+static int64_t ffm_read_write_index(int fd)
+{
+ uint8_t buf[8];
+
+ lseek(fd, 8, SEEK_SET);
+ if (read(fd, buf, 8) != 8)
+ return AVERROR(EIO);
+ return AV_RB64(buf);
+}
+
+static int ffm_write_write_index(int fd, int64_t pos)
+{
+ uint8_t buf[8];
+ int i;
+
+ for(i=0;i<8;i++)
+ buf[i] = (pos >> (56 - i * 8)) & 0xff;
+ lseek(fd, 8, SEEK_SET);
+ if (write(fd, buf, 8) != 8)
+ return AVERROR(EIO);
+ return 8;
+}
+
+static void ffm_set_write_index(AVFormatContext *s, int64_t pos,
+ int64_t file_size)
+{
+ FFMContext *ffm = s->priv_data;
+ ffm->write_index = pos;
+ ffm->file_size = file_size;
+}
+