ARM 嵌入式 系统 设计与实例开发 实验教材 二源码

				/* infcodes.c -- process literals and length/distance pairs				 * 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"								/* simplify the use of the inflate_huft type with some defines */				#define exop word.what.Exop				#define bits word.what.Bits								inflate_codes_statef *zlib_fs_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;								  c = &WS(z)->working_state;				  {				    c->mode = START;				    c->lbits = (Byte)bl;				    c->dbits = (Byte)bd;				    c->ltree = tl;				    c->dtree = td;				  }				  return c;				}												int zlib_fs_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 = zlib_fs_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 & zlib_fs_inflate_mask[j]);				      DUMPBITS(t->bits)				      e = (uInt)(t->exop);				      if (e == 0)               /* literal */				      {				        c->sub.lit = 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 */				      {				        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 & zlib_fs_inflate_mask[j];				      DUMPBITS(j)				      c->sub.code.need = c->dbits;				      c->sub.code.tree = c->dtree;				      c->mode = DIST;				    case DIST:          /* i: get distance next */				      j = c->sub.code.need;				      NEEDBITS(j)				      t = c->sub.code.tree + ((uInt)b & zlib_fs_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 & zlib_fs_inflate_mask[j];				      DUMPBITS(j)				      c->mode = COPY;				    case COPY:          /* o: copying bytes in window, waiting for space */				#ifndef __TURBOC__ /* Turbo C bug for following expression */				      f = (uInt)(q - s->window) < c->sub.copy.dist ?				          s->end - (c->sub.copy.dist - (q - s->window)) :				          q - c->sub.copy.dist;				#else				      f = q - c->sub.copy.dist;				      if ((uInt)(q - s->window) < c->sub.copy.dist)				        f = s->end - (c->sub.copy.dist - (uInt)(q - s->window));				#endif				      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 */				      {				        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 zlib_fs_inflate_codes_free(c, z)				inflate_codes_statef *c;				z_streamp z;				{				}