static WEBP_INLINE void AddSingleLiteral(uint32_t pixel, int use_color_cache,
VP8LColorCache* const hashers,
VP8LBackwardRefs* const refs) {
PixOrCopy v;
if (use_color_cache) {
const uint32_t key = VP8LColorCacheGetIndex(hashers, pixel);
if (VP8LColorCacheLookup(hashers, key) == pixel) {
v = PixOrCopyCreateCacheIdx(key);
} else {
v = PixOrCopyCreateLiteral(pixel);
VP8LColorCacheSet(hashers, key, pixel);
}
} else {
v = PixOrCopyCreateLiteral(pixel);
}
VP8LBackwardRefsCursorAdd(refs, v);
}
static int AnalyzeEntropy(const uint32_t* argb,
int width, int height, int argb_stride,
double* const nonpredicted_bits,
double* const predicted_bits) {
// Allocate histogram set with cache_bits = 0.
VP8LHistogramSet* const histo_set = VP8LAllocateHistogramSet(2, 0);
assert(nonpredicted_bits != NULL);
assert(predicted_bits != NULL);
if (histo_set != NULL) {
int x, y;
const uint32_t* prev_row = argb;
const uint32_t* curr_row = argb + argb_stride;
VP8LHistogram* const histo_non_pred = histo_set->histograms[0];
VP8LHistogram* const histo_pred = histo_set->histograms[1];
for (y = 1; y < height; ++y) {
uint32_t prev_pix = curr_row[0];
for (x = 1; x < width; ++x) {
const uint32_t pix = curr_row[x];
const uint32_t pix_diff = VP8LSubPixels(pix, prev_pix);
if ((pix_diff == 0) || (pix == prev_row[x])) continue;
prev_pix = pix;
{
const PixOrCopy pix_token = PixOrCopyCreateLiteral(pix);
const PixOrCopy pix_diff_token = PixOrCopyCreateLiteral(pix_diff);
VP8LHistogramAddSinglePixOrCopy(histo_non_pred, &pix_token);
VP8LHistogramAddSinglePixOrCopy(histo_pred, &pix_diff_token);
}
}
prev_row = curr_row;
curr_row += argb_stride;
}
*nonpredicted_bits = VP8LHistogramEstimateBitsBulk(histo_non_pred);
*predicted_bits = VP8LHistogramEstimateBitsBulk(histo_pred);
VP8LFreeHistogramSet(histo_set);
return 1;
} else {
return 0;
}
}
