Move GetHistImageSymbols to histogram.c

Planning to revisit memory allocation scheme at several instanaces (next CL).

Change-Id: Id7b9f4854e9577e10b53d5b1d8595b7d862e6e01

src/enc/backward_references.h

@@ -100,6 +100,11 @@ typedef struct {
   uint32_t argb_or_distance;
 } PixOrCopy;
 
+typedef struct {
+  PixOrCopy* refs;
+  int size;
+} VP8LBackwardRefs;
+
 static WEBP_INLINE PixOrCopy PixOrCopyCreateCopy(uint32_t distance,
                                                  uint16_t len) {
   PixOrCopy retval;

src/enc/histogram.c

@@ -68,12 +68,11 @@ void VP8LHistogramAddSinglePixOrCopy(VP8LHistogram* const p,
 }
 
 void VP8LHistogramCreate(VP8LHistogram* const p,
-                         const PixOrCopy* const literal_and_length,
+                         const VP8LBackwardRefs* const refs) {
-                         int n_literal_and_length) {
   int i;
   VP8LHistogramClear(p);
-  for (i = 0; i < n_literal_and_length; ++i) {
+  for (i = 0; i < refs->size; ++i) {
-    VP8LHistogramAddSinglePixOrCopy(p, literal_and_length[i]);
+    VP8LHistogramAddSinglePixOrCopy(p, refs->refs[i]);
   }
 }
 
@@ -196,11 +195,12 @@ double VP8LHistogramEstimateBitsHeader(const VP8LHistogram* const p) {
       HuffmanCost(&p->distance_[0], DISTANCE_CODES_MAX);
 }
 
-int VP8LHistogramBuildImage(int xsize, int ysize,
+static int HistogramBuildImage(int xsize, int ysize,
-                            int histobits, int palettebits,
+                               int histobits, int palettebits,
-                            const PixOrCopy* backward_refs,
+                               const PixOrCopy* const backward_refs,
-                            int backward_refs_size,
+                               int backward_refs_size,
-                            VP8LHistogram*** image_arg, int* image_size) {
+                               VP8LHistogram*** const image_arg,
+                               int* const image_size) {
   int histo_xsize = histobits ? (xsize + (1 << histobits) - 1) >> histobits : 1;
   int histo_ysize = histobits ? (ysize + (1 << histobits) - 1) >> histobits : 1;
   int i;
@@ -241,8 +241,9 @@ int VP8LHistogramBuildImage(int xsize, int ysize,
   return 1;
 }
 
-int VP8LHistogramCombine(VP8LHistogram** in, int in_size, int quality,
+static int HistogramCombine(VP8LHistogram** const in, int in_size, int quality,
-                         VP8LHistogram*** out_arg, int* out_size) {
+                            VP8LHistogram*** const out_arg,
+                            int* const out_size) {
   int ok = 0;
   int i;
   unsigned int seed = 0;
@@ -339,7 +340,7 @@ Error:
 static double HistogramDistance(const VP8LHistogram* const square_histogram,
                                 int cur_symbol,
                                 int candidate_symbol,
-                                VP8LHistogram** candidate_histograms) {
+                                VP8LHistogram** const candidate_histograms) {
   double new_bit_cost;
   double previous_bit_cost;
   VP8LHistogram modified;
@@ -367,8 +368,9 @@ static double HistogramDistance(const VP8LHistogram* const square_histogram,
   return new_bit_cost - previous_bit_cost;
 }
 
-void VP8LHistogramRefine(VP8LHistogram** raw, int raw_size,
+static void HistogramRefine(VP8LHistogram** const raw, int raw_size,
-                         uint32_t* symbols, int out_size, VP8LHistogram** out) {
+                            uint32_t* const symbols, int out_size,
+                            VP8LHistogram** const out) {
   int i;
   // Find the best 'out' histogram for each of the raw histograms
   for (i = 0; i < raw_size; ++i) {
@@ -394,4 +396,45 @@ void VP8LHistogramRefine(VP8LHistogram** raw, int raw_size,
   }
 }
 
+int VP8LGetHistImageSymbols(int xsize, int ysize,
+                            const VP8LBackwardRefs* const refs,
+                            int quality, int histogram_bits,
+                            int cache_bits,
+                            VP8LHistogram*** const histogram_image,
+                            int* const histogram_image_size,
+                            uint32_t* const histogram_symbols) {
+  // Build histogram image.
+  int ok = 0;
+  int i;
+  int histogram_image_raw_size;
+  VP8LHistogram** histogram_image_raw = NULL;
+
+  *histogram_image = NULL;
+  if (!HistogramBuildImage(xsize, ysize, histogram_bits, cache_bits,
+                           refs->refs, refs->size,
+                           &histogram_image_raw,
+                           &histogram_image_raw_size)) {
+    goto Error;
+  }
+  // Collapse similar histograms.
+  if (!HistogramCombine(histogram_image_raw, histogram_image_raw_size,
+                        quality, histogram_image, histogram_image_size)) {
+    goto Error;
+  }
+  // Refine histogram image.
+  for (i = 0; i < histogram_image_raw_size; ++i) {
+    histogram_symbols[i] = -1;
+  }
+  HistogramRefine(histogram_image_raw, histogram_image_raw_size,
+                  histogram_symbols, *histogram_image_size, *histogram_image);
+  ok = 1;
+
+Error:
+  if (!ok) {
+    VP8LDeleteHistograms(*histogram_image, *histogram_image_size);
+  }
+  VP8LDeleteHistograms(histogram_image_raw, histogram_image_raw_size);
+  return ok;
+}
+
 #endif

src/enc/histogram.h

@@ -59,8 +59,7 @@ static WEBP_INLINE void VP8LHistogramInit(VP8LHistogram* const p,
 // The input data is the PixOrCopy data, which models the
 // literals, stop codes and backward references (both distances and lengths)
 void VP8LHistogramCreate(VP8LHistogram* const p,
-                         const PixOrCopy* const literal_and_length,
+                         const VP8LBackwardRefs* const refs);
-                         int n_literal_and_length);
 
 void VP8LHistogramAddSinglePixOrCopy(VP8LHistogram* const p, const PixOrCopy v);
 
@@ -117,32 +116,28 @@ static WEBP_INLINE int VP8LHistogramNumCodes(const VP8LHistogram* const p) {
   return 256 + kLengthCodes + (1 << p->palette_code_bits_);
 }
 
+static WEBP_INLINE void VP8LDeleteHistograms(VP8LHistogram** histograms,
+                                             int size) {
+  if (histograms != NULL) {
+    int i;
+    for (i = 0; i < size; ++i) {
+      free(histograms[i]);
+    }
+    free(histograms);
+  }
+}
+
 void VP8LConvertPopulationCountTableToBitEstimates(
     int n, const int* const population_counts, double* const output);
 
-// Build a 2d image of histograms, subresolutioned by (1 << histobits) to
+// Builds the histogram image.
-// the original image.
+int VP8LGetHistImageSymbols(int xsize, int ysize,
-int VP8LHistogramBuildImage(int xsize, int ysize,
+                            const VP8LBackwardRefs* const refs,
-                            int histobits, int palette_bits,
+                            int quality, int histogram_bits,
-                            const PixOrCopy* backward_refs,
+                            int cache_bits,
-                            int backward_refs_size,
+                            VP8LHistogram*** histogram_image,
-                            VP8LHistogram*** image,
+                            int* const histogram_image_size,
-                            int* histogram_size);
+                            uint32_t* const histogram_symbols);
-
-// Combines several histograms into fewer histograms.
-int VP8LHistogramCombine(VP8LHistogram** in,
-                         int in_size,
-                         int quality,
-                         VP8LHistogram*** out,
-                         int* out_size);
-
-// Moves histograms from one cluster to another if smaller entropy can
-// be achieved by doing that.
-void VP8LHistogramRefine(VP8LHistogram** raw,
-                         int raw_size,
-                         uint32_t* symbols,
-                         int out_size,
-                         VP8LHistogram** out);
 
 #if defined(__cplusplus) || defined(c_plusplus)
 }

src/enc/vp8l.c

@@ -154,13 +154,6 @@ static int VP8LEncAnalyze(VP8LEncoder* const enc) {
 
 // -----------------------------------------------------------------------------
 
-// TODO(urvang): should be moved to backward_reference.h and used more
-// as function parameters.
-typedef struct {
-  PixOrCopy* refs;
-  int size;
-} VP8LBackwardRefs;
-
 static void VP8LInitBackwardRefs(VP8LBackwardRefs* const refs) {
   if (refs != NULL) {
     refs->refs = NULL;
@@ -209,11 +202,11 @@ static int GetBackwardReferences(int width, int height,
     if (histo == NULL) goto Error1;
     // Evaluate lz77 coding
     VP8LHistogramInit(histo, cache_bits);
-    VP8LHistogramCreate(histo, refs_lz77.refs, refs_lz77.size);
+    VP8LHistogramCreate(histo, &refs_lz77);
     bit_cost_lz77 = (int)VP8LHistogramEstimateBits(histo);
     // Evaluate RLE coding
     VP8LHistogramInit(histo, cache_bits);
-    VP8LHistogramCreate(histo, refs_rle.refs, refs_rle.size);
+    VP8LHistogramCreate(histo, &refs_rle);
     bit_cost_rle = (int)VP8LHistogramEstimateBits(histo);
     // Decide if LZ77 is useful.
     lz77_is_useful = (bit_cost_lz77 < bit_cost_rle);
@@ -259,58 +252,6 @@ End:
   return ok;
 }
 
-static void DeleteHistograms(VP8LHistogram** histograms, int size) {
-  if (histograms != NULL) {
-    int i;
-    for (i = 0; i < size; ++i) {
-      free(histograms[i]);
-    }
-    free(histograms);
-  }
-}
-
-static int GetHistImageSymbols(int xsize, int ysize,
-                               const VP8LBackwardRefs* const refs,
-                               int quality, int histogram_bits,
-                               int cache_bits,
-                               VP8LHistogram*** histogram_image,
-                               int* histogram_image_size,
-                               uint32_t* histogram_symbols) {
-  // Build histogram image.
-  int ok = 0;
-  int i;
-  int histogram_image_raw_size;
-  VP8LHistogram** histogram_image_raw = NULL;
-
-  *histogram_image = NULL;
-  if (!VP8LHistogramBuildImage(xsize, ysize, histogram_bits, cache_bits,
-                               refs->refs, refs->size,
-                               &histogram_image_raw,
-                               &histogram_image_raw_size)) {
-    goto Error;
-  }
-  // Collapse similar histograms.
-  if (!VP8LHistogramCombine(histogram_image_raw, histogram_image_raw_size,
-                            quality, histogram_image, histogram_image_size)) {
-    goto Error;
-  }
-  // Refine histogram image.
-  for (i = 0; i < histogram_image_raw_size; ++i) {
-    histogram_symbols[i] = -1;
-  }
-  VP8LHistogramRefine(histogram_image_raw, histogram_image_raw_size,
-                      histogram_symbols, *histogram_image_size,
-                      *histogram_image);
-  ok = 1;
-
-Error:
-  if (!ok) {
-    DeleteHistograms(*histogram_image, *histogram_image_size);
-  }
-  DeleteHistograms(histogram_image_raw, histogram_image_raw_size);
-  return ok;
-}
-
 // Heuristics for selecting the stride ranges to collapse.
 static int ValuesShouldBeCollapsedToStrideAverage(int a, int b) {
   return abs(a - b) < 4;
@@ -750,10 +691,10 @@ static int EncodeImageInternal(VP8LBitWriter* const bw,
     goto Error;
   }
   // Build histogram image & symbols from backward references.
-  if (!GetHistImageSymbols(width, height, &refs,
+  if (!VP8LGetHistImageSymbols(width, height, &refs,
-                           quality, histogram_bits, cache_bits,
+                               quality, histogram_bits, cache_bits,
-                           &histogram_image, &histogram_image_size,
+                               &histogram_image, &histogram_image_size,
-                           histogram_symbols)) {
+                               histogram_symbols)) {
     goto Error;
   }
   // Create Huffman bit lengths & codes for each histogram image.
@@ -816,7 +757,7 @@ static int EncodeImageInternal(VP8LBitWriter* const bw,
   }
 
   // Free combined histograms.
-  DeleteHistograms(histogram_image, histogram_image_size);
+  VP8LDeleteHistograms(histogram_image, histogram_image_size);
   histogram_image = NULL;
 
   // Emit no bits if there is only one symbol in the histogram.
@@ -832,7 +773,7 @@ static int EncodeImageInternal(VP8LBitWriter* const bw,
 
  Error:
   if (!ok) {
-    DeleteHistograms(histogram_image, histogram_image_size);
+    VP8LDeleteHistograms(histogram_image, histogram_image_size);
   }
   VP8LClearBackwardRefs(&refs);
   for (i = 0; i < 5 * histogram_image_size; ++i) {