Fixed bug in joining.

[libucw.git] / lib / fb-mem.c

diff --git a/lib/fb-mem.c b/lib/fb-mem.c
index 2b0d7e941fa6cf1c9e0e408efe02a3a184bb67d8..c304e16db0b988b73aaf630ecb0af0fe335fdebf 100644 (file)
--- a/lib/fb-mem.c
+++ b/lib/fb-mem.c
@@ -1,5 +1,5 @@
 /*
- *     Sherlock Library -- Fast Buffered I/O on Memory Streams
+ *     UCW Library -- Fast Buffered I/O on Memory Streams
  *
  *     (c) 1997--2002 Martin Mares <mj@ucw.cz>
  *
@@ -10,7 +10,7 @@
 #include "lib/lib.h"
 #include "lib/fastbuf.h"
 
-#include <stdlib.h>
+#include <stdio.h>
 
 struct memstream {
   unsigned blocksize;
@@ -95,7 +95,7 @@ fbmem_spout(struct fastbuf *f)
   FB_MEM(f)->block = bb;
 }
 
-static void
+static int
 fbmem_seek(struct fastbuf *f, sh_off_t pos, int whence)
 {
   struct memstream *m = FB_MEM(f)->stream;
@@ -117,9 +117,17 @@ fbmem_seek(struct fastbuf *f, sh_off_t pos, int whence)
          f->bufend = f->bstop = b->data + b->size;
          f->pos = b->pos + b->size;
          FB_MEM(f)->block = b;
-         return;
+         return 1;
        }
     }
+  if (!m->first && !pos)
+    {
+      /* Seeking to offset 0 in an empty file needs an exception */
+      f->buffer = f->bptr = f->bufend = NULL;
+      f->pos = 0;
+      FB_MEM(f)->block = NULL;
+      return 1;
+    }
   die("fbmem_seek to invalid offset");
 }
 
@@ -171,6 +179,7 @@ fbmem_clone_read(struct fastbuf *b)
   f->refill = fbmem_refill;
   f->seek = fbmem_seek;
   f->close = fbmem_close;
+  f->can_overwrite_buffer = 1;
   return f;
 }