From b9edbe9953d43b1bfff6ed5ffe8e615289a5d944 Mon Sep 17 00:00:00 2001
From: Baptiste Coudurier <baptiste.coudurier@gmail.com>
Date: Fri, 20 Mar 2009 01:23:33 +0000
Subject: do not write ffm write index by default, detect if file is being
 written and return EOF

Originally committed as revision 18063 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavformat/ffmdec.c | 37 ++++++++++++++++++++-----------------
 libavformat/ffmenc.c | 12 +-----------
 2 files changed, 21 insertions(+), 28 deletions(-)

(limited to 'libavformat')

diff --git a/libavformat/ffmdec.c b/libavformat/ffmdec.c
index e8e1891b4a..180762b4df 100644
--- a/libavformat/ffmdec.c
+++ b/libavformat/ffmdec.c
@@ -66,19 +66,25 @@ static int ffm_is_avail_data(AVFormatContext *s, int size)
     if (size <= len)
         return 1;
     pos = url_ftell(s->pb);
+    if (!ffm->write_index) {
+        if (pos == ffm->file_size);
+            return AVERROR_EOF;
+        avail_size = ffm->file_size - pos;
+    } else {
     if (pos == ffm->write_index) {
         /* exactly at the end of stream */
-        return 0;
+        return AVERROR(EAGAIN);
     } else if (pos < ffm->write_index) {
         avail_size = ffm->write_index - pos;
     } else {
         avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);
     }
+    }
     avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;
     if (size <= avail_size)
         return 1;
     else
-        return 0;
+        return AVERROR(EAGAIN);
 }
 
 /* first is true if we read the frame header */
@@ -251,7 +257,8 @@ static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap)
     /* get also filesize */
     if (!url_is_streamed(pb)) {
         ffm->file_size = url_fsize(pb);
-        adjust_write_index(s);
+        if (ffm->write_index)
+            adjust_write_index(s);
     } else {
         ffm->file_size = (UINT64_C(1) << 63) - 1;
     }
@@ -360,24 +367,21 @@ static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     int size;
     FFMContext *ffm = s->priv_data;
-    int duration;
-
-    if (url_fsize(s->pb) == FFM_PACKET_SIZE)
-        return -1;
+    int duration, ret;
 
     switch(ffm->read_state) {
     case READ_HEADER:
-        if (!ffm_is_avail_data(s, FRAME_HEADER_SIZE+4)) {
-            return AVERROR(EAGAIN);
-        }
+        if ((ret = ffm_is_avail_data(s, FRAME_HEADER_SIZE+4)) < 0)
+            return ret;
+
         dprintf(s, "pos=%08"PRIx64" spos=%"PRIx64", write_index=%"PRIx64" size=%"PRIx64"\n",
                url_ftell(s->pb), s->pb->pos, ffm->write_index, ffm->file_size);
         if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) !=
             FRAME_HEADER_SIZE)
-            return AVERROR(EAGAIN);
+            return -1;
         if (ffm->header[1] & FLAG_DTS)
             if (ffm_read_data(s, ffm->header+16, 4, 1) != 4)
-                return AVERROR(EAGAIN);
+                return -1;
 #if 0
         av_hexdump_log(s, AV_LOG_DEBUG, ffm->header, FRAME_HEADER_SIZE);
 #endif
@@ -385,9 +389,8 @@ static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt)
         /* fall thru */
     case READ_DATA:
         size = AV_RB24(ffm->header + 2);
-        if (!ffm_is_avail_data(s, size)) {
-            return AVERROR(EAGAIN);
-        }
+        if ((ret = ffm_is_avail_data(s, size)) < 0)
+            return ret;
 
         duration = AV_RB24(ffm->header + 5);
 
@@ -397,7 +400,7 @@ static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt)
             av_log(s, AV_LOG_ERROR, "invalid stream index %d\n", pkt->stream_index);
             av_free_packet(pkt);
             ffm->read_state = READ_HEADER;
-            return AVERROR(EAGAIN);
+            return -1;
         }
         pkt->pos = url_ftell(s->pb);
         if (ffm->header[1] & FLAG_KEY_FRAME)
@@ -407,7 +410,7 @@ static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt)
         if (ffm_read_data(s, pkt->data, size, 0) != size) {
             /* bad case: desynchronized packet. we cancel all the packet loading */
             av_free_packet(pkt);
-            return AVERROR(EAGAIN);
+            return -1;
         }
         pkt->pts = AV_RB64(ffm->header+8);
         if (ffm->header[1] & FLAG_DTS)
diff --git a/libavformat/ffmenc.c b/libavformat/ffmenc.c
index 9a55264b44..3de4984dfe 100644
--- a/libavformat/ffmenc.c
+++ b/libavformat/ffmenc.c
@@ -93,8 +93,7 @@ static int ffm_write_header(AVFormatContext *s)
     /* header */
     put_le32(pb, MKTAG('F', 'F', 'M', '1'));
     put_be32(pb, ffm->packet_size);
-    /* XXX: store write position in other file ? */
-    put_be64(pb, ffm->packet_size); /* current write position */
+    put_be64(pb, 0); /* current write position */
 
     put_be32(pb, s->nb_streams);
     bit_rate = 0;
@@ -224,15 +223,6 @@ static int ffm_write_trailer(AVFormatContext *s)
 
     put_flush_packet(pb);
 
-    if (!url_is_streamed(pb)) {
-        int64_t size;
-        /* update the write offset */
-        size = url_ftell(pb);
-        url_fseek(pb, 8, SEEK_SET);
-        put_be64(pb, size);
-        put_flush_packet(pb);
-    }
-
     return 0;
 }
 
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