inflate: stream filter for deflate (refs #16412)

This handles deflate encoding or application/zlib type transparently.

(Note though that it fails to check and discard the application/zlib
 content-type from the underlying stream.)

NEWS

@@ -94,6 +94,7 @@ Stream filter:
  * Added ARIB STD-B25 TS streams decoder
  * Added stream prebuffering plugin
  * Removed HTTP Live streaming stream filter
+ * Added zlib (a.k.a. deflate) decompression filter
 
 Audio output:
  * Complete rewrite of the AudioTrack Android module. This is now the default.

modules/MODULES_LIST

@@ -193,6 +193,7 @@ $Id$
  * idummy: dummy input
  * image: Image file video output
  * imem: memory input access module
+ * inflate: zlib decompression stream_filter module
  * integer_mixer: Integer audio mixer
  * invert: inverse video filter
  * iomx: IPC/OpenMaxIL for Android

modules/stream_filter/Makefile.am

@@ -16,6 +16,12 @@ stream_filter_LTLIBRARIES += libdecomp_plugin.la
 endif
 endif
 
+libinflate_plugin_la_SOURCES = stream_filter/inflate.c
+libinflate_plugin_la_LIBADD = -lz
+if HAVE_ZLIB
+stream_filter_LTLIBRARIES += libinflate_plugin.la
+endif
+
 libprefetch_plugin_la_SOURCES = stream_filter/prefetch.c
 libprefetch_plugin_la_LIBADD = $(LIBPTHREAD)
 stream_filter_LTLIBRARIES += libprefetch_plugin.la

modules/stream_filter/inflate.c

+/*****************************************************************************
+ * inflate.c: zlib decompression module for VLC
+ *****************************************************************************
+ * Copyright © 2016 Rémi Denis-Courmont
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <stdlib.h>
+#include <string.h>
+#include <zlib.h>
+
+#include <vlc_common.h>
+#include <vlc_plugin.h>
+#include <vlc_stream.h>
+
+struct stream_sys_t
+{
+    z_stream zstream;
+    bool eof;
+    unsigned char buffer[16384];
+};
+
+static ssize_t Read(stream_t *stream, void *buf, size_t buflen)
+{
+    stream_sys_t *sys = stream->p_sys;
+    ssize_t val;
+
+    if (sys->eof || unlikely(buflen == 0))
+        return 0;
+
+    if (buf == NULL)
+    {
+        char dummy[buflen > 4096 ? 4096 : buflen];
+
+        return Read(stream, dummy, sizeof (dummy));
+    }
+
+    sys->zstream.next_out = buf;
+    sys->zstream.avail_out = buflen;
+
+    if (sys->zstream.avail_in == 0)
+        sys->zstream.next_in = sys->buffer;
+
+    val = (sys->buffer + sizeof (sys->buffer))
+        - (sys->zstream.next_in + sys->zstream.avail_in);
+
+    if (val > 0)
+    {   /* Fill input buffer if there is space left */
+        val = stream_Read(stream->p_source,
+                          sys->zstream.next_in + sys->zstream.avail_in, val);
+        if (val >= 0)
+            sys->zstream.avail_in += val;
+    }
+
+    if (sys->zstream.avail_in == 0)
+    {
+        msg_Err(stream, "unexpected end of stream");
+        return 0;
+    }
+
+    val = inflate(&sys->zstream, Z_SYNC_FLUSH);
+    switch (val)
+    {
+        case Z_STREAM_END:
+            msg_Dbg(stream, "end of stream");
+            sys->eof = true;
+            /* fall through */
+        case Z_OK:
+            return buflen - sys->zstream.avail_out;
+        case Z_DATA_ERROR:
+            msg_Err(stream, "corrupt stream");
+            sys->eof = true;
+            return -1;
+        case Z_BUF_ERROR:
+            if (sys->zstream.next_in == sys->buffer)
+                break;
+
+            memmove(sys->buffer, sys->zstream.next_in, sys->zstream.avail_in);
+            sys->zstream.next_in = sys->buffer;
+            return Read(stream, buf, buflen);
+    }
+
+    msg_Err(stream, "unhandled decompression error (%zd)", val);
+    return -1;
+}
+
+static input_item_t *ReadDir(stream_t *stream)
+{
+    (void) stream;
+    return NULL;
+}
+
+static int Seek(stream_t *stream, uint64_t offset)
+{
+    (void) stream; (void) offset;
+    return -1;
+}
+
+static int Control(stream_t *stream, int query, va_list args)
+{
+    switch (query)
+    {
+        case STREAM_CAN_SEEK:
+        case STREAM_CAN_FASTSEEK:
+            *va_arg(args, bool *) = false;
+            break;
+        case STREAM_CAN_PAUSE:
+        case STREAM_CAN_CONTROL_PACE:
+        case STREAM_GET_PTS_DELAY:
+        case STREAM_GET_META:
+        case STREAM_GET_CONTENT_TYPE:
+        case STREAM_GET_SIGNAL:
+        case STREAM_SET_PAUSE_STATE:
+            return stream_vaControl(stream->p_source, query, args);
+        case STREAM_IS_DIRECTORY:
+        case STREAM_GET_SIZE:
+        case STREAM_GET_TITLE_INFO:
+        case STREAM_GET_TITLE:
+        case STREAM_GET_SEEKPOINT:
+        case STREAM_SET_TITLE:
+        case STREAM_SET_SEEKPOINT:
+        case STREAM_SET_PRIVATE_ID_STATE:
+        case STREAM_SET_PRIVATE_ID_CA:
+        case STREAM_GET_PRIVATE_ID_STATE:
+            return VLC_EGENERIC;
+        default:
+            msg_Err(stream, "unimplemented query (%d) in control", query);
+            return VLC_EGENERIC;
+    }
+    return VLC_SUCCESS;
+}
+
+static int Open(vlc_object_t *obj)
+{
+    stream_t *stream = (stream_t *)obj;
+    const uint8_t *peek;
+
+    /* See IETF RFC6713 */
+    if (stream_Peek(stream->p_source, &peek, 2) < 2
+     || (peek[0] & 0xF) != 8 || (peek[0] >> 4) > 7 || (U16_AT(peek) % 31) != 0)
+        return VLC_EGENERIC;
+
+    stream_sys_t *sys = malloc(sizeof (*sys));
+    if (unlikely(sys == NULL))
+        return VLC_ENOMEM;
+
+    sys->zstream.next_in = sys->buffer;
+    sys->zstream.avail_in = 0;
+    sys->zstream.zalloc = Z_NULL;
+    sys->zstream.zfree = Z_NULL;
+    sys->zstream.opaque = Z_NULL;
+    sys->eof = false;
+
+    int ret = inflateInit(&sys->zstream);
+    if (ret != Z_OK)
+    {
+        free(sys);
+        return (ret == Z_MEM_ERROR) ? VLC_ENOMEM : VLC_EGENERIC;
+    }
+
+    stream->p_sys = sys;
+    stream->pf_read = Read;
+    stream->pf_readdir = ReadDir;
+    stream->pf_seek = Seek;
+    stream->pf_control = Control;
+    return VLC_SUCCESS;
+}
+
+static void Close (vlc_object_t *obj)
+{
+    stream_t *stream = (stream_t *)obj;
+    stream_sys_t *sys = stream->p_sys;
+
+    inflateEnd(&sys->zstream);
+    free(sys);
+}
+
+vlc_module_begin()
+    set_category(CAT_INPUT)
+    set_subcategory(SUBCAT_INPUT_STREAM_FILTER)
+    set_capability("stream_filter", 30)
+
+    set_description(N_("Zlib decompression filter"))
+    set_callbacks(Open, Close)
+vlc_module_end()

po/POTFILES.in

@@ -1033,6 +1033,7 @@ modules/stream_filter/cache_block.c
 modules/stream_filter/cache_read.c
 modules/stream_filter/decomp.c
 modules/stream_filter/hds/hds.c
+modules/stream_filter/inflate.c
 modules/stream_filter/prefetch.c
 modules/stream_filter/record.c
 modules/stream_out/autodel.c