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Diffstat (limited to 'Build/source/libs/zlib/inffast.c')
-rw-r--r-- | Build/source/libs/zlib/inffast.c | 318 |
1 files changed, 0 insertions, 318 deletions
diff --git a/Build/source/libs/zlib/inffast.c b/Build/source/libs/zlib/inffast.c deleted file mode 100644 index bbee92ed1e6..00000000000 --- a/Build/source/libs/zlib/inffast.c +++ /dev/null @@ -1,318 +0,0 @@ -/* inffast.c -- fast decoding - * Copyright (C) 1995-2004 Mark Adler - * For conditions of distribution and use, see copyright notice in zlib.h - */ - -#include "zutil.h" -#include "inftrees.h" -#include "inflate.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. - */ -void inflate_fast(strm, start) -z_streamp strm; -unsigned start; /* inflate()'s starting value for strm->avail_out */ -{ - struct inflate_state FAR *state; - unsigned char FAR *in; /* local strm->next_in */ - unsigned char FAR *last; /* while in < last, enough input available */ - unsigned char FAR *out; /* local strm->next_out */ - unsigned char FAR *beg; /* inflate()'s initial strm->next_out */ - unsigned char FAR *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 FAR *window; /* allocated sliding window, if wsize != 0 */ - unsigned long hold; /* local strm->hold */ - unsigned bits; /* local strm->bits */ - code const FAR *lcode; /* local strm->lencode */ - code const FAR *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 FAR *from; /* where to copy match from */ - - /* copy state to local variables */ - state = (struct inflate_state FAR *)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 */ - 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 */ - Tracevv((stderr, this.val >= 0x20 && this.val < 0x7f ? - "inflate: literal '%c'\n" : - "inflate: literal 0x%02x\n", this.val)); - 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; - } - Tracevv((stderr, "inflate: length %u\n", len)); - 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; - Tracevv((stderr, "inflate: distance %u\n", dist)); - 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); - } - } - } - else if ((op & 64) == 0) { /* 2nd level distance code */ - this = dcode[this.val + (hold & ((1U << op) - 1))]; - goto dodist; - } - 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 */ - Tracevv((stderr, "inflate: end of block\n")); - state->mode = TYPE; - 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; -} - -/* - 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 */ |