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
9 #define DONE INFLATE_DONE
10 #define BAD INFLATE_BAD
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 */
29 /* inflate private state */
30 struct internal_state {
33 inflate_mode mode; /* current inflate mode */
35 /* mode dependent information */
37 uInt method; /* if FLAGS, method byte */
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 */
45 /* mode independent information */
46 int nowrap; /* flag for no wrapper */
47 uInt wbits; /* log2(window size) (8..15, defaults to 15) */
49 *blocks; /* current inflate_blocks state */
54 ZEXPORT(int) inflateReset( /* z) */
57 if (z == Z_NULL || z->state == Z_NULL)
58 return Z_STREAM_ERROR;
59 z->total_in = z->total_out = 0;
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"));
68 ZEXPORT(int) inflateEnd( /* z) */
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);
77 Tracev((stderr, "inflate: end\n"));
82 ZEXPORT(int) inflateInit2_( /* z, w, version, stream_size) */
88 if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
89 stream_size != sizeof(z_stream))
90 return Z_VERSION_ERROR;
92 /* initialize state */
94 return Z_STREAM_ERROR;
96 if (z->zalloc == Z_NULL)
99 z->opaque = (voidpf)0;
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)
105 z->state->blocks = Z_NULL;
107 /* handle undocumented nowrap option (no zlib header or check) */
108 z->state->nowrap = 0;
112 z->state->nowrap = 1;
115 /* set window size */
119 return Z_STREAM_ERROR;
121 z->state->wbits = (uInt)w;
123 /* create inflate_blocks state */
124 if ((z->state->blocks =
125 inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, (uInt)1 << w))
131 Tracev((stderr, "inflate: allocated\n"));
141 #define NEEDBYTE {if(z->avail_in==0)return r;r=f;}
144 #define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)
147 ZEXPORT(int) inflate( /* z, f) */
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;
158 while (1) switch (z->state->mode)
162 if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED)
164 z->state->mode = BAD;
165 z->msg = (char*)"unknown compression method";
166 z->state->sub.marker = 5; /* can't try inflateSync */
169 if ((z->state->sub.method >> 4) + 8 > z->state->wbits)
171 z->state->mode = BAD;
172 z->msg = (char*)"invalid window size";
173 z->state->sub.marker = 5; /* can't try inflateSync */
176 z->state->mode = FLAG;
180 if (((z->state->sub.method << 8) + b) % 31)
182 z->state->mode = BAD;
183 z->msg = (char*)"incorrect header check";
184 z->state->sub.marker = 5; /* can't try inflateSync */
187 Tracev((stderr, "inflate: zlib header ok\n"));
188 if (!(b & PRESET_DICT))
190 z->state->mode = BLOCKS;
193 z->state->mode = DICT4;
196 z->state->sub.check.need = (uLong)NEXTBYTE << 24;
197 z->state->mode = DICT3;
200 z->state->sub.check.need += (uLong)NEXTBYTE << 16;
201 z->state->mode = DICT2;
204 z->state->sub.check.need += (uLong)NEXTBYTE << 8;
205 z->state->mode = DICT1;
208 z->state->sub.check.need += (uLong)NEXTBYTE;
209 z->adler = z->state->sub.check.need;
210 z->state->mode = 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;
218 r = inflate_blocks(z->state->blocks, z, r);
219 if (r == Z_DATA_ERROR)
221 z->state->mode = BAD;
222 z->state->sub.marker = 0; /* can try inflateSync */
227 if (r != Z_STREAM_END)
230 inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was);
231 if (z->state->nowrap)
233 z->state->mode = DONE;
236 z->state->mode = CHECK4;
239 z->state->sub.check.need = (uLong)NEXTBYTE << 24;
240 z->state->mode = CHECK3;
243 z->state->sub.check.need += (uLong)NEXTBYTE << 16;
244 z->state->mode = CHECK2;
247 z->state->sub.check.need += (uLong)NEXTBYTE << 8;
248 z->state->mode = CHECK1;
251 z->state->sub.check.need += (uLong)NEXTBYTE;
253 if (z->state->sub.check.was != z->state->sub.check.need)
255 z->state->mode = BAD;
256 z->msg = (char*)"incorrect data check";
257 z->state->sub.marker = 5; /* can't try inflateSync */
260 Tracev((stderr, "inflate: zlib check ok\n"));
261 z->state->mode = DONE;
267 return Z_STREAM_ERROR;
269 #ifdef NEED_DUMMY_RETURN
270 return Z_STREAM_ERROR; /* Some dumb compilers complain without this */