libwebp: update to 0.5.0

third_party/libwebp/utils/filters.c

 // 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
+// filter estimation
 //
 // Author: Urvang (urvang@google.com)
 
 #include "./filters.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;
-  }
-}
-
-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 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);
-}
-
-//------------------------------------------------------------------------------
-// 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;
-  }
-}
-
-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 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);
-}
-
-//------------------------------------------------------------------------------
-// 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;
-  }
-}
-
-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 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);
-}
-
-#undef SANITY_CHECK
-
 // -----------------------------------------------------------------------------
 // Quick estimate of a potentially interesting filter mode to try.
 
 #define SMAX 16
 #define SDIFF(a, b) (abs((a) - (b)) >> 4)   // Scoring diff, in [0..SMAX)
 
-WEBP_FILTER_TYPE EstimateBestFilter(const uint8_t* data,
-                                    int width, int height, int stride) {
+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
+}
+
+WEBP_FILTER_TYPE WebPEstimateBestFilter(const uint8_t* data,
+                                        int width, int height, int stride) {
   int i, j;
   int bins[WEBP_FILTER_LAST][SMAX];
   memset(bins, 0, sizeof(bins));
 
   // We only sample every other pixels. That's enough.
   for (j = 2; j < height - 1; j += 2) {
     const uint8_t* const p = data + j * stride;
     int mean = p[0];
     for (i = 2; i < width - 1; i += 2) {
       const int diff0 = SDIFF(p[i], mean);
@@ skipping 26 matching lines @@
       }
     }
     return best_filter;
   }
 }
 
 #undef SMAX
 #undef SDIFF
 
 //------------------------------------------------------------------------------
-
-const WebPFilterFunc WebPFilters[WEBP_FILTER_LAST] = {
-  NULL,              // WEBP_FILTER_NONE
-  HorizontalFilter,  // WEBP_FILTER_HORIZONTAL
-  VerticalFilter,    // WEBP_FILTER_VERTICAL
-  GradientFilter     // WEBP_FILTER_GRADIENT
-};
-
-const WebPUnfilterFunc WebPUnfilters[WEBP_FILTER_LAST] = {
-  NULL,                // WEBP_FILTER_NONE
-  HorizontalUnfilter,  // WEBP_FILTER_HORIZONTAL
-  VerticalUnfilter,    // WEBP_FILTER_VERTICAL
-  GradientUnfilter     // WEBP_FILTER_GRADIENT
-};
-
-//------------------------------------------------------------------------------
-