MCL/sftools/ana/staticanamdw: comparison srcanamdw/codescanner/pyinstaller/source/zlib/inffast.c

equal deleted inserted replaced

-:509e4801c378
+:22878952f6e2
+/* 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 */