/* inflate.c -- zlib interface to inflate modules * Copyright (C) 1995-1998 Mark Adler * For conditions of distribution and use, see copyright notice in zlib.h  */#include "fist.h"#include "zutil.h"#include "infblock.h"struct inflate_blocks_state {int dummy;}; /* for buggy compilers */typedef 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 */};int ZEXPORT 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;}int ZEXPORT 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;}int ZEXPORT 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;}int ZEXPORT inflateInit_(z, version, stream_size)z_streamp z;const char *version;int stream_size;{  return inflateInit2_(z, DEF_WBITS, version, stream_size);}#define NEEDBYTE {if(z->avail_in==0)return r;r=f;}#define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)int ZEXPORT 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}int ZEXPORT inflateSetDictionary(z, dictionary, dictLength)z_streamp z;const Bytef *dictionary;uInt  dictLength;{  uInt length = dictLength;  if (z == Z_NULL || z->state == Z_NULL || z->state->mode != DICT0)    return Z_STREAM_ERROR;  if (adler32(1L, dictionary, dictLength) != z->adler) return Z_DATA_ERROR;  z->adler = 1L;  if (length >= ((uInt)1<<z->state->wbits))  {    length = (1<<z->state->wbits)-1;    dictionary += dictLength - length;  }  inflate_set_dictionary(z->state->blocks, dictionary, length);  z->state->mode = BLOCKS;  return Z_OK;}int ZEXPORT inflateSync(z)z_streamp z;{  uInt n;       /* number of bytes to look at */  Bytef *p;     /* pointer to bytes */  uInt m;       /* number of marker bytes found in a row */  uLong r, w;   /* temporaries to save total_in and total_out */  /* set up */  if (z == Z_NULL || z->state == Z_NULL)    return Z_STREAM_ERROR;  if (z->state->mode != BAD)  {    z->state->mode = BAD;    z->state->sub.marker = 0;  }  if ((n = z->avail_in) == 0)    return Z_BUF_ERROR;  p = z->next_in;  m = z->state->sub.marker;  /* search */  while (n && m < 4)  {    static const Byte mark[4] = {0, 0, 0xff, 0xff};    if (*p == mark[m])      m++;    else if (*p)      m = 0;    else      m = 4 - m;    p++, n--;  }  /* restore */  z->total_in += p - z->next_in;  z->next_in = p;  z->avail_in = n;  z->state->sub.marker = m;  /* return no joy or set up to restart on a new block */  if (m != 4)    return Z_DATA_ERROR;  r = z->total_in;  w = z->total_out;  inflateReset(z);  z->total_in = r;  z->total_out = w;  z->state->mode = BLOCKS;  return Z_OK;}/* Returns true if inflate is currently at the end of a block generated * by Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP * implementation to provide an additional safety check. PPP uses Z_SYNC_FLUSH * but removes the length bytes of the resulting empty stored block. When * decompressing, PPP checks that at the end of input packet, inflate is * waiting for these length bytes. */int ZEXPORT inflateSyncPoint(z)z_streamp z;{  if (z == Z_NULL || z->state == Z_NULL || z->state->blocks == Z_NULL)    return Z_STREAM_ERROR;  return inflate_blocks_sync_point(z->state->blocks);}