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libwebp/src/dsp/filters.c
James Zern d77bf512bd add WEBP_DSP_INIT / WEBP_DSP_INIT_FUNC 
this internalizes the init checks and provides stronger synchronization
with pthreads when available while still allowing VP8GetCPUInfo to be
modified (mostly for testing purposes). windows is left as is since a
critical section or mutex would cause a leak.

Change-Id: Ieb997e014f2805c0ae39c16f13337663521356f4
2018-04-17 11:45:34 +00:00

288 lines
9.1 KiB
C
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// Copyright 2011 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// Spatial prediction using various filters
//
// Author: Urvang (urvang@google.com)
#include "src/dsp/dsp.h"
#include <assert.h>
#include <stdlib.h>
#include <string.h>
//------------------------------------------------------------------------------
// Helpful macro.
# define SANITY_CHECK(in, out) \
assert((in) != NULL); \
assert((out) != NULL); \
assert(width > 0); \
assert(height > 0); \
assert(stride >= width); \
assert(row >= 0 && num_rows > 0 && row + num_rows <= height); \
(void)height; // Silence unused warning.
#if !WEBP_NEON_OMIT_C_CODE
static WEBP_INLINE void PredictLine_C(const uint8_t* src, const uint8_t* pred,
uint8_t* dst, int length, int inverse) {
int i;
if (inverse) {
for (i = 0; i < length; ++i) dst[i] = src[i] + pred[i];
} else {
for (i = 0; i < length; ++i) dst[i] = src[i] - pred[i];
}
}
//------------------------------------------------------------------------------
// Horizontal filter.
static WEBP_INLINE void DoHorizontalFilter_C(const uint8_t* in,
int width, int height, int stride,
int row, int num_rows,
int inverse, uint8_t* out) {
const uint8_t* preds;
const size_t start_offset = row * stride;
const int last_row = row + num_rows;
SANITY_CHECK(in, out);
in += start_offset;
out += start_offset;
preds = inverse ? out : in;
if (row == 0) {
// Leftmost pixel is the same as input for topmost scanline.
out[0] = in[0];
PredictLine_C(in + 1, preds, out + 1, width - 1, inverse);
row = 1;
preds += stride;
in += stride;
out += stride;
}
// Filter line-by-line.
while (row < last_row) {
// Leftmost pixel is predicted from above.
PredictLine_C(in, preds - stride, out, 1, inverse);
PredictLine_C(in + 1, preds, out + 1, width - 1, inverse);
++row;
preds += stride;
in += stride;
out += stride;
}
}
//------------------------------------------------------------------------------
// Vertical filter.
static WEBP_INLINE void DoVerticalFilter_C(const uint8_t* in,
int width, int height, int stride,
int row, int num_rows,
int inverse, uint8_t* out) {
const uint8_t* preds;
const size_t start_offset = row * stride;
const int last_row = row + num_rows;
SANITY_CHECK(in, out);
in += start_offset;
out += start_offset;
preds = inverse ? out : in;
if (row == 0) {
// Very first top-left pixel is copied.
out[0] = in[0];
// Rest of top scan-line is left-predicted.
PredictLine_C(in + 1, preds, out + 1, width - 1, inverse);
row = 1;
in += stride;
out += stride;
} else {
// We are starting from in-between. Make sure 'preds' points to prev row.
preds -= stride;
}
// Filter line-by-line.
while (row < last_row) {
PredictLine_C(in, preds, out, width, inverse);
++row;
preds += stride;
in += stride;
out += stride;
}
}
#endif // !WEBP_NEON_OMIT_C_CODE
//------------------------------------------------------------------------------
// Gradient filter.
static WEBP_INLINE int GradientPredictor_C(uint8_t a, uint8_t b, uint8_t c) {
const int g = a + b - c;
return ((g & ~0xff) == 0) ? g : (g < 0) ? 0 : 255; // clip to 8bit
}
#if !WEBP_NEON_OMIT_C_CODE
static WEBP_INLINE void DoGradientFilter_C(const uint8_t* in,
int width, int height, int stride,
int row, int num_rows,
int inverse, uint8_t* out) {
const uint8_t* preds;
const size_t start_offset = row * stride;
const int last_row = row + num_rows;
SANITY_CHECK(in, out);
in += start_offset;
out += start_offset;
preds = inverse ? out : in;
// left prediction for top scan-line
if (row == 0) {
out[0] = in[0];
PredictLine_C(in + 1, preds, out + 1, width - 1, inverse);
row = 1;
preds += stride;
in += stride;
out += stride;
}
// Filter line-by-line.
while (row < last_row) {
int w;
// leftmost pixel: predict from above.
PredictLine_C(in, preds - stride, out, 1, inverse);
for (w = 1; w < width; ++w) {
const int pred = GradientPredictor_C(preds[w - 1],
preds[w - stride],
preds[w - stride - 1]);
out[w] = in[w] + (inverse ? pred : -pred);
}
++row;
preds += stride;
in += stride;
out += stride;
}
}
#endif // !WEBP_NEON_OMIT_C_CODE
#undef SANITY_CHECK
//------------------------------------------------------------------------------
#if !WEBP_NEON_OMIT_C_CODE
static void HorizontalFilter_C(const uint8_t* data, int width, int height,
int stride, uint8_t* filtered_data) {
DoHorizontalFilter_C(data, width, height, stride, 0, height, 0,
filtered_data);
}
static void VerticalFilter_C(const uint8_t* data, int width, int height,
int stride, uint8_t* filtered_data) {
DoVerticalFilter_C(data, width, height, stride, 0, height, 0, filtered_data);
}
static void GradientFilter_C(const uint8_t* data, int width, int height,
int stride, uint8_t* filtered_data) {
DoGradientFilter_C(data, width, height, stride, 0, height, 0, filtered_data);
}
#endif // !WEBP_NEON_OMIT_C_CODE
//------------------------------------------------------------------------------
static void HorizontalUnfilter_C(const uint8_t* prev, const uint8_t* in,
uint8_t* out, int width) {
uint8_t pred = (prev == NULL) ? 0 : prev[0];
int i;
for (i = 0; i < width; ++i) {
out[i] = pred + in[i];
pred = out[i];
}
}
#if !WEBP_NEON_OMIT_C_CODE
static void VerticalUnfilter_C(const uint8_t* prev, const uint8_t* in,
uint8_t* out, int width) {
if (prev == NULL) {
HorizontalUnfilter_C(NULL, in, out, width);
} else {
int i;
for (i = 0; i < width; ++i) out[i] = prev[i] + in[i];
}
}
#endif // !WEBP_NEON_OMIT_C_CODE
static void GradientUnfilter_C(const uint8_t* prev, const uint8_t* in,
uint8_t* out, int width) {
if (prev == NULL) {
HorizontalUnfilter_C(NULL, in, out, width);
} else {
uint8_t top = prev[0], top_left = top, left = top;
int i;
for (i = 0; i < width; ++i) {
top = prev[i]; // need to read this first, in case prev==out
left = in[i] + GradientPredictor_C(left, top, top_left);
top_left = top;
out[i] = left;
}
}
}
//------------------------------------------------------------------------------
// Init function
WebPFilterFunc WebPFilters[WEBP_FILTER_LAST];
WebPUnfilterFunc WebPUnfilters[WEBP_FILTER_LAST];
extern void VP8FiltersInitMIPSdspR2(void);
extern void VP8FiltersInitMSA(void);
extern void VP8FiltersInitNEON(void);
extern void VP8FiltersInitSSE2(void);
WEBP_DSP_INIT_FUNC(VP8FiltersInit) {
WebPUnfilters[WEBP_FILTER_NONE] = NULL;
#if !WEBP_NEON_OMIT_C_CODE
WebPUnfilters[WEBP_FILTER_HORIZONTAL] = HorizontalUnfilter_C;
WebPUnfilters[WEBP_FILTER_VERTICAL] = VerticalUnfilter_C;
#endif
WebPUnfilters[WEBP_FILTER_GRADIENT] = GradientUnfilter_C;
WebPFilters[WEBP_FILTER_NONE] = NULL;
#if !WEBP_NEON_OMIT_C_CODE
WebPFilters[WEBP_FILTER_HORIZONTAL] = HorizontalFilter_C;
WebPFilters[WEBP_FILTER_VERTICAL] = VerticalFilter_C;
WebPFilters[WEBP_FILTER_GRADIENT] = GradientFilter_C;
#endif
if (VP8GetCPUInfo != NULL) {
#if defined(WEBP_USE_SSE2)
if (VP8GetCPUInfo(kSSE2)) {
VP8FiltersInitSSE2();
}
#endif
#if defined(WEBP_USE_MIPS_DSP_R2)
if (VP8GetCPUInfo(kMIPSdspR2)) {
VP8FiltersInitMIPSdspR2();
}
#endif
#if defined(WEBP_USE_MSA)
if (VP8GetCPUInfo(kMSA)) {
VP8FiltersInitMSA();
}
#endif
}
#if defined(WEBP_USE_NEON)
if (WEBP_NEON_OMIT_C_CODE ||
(VP8GetCPUInfo != NULL && VP8GetCPUInfo(kNEON))) {
VP8FiltersInitNEON();
}
#endif
assert(WebPUnfilters[WEBP_FILTER_HORIZONTAL] != NULL);
assert(WebPUnfilters[WEBP_FILTER_VERTICAL] != NULL);
assert(WebPUnfilters[WEBP_FILTER_GRADIENT] != NULL);
assert(WebPFilters[WEBP_FILTER_HORIZONTAL] != NULL);
assert(WebPFilters[WEBP_FILTER_VERTICAL] != NULL);
assert(WebPFilters[WEBP_FILTER_GRADIENT] != NULL);
}
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