From: Stephen Adams <edu/mit/csail/zurich/adams>
Date: Mon, 25 Sep 1995 18:10:46 +0000 (+0000)
Subject: Fixed bug in DeleteDIB.
X-Git-Tag: 20090517-FFI~5941
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=824064721e84e6231cb7e2e52277fed53a7dcdfc;p=mit-scheme.git

Fixed bug in DeleteDIB.
Rewrote loop to speed up DIBSetPixelsUnaligned by 2x-3x.
Put in MIT copyright notice.
---

diff --git a/v7/src/win32/dibutils/dibutils.c b/v7/src/win32/dibutils/dibutils.c
index 1a7e948cc..e12c3e0b7 100644
--- a/v7/src/win32/dibutils/dibutils.c
+++ b/v7/src/win32/dibutils/dibutils.c
@@ -1,3 +1,39 @@
+/* -*-C-*-
+
+$Id: dibutils.c,v 1.2 1995/09/25 18:10:46 adams Exp $
+
+Copyright (c) 1994-1995 Massachusetts Institute of Technology
+
+This material was developed by the Scheme project at the Massachusetts
+Institute of Technology, Department of Electrical Engineering and
+Computer Science.  Permission to copy this software, to redistribute
+it, and to use it for any purpose is granted, subject to the following
+restrictions and understandings.
+
+1. Any copy made of this software must include this copyright notice
+in full.
+
+2. Users of this software agree to make their best efforts (a) to
+return to the MIT Scheme project any improvements or extensions that
+they make, so that these may be included in future releases; and (b)
+to inform MIT of noteworthy uses of this software.
+
+3. All materials developed as a consequence of the use of this
+software shall duly acknowledge such use, in accordance with the usual
+standards of acknowledging credit in academic research.
+
+4. MIT has made no warrantee or representation that the operation of
+this software will be error-free, and MIT is under no obligation to
+provide any services, by way of maintenance, update, or otherwise.
+
+5. In conjunction with products arising from the use of this material,
+there shall be no use of the name of the Massachusetts Institute of
+Technology nor of any adaptation thereof in any advertising,
+promotional, or sales literature without prior written consent from
+MIT in each case. */
+
+
+/* This software was derived from the following:  */
 
 /******************************************************************************\
 *       This is a part of the Microsoft Source Code Samples. 
@@ -196,8 +232,10 @@ BOOL WriteDIB (
  ****************************************************************************/
 BOOL DeleteDIB (HANDLE hdib)
 {
-    if (!hdib)
+    if (hdib)
       return  GlobalFree (hdib) == 0;
+    else
+      return  FALSE;
 }
 
 /****************************************************************************
@@ -542,7 +580,7 @@ BOOL DIBSetPixelsUnaligned (HANDLE hdib, BYTE *bytes)
     DWORD width, height;
 
     if (!hdib)
-      return  0;
+      return  FALSE;
 
     lpbmi      = (LPBITMAPINFOHEADER) GlobalLock(hdib);
     lpbci      = (LPBITMAPCOREHEADER) lpbmi;
@@ -568,16 +606,29 @@ BOOL DIBSetPixelsUnaligned (HANDLE hdib, BYTE *bytes)
       {
 	BYTE *src = src_area + width*(height-scanline-1);
 	BYTE *dest = dest_area + aligned_width * scanline;
-	long  column;
-	for (column = width; column>0; column--)
+	long  column = width;
+	*(DWORD*)(dest+aligned_width-sizeof(DWORD)) = 0;  // zero-fill end word
+      loop:
+	if (column>=8)
+	{
+	  ((DWORD*)dest)[0] = ((DWORD*)src)[0];
+	  ((DWORD*)dest)[1] = ((DWORD*)src)[1];
+	  column -= 2*sizeof(DWORD);
+	  src    += 2*sizeof(DWORD);
+	  dest   += 2*sizeof(DWORD);
+	  goto loop;
+	}
+	else if (column>0)
+	{
+	  column -= 1;
 	  *dest++ = *src++;
-	for (column = aligned_width - width;  column>0;  column--)
-	  *dest++ = 0;
+	  goto loop;
+	}
       }
     }
 
     GlobalUnlock (hdib);
-    return  1;
+    return  TRUE;
 }
 
 /****************************************************************************