lib/zlib_inflate/inflate.c

   1 /* inflate.c -- zlib interface to inflate modules
   2  * Copyright (C) 1995-1998 Mark Adler
   3  * For conditions of distribution and use, see copyright notice in zlib.h
   4  */
   5
   6 #include <linux/zutil.h>
   7 #include "infblock.h"
   8 #include "infutil.h"
   9
  10 int zlib_inflate_workspacesize(void)
  11 {
  12   return sizeof(struct inflate_workspace);
  13 }
  14
  15
  16 int zlib_inflateReset(
  17         z_streamp z
  18 )
  19 {
  20   if (z == NULL || z->state == NULL || z->workspace == NULL)
  21     return Z_STREAM_ERROR;
  22   z->total_in = z->total_out = 0;
  23   z->msg = NULL;
  24   z->state->mode = z->state->nowrap ? BLOCKS : METHOD;
  25   zlib_inflate_blocks_reset(z->state->blocks, z, NULL);
  26   return Z_OK;
  27 }
  28
  29
  30 int zlib_inflateEnd(
  31         z_streamp z
  32 )
  33 {
  34   if (z == NULL || z->state == NULL || z->workspace == NULL)
  35     return Z_STREAM_ERROR;
  36   if (z->state->blocks != NULL)
  37     zlib_inflate_blocks_free(z->state->blocks, z);
  38   z->state = NULL;
  39   return Z_OK;
  40 }
  41
  42
  43 int zlib_inflateInit2_(
  44         z_streamp z,
  45         int w,
  46         const char *version,
  47         int stream_size
  48 )
  49 {
  50   if (version == NULL || version[0] != ZLIB_VERSION[0] ||
  51       stream_size != sizeof(z_stream) || z->workspace == NULL)
  52       return Z_VERSION_ERROR;
  53
  54   /* initialize state */
  55   z->msg = NULL;
  56   z->state = &WS(z)->internal_state;
  57   z->state->blocks = NULL;
  58
  59   /* handle undocumented nowrap option (no zlib header or check) */
  60   z->state->nowrap = 0;
  61   if (w < 0)
  62   {
  63     w = - w;
  64     z->state->nowrap = 1;
  65   }
  66
  67   /* set window size */
  68   if (w < 8 || w > 15)
  69   {
  70     zlib_inflateEnd(z);
  71     return Z_STREAM_ERROR;
  72   }
  73   z->state->wbits = (uInt)w;
  74
  75   /* create inflate_blocks state */
  76   if ((z->state->blocks =
  77       zlib_inflate_blocks_new(z, z->state->nowrap ? NULL : zlib_adler32, (uInt)1 << w))
  78       == NULL)
  79   {
  80     zlib_inflateEnd(z);
  81     return Z_MEM_ERROR;
  82   }
  83
  84   /* reset state */
  85   zlib_inflateReset(z);
  86   return Z_OK;
  87 }
  88
  89
  90 /*
  91  * At the end of a Deflate-compressed PPP packet, we expect to have seen
  92  * a `stored' block type value but not the (zero) length bytes.
  93  */
  94 static int zlib_inflate_packet_flush(inflate_blocks_statef *s)
  95 {
  96     if (s->mode != LENS)
  97         return Z_DATA_ERROR;
  98     s->mode = TYPE;
  99     return Z_OK;
 100 }
 101
 102
 103 int zlib_inflateInit_(
 104         z_streamp z,
 105         const char *version,
 106         int stream_size
 107 )
 108 {
 109   return zlib_inflateInit2_(z, DEF_WBITS, version, stream_size);
 110 }
 111
 112 #undef NEEDBYTE
 113 #undef NEXTBYTE
 114 #define NEEDBYTE {if(z->avail_in==0)goto empty;r=trv;}
 115 #define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)
 116
 117 int zlib_inflate(
 118         z_streamp z,
 119         int f
 120 )
 121 {
 122   int r, trv;
 123   uInt b;
 124
 125   if (z == NULL || z->state == NULL || z->next_in == NULL)
 126     return Z_STREAM_ERROR;
 127   trv = f == Z_FINISH ? Z_BUF_ERROR : Z_OK;
 128   r = Z_BUF_ERROR;
 129   while (1) switch (z->state->mode)
 130   {
 131     case METHOD:
 132       NEEDBYTE
 133       if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED)
 134       {
 135         z->state->mode = I_BAD;
 136         z->msg = (char*)"unknown compression method";
 137         z->state->sub.marker = 5;       /* can't try inflateSync */
 138         break;
 139       }
 140       if ((z->state->sub.method >> 4) + 8 > z->state->wbits)
 141       {
 142         z->state->mode = I_BAD;
 143         z->msg = (char*)"invalid window size";
 144         z->state->sub.marker = 5;       /* can't try inflateSync */
 145         break;
 146       }
 147       z->state->mode = FLAG;
 148     case FLAG:
 149       NEEDBYTE
 150       b = NEXTBYTE;
 151       if (((z->state->sub.method << 8) + b) % 31)
 152       {
 153         z->state->mode = I_BAD;
 154         z->msg = (char*)"incorrect header check";
 155         z->state->sub.marker = 5;       /* can't try inflateSync */
 156         break;
 157       }
 158       if (!(b & PRESET_DICT))
 159       {
 160         z->state->mode = BLOCKS;
 161         break;
 162       }
 163       z->state->mode = DICT4;
 164     case DICT4:
 165       NEEDBYTE
 166       z->state->sub.check.need = (uLong)NEXTBYTE << 24;
 167       z->state->mode = DICT3;
 168     case DICT3:
 169       NEEDBYTE
 170       z->state->sub.check.need += (uLong)NEXTBYTE << 16;
 171       z->state->mode = DICT2;
 172     case DICT2:
 173       NEEDBYTE
 174       z->state->sub.check.need += (uLong)NEXTBYTE << 8;
 175       z->state->mode = DICT1;
 176     case DICT1:
 177       NEEDBYTE
 178       z->state->sub.check.need += (uLong)NEXTBYTE;
 179       z->adler = z->state->sub.check.need;
 180       z->state->mode = DICT0;
 181       return Z_NEED_DICT;
 182     case DICT0:
 183       z->state->mode = I_BAD;
 184       z->msg = (char*)"need dictionary";
 185       z->state->sub.marker = 0;       /* can try inflateSync */
 186       return Z_STREAM_ERROR;
 187     case BLOCKS:
 188       r = zlib_inflate_blocks(z->state->blocks, z, r);
 189       if (f == Z_PACKET_FLUSH && z->avail_in == 0 && z->avail_out != 0)
 190           r = zlib_inflate_packet_flush(z->state->blocks);
 191       if (r == Z_DATA_ERROR)
 192       {
 193         z->state->mode = I_BAD;
 194         z->state->sub.marker = 0;       /* can try inflateSync */
 195         break;
 196       }
 197       if (r == Z_OK)
 198         r = trv;
 199       if (r != Z_STREAM_END)
 200         return r;
 201       r = trv;
 202       zlib_inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was);
 203       if (z->state->nowrap)
 204       {
 205         z->state->mode = I_DONE;
 206         break;
 207       }
 208       z->state->mode = CHECK4;
 209     case CHECK4:
 210       NEEDBYTE
 211       z->state->sub.check.need = (uLong)NEXTBYTE << 24;
 212       z->state->mode = CHECK3;
 213     case CHECK3:
 214       NEEDBYTE
 215       z->state->sub.check.need += (uLong)NEXTBYTE << 16;
 216       z->state->mode = CHECK2;
 217     case CHECK2:
 218       NEEDBYTE
 219       z->state->sub.check.need += (uLong)NEXTBYTE << 8;
 220       z->state->mode = CHECK1;
 221     case CHECK1:
 222       NEEDBYTE
 223       z->state->sub.check.need += (uLong)NEXTBYTE;
 224
 225       if (z->state->sub.check.was != z->state->sub.check.need)
 226       {
 227         z->state->mode = I_BAD;
 228         z->msg = (char*)"incorrect data check";
 229         z->state->sub.marker = 5;       /* can't try inflateSync */
 230         break;
 231       }
 232       z->state->mode = I_DONE;
 233     case I_DONE:
 234       return Z_STREAM_END;
 235     case I_BAD:
 236       return Z_DATA_ERROR;
 237     default:
 238       return Z_STREAM_ERROR;
 239   }
 240  empty:
 241   if (f != Z_PACKET_FLUSH)
 242     return r;
 243   z->state->mode = I_BAD;
 244   z->msg = (char *)"need more for packet flush";
 245   z->state->sub.marker = 0;       /* can try inflateSync */
 246   return Z_DATA_ERROR;
 247 }