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Fix invalid memory access and optimise Blit_3or4_to_3or4__*

Fix invalid write at last pixel of the surface:
  when surface has no padding (pitch == w * bpp) and bpp is 3
  with Blit, no colorkey, and NO_ALPHA same or inverse rgb triplet

Optimise by using int32 access:

BGR24 -> ARGB8888 :  faster x1.897875   (362405 -> 190953)
RGB24 -> ABGR8888 :  faster x1.660416   (363304 -> 218803)

ABGR8888 -> RGB24 :  faster x1.686319   (334962 -> 198635)
ARGB8888 -> BGR24 :  faster x1.691868   (324524 -> 191814)
BGR24 -> RGB888 :  faster x1.678459   (326811 -> 194709)
BGR888 -> RGB24 :  faster x1.731772   (327724 -> 189242)
RGB24 -> BGR888 :  faster x1.690989   (328916 -> 194511)
RGB888 -> BGR24 :  faster x1.698333   (326175 -> 192056)
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1bsyl committed Feb 17, 2019
1 parent 1aa2ad2 commit afd1b3dae479db3428476b23c2e901b91121c999
Showing with 63 additions and 9 deletions.
  1. +63 −9 src/video/SDL_blit_N.c
@@ -2938,40 +2938,74 @@ Blit_3or4_to_3or4__same_rgb(SDL_BlitInfo * info)
if (dstfmt->Amask) {
/* SET_ALPHA */
Uint32 mask = info->a << dstfmt->Ashift;
int last_line = 0;
if (srcbpp == 3 && height) {
height -= 1;
last_line = 1;
}

while (height--) {
/* *INDENT-OFF* */
DUFFS_LOOP(
{
Uint32 *dst32 = (Uint32*)dst;
Uint8 s0 = src[0];
Uint8 s1 = src[1];
Uint8 s2 = src[2];
*dst32 = (s0) | (s1 << 8) | (s2 << 16) | mask;
dst += dstbpp;
Uint32 *src32 = (Uint32*)src;
*dst32 = *src32 | mask;
dst += 4;
src += srcbpp;
}, width);
/* *INDENT-ON* */
src += srcskip;
dst += dstskip;
}

if (last_line) {
while (width--) {
Uint32 *dst32 = (Uint32*)dst;
Uint8 s0 = src[0];
Uint8 s1 = src[1];
Uint8 s2 = src[2];
*dst32 = (s0) | (s1 << 8) | (s2 << 16) | mask;
dst += 4;
src += srcbpp;
}
}
} else {
/* NO_ALPHA */
int mask = srcfmt->Rmask | srcfmt->Gmask | srcfmt->Bmask;
int last_line = 0;
if ((dstbpp == 3 || srcbpp == 3) && height) {
height -= 1;
last_line = 1;
}

while (height--) {
/* *INDENT-OFF* */
DUFFS_LOOP(
{
Uint32 *dst32 = (Uint32*)dst;
Uint8 s0 = src[0];
Uint8 s1 = src[1];
Uint8 s2 = src[2];
*dst32 = (s0) | (s1 << 8) | (s2 << 16);
Uint32 *src32 = (Uint32*)src;
*dst32 = *src32 & mask;
dst += dstbpp;
src += srcbpp;
}, width);
/* *INDENT-ON* */
src += srcskip;
dst += dstskip;
}

if (last_line) {
while (width--) {
Uint8 s0 = src[0];
Uint8 s1 = src[1];
Uint8 s2 = src[2];
dst[0] = s0;
dst[1] = s1;
dst[2] = s2;
dst += dstbpp;
src += srcbpp;
}
}
}
return;
}
@@ -3036,6 +3070,12 @@ Blit_3or4_to_3or4__inversed_rgb(SDL_BlitInfo * info)
}
} else {
/* NO_ALPHA */
int last_line = 0;
if (dstbpp == 3 && height) {
height -= 1;
last_line = 1;
}

while (height--) {
/* *INDENT-OFF* */
DUFFS_LOOP(
@@ -3053,6 +3093,20 @@ Blit_3or4_to_3or4__inversed_rgb(SDL_BlitInfo * info)
src += srcskip;
dst += dstskip;
}

if (last_line) {
while (width--) {
Uint8 s0 = src[0];
Uint8 s1 = src[1];
Uint8 s2 = src[2];
/* inversed, compared to Blit_3or4_to_3or4__same_rgb */
dst[0] = s2;
dst[1] = s1;
dst[2] = s0;
dst += dstbpp;
src += srcbpp;
}
}
}
return;
}

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