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/module.h>
   7 #include <linux/zutil.h>
   8 #include "infblock.h"
   9 #include "infutil.h"
  10
  11 int zlib_inflate_workspacesize(void)
  12 {
  13   return sizeof(struct inflate_workspace);
  14 }
  15
  16
  17 int zlib_inflateReset(
  18         z_streamp z
  19 )
  20 {
  21   if (z == NULL || z->state == NULL || z->workspace == NULL)
  22     return Z_STREAM_ERROR;
  23   z->total_in = z->total_out = 0;
  24   z->msg = NULL;
  25   z->state->mode = z->state->nowrap ? BLOCKS : METHOD;
  26   zlib_inflate_blocks_reset(z->state->blocks, z, NULL);
  27   return Z_OK;
  28 }
  29
  30
  31 int zlib_inflateEnd(
  32         z_streamp z
  33 )
  34 {
  35   if (z == NULL || z->state == NULL || z->workspace == NULL)
  36     return Z_STREAM_ERROR;
  37   if (z->state->blocks != NULL)
  38     zlib_inflate_blocks_free(z->state->blocks, z);
  39   z->state = NULL;
  40   return Z_OK;
  41 }
  42
  43
  44 int zlib_inflateInit2_(
  45         z_streamp z,
  46         int w,
  47         const char *version,
  48         int stream_size
  49 )
  50 {
  51   if (version == NULL || version[0] != ZLIB_VERSION[0] ||
  52       stream_size != sizeof(z_stream) || z->workspace == NULL)
  53       return Z_VERSION_ERROR;
  54
  55   /* initialize state */
  56   z->msg = NULL;
  57   z->state = &WS(z)->internal_state;
  58   z->state->blocks = NULL;
  59
  60   /* handle undocumented nowrap option (no zlib header or check) */
  61   z->state->nowrap = 0;
  62   if (w < 0)
  63   {
  64     w = - w;
  65     z->state->nowrap = 1;
  66   }
  67
  68   /* set window size */
  69   if (w < 8 || w > 15)
  70   {
  71     zlib_inflateEnd(z);
  72     return Z_STREAM_ERROR;
  73   }
  74   z->state->wbits = (uInt)w;
  75
  76   /* create inflate_blocks state */
  77   if ((z->state->blocks =
  78       zlib_inflate_blocks_new(z, z->state->nowrap ? NULL : zlib_adler32, (uInt)1 << w))
  79       == NULL)
  80   {
  81     zlib_inflateEnd(z);
  82     return Z_MEM_ERROR;
  83   }
  84
  85   /* reset state */
  86   zlib_inflateReset(z);
  87   return Z_OK;
  88 }
  89
  90
  91 /*
  92  * At the end of a Deflate-compressed PPP packet, we expect to have seen
  93  * a `stored' block type value but not the (zero) length bytes.
  94  */
  95 static int zlib_inflate_packet_flush(inflate_blocks_statef *s)
  96 {
  97     if (s->mode != LENS)
  98         return Z_DATA_ERROR;
  99     s->mode = TYPE;
 100     return Z_OK;
 101 }
 102
 103
 104 int zlib_inflateInit_(
 105         z_streamp z,
 106         const char *version,
 107         int stream_size
 108 )
 109 {
 110   return zlib_inflateInit2_(z, DEF_WBITS, version, stream_size);
 111 }
 112
 113 #undef NEEDBYTE
 114 #undef NEXTBYTE
 115 #define NEEDBYTE {if(z->avail_in==0)goto empty;r=trv;}
 116 #define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)
 117
 118 int zlib_inflate(
 119         z_streamp z,
 120         int f
 121 )
 122 {
 123   int r, trv;
 124   uInt b;
 125
 126   if (z == NULL || z->state == NULL || z->next_in == NULL)
 127     return Z_STREAM_ERROR;
 128   trv = f == Z_FINISH ? Z_BUF_ERROR : Z_OK;
 129   r = Z_BUF_ERROR;
 130   while (1) switch (z->state->mode)
 131   {
 132     case METHOD:
 133       NEEDBYTE
 134       if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED)
 135       {
 136         z->state->mode = I_BAD;
 137         z->msg = (char*)"unknown compression method";
 138         z->state->sub.marker = 5;       /* can't try inflateSync */
 139         break;
 140       }
 141       if ((z->state->sub.method >> 4) + 8 > z->state->wbits)
 142       {
 143         z->state->mode = I_BAD;
 144         z->msg = (char*)"invalid window size";
 145         z->state->sub.marker = 5;       /* can't try inflateSync */
 146         break;
 147       }
 148       z->state->mode = FLAG;
 149     case FLAG:
 150       NEEDBYTE
 151       b = NEXTBYTE;
 152       if (((z->state->sub.method << 8) + b) % 31)
 153       {
 154         z->state->mode = I_BAD;
 155         z->msg = (char*)"incorrect header check";
 156         z->state->sub.marker = 5;       /* can't try inflateSync */
 157         break;
 158       }
 159       if (!(b & PRESET_DICT))
 160       {
 161         z->state->mode = BLOCKS;
 162         break;
 163       }
 164       z->state->mode = DICT4;
 165     case DICT4:
 166       NEEDBYTE
 167       z->state->sub.check.need = (uLong)NEXTBYTE << 24;
 168       z->state->mode = DICT3;
 169     case DICT3:
 170       NEEDBYTE
 171       z->state->sub.check.need += (uLong)NEXTBYTE << 16;
 172       z->state->mode = DICT2;
 173     case DICT2:
 174       NEEDBYTE
 175       z->state->sub.check.need += (uLong)NEXTBYTE << 8;
 176       z->state->mode = DICT1;
 177     case DICT1:
 178       NEEDBYTE
 179       z->state->sub.check.need += (uLong)NEXTBYTE;
 180       z->adler = z->state->sub.check.need;
 181       z->state->mode = DICT0;
 182       return Z_NEED_DICT;
 183     case DICT0:
 184       z->state->mode = I_BAD;
 185       z->msg = (char*)"need dictionary";
 186       z->state->sub.marker = 0;       /* can try inflateSync */
 187       return Z_STREAM_ERROR;
 188     case BLOCKS:
 189       r = zlib_inflate_blocks(z->state->blocks, z, r);
 190       if (f == Z_PACKET_FLUSH && z->avail_in == 0 && z->avail_out != 0)
 191           r = zlib_inflate_packet_flush(z->state->blocks);
 192       if (r == Z_DATA_ERROR)
 193       {
 194         z->state->mode = I_BAD;
 195         z->state->sub.marker = 0;       /* can try inflateSync */
 196         break;
 197       }
 198       if (r == Z_OK)
 199         r = trv;
 200       if (r != Z_STREAM_END)
 201         return r;
 202       r = trv;
 203       zlib_inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was);
 204       if (z->state->nowrap)
 205       {
 206         z->state->mode = I_DONE;
 207         break;
 208       }
 209       z->state->mode = CHECK4;
 210     case CHECK4:
 211       NEEDBYTE
 212       z->state->sub.check.need = (uLong)NEXTBYTE << 24;
 213       z->state->mode = CHECK3;
 214     case CHECK3:
 215       NEEDBYTE
 216       z->state->sub.check.need += (uLong)NEXTBYTE << 16;
 217       z->state->mode = CHECK2;
 218     case CHECK2:
 219       NEEDBYTE
 220       z->state->sub.check.need += (uLong)NEXTBYTE << 8;
 221       z->state->mode = CHECK1;
 222     case CHECK1:
 223       NEEDBYTE
 224       z->state->sub.check.need += (uLong)NEXTBYTE;
 225
 226       if (z->state->sub.check.was != z->state->sub.check.need)
 227       {
 228         z->state->mode = I_BAD;
 229         z->msg = (char*)"incorrect data check";
 230         z->state->sub.marker = 5;       /* can't try inflateSync */
 231         break;
 232       }
 233       z->state->mode = I_DONE;
 234     case I_DONE:
 235       return Z_STREAM_END;
 236     case I_BAD:
 237       return Z_DATA_ERROR;
 238     default:
 239       return Z_STREAM_ERROR;
 240   }
 241  empty:
 242   if (f != Z_PACKET_FLUSH)
 243     return r;
 244   z->state->mode = I_BAD;
 245   z->msg = (char *)"need more for packet flush";
 246   z->state->sub.marker = 0;       /* can try inflateSync */
 247   return Z_DATA_ERROR;
 248 }