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Diffstat (limited to '')
-rw-r--r-- | libraries/irrlicht-1.8/source/Irrlicht/zlib/inffast.c | 340 |
1 files changed, 340 insertions, 0 deletions
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/zlib/inffast.c b/libraries/irrlicht-1.8/source/Irrlicht/zlib/inffast.c new file mode 100644 index 0000000..2dfd412 --- /dev/null +++ b/libraries/irrlicht-1.8/source/Irrlicht/zlib/inffast.c | |||
@@ -0,0 +1,340 @@ | |||
1 | /* inffast.c -- fast decoding | ||
2 | * Copyright (C) 1995-2008, 2010 Mark Adler | ||
3 | * For conditions of distribution and use, see copyright notice in zlib.h | ||
4 | */ | ||
5 | |||
6 | #include "zutil.h" | ||
7 | #include "inftrees.h" | ||
8 | #include "inflate.h" | ||
9 | #include "inffast.h" | ||
10 | |||
11 | #ifndef ASMINF | ||
12 | |||
13 | /* Allow machine dependent optimization for post-increment or pre-increment. | ||
14 | Based on testing to date, | ||
15 | Pre-increment preferred for: | ||
16 | - PowerPC G3 (Adler) | ||
17 | - MIPS R5000 (Randers-Pehrson) | ||
18 | Post-increment preferred for: | ||
19 | - none | ||
20 | No measurable difference: | ||
21 | - Pentium III (Anderson) | ||
22 | - M68060 (Nikl) | ||
23 | */ | ||
24 | #ifdef POSTINC | ||
25 | # define OFF 0 | ||
26 | # define PUP(a) *(a)++ | ||
27 | #else | ||
28 | # define OFF 1 | ||
29 | # define PUP(a) *++(a) | ||
30 | #endif | ||
31 | |||
32 | /* | ||
33 | Decode literal, length, and distance codes and write out the resulting | ||
34 | literal and match bytes until either not enough input or output is | ||
35 | available, an end-of-block is encountered, or a data error is encountered. | ||
36 | When large enough input and output buffers are supplied to inflate(), for | ||
37 | example, a 16K input buffer and a 64K output buffer, more than 95% of the | ||
38 | inflate execution time is spent in this routine. | ||
39 | |||
40 | Entry assumptions: | ||
41 | |||
42 | state->mode == LEN | ||
43 | strm->avail_in >= 6 | ||
44 | strm->avail_out >= 258 | ||
45 | start >= strm->avail_out | ||
46 | state->bits < 8 | ||
47 | |||
48 | On return, state->mode is one of: | ||
49 | |||
50 | LEN -- ran out of enough output space or enough available input | ||
51 | TYPE -- reached end of block code, inflate() to interpret next block | ||
52 | BAD -- error in block data | ||
53 | |||
54 | Notes: | ||
55 | |||
56 | - The maximum input bits used by a length/distance pair is 15 bits for the | ||
57 | length code, 5 bits for the length extra, 15 bits for the distance code, | ||
58 | and 13 bits for the distance extra. This totals 48 bits, or six bytes. | ||
59 | Therefore if strm->avail_in >= 6, then there is enough input to avoid | ||
60 | checking for available input while decoding. | ||
61 | |||
62 | - The maximum bytes that a single length/distance pair can output is 258 | ||
63 | bytes, which is the maximum length that can be coded. inflate_fast() | ||
64 | requires strm->avail_out >= 258 for each loop to avoid checking for | ||
65 | output space. | ||
66 | */ | ||
67 | void ZLIB_INTERNAL inflate_fast(strm, start) | ||
68 | z_streamp strm; | ||
69 | unsigned start; /* inflate()'s starting value for strm->avail_out */ | ||
70 | { | ||
71 | struct inflate_state FAR *state; | ||
72 | unsigned char FAR *in; /* local strm->next_in */ | ||
73 | unsigned char FAR *last; /* while in < last, enough input available */ | ||
74 | unsigned char FAR *out; /* local strm->next_out */ | ||
75 | unsigned char FAR *beg; /* inflate()'s initial strm->next_out */ | ||
76 | unsigned char FAR *end; /* while out < end, enough space available */ | ||
77 | #ifdef INFLATE_STRICT | ||
78 | unsigned dmax; /* maximum distance from zlib header */ | ||
79 | #endif | ||
80 | unsigned wsize; /* window size or zero if not using window */ | ||
81 | unsigned whave; /* valid bytes in the window */ | ||
82 | unsigned wnext; /* window write index */ | ||
83 | unsigned char FAR *window; /* allocated sliding window, if wsize != 0 */ | ||
84 | unsigned long hold; /* local strm->hold */ | ||
85 | unsigned bits; /* local strm->bits */ | ||
86 | code const FAR *lcode; /* local strm->lencode */ | ||
87 | code const FAR *dcode; /* local strm->distcode */ | ||
88 | unsigned lmask; /* mask for first level of length codes */ | ||
89 | unsigned dmask; /* mask for first level of distance codes */ | ||
90 | code here; /* retrieved table entry */ | ||
91 | unsigned op; /* code bits, operation, extra bits, or */ | ||
92 | /* window position, window bytes to copy */ | ||
93 | unsigned len; /* match length, unused bytes */ | ||
94 | unsigned dist; /* match distance */ | ||
95 | unsigned char FAR *from; /* where to copy match from */ | ||
96 | |||
97 | /* copy state to local variables */ | ||
98 | state = (struct inflate_state FAR *)strm->state; | ||
99 | in = strm->next_in - OFF; | ||
100 | last = in + (strm->avail_in - 5); | ||
101 | out = strm->next_out - OFF; | ||
102 | beg = out - (start - strm->avail_out); | ||
103 | end = out + (strm->avail_out - 257); | ||
104 | #ifdef INFLATE_STRICT | ||
105 | dmax = state->dmax; | ||
106 | #endif | ||
107 | wsize = state->wsize; | ||
108 | whave = state->whave; | ||
109 | wnext = state->wnext; | ||
110 | window = state->window; | ||
111 | hold = state->hold; | ||
112 | bits = state->bits; | ||
113 | lcode = state->lencode; | ||
114 | dcode = state->distcode; | ||
115 | lmask = (1U << state->lenbits) - 1; | ||
116 | dmask = (1U << state->distbits) - 1; | ||
117 | |||
118 | /* decode literals and length/distances until end-of-block or not enough | ||
119 | input data or output space */ | ||
120 | do { | ||
121 | if (bits < 15) { | ||
122 | hold += (unsigned long)(PUP(in)) << bits; | ||
123 | bits += 8; | ||
124 | hold += (unsigned long)(PUP(in)) << bits; | ||
125 | bits += 8; | ||
126 | } | ||
127 | here = lcode[hold & lmask]; | ||
128 | dolen: | ||
129 | op = (unsigned)(here.bits); | ||
130 | hold >>= op; | ||
131 | bits -= op; | ||
132 | op = (unsigned)(here.op); | ||
133 | if (op == 0) { /* literal */ | ||
134 | Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ? | ||
135 | "inflate: literal '%c'\n" : | ||
136 | "inflate: literal 0x%02x\n", here.val)); | ||
137 | PUP(out) = (unsigned char)(here.val); | ||
138 | } | ||
139 | else if (op & 16) { /* length base */ | ||
140 | len = (unsigned)(here.val); | ||
141 | op &= 15; /* number of extra bits */ | ||
142 | if (op) { | ||
143 | if (bits < op) { | ||
144 | hold += (unsigned long)(PUP(in)) << bits; | ||
145 | bits += 8; | ||
146 | } | ||
147 | len += (unsigned)hold & ((1U << op) - 1); | ||
148 | hold >>= op; | ||
149 | bits -= op; | ||
150 | } | ||
151 | Tracevv((stderr, "inflate: length %u\n", len)); | ||
152 | if (bits < 15) { | ||
153 | hold += (unsigned long)(PUP(in)) << bits; | ||
154 | bits += 8; | ||
155 | hold += (unsigned long)(PUP(in)) << bits; | ||
156 | bits += 8; | ||
157 | } | ||
158 | here = dcode[hold & dmask]; | ||
159 | dodist: | ||
160 | op = (unsigned)(here.bits); | ||
161 | hold >>= op; | ||
162 | bits -= op; | ||
163 | op = (unsigned)(here.op); | ||
164 | if (op & 16) { /* distance base */ | ||
165 | dist = (unsigned)(here.val); | ||
166 | op &= 15; /* number of extra bits */ | ||
167 | if (bits < op) { | ||
168 | hold += (unsigned long)(PUP(in)) << bits; | ||
169 | bits += 8; | ||
170 | if (bits < op) { | ||
171 | hold += (unsigned long)(PUP(in)) << bits; | ||
172 | bits += 8; | ||
173 | } | ||
174 | } | ||
175 | dist += (unsigned)hold & ((1U << op) - 1); | ||
176 | #ifdef INFLATE_STRICT | ||
177 | if (dist > dmax) { | ||
178 | strm->msg = (char *)"invalid distance too far back"; | ||
179 | state->mode = BAD; | ||
180 | break; | ||
181 | } | ||
182 | #endif | ||
183 | hold >>= op; | ||
184 | bits -= op; | ||
185 | Tracevv((stderr, "inflate: distance %u\n", dist)); | ||
186 | op = (unsigned)(out - beg); /* max distance in output */ | ||
187 | if (dist > op) { /* see if copy from window */ | ||
188 | op = dist - op; /* distance back in window */ | ||
189 | if (op > whave) { | ||
190 | if (state->sane) { | ||
191 | strm->msg = | ||
192 | (char *)"invalid distance too far back"; | ||
193 | state->mode = BAD; | ||
194 | break; | ||
195 | } | ||
196 | #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR | ||
197 | if (len <= op - whave) { | ||
198 | do { | ||
199 | PUP(out) = 0; | ||
200 | } while (--len); | ||
201 | continue; | ||
202 | } | ||
203 | len -= op - whave; | ||
204 | do { | ||
205 | PUP(out) = 0; | ||
206 | } while (--op > whave); | ||
207 | if (op == 0) { | ||
208 | from = out - dist; | ||
209 | do { | ||
210 | PUP(out) = PUP(from); | ||
211 | } while (--len); | ||
212 | continue; | ||
213 | } | ||
214 | #endif | ||
215 | } | ||
216 | from = window - OFF; | ||
217 | if (wnext == 0) { /* very common case */ | ||
218 | from += wsize - op; | ||
219 | if (op < len) { /* some from window */ | ||
220 | len -= op; | ||
221 | do { | ||
222 | PUP(out) = PUP(from); | ||
223 | } while (--op); | ||
224 | from = out - dist; /* rest from output */ | ||
225 | } | ||
226 | } | ||
227 | else if (wnext < op) { /* wrap around window */ | ||
228 | from += wsize + wnext - op; | ||
229 | op -= wnext; | ||
230 | if (op < len) { /* some from end of window */ | ||
231 | len -= op; | ||
232 | do { | ||
233 | PUP(out) = PUP(from); | ||
234 | } while (--op); | ||
235 | from = window - OFF; | ||
236 | if (wnext < len) { /* some from start of window */ | ||
237 | op = wnext; | ||
238 | len -= op; | ||
239 | do { | ||
240 | PUP(out) = PUP(from); | ||
241 | } while (--op); | ||
242 | from = out - dist; /* rest from output */ | ||
243 | } | ||
244 | } | ||
245 | } | ||
246 | else { /* contiguous in window */ | ||
247 | from += wnext - op; | ||
248 | if (op < len) { /* some from window */ | ||
249 | len -= op; | ||
250 | do { | ||
251 | PUP(out) = PUP(from); | ||
252 | } while (--op); | ||
253 | from = out - dist; /* rest from output */ | ||
254 | } | ||
255 | } | ||
256 | while (len > 2) { | ||
257 | PUP(out) = PUP(from); | ||
258 | PUP(out) = PUP(from); | ||
259 | PUP(out) = PUP(from); | ||
260 | len -= 3; | ||
261 | } | ||
262 | if (len) { | ||
263 | PUP(out) = PUP(from); | ||
264 | if (len > 1) | ||
265 | PUP(out) = PUP(from); | ||
266 | } | ||
267 | } | ||
268 | else { | ||
269 | from = out - dist; /* copy direct from output */ | ||
270 | do { /* minimum length is three */ | ||
271 | PUP(out) = PUP(from); | ||
272 | PUP(out) = PUP(from); | ||
273 | PUP(out) = PUP(from); | ||
274 | len -= 3; | ||
275 | } while (len > 2); | ||
276 | if (len) { | ||
277 | PUP(out) = PUP(from); | ||
278 | if (len > 1) | ||
279 | PUP(out) = PUP(from); | ||
280 | } | ||
281 | } | ||
282 | } | ||
283 | else if ((op & 64) == 0) { /* 2nd level distance code */ | ||
284 | here = dcode[here.val + (hold & ((1U << op) - 1))]; | ||
285 | goto dodist; | ||
286 | } | ||
287 | else { | ||
288 | strm->msg = (char *)"invalid distance code"; | ||
289 | state->mode = BAD; | ||
290 | break; | ||
291 | } | ||
292 | } | ||
293 | else if ((op & 64) == 0) { /* 2nd level length code */ | ||
294 | here = lcode[here.val + (hold & ((1U << op) - 1))]; | ||
295 | goto dolen; | ||
296 | } | ||
297 | else if (op & 32) { /* end-of-block */ | ||
298 | Tracevv((stderr, "inflate: end of block\n")); | ||
299 | state->mode = TYPE; | ||
300 | break; | ||
301 | } | ||
302 | else { | ||
303 | strm->msg = (char *)"invalid literal/length code"; | ||
304 | state->mode = BAD; | ||
305 | break; | ||
306 | } | ||
307 | } while (in < last && out < end); | ||
308 | |||
309 | /* return unused bytes (on entry, bits < 8, so in won't go too far back) */ | ||
310 | len = bits >> 3; | ||
311 | in -= len; | ||
312 | bits -= len << 3; | ||
313 | hold &= (1U << bits) - 1; | ||
314 | |||
315 | /* update state and return */ | ||
316 | strm->next_in = in + OFF; | ||
317 | strm->next_out = out + OFF; | ||
318 | strm->avail_in = (unsigned)(in < last ? 5 + (last - in) : 5 - (in - last)); | ||
319 | strm->avail_out = (unsigned)(out < end ? | ||
320 | 257 + (end - out) : 257 - (out - end)); | ||
321 | state->hold = hold; | ||
322 | state->bits = bits; | ||
323 | return; | ||
324 | } | ||
325 | |||
326 | /* | ||
327 | inflate_fast() speedups that turned out slower (on a PowerPC G3 750CXe): | ||
328 | - Using bit fields for code structure | ||
329 | - Different op definition to avoid & for extra bits (do & for table bits) | ||
330 | - Three separate decoding do-loops for direct, window, and wnext == 0 | ||
331 | - Special case for distance > 1 copies to do overlapped load and store copy | ||
332 | - Explicit branch predictions (based on measured branch probabilities) | ||
333 | - Deferring match copy and interspersed it with decoding subsequent codes | ||
334 | - Swapping literal/length else | ||
335 | - Swapping window/direct else | ||
336 | - Larger unrolled copy loops (three is about right) | ||
337 | - Moving len -= 3 statement into middle of loop | ||
338 | */ | ||
339 | |||
340 | #endif /* !ASMINF */ | ||