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1 | /* inflate.c -- zlib interface to inflate modules |
2 | * Copyright (C) 1995-1998 Mark Adler | |
e6ebb514 | 3 | * For conditions of distribution and use, see copyright notice in zlib.h |
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4 | */ |
5 | ||
6 | #include "zutil.h" | |
7 | #include "infblock.h" | |
8 | ||
9 | struct inflate_blocks_state {int dummy;}; /* for buggy compilers */ | |
10 | ||
11 | typedef enum { | |
12 | METHOD, /* waiting for method byte */ | |
13 | FLAG, /* waiting for flag byte */ | |
14 | DICT4, /* four dictionary check bytes to go */ | |
15 | DICT3, /* three dictionary check bytes to go */ | |
16 | DICT2, /* two dictionary check bytes to go */ | |
17 | DICT1, /* one dictionary check byte to go */ | |
18 | DICT0, /* waiting for inflateSetDictionary */ | |
19 | BLOCKS, /* decompressing blocks */ | |
20 | CHECK4, /* four check bytes to go */ | |
21 | CHECK3, /* three check bytes to go */ | |
22 | CHECK2, /* two check bytes to go */ | |
23 | CHECK1, /* one check byte to go */ | |
24 | DONE, /* finished check, done */ | |
25 | BAD} /* got an error--stay here */ | |
26 | inflate_mode; | |
27 | ||
28 | /* inflate private state */ | |
29 | struct internal_state { | |
30 | ||
31 | /* mode */ | |
32 | inflate_mode mode; /* current inflate mode */ | |
33 | ||
34 | /* mode dependent information */ | |
35 | union { | |
36 | uInt method; /* if FLAGS, method byte */ | |
37 | struct { | |
38 | uLong was; /* computed check value */ | |
39 | uLong need; /* stream check value */ | |
40 | } check; /* if CHECK, check values to compare */ | |
41 | uInt marker; /* if BAD, inflateSync's marker bytes count */ | |
42 | } sub; /* submode */ | |
43 | ||
44 | /* mode independent information */ | |
45 | int nowrap; /* flag for no wrapper */ | |
46 | uInt wbits; /* log2(window size) (8..15, defaults to 15) */ | |
e6ebb514 | 47 | inflate_blocks_statef |
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48 | *blocks; /* current inflate_blocks state */ |
49 | ||
50 | }; | |
51 | ||
52 | ||
75bce3ad | 53 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ |
e6ebb514 DW |
54 | int ZEXPORT inflateReset(z_streamp z) |
55 | #else | |
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56 | int ZEXPORT inflateReset(z) |
57 | z_streamp z; | |
e6ebb514 | 58 | #endif |
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59 | { |
60 | if (z == Z_NULL || z->state == Z_NULL) | |
61 | return Z_STREAM_ERROR; | |
62 | z->total_in = z->total_out = 0; | |
63 | z->msg = Z_NULL; | |
64 | z->state->mode = z->state->nowrap ? BLOCKS : METHOD; | |
65 | inflate_blocks_reset(z->state->blocks, z, Z_NULL); | |
66 | Tracev((stderr, "inflate: reset\n")); | |
67 | return Z_OK; | |
68 | } | |
69 | ||
70 | ||
75bce3ad | 71 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ |
e6ebb514 DW |
72 | int ZEXPORT inflateEnd(z_streamp z) |
73 | #else | |
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74 | int ZEXPORT inflateEnd(z) |
75 | z_streamp z; | |
e6ebb514 | 76 | #endif |
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77 | { |
78 | if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL) | |
79 | return Z_STREAM_ERROR; | |
80 | if (z->state->blocks != Z_NULL) | |
81 | inflate_blocks_free(z->state->blocks, z); | |
82 | ZFREE(z, z->state); | |
83 | z->state = Z_NULL; | |
84 | Tracev((stderr, "inflate: end\n")); | |
85 | return Z_OK; | |
86 | } | |
87 | ||
75bce3ad | 88 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ |
e6ebb514 DW |
89 | int ZEXPORT inflateInit2_(z_streamp z, int w, const char* version, int stream_size) |
90 | #else | |
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91 | int ZEXPORT inflateInit2_(z, w, version, stream_size) |
92 | z_streamp z; | |
93 | int w; | |
94 | const char *version; | |
95 | int stream_size; | |
e6ebb514 | 96 | #endif |
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97 | { |
98 | if (version == Z_NULL || version[0] != ZLIB_VERSION[0] || | |
99 | stream_size != sizeof(z_stream)) | |
100 | return Z_VERSION_ERROR; | |
101 | ||
102 | /* initialize state */ | |
103 | if (z == Z_NULL) | |
104 | return Z_STREAM_ERROR; | |
105 | z->msg = Z_NULL; | |
106 | if (z->zalloc == Z_NULL) | |
107 | { | |
108 | z->zalloc = zcalloc; | |
109 | z->opaque = (voidpf)0; | |
110 | } | |
111 | if (z->zfree == Z_NULL) z->zfree = zcfree; | |
112 | if ((z->state = (struct internal_state FAR *) | |
113 | ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL) | |
114 | return Z_MEM_ERROR; | |
115 | z->state->blocks = Z_NULL; | |
116 | ||
117 | /* handle undocumented nowrap option (no zlib header or check) */ | |
118 | z->state->nowrap = 0; | |
119 | if (w < 0) | |
120 | { | |
121 | w = - w; | |
122 | z->state->nowrap = 1; | |
123 | } | |
124 | ||
125 | /* set window size */ | |
126 | if (w < 8 || w > 15) | |
127 | { | |
128 | inflateEnd(z); | |
129 | return Z_STREAM_ERROR; | |
130 | } | |
131 | z->state->wbits = (uInt)w; | |
132 | ||
133 | /* create inflate_blocks state */ | |
134 | if ((z->state->blocks = | |
135 | inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, (uInt)1 << w)) | |
136 | == Z_NULL) | |
137 | { | |
138 | inflateEnd(z); | |
139 | return Z_MEM_ERROR; | |
140 | } | |
141 | Tracev((stderr, "inflate: allocated\n")); | |
142 | ||
143 | /* reset state */ | |
144 | inflateReset(z); | |
145 | return Z_OK; | |
146 | } | |
147 | ||
75bce3ad | 148 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ |
e6ebb514 DW |
149 | int ZEXPORT inflateInit_(z_streamp z, const char* version, int stream_size) |
150 | #else | |
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151 | int ZEXPORT inflateInit_(z, version, stream_size) |
152 | z_streamp z; | |
153 | const char *version; | |
154 | int stream_size; | |
e6ebb514 | 155 | #endif |
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156 | { |
157 | return inflateInit2_(z, DEF_WBITS, version, stream_size); | |
158 | } | |
159 | ||
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160 | #define NEEDBYTE {if(z->avail_in==0)return r;r=f;} |
161 | #define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++) | |
162 | ||
75bce3ad | 163 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ |
e6ebb514 DW |
164 | int ZEXPORT inflate(z_streamp z, int f) |
165 | #else | |
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166 | int ZEXPORT inflate(z, f) |
167 | z_streamp z; | |
168 | int f; | |
e6ebb514 | 169 | #endif |
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170 | { |
171 | int r; | |
172 | uInt b; | |
173 | ||
174 | if (z == Z_NULL || z->state == Z_NULL || z->next_in == Z_NULL) | |
175 | return Z_STREAM_ERROR; | |
176 | f = f == Z_FINISH ? Z_BUF_ERROR : Z_OK; | |
177 | r = Z_BUF_ERROR; | |
178 | while (1) switch (z->state->mode) | |
179 | { | |
180 | case METHOD: | |
181 | NEEDBYTE | |
182 | if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED) | |
183 | { | |
184 | z->state->mode = BAD; | |
185 | z->msg = (char*)"unknown compression method"; | |
186 | z->state->sub.marker = 5; /* can't try inflateSync */ | |
187 | break; | |
188 | } | |
189 | if ((z->state->sub.method >> 4) + 8 > z->state->wbits) | |
190 | { | |
191 | z->state->mode = BAD; | |
192 | z->msg = (char*)"invalid window size"; | |
193 | z->state->sub.marker = 5; /* can't try inflateSync */ | |
194 | break; | |
195 | } | |
196 | z->state->mode = FLAG; | |
197 | case FLAG: | |
198 | NEEDBYTE | |
199 | b = NEXTBYTE; | |
200 | if (((z->state->sub.method << 8) + b) % 31) | |
201 | { | |
202 | z->state->mode = BAD; | |
203 | z->msg = (char*)"incorrect header check"; | |
204 | z->state->sub.marker = 5; /* can't try inflateSync */ | |
205 | break; | |
206 | } | |
207 | Tracev((stderr, "inflate: zlib header ok\n")); | |
208 | if (!(b & PRESET_DICT)) | |
209 | { | |
210 | z->state->mode = BLOCKS; | |
211 | break; | |
212 | } | |
213 | z->state->mode = DICT4; | |
214 | case DICT4: | |
215 | NEEDBYTE | |
216 | z->state->sub.check.need = (uLong)NEXTBYTE << 24; | |
217 | z->state->mode = DICT3; | |
218 | case DICT3: | |
219 | NEEDBYTE | |
220 | z->state->sub.check.need += (uLong)NEXTBYTE << 16; | |
221 | z->state->mode = DICT2; | |
222 | case DICT2: | |
223 | NEEDBYTE | |
224 | z->state->sub.check.need += (uLong)NEXTBYTE << 8; | |
225 | z->state->mode = DICT1; | |
226 | case DICT1: | |
227 | NEEDBYTE | |
228 | z->state->sub.check.need += (uLong)NEXTBYTE; | |
229 | z->adler = z->state->sub.check.need; | |
230 | z->state->mode = DICT0; | |
231 | return Z_NEED_DICT; | |
232 | case DICT0: | |
233 | z->state->mode = BAD; | |
234 | z->msg = (char*)"need dictionary"; | |
235 | z->state->sub.marker = 0; /* can try inflateSync */ | |
236 | return Z_STREAM_ERROR; | |
237 | case BLOCKS: | |
238 | r = inflate_blocks(z->state->blocks, z, r); | |
239 | if (r == Z_DATA_ERROR) | |
240 | { | |
241 | z->state->mode = BAD; | |
242 | z->state->sub.marker = 0; /* can try inflateSync */ | |
243 | break; | |
244 | } | |
245 | if (r == Z_OK) | |
246 | r = f; | |
247 | if (r != Z_STREAM_END) | |
248 | return r; | |
249 | r = f; | |
250 | inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was); | |
251 | if (z->state->nowrap) | |
252 | { | |
253 | z->state->mode = DONE; | |
254 | break; | |
255 | } | |
256 | z->state->mode = CHECK4; | |
257 | case CHECK4: | |
258 | NEEDBYTE | |
259 | z->state->sub.check.need = (uLong)NEXTBYTE << 24; | |
260 | z->state->mode = CHECK3; | |
261 | case CHECK3: | |
262 | NEEDBYTE | |
263 | z->state->sub.check.need += (uLong)NEXTBYTE << 16; | |
264 | z->state->mode = CHECK2; | |
265 | case CHECK2: | |
266 | NEEDBYTE | |
267 | z->state->sub.check.need += (uLong)NEXTBYTE << 8; | |
268 | z->state->mode = CHECK1; | |
269 | case CHECK1: | |
270 | NEEDBYTE | |
271 | z->state->sub.check.need += (uLong)NEXTBYTE; | |
272 | ||
273 | if (z->state->sub.check.was != z->state->sub.check.need) | |
274 | { | |
275 | z->state->mode = BAD; | |
276 | z->msg = (char*)"incorrect data check"; | |
277 | z->state->sub.marker = 5; /* can't try inflateSync */ | |
278 | break; | |
279 | } | |
280 | Tracev((stderr, "inflate: zlib check ok\n")); | |
281 | z->state->mode = DONE; | |
282 | case DONE: | |
283 | return Z_STREAM_END; | |
284 | case BAD: | |
285 | return Z_DATA_ERROR; | |
286 | default: | |
287 | return Z_STREAM_ERROR; | |
288 | } | |
289 | #ifdef NEED_DUMMY_RETURN | |
290 | return Z_STREAM_ERROR; /* Some dumb compilers complain without this */ | |
291 | #endif | |
292 | } | |
293 | ||
75bce3ad | 294 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ |
e6ebb514 DW |
295 | int ZEXPORT inflateSetDictionary(z_streamp z, const Bytef* dictionary, uInt dictLength) |
296 | #else | |
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297 | int ZEXPORT inflateSetDictionary(z, dictionary, dictLength) |
298 | z_streamp z; | |
299 | const Bytef *dictionary; | |
300 | uInt dictLength; | |
e6ebb514 | 301 | #endif |
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302 | { |
303 | uInt length = dictLength; | |
304 | ||
305 | if (z == Z_NULL || z->state == Z_NULL || z->state->mode != DICT0) | |
306 | return Z_STREAM_ERROR; | |
307 | ||
308 | if (adler32(1L, dictionary, dictLength) != z->adler) return Z_DATA_ERROR; | |
309 | z->adler = 1L; | |
310 | ||
311 | if (length >= ((uInt)1<<z->state->wbits)) | |
312 | { | |
313 | length = (1<<z->state->wbits)-1; | |
314 | dictionary += dictLength - length; | |
315 | } | |
316 | inflate_set_dictionary(z->state->blocks, dictionary, length); | |
317 | z->state->mode = BLOCKS; | |
318 | return Z_OK; | |
319 | } | |
320 | ||
75bce3ad | 321 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ |
e6ebb514 DW |
322 | int ZEXPORT inflateSync(z_streamp z) |
323 | #else | |
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324 | int ZEXPORT inflateSync(z) |
325 | z_streamp z; | |
e6ebb514 | 326 | #endif |
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327 | { |
328 | uInt n; /* number of bytes to look at */ | |
329 | Bytef *p; /* pointer to bytes */ | |
330 | uInt m; /* number of marker bytes found in a row */ | |
331 | uLong r, w; /* temporaries to save total_in and total_out */ | |
332 | ||
333 | /* set up */ | |
334 | if (z == Z_NULL || z->state == Z_NULL) | |
335 | return Z_STREAM_ERROR; | |
336 | if (z->state->mode != BAD) | |
337 | { | |
338 | z->state->mode = BAD; | |
339 | z->state->sub.marker = 0; | |
340 | } | |
341 | if ((n = z->avail_in) == 0) | |
342 | return Z_BUF_ERROR; | |
343 | p = z->next_in; | |
344 | m = z->state->sub.marker; | |
345 | ||
346 | /* search */ | |
347 | while (n && m < 4) | |
348 | { | |
349 | static const Byte mark[4] = {0, 0, 0xff, 0xff}; | |
350 | if (*p == mark[m]) | |
351 | m++; | |
352 | else if (*p) | |
353 | m = 0; | |
354 | else | |
355 | m = 4 - m; | |
356 | p++, n--; | |
357 | } | |
358 | ||
359 | /* restore */ | |
360 | z->total_in += p - z->next_in; | |
361 | z->next_in = p; | |
362 | z->avail_in = n; | |
363 | z->state->sub.marker = m; | |
364 | ||
365 | /* return no joy or set up to restart on a new block */ | |
366 | if (m != 4) | |
367 | return Z_DATA_ERROR; | |
368 | r = z->total_in; w = z->total_out; | |
369 | inflateReset(z); | |
370 | z->total_in = r; z->total_out = w; | |
371 | z->state->mode = BLOCKS; | |
372 | return Z_OK; | |
373 | } | |
374 | ||
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375 | /* Returns true if inflate is currently at the end of a block generated |
376 | * by Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP | |
377 | * implementation to provide an additional safety check. PPP uses Z_SYNC_FLUSH | |
378 | * but removes the length bytes of the resulting empty stored block. When | |
379 | * decompressing, PPP checks that at the end of input packet, inflate is | |
380 | * waiting for these length bytes. | |
381 | */ | |
75bce3ad | 382 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ |
e6ebb514 DW |
383 | int ZEXPORT inflateSyncPoint(z_streamp z) |
384 | #else | |
c801d85f KB |
385 | int ZEXPORT inflateSyncPoint(z) |
386 | z_streamp z; | |
e6ebb514 | 387 | #endif |
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388 | { |
389 | if (z == Z_NULL || z->state == Z_NULL || z->state->blocks == Z_NULL) | |
390 | return Z_STREAM_ERROR; | |
391 | return inflate_blocks_sync_point(z->state->blocks); | |
392 | } |