From fd4d090fd1a348eb814f1854637c300a312b0df3 Mon Sep 17 00:00:00 2001 From: James Zern Date: Fri, 4 Nov 2016 07:18:55 +0000 Subject: [PATCH] ConvertWRGBToYUV: use relative pointer offsets avoids int rollover when working with large input BUG=webp:312 Change-Id: I693cbb295df9cf94aa89294b19c0496bdbe84d18 (cherry picked from commit de9fa5074ebc51ca59c435da3a05cd108d06a7bf) --- src/enc/picture_csp.c | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) diff --git a/src/enc/picture_csp.c b/src/enc/picture_csp.c index bab5f8f0..347bb6c8 100644 --- a/src/enc/picture_csp.c +++ b/src/enc/picture_csp.c @@ -381,36 +381,42 @@ 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; }