Fixed the buffer-has-space check in write_buf().

diff --git a/io.c b/io.c
index d79ec1e..7cc4d62 100644 (file)
--- a/io.c
+++ b/io.c
@@ -638,6 +638,7 @@ static char *perform_io(size_t needed, int flags)
                                        iobuf.raw_data_header_pos = iobuf.raw_flushing_ends_before;
                                        if (iobuf.raw_data_header_pos >= iobuf.out.size)
                                                iobuf.raw_data_header_pos -= iobuf.out.size;
+                                       /* Yes, it is possible for this to make len > size for a while. */
                                        iobuf.out.len += 4;
                                }
 
@@ -1906,7 +1907,7 @@ void write_buf(int f, const char *buf, size_t len)
                goto batch_copy;
        }
 
-       if (iobuf.out.size - iobuf.out.len < len)
+       if (iobuf.out.len + len > iobuf.out.size)
                perform_io(len, PIO_NEED_OUTROOM);
 
        pos = iobuf.out.pos + iobuf.out.len; /* Must be set after any flushing. */