istream-concat bugfixes

diff --git a/src/lib/istream-concat.c b/src/lib/istream-concat.c
index df4cff99695fe29e7632459ce8d1ab41d66121fd..7a63fb9509d622e8fda3d5932ae5ed9a2a799cb8 100644 (file)
--- a/src/lib/istream-concat.c
+++ b/src/lib/istream-concat.c
@@ -87,7 +87,7 @@ static ssize_t i_stream_concat_read(struct istream_private *stream)
 {
        struct concat_istream *cstream = (struct concat_istream *)stream;
        const unsigned char *data;
-       size_t size, pos, cur_pos, bytes_skipped;
+       size_t size, pos, cur_pos, bytes_skipped, new_bytes_count;
        ssize_t ret;
        bool last_stream;
 
@@ -154,17 +154,21 @@ static ssize_t i_stream_concat_read(struct istream_private *stream)
                stream->skip = 0;
        } else if (pos == cur_pos) {
                stream->buffer = stream->w_buffer;
+               pos = stream->pos;
        } else {
-               stream->buffer = stream->w_buffer;
-               if (!i_stream_get_buffer_space(stream, pos - cur_pos, &size))
+               new_bytes_count = pos - cur_pos;
+               if (!i_stream_get_buffer_space(stream, new_bytes_count, &size)) {
+                       stream->buffer = stream->w_buffer;
                        return -2;
+               }
+               stream->buffer = stream->w_buffer;
 
-               if (pos > size)
-                       pos = size;
+               if (new_bytes_count > size)
+                       new_bytes_count = size;
                memcpy(stream->w_buffer + stream->pos,
-                      data + cur_pos, pos - cur_pos);
+                      data + cur_pos, new_bytes_count);
+               pos = stream->pos + new_bytes_count;
        }
-       pos += stream->skip + cstream->prev_stream_left;
 
        ret = pos > stream->pos ? (ssize_t)(pos - stream->pos) :
                (ret == 0 ? 0 : -1);