Add SkEncodedFormat, used by SkCodec.

src/images/SkImageDecoder_libico.cpp

Index: src/images/SkImageDecoder_libico.cpp
diff --git a/src/images/SkImageDecoder_libico.cpp b/src/images/SkImageDecoder_libico.cpp
index 1fafd528e58f513abe0ac6d271428324433ade5a..075b6bf6f49620bc0fc3ea0476d71cb367a8a878 100644
--- a/src/images/SkImageDecoder_libico.cpp
+++ b/src/images/SkImageDecoder_libico.cpp
@@ -15,8 +15,8 @@ class SkICOImageDecoder : public SkImageDecoder {
 public:
     SkICOImageDecoder();
 
-    Format getFormat() const SK_OVERRIDE {
-        return kICO_Format;
+    SkEncodedFormat getFormat() const SK_OVERRIDE {
+        return kICO_SkEncodedFormat;
     }
 
 protected:
@@ -76,8 +76,7 @@ SkImageDecoder::Result SkICOImageDecoder::onDecode(SkStream* stream, SkBitmap* b
 {
     SkAutoMalloc autoMal;
     const size_t length = SkCopyStreamToStorage(&autoMal, stream);
-    // Check that the buffer is large enough to read the directory header
-    if (length < 6) {
+    if (0 == length) {
         return kFailure;
     }
 
@@ -92,15 +91,8 @@ SkImageDecoder::Result SkICOImageDecoder::onDecode(SkStream* stream, SkBitmap* b
     }
 
     int count = read2Bytes(buf, 4);
-    // Check that there are directory entries
-    if (count < 1) {
-        return kFailure;
-    }
 
-    // Check that buffer is large enough to read directory entries.
-    // We are guaranteed that count is at least 1.  We might as well assume
-    // count is 1 because this deprecated decoder only looks at the first
-    // directory entry.
+    //need to at least have enough space to hold the initial table of info
     if (length < (size_t)(6 + count*16)) {
         return kFailure;
     }
@@ -110,7 +102,6 @@ SkImageDecoder::Result SkICOImageDecoder::onDecode(SkStream* stream, SkBitmap* b
     //otherwise, they could be used for error checking
     int w = readByte(buf, 6);
     int h = readByte(buf, 7);
-    SkASSERT(w >= 0 && h >= 0);
     int colorCount = readByte(buf, 8);
     //int reservedToo = readByte(buf, 9 + choice*16);   //0
     //int planes = read2Bytes(buf, 10 + choice*16);       //1 - but often 0
@@ -118,7 +109,6 @@ SkImageDecoder::Result SkICOImageDecoder::onDecode(SkStream* stream, SkBitmap* b
     const size_t size = read4Bytes(buf, 14);           //matters?
     const size_t offset = read4Bytes(buf, 18);
     // promote the sum to 64-bits to avoid overflow
-    // Check that buffer is large enough to read image data
     if (offset > length || size > length || ((uint64_t)offset + size) > length) {
         return kFailure;
     }
@@ -130,7 +120,7 @@ SkImageDecoder::Result SkICOImageDecoder::onDecode(SkStream* stream, SkBitmap* b
         if (otherDecoder.get() != NULL) {
             // Disallow nesting ICO files within one another
             // FIXME: Can ICO files contain other formats besides PNG?
-            if (otherDecoder->getFormat() == SkImageDecoder::kICO_Format) {
+            if (otherDecoder->getFormat() == kICO_SkEncodedFormat) {
                 return kFailure;
             }
             // Set fields on the other decoder to be the same as this one.
@@ -149,20 +139,6 @@ SkImageDecoder::Result SkICOImageDecoder::onDecode(SkStream* stream, SkBitmap* b
     //int width = read4Bytes(buf, offset+4);              //should == w
     //int height = read4Bytes(buf, offset+8);             //should == 2*h
     //int planesToo = read2Bytes(buf, offset+12);         //should == 1 (does it?)
-    
-    // For ico images, only a byte is used to store each dimension
-    // 0 is used to represent 256
-    if (w == 0) {
-        w = 256;
-    }
-    if (h == 0) {
-        h = 256;
-    }
-
-    // Check that buffer is large enough to read the bit depth
-    if (length < offset + 16) {
-        return kFailure;
-    }
     int bitCount = read2Bytes(buf, offset+14);
 
     void (*placePixel)(const int pixelNo, const unsigned char* buf,
@@ -204,12 +180,6 @@ SkImageDecoder::Result SkICOImageDecoder::onDecode(SkStream* stream, SkBitmap* b
     //int colorsImportant = read4Bytes(buf, offset+36);   //0
 
     int begin = SkToInt(offset + 40);
-    // Check that the buffer is large enough to read the color table
-    // For bmp-in-icos, there should be 4 bytes per color
-    if (length < (size_t) (begin + 4*colorCount)) {
-        return kFailure;
-    }
-
     //this array represents the colortable
     //if i allow other types of bitmaps, it may actually be used as a part of the bitmap
     SkPMColor* colors = NULL;
@@ -258,45 +228,6 @@ SkImageDecoder::Result SkICOImageDecoder::onDecode(SkStream* stream, SkBitmap* b
         return kFailure;
     }
 
-    // The AND mask is a 1-bit alpha mask for each pixel that comes after the
-    // XOR mask in the bmp.  If we check that the largest AND offset is safe,
-    // it should mean all other buffer accesses will be at smaller indices and
-    // will therefore be safe.
-    size_t maxAndOffset = andOffset + ((andLineWidth*(h-1)+(w-1)) >> 3);
-    if (length <= maxAndOffset) {
-        return kFailure;
-    }
-
-    // Here we assert that all reads from the buffer using the XOR offset are
-    // less than the AND offset.  This should be guaranteed based on the above
-    // calculations.
-#ifdef SK_DEBUG
-    int maxPixelNum = lineWidth*(h-1)+w-1;
-    int maxByte;
-    switch (bitCount) {
-        case 1:
-            maxByte = maxPixelNum >> 3;
-            break;
-        case 4:
-            maxByte = maxPixelNum >> 1;
-            break;
-        case 8:
-            maxByte = maxPixelNum;
-            break;
-        case 24:
-            maxByte = maxPixelNum * 3 + 2;
-            break;
-        case 32:
-            maxByte = maxPixelNum * 4 + 3;
-            break;
-        default:
-            SkASSERT(false);
-            return kFailure;
-    }
-    int maxXOROffset = xorOffset + maxByte;
-    SkASSERT(maxXOROffset < andOffset);
-#endif
-
     SkAutoLockPixels alp(*bm);
 
     for (int y = 0; y < h; y++)
@@ -442,11 +373,11 @@ static SkImageDecoder* sk_libico_dfactory(SkStreamRewindable* stream) {
 
 static SkImageDecoder_DecodeReg gReg(sk_libico_dfactory);
 
-static SkImageDecoder::Format get_format_ico(SkStreamRewindable* stream) {
+SkEncodedFormat get_format_ico(SkStreamRewindable* stream) {
     if (is_ico(stream)) {
-        return SkImageDecoder::kICO_Format;
+        return kICO_SkEncodedFormat;
     }
-    return SkImageDecoder::kUnknown_Format;
+    return kUnknown_SkEncodedFormat;
 }
 
 static SkImageDecoder_FormatReg gFormatReg(get_format_ico);