lemon-project-template-glpk

annotate deps/glpk/src/zlib/inffast.c @ 11:4fc6ad2fb8a6

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Test GLPK in src/main.cc
author Alpar Juttner <alpar@cs.elte.hu>
date Sun, 06 Nov 2011 21:43:29 +0100
parents
children
rev   line source
alpar@9 1 /* inffast.c -- fast decoding
alpar@9 2 * Copyright (C) 1995-2008, 2010 Mark Adler
alpar@9 3 * For conditions of distribution and use, see copyright notice in zlib.h
alpar@9 4 */
alpar@9 5
alpar@9 6 #include "zutil.h"
alpar@9 7 #include "inftrees.h"
alpar@9 8 #include "inflate.h"
alpar@9 9 #include "inffast.h"
alpar@9 10
alpar@9 11 #ifndef ASMINF
alpar@9 12
alpar@9 13 /* Allow machine dependent optimization for post-increment or pre-increment.
alpar@9 14 Based on testing to date,
alpar@9 15 Pre-increment preferred for:
alpar@9 16 - PowerPC G3 (Adler)
alpar@9 17 - MIPS R5000 (Randers-Pehrson)
alpar@9 18 Post-increment preferred for:
alpar@9 19 - none
alpar@9 20 No measurable difference:
alpar@9 21 - Pentium III (Anderson)
alpar@9 22 - M68060 (Nikl)
alpar@9 23 */
alpar@9 24 #ifdef POSTINC
alpar@9 25 # define OFF 0
alpar@9 26 # define PUP(a) *(a)++
alpar@9 27 #else
alpar@9 28 # define OFF 1
alpar@9 29 # define PUP(a) *++(a)
alpar@9 30 #endif
alpar@9 31
alpar@9 32 /*
alpar@9 33 Decode literal, length, and distance codes and write out the resulting
alpar@9 34 literal and match bytes until either not enough input or output is
alpar@9 35 available, an end-of-block is encountered, or a data error is encountered.
alpar@9 36 When large enough input and output buffers are supplied to inflate(), for
alpar@9 37 example, a 16K input buffer and a 64K output buffer, more than 95% of the
alpar@9 38 inflate execution time is spent in this routine.
alpar@9 39
alpar@9 40 Entry assumptions:
alpar@9 41
alpar@9 42 state->mode == LEN
alpar@9 43 strm->avail_in >= 6
alpar@9 44 strm->avail_out >= 258
alpar@9 45 start >= strm->avail_out
alpar@9 46 state->bits < 8
alpar@9 47
alpar@9 48 On return, state->mode is one of:
alpar@9 49
alpar@9 50 LEN -- ran out of enough output space or enough available input
alpar@9 51 TYPE -- reached end of block code, inflate() to interpret next block
alpar@9 52 BAD -- error in block data
alpar@9 53
alpar@9 54 Notes:
alpar@9 55
alpar@9 56 - The maximum input bits used by a length/distance pair is 15 bits for the
alpar@9 57 length code, 5 bits for the length extra, 15 bits for the distance code,
alpar@9 58 and 13 bits for the distance extra. This totals 48 bits, or six bytes.
alpar@9 59 Therefore if strm->avail_in >= 6, then there is enough input to avoid
alpar@9 60 checking for available input while decoding.
alpar@9 61
alpar@9 62 - The maximum bytes that a single length/distance pair can output is 258
alpar@9 63 bytes, which is the maximum length that can be coded. inflate_fast()
alpar@9 64 requires strm->avail_out >= 258 for each loop to avoid checking for
alpar@9 65 output space.
alpar@9 66 */
alpar@9 67 void ZLIB_INTERNAL inflate_fast(strm, start)
alpar@9 68 z_streamp strm;
alpar@9 69 unsigned start; /* inflate()'s starting value for strm->avail_out */
alpar@9 70 {
alpar@9 71 struct inflate_state FAR *state;
alpar@9 72 unsigned char FAR *in; /* local strm->next_in */
alpar@9 73 unsigned char FAR *last; /* while in < last, enough input available */
alpar@9 74 unsigned char FAR *out; /* local strm->next_out */
alpar@9 75 unsigned char FAR *beg; /* inflate()'s initial strm->next_out */
alpar@9 76 unsigned char FAR *end; /* while out < end, enough space available */
alpar@9 77 #ifdef INFLATE_STRICT
alpar@9 78 unsigned dmax; /* maximum distance from zlib header */
alpar@9 79 #endif
alpar@9 80 unsigned wsize; /* window size or zero if not using window */
alpar@9 81 unsigned whave; /* valid bytes in the window */
alpar@9 82 unsigned wnext; /* window write index */
alpar@9 83 unsigned char FAR *window; /* allocated sliding window, if wsize != 0 */
alpar@9 84 unsigned long hold; /* local strm->hold */
alpar@9 85 unsigned bits; /* local strm->bits */
alpar@9 86 code const FAR *lcode; /* local strm->lencode */
alpar@9 87 code const FAR *dcode; /* local strm->distcode */
alpar@9 88 unsigned lmask; /* mask for first level of length codes */
alpar@9 89 unsigned dmask; /* mask for first level of distance codes */
alpar@9 90 code here; /* retrieved table entry */
alpar@9 91 unsigned op; /* code bits, operation, extra bits, or */
alpar@9 92 /* window position, window bytes to copy */
alpar@9 93 unsigned len; /* match length, unused bytes */
alpar@9 94 unsigned dist; /* match distance */
alpar@9 95 unsigned char FAR *from; /* where to copy match from */
alpar@9 96
alpar@9 97 /* copy state to local variables */
alpar@9 98 state = (struct inflate_state FAR *)strm->state;
alpar@9 99 in = strm->next_in - OFF;
alpar@9 100 last = in + (strm->avail_in - 5);
alpar@9 101 out = strm->next_out - OFF;
alpar@9 102 beg = out - (start - strm->avail_out);
alpar@9 103 end = out + (strm->avail_out - 257);
alpar@9 104 #ifdef INFLATE_STRICT
alpar@9 105 dmax = state->dmax;
alpar@9 106 #endif
alpar@9 107 wsize = state->wsize;
alpar@9 108 whave = state->whave;
alpar@9 109 wnext = state->wnext;
alpar@9 110 window = state->window;
alpar@9 111 hold = state->hold;
alpar@9 112 bits = state->bits;
alpar@9 113 lcode = state->lencode;
alpar@9 114 dcode = state->distcode;
alpar@9 115 lmask = (1U << state->lenbits) - 1;
alpar@9 116 dmask = (1U << state->distbits) - 1;
alpar@9 117
alpar@9 118 /* decode literals and length/distances until end-of-block or not enough
alpar@9 119 input data or output space */
alpar@9 120 do {
alpar@9 121 if (bits < 15) {
alpar@9 122 hold += (unsigned long)(PUP(in)) << bits;
alpar@9 123 bits += 8;
alpar@9 124 hold += (unsigned long)(PUP(in)) << bits;
alpar@9 125 bits += 8;
alpar@9 126 }
alpar@9 127 here = lcode[hold & lmask];
alpar@9 128 dolen:
alpar@9 129 op = (unsigned)(here.bits);
alpar@9 130 hold >>= op;
alpar@9 131 bits -= op;
alpar@9 132 op = (unsigned)(here.op);
alpar@9 133 if (op == 0) { /* literal */
alpar@9 134 Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
alpar@9 135 "inflate: literal '%c'\n" :
alpar@9 136 "inflate: literal 0x%02x\n", here.val));
alpar@9 137 PUP(out) = (unsigned char)(here.val);
alpar@9 138 }
alpar@9 139 else if (op & 16) { /* length base */
alpar@9 140 len = (unsigned)(here.val);
alpar@9 141 op &= 15; /* number of extra bits */
alpar@9 142 if (op) {
alpar@9 143 if (bits < op) {
alpar@9 144 hold += (unsigned long)(PUP(in)) << bits;
alpar@9 145 bits += 8;
alpar@9 146 }
alpar@9 147 len += (unsigned)hold & ((1U << op) - 1);
alpar@9 148 hold >>= op;
alpar@9 149 bits -= op;
alpar@9 150 }
alpar@9 151 Tracevv((stderr, "inflate: length %u\n", len));
alpar@9 152 if (bits < 15) {
alpar@9 153 hold += (unsigned long)(PUP(in)) << bits;
alpar@9 154 bits += 8;
alpar@9 155 hold += (unsigned long)(PUP(in)) << bits;
alpar@9 156 bits += 8;
alpar@9 157 }
alpar@9 158 here = dcode[hold & dmask];
alpar@9 159 dodist:
alpar@9 160 op = (unsigned)(here.bits);
alpar@9 161 hold >>= op;
alpar@9 162 bits -= op;
alpar@9 163 op = (unsigned)(here.op);
alpar@9 164 if (op & 16) { /* distance base */
alpar@9 165 dist = (unsigned)(here.val);
alpar@9 166 op &= 15; /* number of extra bits */
alpar@9 167 if (bits < op) {
alpar@9 168 hold += (unsigned long)(PUP(in)) << bits;
alpar@9 169 bits += 8;
alpar@9 170 if (bits < op) {
alpar@9 171 hold += (unsigned long)(PUP(in)) << bits;
alpar@9 172 bits += 8;
alpar@9 173 }
alpar@9 174 }
alpar@9 175 dist += (unsigned)hold & ((1U << op) - 1);
alpar@9 176 #ifdef INFLATE_STRICT
alpar@9 177 if (dist > dmax) {
alpar@9 178 strm->msg = (char *)"invalid distance too far back";
alpar@9 179 state->mode = BAD;
alpar@9 180 break;
alpar@9 181 }
alpar@9 182 #endif
alpar@9 183 hold >>= op;
alpar@9 184 bits -= op;
alpar@9 185 Tracevv((stderr, "inflate: distance %u\n", dist));
alpar@9 186 op = (unsigned)(out - beg); /* max distance in output */
alpar@9 187 if (dist > op) { /* see if copy from window */
alpar@9 188 op = dist - op; /* distance back in window */
alpar@9 189 if (op > whave) {
alpar@9 190 if (state->sane) {
alpar@9 191 strm->msg =
alpar@9 192 (char *)"invalid distance too far back";
alpar@9 193 state->mode = BAD;
alpar@9 194 break;
alpar@9 195 }
alpar@9 196 #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
alpar@9 197 if (len <= op - whave) {
alpar@9 198 do {
alpar@9 199 PUP(out) = 0;
alpar@9 200 } while (--len);
alpar@9 201 continue;
alpar@9 202 }
alpar@9 203 len -= op - whave;
alpar@9 204 do {
alpar@9 205 PUP(out) = 0;
alpar@9 206 } while (--op > whave);
alpar@9 207 if (op == 0) {
alpar@9 208 from = out - dist;
alpar@9 209 do {
alpar@9 210 PUP(out) = PUP(from);
alpar@9 211 } while (--len);
alpar@9 212 continue;
alpar@9 213 }
alpar@9 214 #endif
alpar@9 215 }
alpar@9 216 from = window - OFF;
alpar@9 217 if (wnext == 0) { /* very common case */
alpar@9 218 from += wsize - op;
alpar@9 219 if (op < len) { /* some from window */
alpar@9 220 len -= op;
alpar@9 221 do {
alpar@9 222 PUP(out) = PUP(from);
alpar@9 223 } while (--op);
alpar@9 224 from = out - dist; /* rest from output */
alpar@9 225 }
alpar@9 226 }
alpar@9 227 else if (wnext < op) { /* wrap around window */
alpar@9 228 from += wsize + wnext - op;
alpar@9 229 op -= wnext;
alpar@9 230 if (op < len) { /* some from end of window */
alpar@9 231 len -= op;
alpar@9 232 do {
alpar@9 233 PUP(out) = PUP(from);
alpar@9 234 } while (--op);
alpar@9 235 from = window - OFF;
alpar@9 236 if (wnext < len) { /* some from start of window */
alpar@9 237 op = wnext;
alpar@9 238 len -= op;
alpar@9 239 do {
alpar@9 240 PUP(out) = PUP(from);
alpar@9 241 } while (--op);
alpar@9 242 from = out - dist; /* rest from output */
alpar@9 243 }
alpar@9 244 }
alpar@9 245 }
alpar@9 246 else { /* contiguous in window */
alpar@9 247 from += wnext - op;
alpar@9 248 if (op < len) { /* some from window */
alpar@9 249 len -= op;
alpar@9 250 do {
alpar@9 251 PUP(out) = PUP(from);
alpar@9 252 } while (--op);
alpar@9 253 from = out - dist; /* rest from output */
alpar@9 254 }
alpar@9 255 }
alpar@9 256 while (len > 2) {
alpar@9 257 PUP(out) = PUP(from);
alpar@9 258 PUP(out) = PUP(from);
alpar@9 259 PUP(out) = PUP(from);
alpar@9 260 len -= 3;
alpar@9 261 }
alpar@9 262 if (len) {
alpar@9 263 PUP(out) = PUP(from);
alpar@9 264 if (len > 1)
alpar@9 265 PUP(out) = PUP(from);
alpar@9 266 }
alpar@9 267 }
alpar@9 268 else {
alpar@9 269 from = out - dist; /* copy direct from output */
alpar@9 270 do { /* minimum length is three */
alpar@9 271 PUP(out) = PUP(from);
alpar@9 272 PUP(out) = PUP(from);
alpar@9 273 PUP(out) = PUP(from);
alpar@9 274 len -= 3;
alpar@9 275 } while (len > 2);
alpar@9 276 if (len) {
alpar@9 277 PUP(out) = PUP(from);
alpar@9 278 if (len > 1)
alpar@9 279 PUP(out) = PUP(from);
alpar@9 280 }
alpar@9 281 }
alpar@9 282 }
alpar@9 283 else if ((op & 64) == 0) { /* 2nd level distance code */
alpar@9 284 here = dcode[here.val + (hold & ((1U << op) - 1))];
alpar@9 285 goto dodist;
alpar@9 286 }
alpar@9 287 else {
alpar@9 288 strm->msg = (char *)"invalid distance code";
alpar@9 289 state->mode = BAD;
alpar@9 290 break;
alpar@9 291 }
alpar@9 292 }
alpar@9 293 else if ((op & 64) == 0) { /* 2nd level length code */
alpar@9 294 here = lcode[here.val + (hold & ((1U << op) - 1))];
alpar@9 295 goto dolen;
alpar@9 296 }
alpar@9 297 else if (op & 32) { /* end-of-block */
alpar@9 298 Tracevv((stderr, "inflate: end of block\n"));
alpar@9 299 state->mode = TYPE;
alpar@9 300 break;
alpar@9 301 }
alpar@9 302 else {
alpar@9 303 strm->msg = (char *)"invalid literal/length code";
alpar@9 304 state->mode = BAD;
alpar@9 305 break;
alpar@9 306 }
alpar@9 307 } while (in < last && out < end);
alpar@9 308
alpar@9 309 /* return unused bytes (on entry, bits < 8, so in won't go too far back) */
alpar@9 310 len = bits >> 3;
alpar@9 311 in -= len;
alpar@9 312 bits -= len << 3;
alpar@9 313 hold &= (1U << bits) - 1;
alpar@9 314
alpar@9 315 /* update state and return */
alpar@9 316 strm->next_in = in + OFF;
alpar@9 317 strm->next_out = out + OFF;
alpar@9 318 strm->avail_in = (unsigned)(in < last ? 5 + (last - in) : 5 - (in - last));
alpar@9 319 strm->avail_out = (unsigned)(out < end ?
alpar@9 320 257 + (end - out) : 257 - (out - end));
alpar@9 321 state->hold = hold;
alpar@9 322 state->bits = bits;
alpar@9 323 return;
alpar@9 324 }
alpar@9 325
alpar@9 326 /*
alpar@9 327 inflate_fast() speedups that turned out slower (on a PowerPC G3 750CXe):
alpar@9 328 - Using bit fields for code structure
alpar@9 329 - Different op definition to avoid & for extra bits (do & for table bits)
alpar@9 330 - Three separate decoding do-loops for direct, window, and wnext == 0
alpar@9 331 - Special case for distance > 1 copies to do overlapped load and store copy
alpar@9 332 - Explicit branch predictions (based on measured branch probabilities)
alpar@9 333 - Deferring match copy and interspersed it with decoding subsequent codes
alpar@9 334 - Swapping literal/length else
alpar@9 335 - Swapping window/direct else
alpar@9 336 - Larger unrolled copy loops (three is about right)
alpar@9 337 - Moving len -= 3 statement into middle of loop
alpar@9 338 */
alpar@9 339
alpar@9 340 #endif /* !ASMINF */