From ffdc9baf2892008902e09f0d894947203403679f Mon Sep 17 00:00:00 2001
From: simonmar <unknown>
Date: Tue, 21 Mar 2000 11:22:35 +0000
Subject: [PATCH] [project @ 2000-03-21 11:22:35 by simonmar] Fix several bugs
in readChunk, mainly to do with copying already-buffered data into the user
buffer.
---
ghc/lib/std/cbits/readFile.c | 33 +++++++++++++++++++--------------
1 file changed, 19 insertions(+), 14 deletions(-)
diff --git a/ghc/lib/std/cbits/readFile.c b/ghc/lib/std/cbits/readFile.c
index a68f3aaf8142..69e608b6721e 100644
--- a/ghc/lib/std/cbits/readFile.c
+++ b/ghc/lib/std/cbits/readFile.c
@@ -1,7 +1,7 @@
/*
* (c) The GRASP/AQUA Project, Glasgow University, 1994-1998
*
- * $Id: readFile.c,v 1.11 2000/03/10 15:23:40 simonmar Exp $
+ * $Id: readFile.c,v 1.12 2000/03/21 11:22:35 simonmar Exp $
*
* hGetContents Runtime Support
*/
@@ -155,24 +155,29 @@ readChunk(StgForeignPtr ptr, StgAddr buf, StgInt off, StgInt len)
}
fo->flags = (fo->flags & ~FILEOBJ_RW_WRITE) | FILEOBJ_RW_READ;
+ p = buf+off;
+
/* copy the unread parts of the file buffer..*/
if ( FILEOBJ_READABLE(fo) &&
fo->bufRPtr > 0 &&
fo->bufWPtr >= fo->bufRPtr ) {
- count = ( len < (fo->bufWPtr - fo->bufRPtr)) ? len : (fo->bufWPtr - fo->bufRPtr);
- memcpy(buf,fo->buf, count);
- fo->bufWPtr=0;
- fo->bufRPtr=0;
-
- }
-
- if (len - count <= 0)
- return count;
- len -= count;
- p = buf+off;
- p += count;
- total_count = count;
+ if (fo->bufWPtr - fo->bufRPtr >= len) {
+ /* buffer has enough data to fulfill the request */
+ memcpy(buf, fo->buf + fo->bufRPtr, len);
+ fo->bufRPtr += len;
+ return len;
+ } else {
+ /* can only partially fulfill the request from the buffer */
+ count = fo->bufWPtr - fo->bufRPtr;
+ memcpy(buf, fo->buf + fo->bufRPtr, count);
+ fo->bufWPtr=0;
+ fo->bufRPtr=0;
+ len -= count;
+ p += count;
+ total_count = count;
+ }
+ }
while ((count =
(
--
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