// 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] = (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;

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] = (uint8_t)(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] = (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 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);

}