1/* inflate.c -- zlib interface to inflate modules
2 * Copyright (C) 1995-2002 Mark Adler
3 * For conditions of distribution and use, see copyright notice in zlib.h
4 */
5
6#include "zutil.h"
7#include "infblock.h"
8
9#define DONE INFLATE_DONE
10#define BAD INFLATE_BAD
11
12typedef enum {
13 METHOD, /* waiting for method byte */
14 FLAG, /* waiting for flag byte */
15 DICT4, /* four dictionary check bytes to go */
16 DICT3, /* three dictionary check bytes to go */
17 DICT2, /* two dictionary check bytes to go */
18 DICT1, /* one dictionary check byte to go */
19 DICT0, /* waiting for inflateSetDictionary */
20 BLOCKS, /* decompressing blocks */
21 CHECK4, /* four check bytes to go */
22 CHECK3, /* three check bytes to go */
23 CHECK2, /* two check bytes to go */
24 CHECK1, /* one check byte to go */
25 DONE, /* finished check, done */
26 BAD} /* got an error--stay here */
27inflate_mode;
28
29/* inflate private state */
30struct internal_state {
31
32 /* mode */
33 inflate_mode mode; /* current inflate mode */
34
35 /* mode dependent information */
36 union {
37 uInt method; /* if FLAGS, method byte */
38 struct {
39 uLong was; /* computed check value */
40 uLong need; /* stream check value */
41 } check; /* if CHECK, check values to compare */
42 uInt marker; /* if BAD, inflateSync's marker bytes count */
43 } sub; /* submode */
44
45 /* mode independent information */
46 int nowrap; /* flag for no wrapper */
47 uInt wbits; /* log2(window size) (8..15, defaults to 15) */
48 inflate_blocks_statef
49 *blocks; /* current inflate_blocks state */
50
51};
52
53
54ZEXPORT(int) inflateReset( /* z) */
55z_streamp z )
56{
57 if (z == Z_NULL || z->state == Z_NULL)
58 return Z_STREAM_ERROR;
59 z->total_in = z->total_out = 0;
60 z->msg = Z_NULL;
61 z->state->mode = z->state->nowrap ? BLOCKS : METHOD;
62 inflate_blocks_reset(z->state->blocks, z, Z_NULL);
63 Tracev((stderr, "inflate: reset\n"));
64 return Z_OK;
65}
66
67
68ZEXPORT(int) inflateEnd( /* z) */
69z_streamp z )
70{
71 if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL)
72 return Z_STREAM_ERROR;
73 if (z->state->blocks != Z_NULL)
74 inflate_blocks_free(z->state->blocks, z);
75 ZFREE(z, z->state);
76 z->state = Z_NULL;
77 Tracev((stderr, "inflate: end\n"));
78 return Z_OK;
79}
80
81
82ZEXPORT(int) inflateInit2_( /* z, w, version, stream_size) */
83z_streamp z,
84int w,
85const char *version,
86int stream_size )
87{
88 if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
89 stream_size != sizeof(z_stream))
90 return Z_VERSION_ERROR;
91
92 /* initialize state */
93 if (z == Z_NULL)
94 return Z_STREAM_ERROR;
95 z->msg = Z_NULL;
96 if (z->zalloc == Z_NULL)
97 {
98 z->zalloc = zcalloc;
99 z->opaque = (voidpf)0;
100 }
101 if (z->zfree == Z_NULL) z->zfree = zcfree;
102 if ((z->state = (struct internal_state FAR *)
103 ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL)
104 return Z_MEM_ERROR;
105 z->state->blocks = Z_NULL;
106
107 /* handle undocumented nowrap option (no zlib header or check) */
108 z->state->nowrap = 0;
109 if (w < 0)
110 {
111 w = - w;
112 z->state->nowrap = 1;
113 }
114
115 /* set window size */
116 if (w < 8 || w > 15)
117 {
118 inflateEnd(z);
119 return Z_STREAM_ERROR;
120 }
121 z->state->wbits = (uInt)w;
122
123 /* create inflate_blocks state */
124 if ((z->state->blocks =
125 inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, (uInt)1 << w))
126 == Z_NULL)
127 {
128 inflateEnd(z);
129 return Z_MEM_ERROR;
130 }
131 Tracev((stderr, "inflate: allocated\n"));
132
133 /* reset state */
134 inflateReset(z);
135 return Z_OK;
136}
137
138
139
140#undef NEEDBYTE
141#define NEEDBYTE {if(z->avail_in==0)return r;r=f;}
142
143#undef NEXTBYTE
144#define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)
145
146
147ZEXPORT(int) inflate( /* z, f) */
148z_streamp z,
149int f )
150{
151 int r;
152 uInt b;
153
154 if (z == Z_NULL || z->state == Z_NULL || z->next_in == Z_NULL)
155 return Z_STREAM_ERROR;
156 f = f == Z_FINISH ? Z_BUF_ERROR : Z_OK;
157 r = Z_BUF_ERROR;
158 while (1) switch (z->state->mode)
159 {
160 case METHOD:
161 NEEDBYTE
162 if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED)
163 {
164 z->state->mode = BAD;
165 z->msg = (char*)"unknown compression method";
166 z->state->sub.marker = 5; /* can't try inflateSync */
167 break;
168 }
169 if ((z->state->sub.method >> 4) + 8 > z->state->wbits)
170 {
171 z->state->mode = BAD;
172 z->msg = (char*)"invalid window size";
173 z->state->sub.marker = 5; /* can't try inflateSync */
174 break;
175 }
176 z->state->mode = FLAG;
177 case FLAG:
178 NEEDBYTE
179 b = NEXTBYTE;
180 if (((z->state->sub.method << 8) + b) % 31)
181 {
182 z->state->mode = BAD;
183 z->msg = (char*)"incorrect header check";
184 z->state->sub.marker = 5; /* can't try inflateSync */
185 break;
186 }
187 Tracev((stderr, "inflate: zlib header ok\n"));
188 if (!(b & PRESET_DICT))
189 {
190 z->state->mode = BLOCKS;
191 break;
192 }
193 z->state->mode = DICT4;
194 case DICT4:
195 NEEDBYTE
196 z->state->sub.check.need = (uLong)NEXTBYTE << 24;
197 z->state->mode = DICT3;
198 case DICT3:
199 NEEDBYTE
200 z->state->sub.check.need += (uLong)NEXTBYTE << 16;
201 z->state->mode = DICT2;
202 case DICT2:
203 NEEDBYTE
204 z->state->sub.check.need += (uLong)NEXTBYTE << 8;
205 z->state->mode = DICT1;
206 case DICT1:
207 NEEDBYTE
208 z->state->sub.check.need += (uLong)NEXTBYTE;
209 z->adler = z->state->sub.check.need;
210 z->state->mode = DICT0;
211 return Z_NEED_DICT;
212 case DICT0:
213 z->state->mode = BAD;
214 z->msg = (char*)"need dictionary";
215 z->state->sub.marker = 0; /* can try inflateSync */
216 return Z_STREAM_ERROR;
217 case BLOCKS:
218 r = inflate_blocks(z->state->blocks, z, r);
219 if (r == Z_DATA_ERROR)
220 {
221 z->state->mode = BAD;
222 z->state->sub.marker = 0; /* can try inflateSync */
223 break;
224 }
225 if (r == Z_OK)
226 r = f;
227 if (r != Z_STREAM_END)
228 return r;
229 r = f;
230 inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was);
231 if (z->state->nowrap)
232 {
233 z->state->mode = DONE;
234 break;
235 }
236 z->state->mode = CHECK4;
237 case CHECK4:
238 NEEDBYTE
239 z->state->sub.check.need = (uLong)NEXTBYTE << 24;
240 z->state->mode = CHECK3;
241 case CHECK3:
242 NEEDBYTE
243 z->state->sub.check.need += (uLong)NEXTBYTE << 16;
244 z->state->mode = CHECK2;
245 case CHECK2:
246 NEEDBYTE
247 z->state->sub.check.need += (uLong)NEXTBYTE << 8;
248 z->state->mode = CHECK1;
249 case CHECK1:
250 NEEDBYTE
251 z->state->sub.check.need += (uLong)NEXTBYTE;
252
253 if (z->state->sub.check.was != z->state->sub.check.need)
254 {
255 z->state->mode = BAD;
256 z->msg = (char*)"incorrect data check";
257 z->state->sub.marker = 5; /* can't try inflateSync */
258 break;
259 }
260 Tracev((stderr, "inflate: zlib check ok\n"));
261 z->state->mode = DONE;
262 case DONE:
263 return Z_STREAM_END;
264 case BAD:
265 return Z_DATA_ERROR;
266 default:
267 return Z_STREAM_ERROR;
268 }
269#ifdef NEED_DUMMY_RETURN
270 return Z_STREAM_ERROR; /* Some dumb compilers complain without this */
271#endif
272}
273
274