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x11drv: Avoid unaligned 32 bit reads, and reads beyond the input pixel 

buffer in the convert_888_to_0888_* functions.
This commit is contained in:
Rein Klazes 2006-03-01 16:39:42 +01:00 committed by Alexandre Julliard
parent ac3be957e4
commit 883e0b0edc
1 changed files with 78 additions and 24 deletions
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102
dlls/x11drv/dib_convert.c
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@ -821,18 +821,36 @@ static void convert_888_to_0888_asis(int width, int height,
const DWORD* srcpixel;
DWORD* dstpixel;
int x,y;
int oddwidth;
oddwidth=width & 3;
width=width/4;
int w1, w2, w3;
w1 = min( (INT_PTR)srcbits & 3, width);
w2 = ( width - w1) / 4;
w3 = ( width - w1) & 3;
for (y=0; y<height; y++) {
srcpixel=srcbits;
dstpixel=dstbits;
for (x=0; x<width; x++) {
/* advance w1 pixels to make srcpixel 32 bit alignd */
srcpixel = (const DWORD*)((INT_PTR)srcpixel & ~3);
srcpixel += w1;
dstpixel += w1;
/* and do the w1 pixels */
x = w1;
if( x) {
dstpixel[ -1] = ( srcpixel[ -1] >> 8); /* h4, g4, l4 */
if( --x) {
dstpixel[ -2] = ( srcpixel[ -2] >> 16) | /* g3, l3 */
((srcpixel[ -1] << 16) & 0x00ff0000); /* h3 */
if( --x) {
dstpixel[ -3] = ( srcpixel[ -3] >> 24) | /* l2 */
((srcpixel[ -2] << 8) & 0x00ffff00); /* h2, g2 */
}
}
}
for (x=0; x < w2; x++) {
/* Do 4 pixels at a time: 3 dwords in and 4 dwords out */
DWORD srcval1,srcval2;
srcval1=srcpixel[0];
dstpixel[0]=( srcval1 & 0x00ffffff); /* h1, g1, l1 */
dstpixel[0]=( srcval1 & 0x00ffffff); /* h1, g1, l1 */
srcval2=srcpixel[1];
dstpixel[1]=( srcval1 >> 24) | /* l2 */
((srcval2 << 8) & 0x00ffff00); /* h2, g2 */
@ -843,12 +861,18 @@ static void convert_888_to_0888_asis(int width, int height,
srcpixel+=3;
dstpixel+=4;
}
/* And now up to 3 odd pixels */
for (x=0; x<oddwidth; x++) {
DWORD srcval;
srcval=*srcpixel;
srcpixel=(const DWORD*)(((const char*)srcpixel)+3);
*dstpixel++=( srcval & 0x00ffffff); /* h, g, l */
/* do last w3 pixels */
x = w3;
if( x) {
dstpixel[0]=( srcpixel[0] & 0x00ffffff); /* h1, g1, l1 */
if( --x) {
dstpixel[1]=( srcpixel[0]>> 24) | /* l2 */
((srcpixel[1]<< 8) & 0x00ffff00); /* h2, g2 */
if( --x) {
dstpixel[2]=( srcpixel[1]>> 16) | /* g3, l3 */
((srcpixel[2]<< 16) & 0x00ff0000); /* h3 */
}
}
}
srcbits = (const char*)srcbits + srclinebytes;
dstbits = (char*)dstbits + dstlinebytes;
@ -862,14 +886,36 @@ static void convert_888_to_0888_reverse(int width, int height,
const DWORD* srcpixel;
DWORD* dstpixel;
int x,y;
int oddwidth;
int w1, w2, w3;
oddwidth=width & 3;
width=width/4;
w1 = min( (INT_PTR)srcbits & 3, width);
w2 = ( width - w1) / 4;
w3 = ( width - w1) & 3;
for (y=0; y<height; y++) {
srcpixel=srcbits;
dstpixel=dstbits;
for (x=0; x<width; x++) {
/* advance w1 pixels to make srcpixel 32 bit alignd */
srcpixel = (const DWORD*)((INT_PTR)srcpixel & ~3);
srcpixel += w1;
dstpixel += w1;
/* and do the w1 pixels */
x = w1;
if( x) {
dstpixel[ -1]=((srcpixel[ -1] >> 24) & 0x0000ff) | /* h4 */
((srcpixel[ -1] >> 8) & 0x00ff00) | /* g4 */
((srcpixel[ -1] << 8) & 0xff0000); /* l4 */
if( --x) {
dstpixel[ -2]=( srcpixel[ -2] & 0xff0000) | /* l3 */
((srcpixel[ -2] >> 16) & 0x00ff00) | /* g3 */
( srcpixel[ -1] & 0x0000ff); /* h3 */
if( --x) {
dstpixel[ -3]=((srcpixel[ -3] >> 8) & 0xff0000) | /* l2 */
((srcpixel[ -2] << 8) & 0x00ff00) | /* g2 */
((srcpixel[ -2] >> 8) & 0x0000ff); /* h2 */
}
}
}
for (x=0; x < w2; x++) {
/* Do 4 pixels at a time: 3 dwords in and 4 dwords out */
DWORD srcval1,srcval2;
@ -891,14 +937,22 @@ static void convert_888_to_0888_reverse(int width, int height,
srcpixel+=3;
dstpixel+=4;
}
/* And now up to 3 odd pixels */
for (x=0; x<oddwidth; x++) {
DWORD srcval;
srcval=*srcpixel;
srcpixel=(const DWORD*)(((const char*)srcpixel)+3);
*dstpixel++=((srcval >> 16) & 0x0000ff) | /* h */
( srcval & 0x00ff00) | /* g */
((srcval << 16) & 0xff0000); /* l */
/* do last w3 pixels */
x = w3;
if( x) {
dstpixel[0]=((srcpixel[0] >> 16) & 0x0000ff) | /* h1 */
( srcpixel[0] & 0x00ff00) | /* g1 */
((srcpixel[0] << 16) & 0xff0000); /* l1 */
if( --x) {
dstpixel[1]=((srcpixel[0] >> 8) & 0xff0000) | /* l2 */
((srcpixel[1] << 8) & 0x00ff00) | /* g2 */
((srcpixel[1] >> 8) & 0x0000ff); /* h2 */
if( --x) {
dstpixel[2]=( srcpixel[1] & 0xff0000) | /* l3 */
((srcpixel[1] >> 16) & 0x00ff00) | /* g3 */
( srcpixel[2] & 0x0000ff); /* h3 */
}
}
}
srcbits = (const char*)srcbits + srclinebytes;
dstbits = (char*)dstbits + dstlinebytes;