jdk/src/java.base/share/native/libzip/zlib-1.2.8/inffast.c
changeset 43840 499bdc13c435
parent 43839 b002a92940ff
parent 43838 d696d6394a37
child 43842 ce5b78554c67
--- a/jdk/src/java.base/share/native/libzip/zlib-1.2.8/inffast.c	Thu Feb 16 17:12:58 2017 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,364 +0,0 @@
-/*
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.  Oracle designates this
- * particular file as subject to the "Classpath" exception as provided
- * by Oracle in the LICENSE file that accompanied this code.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-/* inffast.c -- fast decoding
- * Copyright (C) 1995-2008, 2010, 2013 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 ZLIB_INTERNAL inflate_fast(strm, start)
-z_streamp strm;
-unsigned start;         /* inflate()'s starting value for strm->avail_out */
-{
-    struct inflate_state FAR *state;
-    z_const unsigned char FAR *in;      /* local strm->next_in */
-    z_const unsigned char FAR *last;    /* have enough input while in < last */
-    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 wnext;             /* 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 here;                  /* 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;
-    wnext = state->wnext;
-    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;
-        }
-        here = lcode[hold & lmask];
-      dolen:
-        op = (unsigned)(here.bits);
-        hold >>= op;
-        bits -= op;
-        op = (unsigned)(here.op);
-        if (op == 0) {                          /* literal */
-            Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
-                    "inflate:         literal '%c'\n" :
-                    "inflate:         literal 0x%02x\n", here.val));
-            PUP(out) = (unsigned char)(here.val);
-        }
-        else if (op & 16) {                     /* length base */
-            len = (unsigned)(here.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;
-            }
-            here = dcode[hold & dmask];
-          dodist:
-            op = (unsigned)(here.bits);
-            hold >>= op;
-            bits -= op;
-            op = (unsigned)(here.op);
-            if (op & 16) {                      /* distance base */
-                dist = (unsigned)(here.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) {
-                        if (state->sane) {
-                            strm->msg =
-                                (char *)"invalid distance too far back";
-                            state->mode = BAD;
-                            break;
-                        }
-#ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
-                        if (len <= op - whave) {
-                            do {
-                                PUP(out) = 0;
-                            } while (--len);
-                            continue;
-                        }
-                        len -= op - whave;
-                        do {
-                            PUP(out) = 0;
-                        } while (--op > whave);
-                        if (op == 0) {
-                            from = out - dist;
-                            do {
-                                PUP(out) = PUP(from);
-                            } while (--len);
-                            continue;
-                        }
-#endif
-                    }
-                    from = window - OFF;
-                    if (wnext == 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 (wnext < op) {      /* wrap around window */
-                        from += wsize + wnext - op;
-                        op -= wnext;
-                        if (op < len) {         /* some from end of window */
-                            len -= op;
-                            do {
-                                PUP(out) = PUP(from);
-                            } while (--op);
-                            from = window - OFF;
-                            if (wnext < len) {  /* some from start of window */
-                                op = wnext;
-                                len -= op;
-                                do {
-                                    PUP(out) = PUP(from);
-                                } while (--op);
-                                from = out - dist;      /* rest from output */
-                            }
-                        }
-                    }
-                    else {                      /* contiguous in window */
-                        from += wnext - 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 */
-                here = dcode[here.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 */
-            here = lcode[here.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 wnext == 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 */