1/*
2 * librd - Rapid Development C library
3 *
4 * Copyright (c) 2012, Magnus Edenhill
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright notice,
11 * this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright notice,
13 * this list of conditions and the following disclaimer in the documentation
14 * and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include "rd.h"
30#include "rdgz.h"
31
32#include <zlib.h>
33
34
35#define RD_GZ_CHUNK 262144
36
37void *rd_gz_decompress (const void *compressed, int compressed_len,
38 uint64_t *decompressed_lenp) {
39 int pass = 1;
40 char *decompressed = NULL;
41
42 /* First pass (1): calculate decompressed size.
43 * (pass-1 is skipped if *decompressed_lenp is
44 * non-zero).
45 * Second pass (2): perform actual decompression.
46 */
47
48 if (*decompressed_lenp != 0LLU)
49 pass++;
50
51 for (; pass <= 2 ; pass++) {
52 z_stream strm = RD_ZERO_INIT;
53 gz_header hdr;
54 char buf[512];
55 char *p;
56 int len;
57 int r;
58
59 if ((r = inflateInit2(&strm, 15+32)) != Z_OK)
60 goto fail;
61
62 strm.next_in = (void *)compressed;
63 strm.avail_in = compressed_len;
64
65 if ((r = inflateGetHeader(&strm, &hdr)) != Z_OK) {
66 inflateEnd(&strm);
67 goto fail;
68 }
69
70 if (pass == 1) {
71 /* Use dummy output buffer */
72 p = buf;
73 len = sizeof(buf);
74 } else {
75 /* Use real output buffer */
76 p = decompressed;
77 len = (int)*decompressed_lenp;
78 }
79
80 do {
81 strm.next_out = (unsigned char *)p;
82 strm.avail_out = len;
83
84 r = inflate(&strm, Z_NO_FLUSH);
85 switch (r) {
86 case Z_STREAM_ERROR:
87 case Z_NEED_DICT:
88 case Z_DATA_ERROR:
89 case Z_MEM_ERROR:
90 inflateEnd(&strm);
91 goto fail;
92 }
93
94 if (pass == 2) {
95 /* Advance output pointer (in pass 2). */
96 p += len - strm.avail_out;
97 len -= len - strm.avail_out;
98 }
99
100 } while (strm.avail_out == 0 && r != Z_STREAM_END);
101
102
103 if (pass == 1) {
104 *decompressed_lenp = strm.total_out;
105 if (!(decompressed = malloc((size_t)(*decompressed_lenp)+1))) {
106 inflateEnd(&strm);
107 return NULL;
108 }
109 /* For convenience of the caller we nul-terminate
110 * the buffer. If it happens to be a string there
111 * is no need for extra copies. */
112 decompressed[*decompressed_lenp] = '\0';
113 }
114
115 inflateEnd(&strm);
116 }
117
118 return decompressed;
119
120fail:
121 if (decompressed)
122 free(decompressed);
123 return NULL;
124}
125