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swscale: Do not shift negative values directly

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It is undefined in C as reported:
    warning: shifting a negative signed value is undefined
pull/272/head
Luca Barbato 8 years ago
parent 378460fef1
commit f56fa95cd1
1 changed files with 13 additions and 10 deletions
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  1. 23
      libswscale/output.c

23
libswscale/output.c
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@ -130,6 +130,9 @@ DECLARE_ALIGNED(8, const uint8_t, ff_dither_8x8_220)[8][8] = {
AV_WL16(pos, bias + av_clip_ ## signedness ## 16(val >> shift)); \ AV_WL16(pos, bias + av_clip_ ## signedness ## 16(val >> shift)); \
} }
// Shifting negative amounts is undefined in C
#define SHIFT_LEFT(val, shift) ((val) * (1 << (shift)))
static av_always_inline void static av_always_inline void
yuv2plane1_16_c_template(const int32_t *src, uint16_t *dest, int dstW, yuv2plane1_16_c_template(const int32_t *src, uint16_t *dest, int dstW,
int big_endian, int output_bits) int big_endian, int output_bits)
@ -601,8 +604,8 @@ yuv2rgb48_X_c_template(SwsContext *c, const int16_t *lumFilter,
int j; int j;
int Y1 = -0x40000000; int Y1 = -0x40000000;
int Y2 = -0x40000000; int Y2 = -0x40000000;
int U = -128 << 23; // 19 int U = SHIFT_LEFT(-128, 23); // 19
int V = -128 << 23; int V = SHIFT_LEFT(-128, 23);
int R, G, B; int R, G, B;
for (j = 0; j < lumFilterSize; j++) { for (j = 0; j < lumFilterSize; j++) {
@ -663,8 +666,8 @@ yuv2rgb48_2_c_template(SwsContext *c, const int32_t *buf[2],
for (i = 0; i < ((dstW + 1) >> 1); i++) { for (i = 0; i < ((dstW + 1) >> 1); i++) {
int Y1 = (buf0[i * 2] * yalpha1 + buf1[i * 2] * yalpha) >> 14; int Y1 = (buf0[i * 2] * yalpha1 + buf1[i * 2] * yalpha) >> 14;
int Y2 = (buf0[i * 2 + 1] * yalpha1 + buf1[i * 2 + 1] * yalpha) >> 14; int Y2 = (buf0[i * 2 + 1] * yalpha1 + buf1[i * 2 + 1] * yalpha) >> 14;
int U = (ubuf0[i] * uvalpha1 + ubuf1[i] * uvalpha + (-128 << 23)) >> 14; int U = (ubuf0[i] * uvalpha1 + ubuf1[i] * uvalpha + SHIFT_LEFT(-128, 23)) >> 14;
int V = (vbuf0[i] * uvalpha1 + vbuf1[i] * uvalpha + (-128 << 23)) >> 14; int V = (vbuf0[i] * uvalpha1 + vbuf1[i] * uvalpha + SHIFT_LEFT(-128, 23)) >> 14;
int R, G, B; int R, G, B;
Y1 -= c->yuv2rgb_y_offset; Y1 -= c->yuv2rgb_y_offset;
@ -701,8 +704,8 @@ yuv2rgb48_1_c_template(SwsContext *c, const int32_t *buf0,
for (i = 0; i < ((dstW + 1) >> 1); i++) { for (i = 0; i < ((dstW + 1) >> 1); i++) {
int Y1 = (buf0[i * 2] ) >> 2; int Y1 = (buf0[i * 2] ) >> 2;
int Y2 = (buf0[i * 2 + 1]) >> 2; int Y2 = (buf0[i * 2 + 1]) >> 2;
int U = (ubuf0[i] + (-128 << 11)) >> 2; int U = (ubuf0[i] + SHIFT_LEFT(-128, 11)) >> 2;
int V = (vbuf0[i] + (-128 << 11)) >> 2; int V = (vbuf0[i] + SHIFT_LEFT(-128, 11)) >> 2;
int R, G, B; int R, G, B;
Y1 -= c->yuv2rgb_y_offset; Y1 -= c->yuv2rgb_y_offset;
@ -729,8 +732,8 @@ yuv2rgb48_1_c_template(SwsContext *c, const int32_t *buf0,
for (i = 0; i < ((dstW + 1) >> 1); i++) { for (i = 0; i < ((dstW + 1) >> 1); i++) {
int Y1 = (buf0[i * 2] ) >> 2; int Y1 = (buf0[i * 2] ) >> 2;
int Y2 = (buf0[i * 2 + 1]) >> 2; int Y2 = (buf0[i * 2 + 1]) >> 2;
int U = (ubuf0[i] + ubuf1[i] + (-128 << 12)) >> 3; int U = (ubuf0[i] + ubuf1[i] + SHIFT_LEFT(-128, 12)) >> 3;
int V = (vbuf0[i] + vbuf1[i] + (-128 << 12)) >> 3; int V = (vbuf0[i] + vbuf1[i] + SHIFT_LEFT(-128, 12)) >> 3;
int R, G, B; int R, G, B;
Y1 -= c->yuv2rgb_y_offset; Y1 -= c->yuv2rgb_y_offset;
@ -1172,8 +1175,8 @@ yuv2rgb_full_X_c_template(SwsContext *c, const int16_t *lumFilter,
for (i = 0; i < dstW; i++) { for (i = 0; i < dstW; i++) {
int j; int j;
int Y = 0; int Y = 0;
int U = -128 << 19; int U = SHIFT_LEFT(-128, 19);
int V = -128 << 19; int V = SHIFT_LEFT(-128, 19);
int R, G, B, A; int R, G, B, A;
for (j = 0; j < lumFilterSize; j++) { for (j = 0; j < lumFilterSize; j++) {

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