diff options
| author | Hui Su <huisu@google.com> | 2016-08-11 18:28:40 +0000 |
|---|---|---|
| committer | James Zern <jzern@google.com> | 2016-12-09 20:22:25 -0800 |
| commit | 408858308a05e094a553bb405a3cbd8c4e28724e (patch) | |
| tree | 72f4d0c4bc367a822c7171f6e3ab3b738827e80b | |
| parent | 8f38c72e11f26b75593bed1946f02b922b0521fb (diff) | |
| download | libwebp-408858308a05e094a553bb405a3cbd8c4e28724e.tar.gz | |
Fix assertions in WebPRescalerExportRow()
Change-Id: I25711dd54e71c90a25f7b18e0ef9155e8151a15e
(cherry picked from commit 27b5d991e2a3d87bd45610765af6f2a9a3530d69)
| -rw-r--r-- | src/dsp/rescaler.c | 4 | ||||
| -rw-r--r-- | src/utils/rescaler.c | 8 |
2 files changed, 8 insertions, 4 deletions
diff --git a/src/dsp/rescaler.c b/src/dsp/rescaler.c index bc743d5d..f5b07756 100644 --- a/src/dsp/rescaler.c +++ b/src/dsp/rescaler.c @@ -173,10 +173,10 @@ void WebPRescalerExportRow(WebPRescaler* const wrk) { WebPRescalerExportRowExpand(wrk); } else if (wrk->fxy_scale) { WebPRescalerExportRowShrink(wrk); - } else { // very special case for src = dst = 1x1 + } else { // special case int i; + assert(wrk->src_height == wrk->dst_height && wrk->x_add == 1); assert(wrk->src_width == 1 && wrk->dst_width <= 2); - assert(wrk->src_height == 1 && wrk->dst_height == 1); for (i = 0; i < wrk->num_channels * wrk->dst_width; ++i) { wrk->dst[i] = wrk->irow[i]; wrk->irow[i] = 0; diff --git a/src/utils/rescaler.c b/src/utils/rescaler.c index 00c9300b..d2278a52 100644 --- a/src/utils/rescaler.c +++ b/src/utils/rescaler.c @@ -48,11 +48,15 @@ void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height, wrk->y_sub = wrk->y_expand ? y_sub - 1 : y_sub; wrk->y_accum = wrk->y_expand ? wrk->y_sub : wrk->y_add; if (!wrk->y_expand) { - // this is WEBP_RESCALER_FRAC(dst_height, x_add * y_add) without the cast. + // This is WEBP_RESCALER_FRAC(dst_height, x_add * y_add) without the cast. + // Its value is <= WEBP_RESCALER_ONE, because dst_height <= wrk->y_add, and + // wrk->x_add >= 1; const uint64_t ratio = (uint64_t)dst_height * WEBP_RESCALER_ONE / (wrk->x_add * wrk->y_add); if (ratio != (uint32_t)ratio) { - // We can't represent the ratio with the current fixed-point precision. + // When ratio == WEBP_RESCALER_ONE, we can't represent the ratio with the + // current fixed-point precision. This happens when src_height == + // wrk->y_add (which == src_height), and wrk->x_add == 1. // => We special-case fxy_scale = 0, in WebPRescalerExportRow(). wrk->fxy_scale = 0; } else { |