X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;f=lib%2Ffb-mem.c;h=c304e16db0b988b73aaf630ecb0af0fe335fdebf;hb=5dea0be536bd0e658f231efd5631b331a8764e5a;hp=0f3158c379dbc9e7ae666c35d90e0d91c6bdfb32;hpb=cf83e06e4158617e981fef5bf3878315b23bf7f9;p=libucw.git

diff --git a/lib/fb-mem.c b/lib/fb-mem.c
index 0f3158c3..c304e16d 100644
--- 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;
@@ -110,16 +110,24 @@ fbmem_seek(struct fastbuf *f, sh_off_t pos, int whence)
   /* Yes, this is linear. But considering the average number of buckets, it doesn't matter. */
   for (b=m->first; b; b=b->next)
     {
-      if (pos <= b->pos + b->size) /* <=, because we need to be able to seek just after file end */
+      if (pos <= b->pos + (sh_off_t)b->size) /* <=, because we need to be able to seek just after file end */
 	{
 	  f->buffer = b->data;
 	  f->bptr = b->data + (pos - b->pos);
 	  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;
 }