| /* |
| * 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. Sun designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| * CA 95054 USA or visit www.sun.com if you need additional information or |
| * have any questions. |
| */ |
| |
| /* |
| * This file is available under and governed by the GNU General Public |
| * License version 2 only, as published by the Free Software Foundation. |
| * However, the following notice accompanied the original version of this |
| * file and, per its terms, should not be removed: |
| * |
| * 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 "zutil.h" |
| #include "inftrees.h" |
| #include "infblock.h" |
| #include "infcodes.h" |
| #include "infutil.h" |
| #include "inffast.h" |
| |
| struct inflate_codes_state {int dummy;}; /* for buggy compilers */ |
| |
| /* 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)<<k;k+=8;}} |
| #define UNGRAB {c=z->avail_in-n;c=(k>>3)<c?k>>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 inflate_fast(bl, bd, tl, td, s, z) |
| uInt bl, bd; |
| inflate_huft *tl; |
| inflate_huft *td; /* need separate declaration for Borland C++ */ |
| inflate_blocks_statef *s; |
| z_streamp z; |
| { |
| inflate_huft *t; /* temporary pointer */ |
| uInt e; /* extra bits or operation */ |
| uLong b; /* bit buffer */ |
| uInt k; /* bits in bit buffer */ |
| Bytef *p; /* input data pointer */ |
| uInt n; /* bytes available there */ |
| Bytef *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 */ |
| Bytef *r; /* copy source pointer */ |
| |
| /* load input, output, bit values */ |
| LOAD |
| |
| /* initialize masks */ |
| ml = inflate_mask[bl]; |
| md = 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) |
| Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ? |
| "inflate: * literal '%c'\n" : |
| "inflate: * literal 0x%02x\n", t->base)); |
| *q++ = (Byte)t->base; |
| m--; |
| continue; |
| } |
| do { |
| DUMPBITS(t->bits) |
| if (e & 16) |
| { |
| /* get extra bits for length */ |
| e &= 15; |
| c = t->base + ((uInt)b & inflate_mask[e]); |
| DUMPBITS(e) |
| Tracevv((stderr, "inflate: * length %u\n", c)); |
| |
| /* 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 & inflate_mask[e]); |
| DUMPBITS(e) |
| Tracevv((stderr, "inflate: * distance %u\n", d)); |
| |
| /* do the copy */ |
| m -= c; |
| if ((uInt)(q - s->window) >= d) /* offset before dest */ |
| { /* just copy */ |
| r = q - d; |
| *q++ = *r++; c--; /* minimum count is three, */ |
| *q++ = *r++; c--; /* so unroll loop a little */ |
| } |
| else /* else offset after destination */ |
| { |
| e = d - (uInt)(q - s->window); /* bytes from offset to end */ |
| r = s->end - e; /* pointer to offset */ |
| if (c > e) /* if source crosses, */ |
| { |
| c -= e; /* copy to end of window */ |
| do { |
| *q++ = *r++; |
| } while (--e); |
| r = s->window; /* copy rest from start of window */ |
| } |
| } |
| do { /* copy all or what's left */ |
| *q++ = *r++; |
| } while (--c); |
| break; |
| } |
| else if ((e & 64) == 0) |
| { |
| t += t->base; |
| e = (t += ((uInt)b & 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 & inflate_mask[e]))->exop) == 0) |
| { |
| DUMPBITS(t->bits) |
| Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ? |
| "inflate: * literal '%c'\n" : |
| "inflate: * literal 0x%02x\n", t->base)); |
| *q++ = (Byte)t->base; |
| m--; |
| break; |
| } |
| } |
| else if (e & 32) |
| { |
| Tracevv((stderr, "inflate: * end of block\n")); |
| 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; |
| } |