avio: Add an internal function for reading without copying

As long as there is enough contiguous data in the avio buffer,
just return a pointer to it instead of copying it to the caller
provided buffer.

Signed-off-by: Martin Storsjö <martin@martin.st>

1 files changed, 12 insertions, 0 deletions

diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
index bc89768ef6..07aa88068f 100644
--- a/libavformat/aviobuf.c
+++ b/libavformat/aviobuf.c
@@ -490,6 +490,18 @@ int avio_read(AVIOContext *s, unsigned char *buf, int size)
     return size1 - size;
 }
 
+int ffio_read_indirect(AVIOContext *s, unsigned char *buf, int size, unsigned char **data)
+{
+    if (s->buf_end - s->buf_ptr >= size && !s->write_flag) {
+        *data = s->buf_ptr;
+        s->buf_ptr += size;
+        return size;
+    } else {
+        *data = buf;
+        return avio_read(s, buf, size);
+    }
+}
+
 int ffio_read_partial(AVIOContext *s, unsigned char *buf, int size)
 {
     int len;