text: /* 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 "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_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_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_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_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_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
  }
  