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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 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) */
47 inflate_blocks_statef
48 *blocks; /* current inflate_blocks state */
49
50 };
51
52
53 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
54 int ZEXPORT inflateReset(z_streamp z)
55 #else
56 int ZEXPORT inflateReset(z)
57 z_streamp z;
58 #endif
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
71 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
72 int ZEXPORT inflateEnd(z_streamp z)
73 #else
74 int ZEXPORT inflateEnd(z)
75 z_streamp z;
76 #endif
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
88 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
89 int ZEXPORT inflateInit2_(z_streamp z, int w, const char* version, int stream_size)
90 #else
91 int ZEXPORT inflateInit2_(z, w, version, stream_size)
92 z_streamp z;
93 int w;
94 const char *version;
95 int stream_size;
96 #endif
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
148 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
149 int ZEXPORT inflateInit_(z_streamp z, const char* version, int stream_size)
150 #else
151 int ZEXPORT inflateInit_(z, version, stream_size)
152 z_streamp z;
153 const char *version;
154 int stream_size;
155 #endif
156 {
157 return inflateInit2_(z, DEF_WBITS, version, stream_size);
158 }
159
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
163 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
164 int ZEXPORT inflate(z_streamp z, int f)
165 #else
166 int ZEXPORT inflate(z, f)
167 z_streamp z;
168 int f;
169 #endif
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
294 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
295 int ZEXPORT inflateSetDictionary(z_streamp z, const Bytef* dictionary, uInt dictLength)
296 #else
297 int ZEXPORT inflateSetDictionary(z, dictionary, dictLength)
298 z_streamp z;
299 const Bytef *dictionary;
300 uInt dictLength;
301 #endif
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
321 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
322 int ZEXPORT inflateSync(z_streamp z)
323 #else
324 int ZEXPORT inflateSync(z)
325 z_streamp z;
326 #endif
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
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 */
382 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
383 int ZEXPORT inflateSyncPoint(z_streamp z)
384 #else
385 int ZEXPORT inflateSyncPoint(z)
386 z_streamp z;
387 #endif
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 }