stream-base64-encoder: Added support for seeking backwards in stream.

diff --git a/src/lib/istream-base64-encoder.c b/src/lib/istream-base64-encoder.c
index a4a01b6257c14f1ad7614d863e25f0574a5bc334..2f5b1709e8421b95acbb2022761309124874765c 100644 (file)
--- a/src/lib/istream-base64-encoder.c
+++ b/src/lib/istream-base64-encoder.c
@@ -128,6 +128,24 @@ i_stream_base64_encoder_stat(struct istream_private *stream, bool exact)
        return i_stream_stat(stream->parent, exact);
 }
 
+static void
+i_stream_base64_encoder_seek(struct istream_private *stream,
+                            uoff_t v_offset, bool mark)
+{
+       struct base64_encoder_istream *bstream =
+               (struct base64_encoder_istream *)stream;
+
+       if (v_offset < stream->istream.v_offset) {
+               /* seeking backwards - go back to beginning and seek
+                  forward from there. */
+               stream->parent_expected_offset = stream->parent_start_offset;
+               stream->skip = stream->pos = 0;
+               stream->istream.v_offset = 0;
+               bstream->cur_line_len = 0;
+       }
+       i_stream_default_seek(stream, v_offset, mark);
+}
+
 struct istream *
 i_stream_create_base64_encoder(struct istream *input,
                               unsigned int chars_per_line, bool crlf)
@@ -144,6 +162,7 @@ i_stream_create_base64_encoder(struct istream *input,
        bstream->istream.parent = input;
        bstream->istream.read = i_stream_base64_encoder_read;
        bstream->istream.stat = i_stream_base64_encoder_stat;
+       bstream->istream.seek = i_stream_base64_encoder_seek;
 
        bstream->istream.istream.readable_fd = FALSE;
        bstream->istream.istream.blocking = input->blocking;