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rescaler: simplify ImportRow logic

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incorporates the loop over 'channel' and removes one parameter

Change-Id: I4e3b33c111ca825fe96461583420413b17326409
This commit is contained in:
Pascal Massimino
2015-09-19 09:59:32 -07:00
parent 5ff0079ece
commit 9ba1894b9b
5 changed files with 250 additions and 239 deletions
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100
src/dsp/rescaler.c
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@ -23,66 +23,69 @@
//------------------------------------------------------------------------------
// Row import
void WebPRescalerImportRowExpandC(WebPRescaler* const wrk,
const uint8_t* const src, int channel) {
void WebPRescalerImportRowExpandC(WebPRescaler* wrk, const uint8_t* src) {
const int x_stride = wrk->num_channels;
const int x_out_max = wrk->dst_width * wrk->num_channels;
int x_in = channel;
int x_out;
// simple bilinear interpolation
int accum = wrk->x_add;
int left = src[x_in];
int right = (wrk->src_width > 1) ? src[x_in + x_stride] : left;
x_in += x_stride;
x_out = channel;
int channel;
assert(!WebPRescalerInputDone(wrk));
assert(wrk->x_expand);
while (1) {
wrk->frow[x_out] = right * wrk->x_add + (left - right) * accum;
x_out += x_stride;
if (x_out >= x_out_max) break;
accum -= wrk->x_sub;
if (accum < 0) {
left = right;
x_in += x_stride;
assert(x_in < wrk->src_width * x_stride);
right = src[x_in];
accum += wrk->x_add;
for (channel = 0; channel < x_stride; ++channel) {
int x_in = channel;
int x_out = channel;
// simple bilinear interpolation
int accum = wrk->x_add;
int left = src[x_in];
int right = (wrk->src_width > 1) ? src[x_in + x_stride] : left;
x_in += x_stride;
while (1) {
wrk->frow[x_out] = right * wrk->x_add + (left - right) * accum;
x_out += x_stride;
if (x_out >= x_out_max) break;
accum -= wrk->x_sub;
if (accum < 0) {
left = right;
x_in += x_stride;
assert(x_in < wrk->src_width * x_stride);
right = src[x_in];
accum += wrk->x_add;
}
}
assert(wrk->x_sub == 0 /* <- special case for src_width=1 */ || accum == 0);
}
assert(wrk->x_sub == 0 /* <- special case for src_width=1 */ || accum == 0);
}
void WebPRescalerImportRowShrinkC(WebPRescaler* const wrk,
const uint8_t* const src, int channel) {
const uint8_t* src) {
const int x_stride = wrk->num_channels;
const int x_out_max = wrk->dst_width * wrk->num_channels;
int x_in = channel;
int x_out;
uint32_t sum = 0;
int accum = 0;
int channel;
assert(!WebPRescalerInputDone(wrk));
assert(!wrk->x_expand);
for (x_out = channel; x_out < x_out_max; x_out += x_stride) {
uint32_t base = 0;
accum += wrk->x_add;
while (accum > 0) {
accum -= wrk->x_sub;
assert(x_in < wrk->src_width * x_stride);
base = src[x_in];
sum += base;
x_in += x_stride;
}
{ // Emit next horizontal pixel.
const rescaler_t frac = base * (-accum);
wrk->frow[x_out] = sum * wrk->x_sub - frac;
// fresh fractional start for next pixel
sum = (int)MULT_FIX(frac, wrk->fx_scale);
for (channel = 0; channel < x_stride; ++channel) {
int x_in = channel;
int x_out = channel;
uint32_t sum = 0;
int accum = 0;
while (x_out < x_out_max) {
uint32_t base = 0;
accum += wrk->x_add;
while (accum > 0) {
accum -= wrk->x_sub;
assert(x_in < wrk->src_width * x_stride);
base = src[x_in];
sum += base;
x_in += x_stride;
}
{ // Emit next horizontal pixel.
const rescaler_t frac = base * (-accum);
wrk->frow[x_out] = sum * wrk->x_sub - frac;
// fresh fractional start for next pixel
sum = (int)MULT_FIX(frac, wrk->fx_scale);
}
x_out += x_stride;
}
assert(accum == 0);
}
assert(accum == 0);
}
//------------------------------------------------------------------------------
@ -145,13 +148,12 @@ void WebPRescalerExportRowShrinkC(WebPRescaler* const wrk) {
//------------------------------------------------------------------------------
// Main entry calls
void WebPRescalerImportRow(WebPRescaler* const wrk,
const uint8_t* const src, int channel) {
void WebPRescalerImportRow(WebPRescaler* const wrk, const uint8_t* const src) {
assert(!WebPRescalerInputDone(wrk));
if (!wrk->x_expand) {
WebPRescalerImportRowShrink(wrk, src, channel);
WebPRescalerImportRowShrink(wrk, src);
} else {
WebPRescalerImportRowExpand(wrk, src, channel);
WebPRescalerImportRowExpand(wrk, src);
}
}