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avcodec/gdv: Optimize and factorize scaling loops 

Fixes: Timeout
Fixes: 11067/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_GDV_fuzzer-5686623711264768

Before change: Executed clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_GDV_fuzzer-5686623711264768 in 34386 ms
After  change: Executed clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_GDV_fuzzer-5686623711264768 in 24327 ms

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2019-01-04 19:51:04 +01:00
parent 75ea329b78
commit 6e23736aef
1 changed files with 64 additions and 23 deletions
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87
libavcodec/gdv.c
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@ -72,9 +72,64 @@ static av_cold int gdv_decode_init(AVCodecContext *avctx)
return 0;
}
static void scaleup(uint8_t *dst, const uint8_t *src, int w)
{
int x;
for (x = 0; x < w - 7; x+=8) {
dst[x + 0] =
dst[x + 1] = src[(x>>1) + 0];
dst[x + 2] =
dst[x + 3] = src[(x>>1) + 1];
dst[x + 4] =
dst[x + 5] = src[(x>>1) + 2];
dst[x + 6] =
dst[x + 7] = src[(x>>1) + 3];
}
for (; x < w; x++) {
dst[x] = src[(x>>1)];
}
}
static void scaleup_rev(uint8_t *dst, const uint8_t *src, int w)
{
int x;
for (x = w - 1; (x+1) & 7; x--) {
dst[x] = src[(x>>1)];
}
for (x -= 7; x >= 0; x -= 8) {
dst[x + 6] =
dst[x + 7] = src[(x>>1) + 3];
dst[x + 4] =
dst[x + 5] = src[(x>>1) + 2];
dst[x + 2] =
dst[x + 3] = src[(x>>1) + 1];
dst[x + 0] =
dst[x + 1] = src[(x>>1) + 0];
}
}
static void scaledown(uint8_t *dst, const uint8_t *src, int w)
{
int x;
for (x = 0; x < w - 7; x+=8) {
dst[x + 0] = src[2*x + 0];
dst[x + 1] = src[2*x + 2];
dst[x + 2] = src[2*x + 4];
dst[x + 3] = src[2*x + 6];
dst[x + 4] = src[2*x + 8];
dst[x + 5] = src[2*x +10];
dst[x + 6] = src[2*x +12];
dst[x + 7] = src[2*x +14];
}
for (; x < w; x++) {
dst[x] = src[2*x];
}
}
static void rescale(GDVContext *gdv, uint8_t *dst, int w, int h, int scale_v, int scale_h)
{
int j, y, x;
int j, y;
if ((gdv->scale_v == scale_v) && (gdv->scale_h == scale_h)) {
return;
@ -86,14 +141,7 @@ static void rescale(GDVContext *gdv, uint8_t *dst, int w, int h, int scale_v, in
uint8_t *dst1 = dst + PREAMBLE_SIZE + y * w;
uint8_t *src1 = dst + PREAMBLE_SIZE + (y>>!!gdv->scale_h) * (w>>1);
for (x = w - 1; x >= 0 && !(x&1); x--) {
dst1[x] = src1[(x>>1)];
}
for (x--; x >= 0; x-=2) {
dst1[x ] =
dst1[x+1] = src1[(x>>1)];
}
scaleup_rev(dst1, src1, w);
}
} else if (gdv->scale_h) {
for (j = 0; j < h; j++) {
@ -108,9 +156,7 @@ static void rescale(GDVContext *gdv, uint8_t *dst, int w, int h, int scale_v, in
for (y = 0; y < (h>>1); y++) {
uint8_t *dst1 = dst + PREAMBLE_SIZE + y * (w>>1);
uint8_t *src1 = dst + PREAMBLE_SIZE + y*2 * w;
for (x = 0; x < (w>>1); x++) {
dst1[x] = src1[x*2];
}
scaledown(dst1, src1, w>>1);
}
} else if (scale_h) {
for (y = 0; y < (h>>1); y++) {
@ -121,9 +167,7 @@ static void rescale(GDVContext *gdv, uint8_t *dst, int w, int h, int scale_v, in
} else if (scale_v) {
for (y = 0; y < h; y++) {
uint8_t *dst1 = dst + PREAMBLE_SIZE + y * w;
for (x = 0; x < (w>>1); x++) {
dst1[x] = dst1[x*2];
}
scaledown(dst1, dst1, w>>1);
}
}
@ -479,19 +523,16 @@ static int gdv_decode_frame(AVCodecContext *avctx, void *data,
}
} else {
int sidx = PREAMBLE_SIZE, didx = 0;
int y, x;
int y;
for (y = 0; y < avctx->height; y++) {
if (!gdv->scale_v) {
memcpy(dst + didx, gdv->frame + sidx, avctx->width);
} else {
for (x = 0; x < avctx->width - 1; x+=2) {
dst[didx + x ] =
dst[didx + x + 1] = gdv->frame[sidx + (x>>1)];
}
for (; x < avctx->width; x++) {
dst[didx + x] = gdv->frame[sidx + (x>>1)];
}
uint8_t *dst2 = dst + didx;
uint8_t *src2 = gdv->frame + sidx;
scaleup(dst2, src2, avctx->width);
}
if (!gdv->scale_h || ((y & 1) == 1)) {
sidx += !gdv->scale_v ? avctx->width : avctx->width/2;