/* inflate.c -- zlib interface to inflate modules * Copyright (C) 1995-2002 Mark Adler * For conditions of distribution and use, see copyright notice in zlib.h */#include "zutil.h"#include "infblock.h"#define  DONE  INFLATE_DONE#define  BAD   INFLATE_BADtypedef enum {      METHOD,   /* waiting for method byte */      FLAG,     /* waiting for flag byte */      DICT4,    /* four dictionary check bytes to go */      DICT3,    /* three dictionary check bytes to go */      DICT2,    /* two dictionary check bytes to go */      DICT1,    /* one dictionary check byte to go */      DICT0,    /* waiting for inflateSetDictionary */      BLOCKS,   /* decompressing blocks */      CHECK4,   /* four check bytes to go */      CHECK3,   /* three check bytes to go */      CHECK2,   /* two check bytes to go */      CHECK1,   /* one check byte to go */      DONE,     /* finished check, done */      BAD}      /* got an error--stay here */inflate_mode;/* inflate private state */struct internal_state {  /* mode */  inflate_mode  mode;   /* current inflate mode */  /* mode dependent information */  union {    uInt method;        /* if FLAGS, method byte */    struct {      uLong was;                /* computed check value */      uLong need;               /* stream check value */    } check;            /* if CHECK, check values to compare */    uInt marker;        /* if BAD, inflateSync's marker bytes count */  } sub;        /* submode */  /* mode independent information */  int  nowrap;          /* flag for no wrapper */  uInt wbits;           /* log2(window size)  (8..15, defaults to 15) */  inflate_blocks_statef    *blocks;            /* current inflate_blocks state */};ZEXPORT(int) inflateReset( /* z) */z_streamp z ){  if (z == Z_NULL || z->state == Z_NULL)    return Z_STREAM_ERROR;  z->total_in = z->total_out = 0;  z->msg = Z_NULL;  z->state->mode = z->state->nowrap ? BLOCKS : METHOD;  inflate_blocks_reset(z->state->blocks, z, Z_NULL);  Tracev((stderr, "inflate: reset\n"));  return Z_OK;}ZEXPORT(int) inflateEnd( /* z) */z_streamp z ){  if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL)    return Z_STREAM_ERROR;  if (z->state->blocks != Z_NULL)    inflate_blocks_free(z->state->blocks, z);  ZFREE(z, z->state);  z->state = Z_NULL;  Tracev((stderr, "inflate: end\n"));  return Z_OK;}ZEXPORT(int) inflateInit2_( /* z, w, version, stream_size) */z_streamp z,int w,const char *version,int stream_size ){  if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||      stream_size != sizeof(z_stream))      return Z_VERSION_ERROR;  /* initialize state */  if (z == Z_NULL)    return Z_STREAM_ERROR;  z->msg = Z_NULL;  if (z->zalloc == Z_NULL)  {    z->zalloc = zcalloc;    z->opaque = (voidpf)0;  }  if (z->zfree == Z_NULL) z->zfree = zcfree;  if ((z->state = (struct internal_state FAR *)       ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL)    return Z_MEM_ERROR;  z->state->blocks = Z_NULL;  /* handle undocumented nowrap option (no zlib header or check) */  z->state->nowrap = 0;  if (w < 0)  {    w = - w;    z->state->nowrap = 1;  }  /* set window size */  if (w < 8 || w > 15)  {    inflateEnd(z);    return Z_STREAM_ERROR;  }  z->state->wbits = (uInt)w;  /* create inflate_blocks state */  if ((z->state->blocks =      inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, (uInt)1 << w))      == Z_NULL)  {    inflateEnd(z);    return Z_MEM_ERROR;  }  Tracev((stderr, "inflate: allocated\n"));  /* reset state */  inflateReset(z);  return Z_OK;}#undef  NEEDBYTE#define NEEDBYTE {if(z->avail_in==0)return r;r=f;}#undef  NEXTBYTE#define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)ZEXPORT(int) inflate( /* z, f) */z_streamp z,int f ){  int r;  uInt b;  if (z == Z_NULL || z->state == Z_NULL || z->next_in == Z_NULL)    return Z_STREAM_ERROR;  f = f == Z_FINISH ? Z_BUF_ERROR : Z_OK;  r = Z_BUF_ERROR;  while (1) switch (z->state->mode)  {    case METHOD:      NEEDBYTE      if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED)      {        z->state->mode = BAD;        z->msg = (char*)"unknown compression method";        z->state->sub.marker = 5;       /* can't try inflateSync */        break;      }      if ((z->state->sub.method >> 4) + 8 > z->state->wbits)      {        z->state->mode = BAD;        z->msg = (char*)"invalid window size";        z->state->sub.marker = 5;       /* can't try inflateSync */        break;      }      z->state->mode = FLAG;    case FLAG:      NEEDBYTE      b = NEXTBYTE;      if (((z->state->sub.method << 8) + b) % 31)      {        z->state->mode = BAD;        z->msg = (char*)"incorrect header check";        z->state->sub.marker = 5;       /* can't try inflateSync */        break;      }      Tracev((stderr, "inflate: zlib header ok\n"));      if (!(b & PRESET_DICT))      {        z->state->mode = BLOCKS;        break;      }      z->state->mode = DICT4;    case DICT4:      NEEDBYTE      z->state->sub.check.need = (uLong)NEXTBYTE << 24;      z->state->mode = DICT3;    case DICT3:      NEEDBYTE      z->state->sub.check.need += (uLong)NEXTBYTE << 16;      z->state->mode = DICT2;    case DICT2:      NEEDBYTE      z->state->sub.check.need += (uLong)NEXTBYTE << 8;      z->state->mode = DICT1;    case DICT1:      NEEDBYTE      z->state->sub.check.need += (uLong)NEXTBYTE;      z->adler = z->state->sub.check.need;      z->state->mode = DICT0;      return Z_NEED_DICT;    case DICT0:      z->state->mode = BAD;      z->msg = (char*)"need dictionary";      z->state->sub.marker = 0;       /* can try inflateSync */      return Z_STREAM_ERROR;    case BLOCKS:      r = inflate_blocks(z->state->blocks, z, r);      if (r == Z_DATA_ERROR)      {        z->state->mode = BAD;        z->state->sub.marker = 0;       /* can try inflateSync */        break;      }      if (r == Z_OK)        r = f;      if (r != Z_STREAM_END)        return r;      r = f;      inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was);      if (z->state->nowrap)      {        z->state->mode = DONE;        break;      }      z->state->mode = CHECK4;    case CHECK4:      NEEDBYTE      z->state->sub.check.need = (uLong)NEXTBYTE << 24;      z->state->mode = CHECK3;    case CHECK3:      NEEDBYTE      z->state->sub.check.need += (uLong)NEXTBYTE << 16;      z->state->mode = CHECK2;    case CHECK2:      NEEDBYTE      z->state->sub.check.need += (uLong)NEXTBYTE << 8;      z->state->mode = CHECK1;    case CHECK1:      NEEDBYTE      z->state->sub.check.need += (uLong)NEXTBYTE;      if (z->state->sub.check.was != z->state->sub.check.need)      {        z->state->mode = BAD;        z->msg = (char*)"incorrect data check";        z->state->sub.marker = 5;       /* can't try inflateSync */        break;      }      Tracev((stderr, "inflate: zlib check ok\n"));      z->state->mode = DONE;    case DONE:      return Z_STREAM_END;    case BAD:      return Z_DATA_ERROR;    default:      return Z_STREAM_ERROR;  }#ifdef NEED_DUMMY_RETURN  return Z_STREAM_ERROR;  /* Some dumb compilers complain without this */#endif}