Add initial pipeline for decompressors

src/utils/SkTextureCompressor.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkTextureCompressor.h"
 #include "SkTextureCompressor_ASTC.h"
 #include "SkTextureCompressor_LATC.h"
 #include "SkTextureCompressor_R11EAC.h"
 
 #include "SkBitmap.h"
 #include "SkData.h"
 #include "SkEndian.h"
 
 #include "SkTextureCompression_opts.h"
 
 ////////////////////////////////////////////////////////////////////////////////
 
 namespace SkTextureCompressor {
 
-void GetBlockDimensions(Format format, int* dimX, int* dimY) {
+void GetBlockDimensions(Format format, int* dimX, int* dimY, bool matchSpec) {
     if (NULL == dimX || NULL == dimY) {
         return;
     }
 
-    if (SkTextureCompressorGetPlatformDims(format, dimX, dimY)) {
+    if (!matchSpec && SkTextureCompressorGetPlatformDims(format, dimX, dimY)) {
         return;
     }
 
+    // No specialized arguments, return the dimensions as they are in the spec.
     switch(format) {
         // These formats are 64 bits per 4x4 block.
         default:
             SkDEBUGFAIL("Unknown compression format!");
             // fall through
         case kR11_EAC_Format:
         case kLATC_Format:
             *dimX = 4;
             *dimY = 4;
             break;
 
         // This format is 12x12 blocks to 128 bits.
         case kASTC_12x12_Format:
             *dimX = 12;
             *dimY = 12;
             break;        
     }
 }
 
 int GetCompressedDataSize(Format fmt, int width, int height) {
     int dimX, dimY;
-    GetBlockDimensions(fmt, &dimX, &dimY);
+    GetBlockDimensions(fmt, &dimX, &dimY, true);
+
     int encodedBlockSize = 0;
             
     switch (fmt) {
         // These formats are 64 bits per 4x4 block.
         case kR11_EAC_Format:
         case kLATC_Format:
             encodedBlockSize = 8;
             break;
 
         // This format is 12x12 blocks to 128 bits.
@@ skipping 88 matching lines @@
         case kASTC_12x12_Format:
             return CreateASTCBlitter(width, height, compressedBuffer);
 
         default:
             return NULL;
     }
 
     return NULL;
 }
 
+bool DecompressBufferFromFormat(uint8_t* dst, int dstRowBytes, const uint8_t* src,
+                                int width, int height, Format format) {
+    int dimX, dimY;
+    GetBlockDimensions(format, &dimX, &dimY, true);
+
+    if (width < 0 || ((width % dimX) != 0) || height < 0 || ((height % dimY) != 0)) {
+        return false;
+    }
+
+    switch(format) {
+        case kLATC_Format:
+            DecompressLATC(dst, dstRowBytes, src, width, height);
+            return true;
+
+        case kR11_EAC_Format:
+            DecompressR11EAC(dst, dstRowBytes, src, width, height);
+            return true;
+
+        case kASTC_12x12_Format:
+            // TODO(krajcevski) .. right now just fall through and return false.
+            return false;
+    }
+
+    return false;
+}
+
 }  // namespace SkTextureCompressor