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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 DCHECK(in, out) \
do { \
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. */ \
} while (0)
#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] = (uint8_t)(src[i] + pred[i]);
} else {
for (i = 0; i < length; ++i) dst[i] = (uint8_t)(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;
DCHECK(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;
DCHECK(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;
DCHECK(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] = (uint8_t)(in[w] + (inverse ? pred : -pred));
}
++row;
preds += stride;
in += stride;
out += stride;
}
}
#endif // !WEBP_NEON_OMIT_C_CODE
#undef DCHECK
//------------------------------------------------------------------------------
#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 NoneUnfilter_C(const uint8_t* prev, const uint8_t* in,
uint8_t* out, int width) {
(void)prev;
if (out != in) memcpy(out, in, width * sizeof(*out));
}
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] = (uint8_t)(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] = (uint8_t)(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 = (uint8_t)(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 VP8CPUInfo VP8GetCPUInfo;
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] = NoneUnfilter_C;
#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_HAVE_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_HAVE_NEON)
if (WEBP_NEON_OMIT_C_CODE ||
(VP8GetCPUInfo != NULL && VP8GetCPUInfo(kNEON))) {
VP8FiltersInitNEON();
}
#endif
assert(WebPUnfilters[WEBP_FILTER_NONE] != NULL);
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);
}