X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fzlib_inflate%2Finffast.c;fp=lib%2Fzlib_inflate%2Finffast.c;h=0bd7623fc85acefb2698cfc447ff2f6ca986a280;hb=64ba3f394c830ec48a1c31b53dcae312c56f1604;hp=d84560c076d83cfca8a0d2d19b6214ed1cac23ca;hpb=be1e6109ac94a859551f8e1774eb9a8469fe055c;p=linux-2.6.git diff --git a/lib/zlib_inflate/inffast.c b/lib/zlib_inflate/inffast.c index d84560c07..0bd7623fc 100644 --- a/lib/zlib_inflate/inffast.c +++ b/lib/zlib_inflate/inffast.c @@ -1,312 +1,176 @@ -/* inffast.c -- fast decoding - * Copyright (C) 1995-2004 Mark Adler - * For conditions of distribution and use, see copyright notice in zlib.h +/* inffast.c -- process literals and length/distance pairs fast + * Copyright (C) 1995-1998 Mark Adler + * For conditions of distribution and use, see copyright notice in zlib.h */ #include #include "inftrees.h" -#include "inflate.h" +#include "infblock.h" +#include "infcodes.h" +#include "infutil.h" #include "inffast.h" -#ifndef ASMINF - -/* Allow machine dependent optimization for post-increment or pre-increment. - Based on testing to date, - Pre-increment preferred for: - - PowerPC G3 (Adler) - - MIPS R5000 (Randers-Pehrson) - Post-increment preferred for: - - none - No measurable difference: - - Pentium III (Anderson) - - M68060 (Nikl) - */ -#ifdef POSTINC -# define OFF 0 -# define PUP(a) *(a)++ -#else -# define OFF 1 -# define PUP(a) *++(a) -#endif - -/* - Decode literal, length, and distance codes and write out the resulting - literal and match bytes until either not enough input or output is - available, an end-of-block is encountered, or a data error is encountered. - When large enough input and output buffers are supplied to inflate(), for - example, a 16K input buffer and a 64K output buffer, more than 95% of the - inflate execution time is spent in this routine. - - Entry assumptions: - - state->mode == LEN - strm->avail_in >= 6 - strm->avail_out >= 258 - start >= strm->avail_out - state->bits < 8 - - On return, state->mode is one of: - - LEN -- ran out of enough output space or enough available input - TYPE -- reached end of block code, inflate() to interpret next block - BAD -- error in block data - - Notes: - - - The maximum input bits used by a length/distance pair is 15 bits for the - length code, 5 bits for the length extra, 15 bits for the distance code, - and 13 bits for the distance extra. This totals 48 bits, or six bytes. - Therefore if strm->avail_in >= 6, then there is enough input to avoid - checking for available input while decoding. - - - The maximum bytes that a single length/distance pair can output is 258 - bytes, which is the maximum length that can be coded. inflate_fast() - requires strm->avail_out >= 258 for each loop to avoid checking for - output space. - - - @start: inflate()'s starting value for strm->avail_out - */ -void inflate_fast(z_streamp strm, unsigned start) +struct inflate_codes_state; + +/* simplify the use of the inflate_huft type with some defines */ +#define exop word.what.Exop +#define bits word.what.Bits + +/* macros for bit input with no checking and for returning unused bytes */ +#define GRABBITS(j) {while(k<(j)){b|=((uLong)NEXTBYTE)<avail_in-n;c=(k>>3)>3:c;n+=c;p-=c;k-=c<<3;} + +/* Called with number of bytes left to write in window at least 258 + (the maximum string length) and number of input bytes available + at least ten. The ten bytes are six bytes for the longest length/ + distance pair plus four bytes for overloading the bit buffer. */ + +int zlib_inflate_fast( + uInt bl, + uInt bd, + inflate_huft *tl, + inflate_huft *td, /* need separate declaration for Borland C++ */ + inflate_blocks_statef *s, + z_streamp z +) { - struct inflate_state *state; - unsigned char *in; /* local strm->next_in */ - unsigned char *last; /* while in < last, enough input available */ - unsigned char *out; /* local strm->next_out */ - unsigned char *beg; /* inflate()'s initial strm->next_out */ - unsigned char *end; /* while out < end, enough space available */ -#ifdef INFLATE_STRICT - unsigned dmax; /* maximum distance from zlib header */ -#endif - unsigned wsize; /* window size or zero if not using window */ - unsigned whave; /* valid bytes in the window */ - unsigned write; /* window write index */ - unsigned char *window; /* allocated sliding window, if wsize != 0 */ - unsigned long hold; /* local strm->hold */ - unsigned bits; /* local strm->bits */ - code const *lcode; /* local strm->lencode */ - code const *dcode; /* local strm->distcode */ - unsigned lmask; /* mask for first level of length codes */ - unsigned dmask; /* mask for first level of distance codes */ - code this; /* retrieved table entry */ - unsigned op; /* code bits, operation, extra bits, or */ - /* window position, window bytes to copy */ - unsigned len; /* match length, unused bytes */ - unsigned dist; /* match distance */ - unsigned char *from; /* where to copy match from */ - - /* copy state to local variables */ - state = (struct inflate_state *)strm->state; - in = strm->next_in - OFF; - last = in + (strm->avail_in - 5); - out = strm->next_out - OFF; - beg = out - (start - strm->avail_out); - end = out + (strm->avail_out - 257); -#ifdef INFLATE_STRICT - dmax = state->dmax; -#endif - wsize = state->wsize; - whave = state->whave; - write = state->write; - window = state->window; - hold = state->hold; - bits = state->bits; - lcode = state->lencode; - dcode = state->distcode; - lmask = (1U << state->lenbits) - 1; - dmask = (1U << state->distbits) - 1; - - /* decode literals and length/distances until end-of-block or not enough - input data or output space */ + inflate_huft *t; /* temporary pointer */ + uInt e; /* extra bits or operation */ + uLong b; /* bit buffer */ + uInt k; /* bits in bit buffer */ + Byte *p; /* input data pointer */ + uInt n; /* bytes available there */ + Byte *q; /* output window write pointer */ + uInt m; /* bytes to end of window or read pointer */ + uInt ml; /* mask for literal/length tree */ + uInt md; /* mask for distance tree */ + uInt c; /* bytes to copy */ + uInt d; /* distance back to copy from */ + Byte *r; /* copy source pointer */ + + /* load input, output, bit values */ + LOAD + + /* initialize masks */ + ml = zlib_inflate_mask[bl]; + md = zlib_inflate_mask[bd]; + + /* do until not enough input or output space for fast loop */ + do { /* assume called with m >= 258 && n >= 10 */ + /* get literal/length code */ + GRABBITS(20) /* max bits for literal/length code */ + if ((e = (t = tl + ((uInt)b & ml))->exop) == 0) + { + DUMPBITS(t->bits) + *q++ = (Byte)t->base; + m--; + continue; + } do { - if (bits < 15) { - hold += (unsigned long)(PUP(in)) << bits; - bits += 8; - hold += (unsigned long)(PUP(in)) << bits; - bits += 8; - } - this = lcode[hold & lmask]; - dolen: - op = (unsigned)(this.bits); - hold >>= op; - bits -= op; - op = (unsigned)(this.op); - if (op == 0) { /* literal */ - PUP(out) = (unsigned char)(this.val); - } - else if (op & 16) { /* length base */ - len = (unsigned)(this.val); - op &= 15; /* number of extra bits */ - if (op) { - if (bits < op) { - hold += (unsigned long)(PUP(in)) << bits; - bits += 8; - } - len += (unsigned)hold & ((1U << op) - 1); - hold >>= op; - bits -= op; - } - if (bits < 15) { - hold += (unsigned long)(PUP(in)) << bits; - bits += 8; - hold += (unsigned long)(PUP(in)) << bits; - bits += 8; - } - this = dcode[hold & dmask]; - dodist: - op = (unsigned)(this.bits); - hold >>= op; - bits -= op; - op = (unsigned)(this.op); - if (op & 16) { /* distance base */ - dist = (unsigned)(this.val); - op &= 15; /* number of extra bits */ - if (bits < op) { - hold += (unsigned long)(PUP(in)) << bits; - bits += 8; - if (bits < op) { - hold += (unsigned long)(PUP(in)) << bits; - bits += 8; - } - } - dist += (unsigned)hold & ((1U << op) - 1); -#ifdef INFLATE_STRICT - if (dist > dmax) { - strm->msg = (char *)"invalid distance too far back"; - state->mode = BAD; - break; - } -#endif - hold >>= op; - bits -= op; - op = (unsigned)(out - beg); /* max distance in output */ - if (dist > op) { /* see if copy from window */ - op = dist - op; /* distance back in window */ - if (op > whave) { - strm->msg = (char *)"invalid distance too far back"; - state->mode = BAD; - break; - } - from = window - OFF; - if (write == 0) { /* very common case */ - from += wsize - op; - if (op < len) { /* some from window */ - len -= op; - do { - PUP(out) = PUP(from); - } while (--op); - from = out - dist; /* rest from output */ - } - } - else if (write < op) { /* wrap around window */ - from += wsize + write - op; - op -= write; - if (op < len) { /* some from end of window */ - len -= op; - do { - PUP(out) = PUP(from); - } while (--op); - from = window - OFF; - if (write < len) { /* some from start of window */ - op = write; - len -= op; - do { - PUP(out) = PUP(from); - } while (--op); - from = out - dist; /* rest from output */ - } - } - } - else { /* contiguous in window */ - from += write - op; - if (op < len) { /* some from window */ - len -= op; - do { - PUP(out) = PUP(from); - } while (--op); - from = out - dist; /* rest from output */ - } - } - while (len > 2) { - PUP(out) = PUP(from); - PUP(out) = PUP(from); - PUP(out) = PUP(from); - len -= 3; - } - if (len) { - PUP(out) = PUP(from); - if (len > 1) - PUP(out) = PUP(from); - } - } - else { - from = out - dist; /* copy direct from output */ - do { /* minimum length is three */ - PUP(out) = PUP(from); - PUP(out) = PUP(from); - PUP(out) = PUP(from); - len -= 3; - } while (len > 2); - if (len) { - PUP(out) = PUP(from); - if (len > 1) - PUP(out) = PUP(from); - } - } + DUMPBITS(t->bits) + if (e & 16) + { + /* get extra bits for length */ + e &= 15; + c = t->base + ((uInt)b & zlib_inflate_mask[e]); + DUMPBITS(e) + + /* decode distance base of block to copy */ + GRABBITS(15); /* max bits for distance code */ + e = (t = td + ((uInt)b & md))->exop; + do { + DUMPBITS(t->bits) + if (e & 16) + { + /* get extra bits to add to distance base */ + e &= 15; + GRABBITS(e) /* get extra bits (up to 13) */ + d = t->base + ((uInt)b & zlib_inflate_mask[e]); + DUMPBITS(e) + + /* do the copy */ + m -= c; + r = q - d; + if (r < s->window) /* wrap if needed */ + { + do { + r += s->end - s->window; /* force pointer in window */ + } while (r < s->window); /* covers invalid distances */ + e = s->end - r; + if (c > e) + { + c -= e; /* wrapped copy */ + do { + *q++ = *r++; + } while (--e); + r = s->window; + do { + *q++ = *r++; + } while (--c); + } + else /* normal copy */ + { + *q++ = *r++; c--; + *q++ = *r++; c--; + do { + *q++ = *r++; + } while (--c); + } } - else if ((op & 64) == 0) { /* 2nd level distance code */ - this = dcode[this.val + (hold & ((1U << op) - 1))]; - goto dodist; + else /* normal copy */ + { + *q++ = *r++; c--; + *q++ = *r++; c--; + do { + *q++ = *r++; + } while (--c); } - else { - strm->msg = (char *)"invalid distance code"; - state->mode = BAD; - break; - } - } - else if ((op & 64) == 0) { /* 2nd level length code */ - this = lcode[this.val + (hold & ((1U << op) - 1))]; - goto dolen; - } - else if (op & 32) { /* end-of-block */ - state->mode = TYPE; break; + } + else if ((e & 64) == 0) + { + t += t->base; + e = (t += ((uInt)b & zlib_inflate_mask[e]))->exop; + } + else + { + z->msg = (char*)"invalid distance code"; + UNGRAB + UPDATE + return Z_DATA_ERROR; + } + } while (1); + break; + } + if ((e & 64) == 0) + { + t += t->base; + if ((e = (t += ((uInt)b & zlib_inflate_mask[e]))->exop) == 0) + { + DUMPBITS(t->bits) + *q++ = (Byte)t->base; + m--; + break; } - else { - strm->msg = (char *)"invalid literal/length code"; - state->mode = BAD; - break; - } - } while (in < last && out < end); - - /* return unused bytes (on entry, bits < 8, so in won't go too far back) */ - len = bits >> 3; - in -= len; - bits -= len << 3; - hold &= (1U << bits) - 1; - - /* update state and return */ - strm->next_in = in + OFF; - strm->next_out = out + OFF; - strm->avail_in = (unsigned)(in < last ? 5 + (last - in) : 5 - (in - last)); - strm->avail_out = (unsigned)(out < end ? - 257 + (end - out) : 257 - (out - end)); - state->hold = hold; - state->bits = bits; - return; + } + else if (e & 32) + { + UNGRAB + UPDATE + return Z_STREAM_END; + } + else + { + z->msg = (char*)"invalid literal/length code"; + UNGRAB + UPDATE + return Z_DATA_ERROR; + } + } while (1); + } while (m >= 258 && n >= 10); + + /* not enough input or output--restore pointers and return */ + UNGRAB + UPDATE + return Z_OK; } - -/* - inflate_fast() speedups that turned out slower (on a PowerPC G3 750CXe): - - Using bit fields for code structure - - Different op definition to avoid & for extra bits (do & for table bits) - - Three separate decoding do-loops for direct, window, and write == 0 - - Special case for distance > 1 copies to do overlapped load and store copy - - Explicit branch predictions (based on measured branch probabilities) - - Deferring match copy and interspersed it with decoding subsequent codes - - Swapping literal/length else - - Swapping window/direct else - - Larger unrolled copy loops (three is about right) - - Moving len -= 3 statement into middle of loop - */ - -#endif /* !ASMINF */