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203 lines
5.3 KiB
203 lines
5.3 KiB
20 years ago
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/* infcodes.c -- process literals and length/distance pairs
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* Copyright (C) 1995-1998 Mark Adler
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* For conditions of distribution and use, see copyright notice in zlib.h
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*/
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#include <linux/zutil.h>
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#include "inftrees.h"
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#include "infblock.h"
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#include "infcodes.h"
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#include "infutil.h"
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#include "inffast.h"
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/* simplify the use of the inflate_huft type with some defines */
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#define exop word.what.Exop
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#define bits word.what.Bits
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inflate_codes_statef *zlib_inflate_codes_new(
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uInt bl,
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uInt bd,
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inflate_huft *tl,
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inflate_huft *td, /* need separate declaration for Borland C++ */
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z_streamp z
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)
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{
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inflate_codes_statef *c;
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c = &WS(z)->working_state;
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{
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c->mode = START;
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c->lbits = (Byte)bl;
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c->dbits = (Byte)bd;
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c->ltree = tl;
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c->dtree = td;
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}
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return c;
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}
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int zlib_inflate_codes(
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inflate_blocks_statef *s,
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z_streamp z,
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int r
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)
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{
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uInt j; /* temporary storage */
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inflate_huft *t; /* temporary pointer */
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uInt e; /* extra bits or operation */
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uLong b; /* bit buffer */
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uInt k; /* bits in bit buffer */
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Byte *p; /* input data pointer */
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uInt n; /* bytes available there */
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Byte *q; /* output window write pointer */
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uInt m; /* bytes to end of window or read pointer */
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Byte *f; /* pointer to copy strings from */
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inflate_codes_statef *c = s->sub.decode.codes; /* codes state */
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/* copy input/output information to locals (UPDATE macro restores) */
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LOAD
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/* process input and output based on current state */
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while (1) switch (c->mode)
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{ /* waiting for "i:"=input, "o:"=output, "x:"=nothing */
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case START: /* x: set up for LEN */
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#ifndef SLOW
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if (m >= 258 && n >= 10)
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{
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UPDATE
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r = zlib_inflate_fast(c->lbits, c->dbits, c->ltree, c->dtree, s, z);
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LOAD
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if (r != Z_OK)
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{
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c->mode = r == Z_STREAM_END ? WASH : BADCODE;
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break;
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}
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}
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#endif /* !SLOW */
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c->sub.code.need = c->lbits;
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c->sub.code.tree = c->ltree;
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c->mode = LEN;
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case LEN: /* i: get length/literal/eob next */
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j = c->sub.code.need;
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NEEDBITS(j)
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t = c->sub.code.tree + ((uInt)b & zlib_inflate_mask[j]);
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DUMPBITS(t->bits)
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e = (uInt)(t->exop);
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if (e == 0) /* literal */
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{
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c->sub.lit = t->base;
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c->mode = LIT;
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break;
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}
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if (e & 16) /* length */
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{
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c->sub.copy.get = e & 15;
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c->len = t->base;
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c->mode = LENEXT;
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break;
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}
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if ((e & 64) == 0) /* next table */
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{
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c->sub.code.need = e;
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c->sub.code.tree = t + t->base;
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break;
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}
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if (e & 32) /* end of block */
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{
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c->mode = WASH;
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break;
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}
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c->mode = BADCODE; /* invalid code */
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z->msg = (char*)"invalid literal/length code";
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r = Z_DATA_ERROR;
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LEAVE
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case LENEXT: /* i: getting length extra (have base) */
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j = c->sub.copy.get;
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NEEDBITS(j)
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c->len += (uInt)b & zlib_inflate_mask[j];
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DUMPBITS(j)
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c->sub.code.need = c->dbits;
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c->sub.code.tree = c->dtree;
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c->mode = DIST;
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case DIST: /* i: get distance next */
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j = c->sub.code.need;
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NEEDBITS(j)
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t = c->sub.code.tree + ((uInt)b & zlib_inflate_mask[j]);
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DUMPBITS(t->bits)
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e = (uInt)(t->exop);
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if (e & 16) /* distance */
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{
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c->sub.copy.get = e & 15;
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c->sub.copy.dist = t->base;
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c->mode = DISTEXT;
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break;
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}
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if ((e & 64) == 0) /* next table */
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{
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c->sub.code.need = e;
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c->sub.code.tree = t + t->base;
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break;
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}
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c->mode = BADCODE; /* invalid code */
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z->msg = (char*)"invalid distance code";
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r = Z_DATA_ERROR;
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LEAVE
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case DISTEXT: /* i: getting distance extra */
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j = c->sub.copy.get;
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NEEDBITS(j)
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c->sub.copy.dist += (uInt)b & zlib_inflate_mask[j];
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DUMPBITS(j)
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c->mode = COPY;
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case COPY: /* o: copying bytes in window, waiting for space */
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f = q - c->sub.copy.dist;
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while (f < s->window) /* modulo window size-"while" instead */
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f += s->end - s->window; /* of "if" handles invalid distances */
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while (c->len)
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{
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NEEDOUT
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OUTBYTE(*f++)
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if (f == s->end)
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f = s->window;
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c->len--;
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}
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c->mode = START;
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break;
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case LIT: /* o: got literal, waiting for output space */
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NEEDOUT
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OUTBYTE(c->sub.lit)
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c->mode = START;
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break;
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case WASH: /* o: got eob, possibly more output */
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if (k > 7) /* return unused byte, if any */
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{
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k -= 8;
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n++;
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p--; /* can always return one */
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}
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FLUSH
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if (s->read != s->write)
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LEAVE
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c->mode = END;
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case END:
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r = Z_STREAM_END;
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LEAVE
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case BADCODE: /* x: got error */
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r = Z_DATA_ERROR;
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LEAVE
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default:
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r = Z_STREAM_ERROR;
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LEAVE
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}
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#ifdef NEED_DUMMY_RETURN
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return Z_STREAM_ERROR; /* Some dumb compilers complain without this */
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#endif
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}
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void zlib_inflate_codes_free(
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inflate_codes_statef *c,
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z_streamp z
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)
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{
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}
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