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uncompr.c
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1 /* uncompr.c -- decompress a memory buffer
2  * Copyright (C) 1995-2003, 2010, 2014, 2016 Jean-loup Gailly, Mark Adler
3  * For conditions of distribution and use, see copyright notice in zlib.h
4  */
5 
6 /* @(#) $Id$ */
7 
8 #define ZLIB_INTERNAL
9 #include "zlib.h"
10 
11 /* ===========================================================================
12  Decompresses the source buffer into the destination buffer. *sourceLen is
13  the byte length of the source buffer. Upon entry, *destLen is the total size
14  of the destination buffer, which must be large enough to hold the entire
15  uncompressed data. (The size of the uncompressed data must have been saved
16  previously by the compressor and transmitted to the decompressor by some
17  mechanism outside the scope of this compression library.) Upon exit,
18  *destLen is the size of the decompressed data and *sourceLen is the number
19  of source bytes consumed. Upon return, source + *sourceLen points to the
20  first unused input byte.
21 
22  uncompress returns Z_OK if success, Z_MEM_ERROR if there was not enough
23  memory, Z_BUF_ERROR if there was not enough room in the output buffer, or
24  Z_DATA_ERROR if the input data was corrupted, including if the input data is
25  an incomplete zlib stream.
26 */
27 int ZEXPORT uncompress2 (dest, destLen, source, sourceLen)
28  Bytef *dest;
29  uLongf *destLen;
30  const Bytef *source;
31  uLong *sourceLen;
32 {
33  z_stream stream;
34  int err;
35  const uInt max = (uInt)-1;
36  uLong len, left;
37  Byte buf[1]; /* for detection of incomplete stream when *destLen == 0 */
38 
39  len = *sourceLen;
40  if (*destLen) {
41  left = *destLen;
42  *destLen = 0;
43  }
44  else {
45  left = 1;
46  dest = buf;
47  }
48 
49  stream.next_in = (z_const Bytef *)source;
50  stream.avail_in = 0;
51  stream.zalloc = (alloc_func)0;
52  stream.zfree = (free_func)0;
53  stream.opaque = (voidpf)0;
54 
55  err = inflateInit(&stream);
56  if (err != Z_OK) return err;
57 
58  stream.next_out = dest;
59  stream.avail_out = 0;
60 
61  do {
62  if (stream.avail_out == 0) {
63  stream.avail_out = left > (uLong)max ? max : (uInt)left;
64  left -= stream.avail_out;
65  }
66  if (stream.avail_in == 0) {
67  stream.avail_in = len > (uLong)max ? max : (uInt)len;
68  len -= stream.avail_in;
69  }
70  err = inflate(&stream, Z_NO_FLUSH);
71  } while (err == Z_OK);
72 
73  *sourceLen -= len + stream.avail_in;
74  if (dest != buf)
75  *destLen = stream.total_out;
76  else if (stream.total_out && err == Z_BUF_ERROR)
77  left = 1;
78 
79  inflateEnd(&stream);
80  return err == Z_STREAM_END ? Z_OK :
81  err == Z_NEED_DICT ? Z_DATA_ERROR :
82  err == Z_BUF_ERROR && left + stream.avail_out ? Z_DATA_ERROR :
83  err;
84 }
85 
86 int ZEXPORT uncompress (dest, destLen, source, sourceLen)
87  Bytef *dest;
88  uLongf *destLen;
89  const Bytef *source;
90  uLong sourceLen;
91 {
92  return uncompress2(dest, destLen, source, &sourceLen);
93 }
Bytef
Byte FAR Bytef
Definition: zconf.h:400
Z_BUF_ERROR
#define Z_BUF_ERROR
Definition: zlib.h:184
uLong
unsigned long uLong
Definition: zconf.h:394
uncompress2
int ZEXPORT uncompress2(Bytef *dest, uLongf *destLen, const Bytef *source, uLong *sourceLen)
Definition: uncompr.c:27
z_stream_s::zfree
free_func zfree
Definition: zlib.h:99
Z_DATA_ERROR
#define Z_DATA_ERROR
Definition: zlib.h:182
z_stream_s::avail_in
uInt avail_in
Definition: zlib.h:88
Z_NEED_DICT
#define Z_NEED_DICT
Definition: zlib.h:179
uncompress
int ZEXPORT uncompress(Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen)
Definition: uncompr.c:86
inflateInit
#define inflateInit(strm)
Definition: zlib.h:1795
voidpf
Byte FAR * voidpf
Definition: zconf.h:413
z_stream_s::avail_out
uInt avail_out
Definition: zlib.h:92
Byte
unsigned char Byte
Definition: zconf.h:391
z_const
#define z_const
Definition: zconf.h:237
Z_NO_FLUSH
#define Z_NO_FLUSH
Definition: zlib.h:168
Z_OK
#define Z_OK
Definition: zlib.h:177
z_stream_s::zalloc
alloc_func zalloc
Definition: zlib.h:98
uLongf
uLong FAR uLongf
Definition: zconf.h:405
Z_STREAM_END
#define Z_STREAM_END
Definition: zlib.h:178
z_stream_s
Definition: zlib.h:86
z_stream_s::next_in
z_const Bytef * next_in
Definition: zlib.h:87
z_stream_s::next_out
Bytef * next_out
Definition: zlib.h:91
ZEXPORT
#define ZEXPORT
Definition: zconf.h:380
uInt
unsigned int uInt
Definition: zconf.h:393
inflateEnd
int ZEXPORT inflateEnd(z_streamp strm)
Definition: inflate.c:1277
z_stream_s::opaque
voidpf opaque
Definition: zlib.h:100
inflate
int ZEXPORT inflate(z_streamp strm, int flush)
Definition: inflate.c:622
z_stream_s::total_out
uLong total_out
Definition: zlib.h:93
zlib.h