summaryrefslogtreecommitdiff
path: root/zlib.c
blob: fe537e3ff69880f2d5c69575c2c2575bac503323 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
/*
 * zlib wrappers to make sure we don't silently miss errors
 * at init time.
 */
#include "cache.h"
 
static const char *zerr_to_string(int status)
{
	switch (status) {
	case Z_MEM_ERROR:
		return "out of memory";
	case Z_VERSION_ERROR:
		return "wrong version";
	case Z_NEED_DICT:
		return "needs dictionary";
	case Z_DATA_ERROR:
		return "data stream error";
	case Z_STREAM_ERROR:
		return "stream consistency error";
	default:
		return "unknown error";
	}
}
 
/*
 * avail_in and avail_out in zlib are counted in uInt, which typically
 * limits the size of the buffer we can use to 4GB when interacting
 * with zlib in a single call to inflate/deflate.
 */
#define ZLIB_BUF_MAX ((uInt)-1)
static inline uInt zlib_buf_cap(unsigned long len)
{
	if (ZLIB_BUF_MAX < len)
		die("working buffer for zlib too large");
	return len;
}
 
static void zlib_pre_call(git_zstream *s)
{
	s->z.next_in = s->next_in;
	s->z.next_out = s->next_out;
	s->z.total_in = s->total_in;
	s->z.total_out = s->total_out;
	s->z.avail_in = zlib_buf_cap(s->avail_in);
	s->z.avail_out = zlib_buf_cap(s->avail_out);
}
 
static void zlib_post_call(git_zstream *s)
{
	s->next_in = s->z.next_in;
	s->next_out = s->z.next_out;
	s->total_in = s->z.total_in;
	s->total_out = s->z.total_out;
	s->avail_in = s->z.avail_in;
	s->avail_out = s->z.avail_out;
}
 
void git_inflate_init(git_zstream *strm)
{
	int status;
 
	zlib_pre_call(strm);
	status = inflateInit(&strm->z);
	zlib_post_call(strm);
	if (status == Z_OK)
		return;
	die("inflateInit: %s (%s)", zerr_to_string(status),
	    strm->z.msg ? strm->z.msg : "no message");
}
 
void git_inflate_init_gzip_only(git_zstream *strm)
{
	/*
	 * Use default 15 bits, +16 is to accept only gzip and to
	 * yield Z_DATA_ERROR when fed zlib format.
	 */
	const int windowBits = 15 + 16;
	int status;
 
	zlib_pre_call(strm);
	status = inflateInit2(&strm->z, windowBits);
	zlib_post_call(strm);
	if (status == Z_OK)
		return;
	die("inflateInit2: %s (%s)", zerr_to_string(status),
	    strm->z.msg ? strm->z.msg : "no message");
}
 
void git_inflate_end(git_zstream *strm)
{
	int status;
 
	zlib_pre_call(strm);
	status = inflateEnd(&strm->z);
	zlib_post_call(strm);
	if (status == Z_OK)
		return;
	error("inflateEnd: %s (%s)", zerr_to_string(status),
	      strm->z.msg ? strm->z.msg : "no message");
}
 
int git_inflate(git_zstream *strm, int flush)
{
	int status;
 
	zlib_pre_call(strm);
	status = inflate(&strm->z, flush);
	zlib_post_call(strm);
	switch (status) {
	/* Z_BUF_ERROR: normal, needs more space in the output buffer */
	case Z_BUF_ERROR:
	case Z_OK:
	case Z_STREAM_END:
		return status;
 
	case Z_MEM_ERROR:
		die("inflate: out of memory");
	default:
		break;
	}
	error("inflate: %s (%s)", zerr_to_string(status),
	      strm->z.msg ? strm->z.msg : "no message");
	return status;
}
 
#if defined(NO_DEFLATE_BOUND) || ZLIB_VERNUM < 0x1200
#define deflateBound(c,s)  ((s) + (((s) + 7) >> 3) + (((s) + 63) >> 6) + 11)
#endif
 
unsigned long git_deflate_bound(git_zstream *strm, unsigned long size)
{
	return deflateBound(&strm->z, size);
}
 
void git_deflate_init(git_zstream *strm, int level)
{
	int status;
 
	zlib_pre_call(strm);
	status = deflateInit(&strm->z, level);
	zlib_post_call(strm);
	if (status == Z_OK)
		return;
	die("deflateInit: %s (%s)", zerr_to_string(status),
	    strm->z.msg ? strm->z.msg : "no message");
}
 
void git_deflate_init_gzip(git_zstream *strm, int level)
{
	/*
	 * Use default 15 bits, +16 is to generate gzip header/trailer
	 * instead of the zlib wrapper.
	 */
	const int windowBits = 15 + 16;
	int status;
 
	zlib_pre_call(strm);
	status = deflateInit2(&strm->z, level,
				  Z_DEFLATED, windowBits,
				  8, Z_DEFAULT_STRATEGY);
	zlib_post_call(strm);
	if (status == Z_OK)
		return;
	die("deflateInit2: %s (%s)", zerr_to_string(status),
	    strm->z.msg ? strm->z.msg : "no message");
}
 
void git_deflate_end(git_zstream *strm)
{
	int status;
 
	zlib_pre_call(strm);
	status = deflateEnd(&strm->z);
	zlib_post_call(strm);
	if (status == Z_OK)
		return;
	error("deflateEnd: %s (%s)", zerr_to_string(status),
	      strm->z.msg ? strm->z.msg : "no message");
}
 
int git_deflate_end_gently(git_zstream *strm)
{
	int status;
 
	zlib_pre_call(strm);
	status = deflateEnd(&strm->z);
	zlib_post_call(strm);
	return status;
}
 
int git_deflate(git_zstream *strm, int flush)
{
	int status;
 
	zlib_pre_call(strm);
	status = deflate(&strm->z, flush);
	zlib_post_call(strm);
	switch (status) {
	/* Z_BUF_ERROR: normal, needs more space in the output buffer */
	case Z_BUF_ERROR:
	case Z_OK:
	case Z_STREAM_END:
		return status;
 
	case Z_MEM_ERROR:
		die("deflate: out of memory");
	default:
		break;
	}
	error("deflate: %s (%s)", zerr_to_string(status),
	      strm->z.msg ? strm->z.msg : "no message");
	return status;
}