Add a tool that uses avio to read and write, doing a plain copy of data

It also optionally can throttle its operation to a particular
speed, to simulate realtime writing.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/Makefile

@@ -354,6 +354,6 @@ SKIPHEADERS-$(CONFIG_NETWORK)            += network.h rtsp.h
 
 EXAMPLES  = metadata output
 TESTPROGS = seek
-TOOLS     = pktdumper probetest
+TOOLS     = aviocat pktdumper probetest
 
 $(SUBDIR)output-example$(EXESUF): ELIBS = -lswscale

tools/aviocat.c

+/*
+ * Copyright (c) 2012 Martin Storsjo
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include "libavformat/avformat.h"
+#include "libavformat/riff.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/mathematics.h"
+
+static int usage(const char *argv0, int ret)
+{
+    fprintf(stderr, "%s [-b bytespersec] input_url output_url\n", argv0);
+    return ret;
+}
+
+int main(int argc, char **argv)
+{
+    int bps = 0, ret, i;
+    const char *input_url = NULL, *output_url = NULL;
+    int64_t stream_pos = 0;
+    int64_t start_time;
+    char errbuf[50];
+    AVIOContext *input, *output;
+
+    av_register_all();
+    avformat_network_init();
+
+    for (i = 1; i < argc; i++) {
+        if (!strcmp(argv[i], "-b")) {
+            bps = atoi(argv[i + 1]);
+            i++;
+        } else if (!input_url) {
+            input_url = argv[i];
+        } else if (!output_url) {
+            output_url = argv[i];
+        } else {
+            return usage(argv[0], 1);
+        }
+    }
+    if (!output_url)
+        return usage(argv[0], 1);
+
+    ret = avio_open2(&input, input_url, AVIO_FLAG_READ, NULL, NULL);
+    if (ret) {
+        av_strerror(ret, errbuf, sizeof(errbuf));
+        fprintf(stderr, "Unable to open %s: %s\n", input_url, errbuf);
+        return 1;
+    }
+    ret = avio_open2(&output, output_url, AVIO_FLAG_WRITE, NULL, NULL);
+    if (ret) {
+        av_strerror(ret, errbuf, sizeof(errbuf));
+        fprintf(stderr, "Unable to open %s: %s\n", output_url, errbuf);
+        goto fail;
+    }
+
+    start_time = av_gettime();
+    while (1) {
+        uint8_t buf[1024];
+        int n;
+        n = avio_read(input, buf, sizeof(buf));
+        if (n <= 0)
+            break;
+        avio_write(output, buf, n);
+        stream_pos += n;
+        if (bps) {
+            avio_flush(output);
+            while ((av_gettime() - start_time)*bps/AV_TIME_BASE < stream_pos)
+                usleep(50*1000);
+        }
+    }
+
+    avio_close(output);
+fail:
+    avio_close(input);
+    avformat_network_deinit();
+    return ret ? 1 : 0;
+}