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ConvertWRGBToYUV: use relative pointer offsets

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avoids int rollover when working with large input

BUG=webp:312

Change-Id: I693cbb295df9cf94aa89294b19c0496bdbe84d18
This commit is contained in:
James Zern 2016-11-04 07:18:55 +00:00
parent deb1b83199
commit de9fa5074e
1 changed files with 17 additions and 11 deletions
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28
src/enc/picture_csp.c
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@ -393,36 +393,42 @@ static WEBP_INLINE uint8_t ConvertRGBToV(int r, int g, int b) {
return clip_8b(128 + (v >> (YUV_FIX + SFIX)));
}
static int ConvertWRGBToYUV(const fixed_y_t* const best_y,
const fixed_t* const best_uv,
static int ConvertWRGBToYUV(const fixed_y_t* best_y, const fixed_t* best_uv,
WebPPicture* const picture) {
int i, j;
uint8_t* dst_y = picture->y;
uint8_t* dst_u = picture->u;
uint8_t* dst_v = picture->v;
const fixed_t* const best_uv_base = best_uv;
const int w = (picture->width + 1) & ~1;
const int h = (picture->height + 1) & ~1;
const int uv_w = w >> 1;
const int uv_h = h >> 1;
for (j = 0; j < picture->height; ++j) {
for (best_uv = best_uv_base, j = 0; j < picture->height; ++j) {
for (i = 0; i < picture->width; ++i) {
const int off = 3 * ((i >> 1) + (j >> 1) * uv_w);
const int off2 = i + j * picture->y_stride;
const int W = best_y[i + j * w];
const int off = 3 * (i >> 1);
const int W = best_y[i];
const int r = best_uv[off + 0] + W;
const int g = best_uv[off + 1] + W;
const int b = best_uv[off + 2] + W;
picture->y[off2] = ConvertRGBToY(r, g, b);
dst_y[i] = ConvertRGBToY(r, g, b);
}
best_y += w;
best_uv += (j & 1) * 3 * uv_w;
dst_y += picture->y_stride;
}
for (j = 0; j < uv_h; ++j) {
uint8_t* const dst_u = picture->u + j * picture->uv_stride;
uint8_t* const dst_v = picture->v + j * picture->uv_stride;
for (best_uv = best_uv_base, j = 0; j < uv_h; ++j) {
for (i = 0; i < uv_w; ++i) {
const int off = 3 * (i + j * uv_w);
const int off = 3 * i;
const int r = best_uv[off + 0];
const int g = best_uv[off + 1];
const int b = best_uv[off + 2];
dst_u[i] = ConvertRGBToU(r, g, b);
dst_v[i] = ConvertRGBToV(r, g, b);
}
best_uv += 3 * uv_w;
dst_u += picture->uv_stride;
dst_v += picture->uv_stride;
}
return 1;
}