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author Ritor1
date Sat, 12 Jan 2013 09:45:18 +0600
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-1:000000000000 0:9c0607679772
1 /* inflate.c -- zlib interface to inflate modules
2 * Copyright (C) 1995-1998 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 int ZEXPORT inflateReset(z)
54 z_streamp z;
55 {
56 if (z == Z_NULL || z->state == Z_NULL)
57 return Z_STREAM_ERROR;
58 z->total_in = z->total_out = 0;
59 z->msg = Z_NULL;
60 z->state->mode = z->state->nowrap ? BLOCKS : METHOD;
61 inflate_blocks_reset(z->state->blocks, z, Z_NULL);
62 Tracev((stderr, "inflate: reset\n"));
63 return Z_OK;
64 }
65
66
67 int ZEXPORT inflateEnd(z)
68 z_streamp z;
69 {
70 if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL)
71 return Z_STREAM_ERROR;
72 if (z->state->blocks != Z_NULL)
73 inflate_blocks_free(z->state->blocks, z);
74 ZFREE(z, z->state);
75 z->state = Z_NULL;
76 Tracev((stderr, "inflate: end\n"));
77 return Z_OK;
78 }
79
80
81 int ZEXPORT inflateInit2_(z, w, version, stream_size)
82 z_streamp z;
83 int w;
84 const char *version;
85 int stream_size;
86 {
87 if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
88 stream_size != sizeof(z_stream))
89 return Z_VERSION_ERROR;
90
91 /* initialize state */
92 if (z == Z_NULL)
93 return Z_STREAM_ERROR;
94 z->msg = Z_NULL;
95 if (z->zalloc == Z_NULL)
96 {
97 z->zalloc = zcalloc;
98 z->opaque = (voidpf)0;
99 }
100 if (z->zfree == Z_NULL) z->zfree = zcfree;
101 if ((z->state = (struct internal_state FAR *)
102 ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL)
103 return Z_MEM_ERROR;
104 z->state->blocks = Z_NULL;
105
106 /* handle undocumented nowrap option (no zlib header or check) */
107 z->state->nowrap = 0;
108 if (w < 0)
109 {
110 w = - w;
111 z->state->nowrap = 1;
112 }
113
114 /* set window size */
115 if (w < 8 || w > 15)
116 {
117 inflateEnd(z);
118 return Z_STREAM_ERROR;
119 }
120 z->state->wbits = (uInt)w;
121
122 /* create inflate_blocks state */
123 if ((z->state->blocks =
124 inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, (uInt)1 << w))
125 == Z_NULL)
126 {
127 inflateEnd(z);
128 return Z_MEM_ERROR;
129 }
130 Tracev((stderr, "inflate: allocated\n"));
131
132 /* reset state */
133 inflateReset(z);
134 return Z_OK;
135 }
136
137
138 int ZEXPORT inflateInit_(z, version, stream_size)
139 z_streamp z;
140 const char *version;
141 int stream_size;
142 {
143 return inflateInit2_(z, DEF_WBITS, version, stream_size);
144 }
145
146
147 #define NEEDBYTE {if(z->avail_in==0)return r;r=f;}
148 #define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)
149
150 int ZEXPORT inflate(z, f)
151 z_streamp z;
152 int f;
153 {
154 int r;
155 uInt b;
156
157 if (z == Z_NULL || z->state == Z_NULL || z->next_in == Z_NULL)
158 return Z_STREAM_ERROR;
159 f = f == Z_FINISH ? Z_BUF_ERROR : Z_OK;
160 r = Z_BUF_ERROR;
161 while (1) switch (z->state->mode)
162 {
163 case METHOD:
164 NEEDBYTE
165 if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED)
166 {
167 z->state->mode = BAD;
168 z->msg = (char*)"unknown compression method";
169 z->state->sub.marker = 5; /* can't try inflateSync */
170 break;
171 }
172 if ((z->state->sub.method >> 4) + 8 > z->state->wbits)
173 {
174 z->state->mode = BAD;
175 z->msg = (char*)"invalid window size";
176 z->state->sub.marker = 5; /* can't try inflateSync */
177 break;
178 }
179 z->state->mode = FLAG;
180 case FLAG:
181 NEEDBYTE
182 b = NEXTBYTE;
183 if (((z->state->sub.method << 8) + b) % 31)
184 {
185 z->state->mode = BAD;
186 z->msg = (char*)"incorrect header check";
187 z->state->sub.marker = 5; /* can't try inflateSync */
188 break;
189 }
190 Tracev((stderr, "inflate: zlib header ok\n"));
191 if (!(b & PRESET_DICT))
192 {
193 z->state->mode = BLOCKS;
194 break;
195 }
196 z->state->mode = DICT4;
197 case DICT4:
198 NEEDBYTE
199 z->state->sub.check.need = (uLong)NEXTBYTE << 24;
200 z->state->mode = DICT3;
201 case DICT3:
202 NEEDBYTE
203 z->state->sub.check.need += (uLong)NEXTBYTE << 16;
204 z->state->mode = DICT2;
205 case DICT2:
206 NEEDBYTE
207 z->state->sub.check.need += (uLong)NEXTBYTE << 8;
208 z->state->mode = DICT1;
209 case DICT1:
210 NEEDBYTE
211 z->state->sub.check.need += (uLong)NEXTBYTE;
212 z->adler = z->state->sub.check.need;
213 z->state->mode = DICT0;
214 return Z_NEED_DICT;
215 case DICT0:
216 z->state->mode = BAD;
217 z->msg = (char*)"need dictionary";
218 z->state->sub.marker = 0; /* can try inflateSync */
219 return Z_STREAM_ERROR;
220 case BLOCKS:
221 r = inflate_blocks(z->state->blocks, z, r);
222 if (r == Z_DATA_ERROR)
223 {
224 z->state->mode = BAD;
225 z->state->sub.marker = 0; /* can try inflateSync */
226 break;
227 }
228 if (r == Z_OK)
229 r = f;
230 if (r != Z_STREAM_END)
231 return r;
232 r = f;
233 inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was);
234 if (z->state->nowrap)
235 {
236 z->state->mode = DONE;
237 break;
238 }
239 z->state->mode = CHECK4;
240 case CHECK4:
241 NEEDBYTE
242 z->state->sub.check.need = (uLong)NEXTBYTE << 24;
243 z->state->mode = CHECK3;
244 case CHECK3:
245 NEEDBYTE
246 z->state->sub.check.need += (uLong)NEXTBYTE << 16;
247 z->state->mode = CHECK2;
248 case CHECK2:
249 NEEDBYTE
250 z->state->sub.check.need += (uLong)NEXTBYTE << 8;
251 z->state->mode = CHECK1;
252 case CHECK1:
253 NEEDBYTE
254 z->state->sub.check.need += (uLong)NEXTBYTE;
255
256 if (z->state->sub.check.was != z->state->sub.check.need)
257 {
258 z->state->mode = BAD;
259 z->msg = (char*)"incorrect data check";
260 z->state->sub.marker = 5; /* can't try inflateSync */
261 break;
262 }
263 Tracev((stderr, "inflate: zlib check ok\n"));
264 z->state->mode = DONE;
265 case DONE:
266 return Z_STREAM_END;
267 case BAD:
268 return Z_DATA_ERROR;
269 default:
270 return Z_STREAM_ERROR;
271 }
272 #ifdef NEED_DUMMY_RETURN
273 return Z_STREAM_ERROR; /* Some dumb compilers complain without this */
274 #endif
275 }
276
277
278 int ZEXPORT inflateSetDictionary(z, dictionary, dictLength)
279 z_streamp z;
280 const Bytef *dictionary;
281 uInt dictLength;
282 {
283 uInt length = dictLength;
284
285 if (z == Z_NULL || z->state == Z_NULL || z->state->mode != DICT0)
286 return Z_STREAM_ERROR;
287
288 if (adler32(1L, dictionary, dictLength) != z->adler) return Z_DATA_ERROR;
289 z->adler = 1L;
290
291 if (length >= ((uInt)1<<z->state->wbits))
292 {
293 length = (1<<z->state->wbits)-1;
294 dictionary += dictLength - length;
295 }
296 inflate_set_dictionary(z->state->blocks, dictionary, length);
297 z->state->mode = BLOCKS;
298 return Z_OK;
299 }
300
301
302 int ZEXPORT inflateSync(z)
303 z_streamp z;
304 {
305 uInt n; /* number of bytes to look at */
306 Bytef *p; /* pointer to bytes */
307 uInt m; /* number of marker bytes found in a row */
308 uLong r, w; /* temporaries to save total_in and total_out */
309
310 /* set up */
311 if (z == Z_NULL || z->state == Z_NULL)
312 return Z_STREAM_ERROR;
313 if (z->state->mode != BAD)
314 {
315 z->state->mode = BAD;
316 z->state->sub.marker = 0;
317 }
318 if ((n = z->avail_in) == 0)
319 return Z_BUF_ERROR;
320 p = z->next_in;
321 m = z->state->sub.marker;
322
323 /* search */
324 while (n && m < 4)
325 {
326 static const Byte mark[4] = {0, 0, 0xff, 0xff};
327 if (*p == mark[m])
328 m++;
329 else if (*p)
330 m = 0;
331 else
332 m = 4 - m;
333 p++, n--;
334 }
335
336 /* restore */
337 z->total_in += p - z->next_in;
338 z->next_in = p;
339 z->avail_in = n;
340 z->state->sub.marker = m;
341
342 /* return no joy or set up to restart on a new block */
343 if (m != 4)
344 return Z_DATA_ERROR;
345 r = z->total_in; w = z->total_out;
346 inflateReset(z);
347 z->total_in = r; z->total_out = w;
348 z->state->mode = BLOCKS;
349 return Z_OK;
350 }
351
352
353 /* Returns true if inflate is currently at the end of a block generated
354 * by Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
355 * implementation to provide an additional safety check. PPP uses Z_SYNC_FLUSH
356 * but removes the length bytes of the resulting empty stored block. When
357 * decompressing, PPP checks that at the end of input packet, inflate is
358 * waiting for these length bytes.
359 */
360 int ZEXPORT inflateSyncPoint(z)
361 z_streamp z;
362 {
363 if (z == Z_NULL || z->state == Z_NULL || z->state->blocks == Z_NULL)
364 return Z_STREAM_ERROR;
365 return inflate_blocks_sync_point(z->state->blocks);
366 }