clarify variable names in HistogramRemap()

also simplify the loop by removing the initial special case

Change-Id: I4fc1b9eb14a42381a815354599137703c21ed9e6
This commit is contained in:
Pascal Massimino 2016-06-08 13:36:04 +02:00
parent 5f8f998d0e
commit fe9e31ef5e

View File

@ -808,24 +808,23 @@ static VP8LHistogram* HistogramCombineStochastic(
// Find the best 'out' histogram for each of the 'in' histograms.
// Note: we assume that out[]->bit_cost_ is already up-to-date.
static void HistogramRemap(const VP8LHistogramSet* const orig_histo,
const VP8LHistogramSet* const image_histo,
static void HistogramRemap(const VP8LHistogramSet* const in,
const VP8LHistogramSet* const out,
uint16_t* const symbols) {
int i;
VP8LHistogram** const orig_histograms = orig_histo->histograms;
VP8LHistogram** const histograms = image_histo->histograms;
const int orig_histo_size = orig_histo->size;
const int image_histo_size = image_histo->size;
if (image_histo_size > 1) {
for (i = 0; i < orig_histo_size; ++i) {
VP8LHistogram** const in_histo = in->histograms;
VP8LHistogram** const out_histo = out->histograms;
const int in_size = in->size;
const int out_size = out->size;
if (out_size > 1) {
for (i = 0; i < in_size; ++i) {
int best_out = 0;
double best_bits =
HistogramAddThresh(histograms[0], orig_histograms[i], MAX_COST);
double best_bits = MAX_COST;
int k;
for (k = 1; k < image_histo_size; ++k) {
for (k = 0; k < out_size; ++k) {
const double cur_bits =
HistogramAddThresh(histograms[k], orig_histograms[i], best_bits);
if (cur_bits < best_bits) {
HistogramAddThresh(out_histo[k], in_histo[i], best_bits);
if (k == 0 || cur_bits < best_bits) {
best_bits = cur_bits;
best_out = k;
}
@ -833,20 +832,20 @@ static void HistogramRemap(const VP8LHistogramSet* const orig_histo,
symbols[i] = best_out;
}
} else {
assert(image_histo_size == 1);
for (i = 0; i < orig_histo_size; ++i) {
assert(out_size == 1);
for (i = 0; i < in_size; ++i) {
symbols[i] = 0;
}
}
// Recompute each out based on raw and symbols.
for (i = 0; i < image_histo_size; ++i) {
HistogramClear(histograms[i]);
for (i = 0; i < out_size; ++i) {
HistogramClear(out_histo[i]);
}
for (i = 0; i < orig_histo_size; ++i) {
for (i = 0; i < in_size; ++i) {
const int idx = symbols[i];
VP8LHistogramAdd(orig_histograms[i], histograms[idx], histograms[idx]);
VP8LHistogramAdd(in_histo[i], out_histo[idx], out_histo[idx]);
}
}