summaryrefslogtreecommitdiffstats
path: root/libavformat/cache.c
diff options
context:
space:
mode:
Diffstat (limited to 'libavformat/cache.c')
-rw-r--r--libavformat/cache.c140
1 files changed, 140 insertions, 0 deletions
diff --git a/libavformat/cache.c b/libavformat/cache.c
new file mode 100644
index 0000000..35f81e8
--- /dev/null
+++ b/libavformat/cache.c
@@ -0,0 +1,140 @@
+/*
+ * Input cache protocol.
+ * Copyright (c) 2011 Michael Niedermayer
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Based on file.c by Fabrice Bellard
+ */
+
+/**
+ * @TODO
+ * support non continuous caching
+ * support keeping files
+ * support filling with a background thread
+ */
+
+#include "libavutil/avassert.h"
+#include "libavutil/avstring.h"
+#include "libavutil/file.h"
+#include "avformat.h"
+#include <fcntl.h>
+#if HAVE_IO_H
+#include <io.h>
+#endif
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <sys/stat.h>
+#include <stdlib.h>
+#include "os_support.h"
+#include "url.h"
+
+typedef struct Context {
+ int fd;
+ int64_t end;
+ int64_t pos;
+ URLContext *inner;
+} Context;
+
+static int cache_open(URLContext *h, const char *arg, int flags)
+{
+ char *buffername;
+ Context *c= h->priv_data;
+
+ av_strstart(arg, "cache:", &arg);
+
+ c->fd = av_tempfile("ffcache", &buffername, 0, h);
+ if (c->fd < 0){
+ av_log(h, AV_LOG_ERROR, "Failed to create tempfile\n");
+ return c->fd;
+ }
+
+ unlink(buffername);
+ av_freep(&buffername);
+
+ return ffurl_open(&c->inner, arg, flags, &h->interrupt_callback, NULL);
+}
+
+static int cache_read(URLContext *h, unsigned char *buf, int size)
+{
+ Context *c= h->priv_data;
+ int r;
+
+ if(c->pos<c->end){
+ r = read(c->fd, buf, FFMIN(size, c->end - c->pos));
+ if(r>0)
+ c->pos += r;
+ return (-1 == r)?AVERROR(errno):r;
+ }else{
+ r = ffurl_read(c->inner, buf, size);
+ if(r > 0){
+ int r2= write(c->fd, buf, r);
+ av_assert0(r2==r); // FIXME handle cache failure
+ c->pos += r;
+ c->end += r;
+ }
+ return r;
+ }
+}
+
+static int64_t cache_seek(URLContext *h, int64_t pos, int whence)
+{
+ Context *c= h->priv_data;
+
+ if (whence == AVSEEK_SIZE) {
+ pos= ffurl_seek(c->inner, pos, whence);
+ if(pos <= 0){
+ pos= ffurl_seek(c->inner, -1, SEEK_END);
+ ffurl_seek(c->inner, c->end, SEEK_SET);
+ if(pos <= 0)
+ return c->end;
+ }
+ return pos;
+ }
+
+ pos= lseek(c->fd, pos, whence);
+ if(pos<0){
+ return pos;
+ }else if(pos <= c->end){
+ c->pos= pos;
+ return pos;
+ }else{
+ if(lseek(c->fd, c->pos, SEEK_SET) < 0) {
+ av_log(h, AV_LOG_ERROR, "Failure to seek in cache\n");
+ }
+ return AVERROR(EPIPE);
+ }
+}
+
+static int cache_close(URLContext *h)
+{
+ Context *c= h->priv_data;
+ close(c->fd);
+ ffurl_close(c->inner);
+
+ return 0;
+}
+
+URLProtocol ff_cache_protocol = {
+ .name = "cache",
+ .url_open = cache_open,
+ .url_read = cache_read,
+ .url_seek = cache_seek,
+ .url_close = cache_close,
+ .priv_data_size = sizeof(Context),
+};
OpenPOWER on IntegriCloud