrun_copy(dst, pcpy, match_len);
115  else
116  dst = safe_copy(dst, pcpy, match_len);
117  out_size -= match_len;
118  }
119 
120  if (literal > src_end - literal_len || literal_len > out_size)
121  return -1;
122  dst = fast_copy(dst, literal, literal_len);
123 
124  return int(dst - (u8*)out);
125 }
#define b
Definition: jpegint.h:372
#define s
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FILE * out
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#define u16
Definition: jbig2arith.cc:25
#define u32
Definition: jbig2arith.cc:24
#define u8
Definition: jbig2arith.cc:26
int decompress(void const *in, size_t in_size, void *out, size_t out_size)
#define align(x, k)
Definition: obcommon.h:49
static unsigned read_sequence(OTF *otf, OTF_Stream *stream, long offset, OTF_Sequence **seq)
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ShellFileEnvironment e
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static FILE * in
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return() int(((double) *(font_tbl[cur_fnt].wtbl+(int)(*(font_tbl[cur_fnt].char_wi+(int)(ch - font_tbl[cur_fnt].char_f)% 256)))/(double)(1L<< 20)) *(double) font_tbl[cur_fnt].scale)
#define end(cp)
Definition: zic.c:71