+++ /dev/null
-/* infcodes.c -- process literals and length/distance pairs
- * Copyright (C) 1995-2002 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"
-
-/* simplify the use of the inflate_huft type with some defines */
-#define exop word.what.Exop
-#define bits word.what.Bits
-
-typedef enum { /* waiting for "i:"=input, "o:"=output, "x:"=nothing */
- START, /* x: set up for LEN */
- LEN, /* i: get length/literal/eob next */
- LENEXT, /* i: getting length extra (have base) */
- DIST, /* i: get distance next */
- DISTEXT, /* i: getting distance extra */
- COPY, /* o: copying bytes in window, waiting for space */
- LIT, /* o: got literal, waiting for output space */
- WASH, /* o: got eob, possibly still output waiting */
- END, /* x: got eob and all data flushed */
- BADCODE} /* x: got error */
-inflate_codes_mode;
-
-/* inflate codes private state */
-struct inflate_codes_state {
-
- /* mode */
- inflate_codes_mode mode; /* current inflate_codes mode */
-
- /* mode dependent information */
- uInt len;
- union {
- struct {
- inflate_huft *tree; /* pointer into tree */
- uInt need; /* bits needed */
- } code; /* if LEN or DIST, where in tree */
- uInt lit; /* if LIT, literal */
- struct {
- uInt get; /* bits to get for extra */
- uInt dist; /* distance back to copy from */
- } copy; /* if EXT or COPY, where and how much */
- } sub; /* submode */
-
- /* mode independent information */
- Byte lbits; /* ltree bits decoded per branch */
- Byte dbits; /* dtree bits decoder per branch */
- inflate_huft *ltree; /* literal/length/eob tree */
- inflate_huft *dtree; /* distance tree */
-
-};
-
-
-inflate_codes_statef *inflate_codes_new(bl, bd, tl, td, z)
-uInt bl, bd;
-inflate_huft *tl;
-inflate_huft *td; /* need separate declaration for Borland C++ */
-z_streamp z;
-{
- inflate_codes_statef *c;
-
- if ((c = (inflate_codes_statef *)
- ZALLOC(z,1,sizeof(struct inflate_codes_state))) != Z_NULL)
- {
- c->mode = START;
- c->lbits = (Byte)bl;
- c->dbits = (Byte)bd;
- c->ltree = tl;
- c->dtree = td;
- Tracev((stderr, "inflate: codes new\n"));
- }
- return c;
-}
-
-
-int inflate_codes(s, z, r)
-inflate_blocks_statef *s;
-z_streamp z;
-int r;
-{
- uInt j; /* temporary storage */
- 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 */
- Bytef *f; /* pointer to copy strings from */
- inflate_codes_statef *c = s->sub.decode.codes; /* codes state */
-
- /* copy input/output information to locals (UPDATE macro restores) */
- LOAD
-
- /* process input and output based on current state */
- while (1) switch (c->mode)
- { /* waiting for "i:"=input, "o:"=output, "x:"=nothing */
- case START: /* x: set up for LEN */
-#ifndef SLOW
- if (m >= 258 && n >= 10)
- {
- UPDATE
- r = inflate_fast(c->lbits, c->dbits, c->ltree, c->dtree, s, z);
- LOAD
- if (r != Z_OK)
- {
- c->mode = r == Z_STREAM_END ? WASH : BADCODE;
- break;
- }
- }
-#endif /* !SLOW */
- c->sub.code.need = c->lbits;
- c->sub.code.tree = c->ltree;
- c->mode = LEN;
- case LEN: /* i: get length/literal/eob next */
- j = c->sub.code.need;
- NEEDBITS(j)
- t = c->sub.code.tree + ((uInt)b & inflate_mask[j]);
- DUMPBITS(t->bits)
- e = (uInt)(t->exop);
- if (e == 0) /* literal */
- {
- c->sub.lit = t->base;
- Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ?
- "inflate: literal '%c'\n" :
- "inflate: literal 0x%02x\n", t->base));
- c->mode = LIT;
- break;
- }
- if (e & 16) /* length */
- {
- c->sub.copy.get = e & 15;
- c->len = t->base;
- c->mode = LENEXT;
- break;
- }
- if ((e & 64) == 0) /* next table */
- {
- c->sub.code.need = e;
- c->sub.code.tree = t + t->base;
- break;
- }
- if (e & 32) /* end of block */
- {
- Tracevv((stderr, "inflate: end of block\n"));
- c->mode = WASH;
- break;
- }
- c->mode = BADCODE; /* invalid code */
- z->msg = (char*)"invalid literal/length code";
- r = Z_DATA_ERROR;
- LEAVE
- case LENEXT: /* i: getting length extra (have base) */
- j = c->sub.copy.get;
- NEEDBITS(j)
- c->len += (uInt)b & inflate_mask[j];
- DUMPBITS(j)
- c->sub.code.need = c->dbits;
- c->sub.code.tree = c->dtree;
- Tracevv((stderr, "inflate: length %u\n", c->len));
- c->mode = DIST;
- case DIST: /* i: get distance next */
- j = c->sub.code.need;
- NEEDBITS(j)
- t = c->sub.code.tree + ((uInt)b & inflate_mask[j]);
- DUMPBITS(t->bits)
- e = (uInt)(t->exop);
- if (e & 16) /* distance */
- {
- c->sub.copy.get = e & 15;
- c->sub.copy.dist = t->base;
- c->mode = DISTEXT;
- break;
- }
- if ((e & 64) == 0) /* next table */
- {
- c->sub.code.need = e;
- c->sub.code.tree = t + t->base;
- break;
- }
- c->mode = BADCODE; /* invalid code */
- z->msg = (char*)"invalid distance code";
- r = Z_DATA_ERROR;
- LEAVE
- case DISTEXT: /* i: getting distance extra */
- j = c->sub.copy.get;
- NEEDBITS(j)
- c->sub.copy.dist += (uInt)b & inflate_mask[j];
- DUMPBITS(j)
- Tracevv((stderr, "inflate: distance %u\n", c->sub.copy.dist));
- c->mode = COPY;
- case COPY: /* o: copying bytes in window, waiting for space */
- f = q - c->sub.copy.dist;
- while (f < s->window) /* modulo window size-"while" instead */
- f += s->end - s->window; /* of "if" handles invalid distances */
- while (c->len)
- {
- NEEDOUT
- OUTBYTE(*f++)
- if (f == s->end)
- f = s->window;
- c->len--;
- }
- c->mode = START;
- break;
- case LIT: /* o: got literal, waiting for output space */
- NEEDOUT
- OUTBYTE(c->sub.lit)
- c->mode = START;
- break;
- case WASH: /* o: got eob, possibly more output */
- if (k > 7) /* return unused byte, if any */
- {
- Assert(k < 16, "inflate_codes grabbed too many bytes")
- k -= 8;
- n++;
- p--; /* can always return one */
- }
- FLUSH
- if (s->read != s->write)
- LEAVE
- c->mode = END;
- case END:
- r = Z_STREAM_END;
- LEAVE
- case BADCODE: /* x: got error */
- r = Z_DATA_ERROR;
- LEAVE
- default:
- r = Z_STREAM_ERROR;
- LEAVE
- }
-#ifdef NEED_DUMMY_RETURN
- return Z_STREAM_ERROR; /* Some dumb compilers complain without this */
-#endif
-}
-
-
-void inflate_codes_free(c, z)
-inflate_codes_statef *c;
-z_streamp z;
-{
- ZFREE(z, c);
- Tracev((stderr, "inflate: codes free\n"));
-}
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