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-rw-r--r--src/3rdparty/libwebp/src/dsp/filters.c240
1 files changed, 240 insertions, 0 deletions
diff --git a/src/3rdparty/libwebp/src/dsp/filters.c b/src/3rdparty/libwebp/src/dsp/filters.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 "./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.
+
+static WEBP_INLINE void PredictLine(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(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(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(in, preds - stride, out, 1, inverse);
+ PredictLine(in + 1, preds, out + 1, width - 1, inverse);
+ ++row;
+ preds += stride;
+ in += stride;
+ out += stride;
+ }
+}
+
+//------------------------------------------------------------------------------
+// Vertical filter.
+
+static WEBP_INLINE void DoVerticalFilter(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(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(in, preds, out, width, inverse);
+ ++row;
+ preds += stride;
+ in += stride;
+ out += stride;
+ }
+}
+
+//------------------------------------------------------------------------------
+// Gradient filter.
+
+static WEBP_INLINE int GradientPredictor(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
+}
+
+static WEBP_INLINE void DoGradientFilter(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(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(in, preds - stride, out, 1, inverse);
+ for (w = 1; w < width; ++w) {
+ const int pred = GradientPredictor(preds[w - 1],
+ preds[w - stride],
+ preds[w - stride - 1]);
+ out[w] = in[w] + (inverse ? pred : -pred);
+ }
+ ++row;
+ preds += stride;
+ in += stride;
+ out += stride;
+ }
+}
+
+#undef SANITY_CHECK
+
+//------------------------------------------------------------------------------
+
+static void HorizontalFilter(const uint8_t* data, int width, int height,
+ int stride, uint8_t* filtered_data) {
+ DoHorizontalFilter(data, width, height, stride, 0, height, 0, filtered_data);
+}
+
+static void VerticalFilter(const uint8_t* data, int width, int height,
+ int stride, uint8_t* filtered_data) {
+ DoVerticalFilter(data, width, height, stride, 0, height, 0, filtered_data);
+}
+
+
+static void GradientFilter(const uint8_t* data, int width, int height,
+ int stride, uint8_t* filtered_data) {
+ DoGradientFilter(data, width, height, stride, 0, height, 0, filtered_data);
+}
+
+
+//------------------------------------------------------------------------------
+
+static void VerticalUnfilter(int width, int height, int stride, int row,
+ int num_rows, uint8_t* data) {
+ DoVerticalFilter(data, width, height, stride, row, num_rows, 1, data);
+}
+
+static void HorizontalUnfilter(int width, int height, int stride, int row,
+ int num_rows, uint8_t* data) {
+ DoHorizontalFilter(data, width, height, stride, row, num_rows, 1, data);
+}
+
+static void GradientUnfilter(int width, int height, int stride, int row,
+ int num_rows, uint8_t* data) {
+ DoGradientFilter(data, width, height, stride, row, num_rows, 1, data);
+}
+
+//------------------------------------------------------------------------------
+// Init function
+
+WebPFilterFunc WebPFilters[WEBP_FILTER_LAST];
+WebPUnfilterFunc WebPUnfilters[WEBP_FILTER_LAST];
+
+extern void VP8FiltersInitMIPSdspR2(void);
+extern void VP8FiltersInitSSE2(void);
+
+static volatile VP8CPUInfo filters_last_cpuinfo_used =
+ (VP8CPUInfo)&filters_last_cpuinfo_used;
+
+WEBP_TSAN_IGNORE_FUNCTION void VP8FiltersInit(void) {
+ if (filters_last_cpuinfo_used == VP8GetCPUInfo) return;
+
+ WebPUnfilters[WEBP_FILTER_NONE] = NULL;
+ WebPUnfilters[WEBP_FILTER_HORIZONTAL] = HorizontalUnfilter;
+ WebPUnfilters[WEBP_FILTER_VERTICAL] = VerticalUnfilter;
+ WebPUnfilters[WEBP_FILTER_GRADIENT] = GradientUnfilter;
+
+ WebPFilters[WEBP_FILTER_NONE] = NULL;
+ WebPFilters[WEBP_FILTER_HORIZONTAL] = HorizontalFilter;
+ WebPFilters[WEBP_FILTER_VERTICAL] = VerticalFilter;
+ WebPFilters[WEBP_FILTER_GRADIENT] = GradientFilter;
+
+ 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
+ }
+ filters_last_cpuinfo_used = VP8GetCPUInfo;
+}
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