modules/stream_filter/inflate.c

   1 /*****************************************************************************
   2  * inflate.c: zlib decompression module for VLC
   3  *****************************************************************************
   4  * Copyright © 2016 Rémi Denis-Courmont
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2.1 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 #ifdef HAVE_CONFIG_H
  22 # include "config.h"
  23 #endif
  24
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <zlib.h>
  28
  29 #include <vlc_common.h>
  30 #include <vlc_plugin.h>
  31 #include <vlc_stream.h>
  32
  33 typedef struct
  34 {
  35     z_stream zstream;
  36     bool eof;
  37     unsigned char buffer[16384];
  38 } stream_sys_t;
  39
  40 static ssize_t Read(stream_t *stream, void *buf, size_t buflen)
  41 {
  42     stream_sys_t *sys = stream->p_sys;
  43     ssize_t val;
  44
  45     if (sys->eof || unlikely(buflen == 0))
  46         return 0;
  47
  48     sys->zstream.next_out = buf;
  49     sys->zstream.avail_out = buflen;
  50
  51     if (sys->zstream.avail_in == 0)
  52         sys->zstream.next_in = sys->buffer;
  53
  54     val = (sys->buffer + sizeof (sys->buffer))
  55         - (sys->zstream.next_in + sys->zstream.avail_in);
  56
  57     if (val > 0)
  58     {   /* Fill input buffer if there is space left */
  59         val = vlc_stream_Read(stream->s,
  60                           sys->zstream.next_in + sys->zstream.avail_in, val);
  61         if (val >= 0)
  62             sys->zstream.avail_in += val;
  63     }
  64
  65     if (sys->zstream.avail_in == 0)
  66     {
  67         msg_Err(stream, "unexpected end of stream");
  68         return 0;
  69     }
  70
  71     val = inflate(&sys->zstream, Z_SYNC_FLUSH);
  72     switch (val)
  73     {
  74         case Z_STREAM_END:
  75             msg_Dbg(stream, "end of stream");
  76             sys->eof = true;
  77             /* fall through */
  78         case Z_OK:
  79             return buflen - sys->zstream.avail_out;
  80         case Z_DATA_ERROR:
  81             msg_Err(stream, "corrupt stream");
  82             sys->eof = true;
  83             return -1;
  84         case Z_BUF_ERROR:
  85             if (sys->zstream.next_in == sys->buffer)
  86                 break;
  87
  88             memmove(sys->buffer, sys->zstream.next_in, sys->zstream.avail_in);
  89             sys->zstream.next_in = sys->buffer;
  90             return Read(stream, buf, buflen);
  91     }
  92
  93     msg_Err(stream, "unhandled decompression error (%zd)", val);
  94     return -1;
  95 }
  96
  97 static int Seek(stream_t *stream, uint64_t offset)
  98 {
  99     (void) stream; (void) offset;
 100     return -1;
 101 }
 102
 103 static int Control(stream_t *stream, int query, va_list args)
 104 {
 105     switch (query)
 106     {
 107         case STREAM_CAN_SEEK:
 108         case STREAM_CAN_FASTSEEK:
 109             *va_arg(args, bool *) = false;
 110             break;
 111         case STREAM_CAN_PAUSE:
 112         case STREAM_CAN_CONTROL_PACE:
 113         case STREAM_GET_PTS_DELAY:
 114         case STREAM_GET_META:
 115         case STREAM_GET_CONTENT_TYPE:
 116         case STREAM_GET_SIGNAL:
 117         case STREAM_SET_PAUSE_STATE:
 118             return vlc_stream_vaControl(stream->s, query, args);
 119         case STREAM_GET_SIZE:
 120         case STREAM_GET_TITLE_INFO:
 121         case STREAM_GET_TITLE:
 122         case STREAM_GET_SEEKPOINT:
 123         case STREAM_SET_TITLE:
 124         case STREAM_SET_SEEKPOINT:
 125         case STREAM_SET_PRIVATE_ID_STATE:
 126         case STREAM_SET_PRIVATE_ID_CA:
 127         case STREAM_GET_PRIVATE_ID_STATE:
 128             return VLC_EGENERIC;
 129         default:
 130             msg_Err(stream, "unimplemented query (%d) in control", query);
 131             return VLC_EGENERIC;
 132     }
 133     return VLC_SUCCESS;
 134 }
 135
 136 static int Open(vlc_object_t *obj)
 137 {
 138     stream_t *stream = (stream_t *)obj;
 139     const uint8_t *peek;
 140     int bits;
 141
 142     /* See IETF RFC6713 */
 143     if (vlc_stream_Peek(stream->s, &peek, 2) < 2)
 144         return VLC_EGENERIC;
 145
 146     if ((peek[0] & 0xF) == 8 && (peek[0] >> 4) < 8 && (U16_AT(peek) % 31) == 0)
 147         bits = 15; /* zlib */
 148     else
 149     if (!memcmp(peek, "\x1F\x8B", 2))
 150         bits = 15 + 32; /* gzip */
 151     else
 152         return VLC_EGENERIC;
 153
 154     stream_sys_t *sys = malloc(sizeof (*sys));
 155     if (unlikely(sys == NULL))
 156         return VLC_ENOMEM;
 157
 158     sys->zstream.next_in = sys->buffer;
 159     sys->zstream.avail_in = 0;
 160     sys->zstream.zalloc = Z_NULL;
 161     sys->zstream.zfree = Z_NULL;
 162     sys->zstream.opaque = Z_NULL;
 163     sys->eof = false;
 164
 165     int ret = inflateInit2(&sys->zstream, bits);
 166     if (ret != Z_OK)
 167     {
 168         free(sys);
 169         return (ret == Z_MEM_ERROR) ? VLC_ENOMEM : VLC_EGENERIC;
 170     }
 171
 172     stream->p_sys = sys;
 173     stream->pf_read = Read;
 174     stream->pf_seek = Seek;
 175     stream->pf_control = Control;
 176     return VLC_SUCCESS;
 177 }
 178
 179 static void Close (vlc_object_t *obj)
 180 {
 181     stream_t *stream = (stream_t *)obj;
 182     stream_sys_t *sys = stream->p_sys;
 183
 184     inflateEnd(&sys->zstream);
 185     free(sys);
 186 }
 187
 188 vlc_module_begin()
 189     set_category(CAT_INPUT)
 190     set_subcategory(SUBCAT_INPUT_STREAM_FILTER)
 191     set_capability("stream_filter", 330)
 192
 193     set_description(N_("Zlib decompression filter"))
 194     set_callbacks(Open, Close)
 195 vlc_module_end()