Merge "Move the HuffmanCost() function to dsp lib"

src/dsp/lossless.c

@@ -1458,15 +1458,14 @@ void VP8LBundleColorMap(const uint8_t* const row, int width,
   }
 }
 
-static double ExtraCost(const int* const population, int length) {
+static double ExtraCost(const int* population, int length) {
   int i;
   double cost = 0.;
   for (i = 2; i < length - 2; ++i) cost += (i >> 1) * population[i + 2];
   return cost;
 }
 
-static double ExtraCostCombined(const int* const X, const int* const Y,
-                                int length) {
+static double ExtraCostCombined(const int* X, const int* Y, int length) {
   int i;
   double cost = 0.;
   for (i = 2; i < length - 2; ++i) {
@@ -1476,6 +1475,53 @@ static double ExtraCostCombined(const int* const X, const int* const Y,
   return cost;
 }
 
+// Returns the various RLE counts
+static VP8LStreaks HuffmanCostCount(const int* population, int length) {
+  int i;
+  int streak = 0;
+  VP8LStreaks stats;
+  memset(&stats, 0, sizeof(stats));
+  for (i = 0; i < length - 1; ++i) {
+    ++streak;
+    if (population[i] == population[i + 1]) {
+      continue;
+    }
+    stats.counts[population[i] != 0] += (streak > 3);
+    stats.streaks[population[i] != 0][(streak > 3)] += streak;
+    streak = 0;
+  }
+  ++streak;
+  stats.counts[population[i] != 0] += (streak > 3);
+  stats.streaks[population[i] != 0][(streak > 3)] += streak;
+  return stats;
+}
+
+static VP8LStreaks HuffmanCostCombinedCount(const int* X, const int* Y,
+                                            int length) {
+  int i;
+  int streak = 0;
+  VP8LStreaks stats;
+  memset(&stats, 0, sizeof(stats));
+  for (i = 0; i < length - 1; ++i) {
+    const int xy = X[i] + Y[i];
+    const int xy_next = X[i + 1] + Y[i + 1];
+    ++streak;
+    if (xy == xy_next) {
+      continue;
+    }
+    stats.counts[xy != 0] += (streak > 3);
+    stats.streaks[xy != 0][(streak > 3)] += streak;
+    streak = 0;
+  }
+  {
+    const int xy = X[i] + Y[i];
+    ++streak;
+    stats.counts[xy != 0] += (streak > 3);
+    stats.streaks[xy != 0][(streak > 3)] += streak;
+  }
+  return stats;
+}
+
 //------------------------------------------------------------------------------
 
 VP8LProcessBlueAndRedFunc VP8LSubtractGreenFromBlueAndRed;
@@ -1497,6 +1543,9 @@ VP8LFastLog2SlowFunc VP8LFastSLog2Slow;
 VP8LCostFunc VP8LExtraCost;
 VP8LCostCombinedFunc VP8LExtraCostCombined;
 
+VP8LCostCountFunc VP8LHuffmanCostCount;
+VP8LCostCombinedCountFunc VP8LHuffmanCostCombinedCount;
+
 extern void VP8LDspInitSSE2(void);
 extern void VP8LDspInitNEON(void);
 extern void VP8LDspInitMIPS32(void);
@@ -1522,6 +1571,9 @@ void VP8LDspInit(void) {
   VP8LExtraCost = ExtraCost;
   VP8LExtraCostCombined = ExtraCostCombined;
 
+  VP8LHuffmanCostCount = HuffmanCostCount;
+  VP8LHuffmanCostCombinedCount = HuffmanCostCombinedCount;
+
   // If defined, use CPUInfo() to overwrite some pointers with faster versions.
   if (VP8GetCPUInfo != NULL) {
 #if defined(WEBP_USE_SSE2)

src/dsp/lossless.h

@@ -139,14 +139,24 @@ static WEBP_INLINE float VP8LFastSLog2(int v) {
 // -----------------------------------------------------------------------------
 // Huffman-cost related functions.
 
-typedef double (*VP8LCostFunc)(const int* const population, int length);
-typedef double (*VP8LCostCombinedFunc)(const int* const X,
-                                       const int* const Y,
-                                       int length);
+typedef double (*VP8LCostFunc)(const int* population, int length);
+typedef double (*VP8LCostCombinedFunc)(const int* X, const int* Y, int length);
 
 extern VP8LCostFunc VP8LExtraCost;
 extern VP8LCostCombinedFunc VP8LExtraCostCombined;
 
+typedef struct {        // small struct to hold counters
+  int counts[2];        // index: 0=zero steak, 1=non-zero streak
+  int streaks[2][2];    // [zero/non-zero][streak<3 / streak>=3]
+} VP8LStreaks;
+
+typedef VP8LStreaks (*VP8LCostCountFunc)(const int* population, int length);
+typedef VP8LStreaks (*VP8LCostCombinedCountFunc)(const int* X, const int* Y,
+                                                 int length);
+
+extern VP8LCostCountFunc VP8LHuffmanCostCount;
+extern VP8LCostCombinedCountFunc VP8LHuffmanCostCombinedCount;
+
 // -----------------------------------------------------------------------------
 // PrefixEncode()
 

src/enc/histogram.c

@@ -180,7 +180,7 @@ static double BitsEntropyCombined(const int* const X, const int* const Y,
   return BitsEntropyRefine(nonzeros, sum, max_val, retval);
 }
 
-static WEBP_INLINE double InitialHuffmanCost(void) {
+static double InitialHuffmanCost(void) {
   // Small bias because Huffman code length is typically not stored in
   // full length.
   static const int kHuffmanCodeOfHuffmanCodeSize = CODE_LENGTH_CODES * 3;
@@ -188,66 +188,29 @@ static WEBP_INLINE double InitialHuffmanCost(void) {
   return kHuffmanCodeOfHuffmanCodeSize - kSmallBias;
 }
 
-double VP8FinalHuffmanCost(int cnt_z, int streak_z_le3, int streak_z_gt3,
-                           int cnt_nz, int streak_nz_le3, int streak_nz_gt3) {
+// Finalize the Huffman cost based on streak numbers and length type (<3 or >=3)
+static double FinalHuffmanCost(const VP8LStreaks* const stats) {
   double retval = InitialHuffmanCost();
-  retval += cnt_z * 1.5625 + 0.234375 * streak_z_gt3;
-  retval += cnt_nz * 2.578125 + 0.703125 * streak_nz_gt3;
-  retval += 1.796875 * streak_z_le3;
-  retval += 3.28125 * streak_nz_le3;
+  retval += stats->counts[0] * 1.5625 + 0.234375 * stats->streaks[0][1];
+  retval += stats->counts[1] * 2.578125 + 0.703125 * stats->streaks[1][1];
+  retval += 1.796875 * stats->streaks[0][0];
+  retval += 3.28125 * stats->streaks[1][0];
   return retval;
 }
 
-// Returns the cost encode the rle-encoded entropy code.
-// The constants in this function are experimental.
+// Trampolines
 static double HuffmanCost(const int* const population, int length) {
-  int cnts[2] = { 0, 0 };
-  int streaks[2][2] = { { 0, 0 }, { 0, 0 } };
-  int streak = 0;
-  int i;
-  for (i = 0; i < length - 1; ++i) {
-    ++streak;
-    if (population[i] == population[i + 1]) {
-      continue;
-    }
-    cnts[population[i] != 0] += (streak > 3);
-    streaks[population[i] != 0][(streak > 3)] += streak;
-    streak = 0;
-  }
-  ++streak;
-  cnts[population[i] != 0] += (streak > 3);
-  streaks[population[i] != 0][(streak > 3)] += streak;
-  return VP8FinalHuffmanCost(cnts[0], streaks[0][0], streaks[0][1],
-                             cnts[1], streaks[1][0], streaks[1][1]);
+  const VP8LStreaks stats = VP8LHuffmanCostCount(population, length);
+  return FinalHuffmanCost(&stats);
 }
 
 static double HuffmanCostCombined(const int* const X, const int* const Y,
                                   int length) {
-  int cnts[2] = { 0, 0 };
-  int streaks[2][2] = { { 0, 0 }, { 0, 0 } };
-  int streak = 0;
-  int i;
-  for (i = 0; i < length - 1; ++i) {
-    const int xy = X[i] + Y[i];
-    const int xy_next = X[i + 1] + Y[i + 1];
-    ++streak;
-    if (xy == xy_next) {
-      continue;
-    }
-    cnts[xy != 0] += (streak > 3);
-    streaks[xy != 0][streak > 3] += streak;
-    streak = 0;
-  }
-  {
-    const int xy = X[i] + Y[i];
-    ++streak;
-    cnts[xy != 0] += (streak > 3);
-    streaks[xy != 0][streak > 3] += streak;
-  }
-  return VP8FinalHuffmanCost(cnts[0], streaks[0][0], streaks[0][1],
-                             cnts[1], streaks[1][0], streaks[1][1]);
+  const VP8LStreaks stats = VP8LHuffmanCostCombinedCount(X, Y, length);
+  return FinalHuffmanCost(&stats);
 }
 
+// Aggregated costs
 static double PopulationCost(const int* const population, int length) {
   return BitsEntropy(population, length) + HuffmanCost(population, length);
 }

src/enc/histogram.h

@@ -90,13 +90,6 @@ static WEBP_INLINE int VP8LHistogramNumCodes(int palette_code_bits) {
       ((palette_code_bits > 0) ? (1 << palette_code_bits) : 0);
 }
 
-// Used to finalized the Huffman cost:
-// cnt_z / cnt_nz: counts the number of 0's and non-0's
-// streak_{z,nz}_le3 / streak_{z,nz}_gt3: number of streaks larger than 3
-// or less-or-equal than 3.
-double VP8FinalHuffmanCost(int cnt_z, int streak_z_le3, int streak_z_gt3,
-                           int cnt_nz, int streak_nz_le3, int streak_nz_gt3);
-
 // Builds the histogram image.
 int VP8LGetHistoImageSymbols(int xsize, int ysize,
                              const VP8LBackwardRefs* const refs,