Add SkEncodedFormat, used by SkCodec.

src/images/SkImageDecoder_libico.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColorPriv.h"
 #include "SkImageDecoder.h"
 #include "SkStream.h"
 #include "SkStreamPriv.h"
 #include "SkTypes.h"
 
 class SkICOImageDecoder : public SkImageDecoder {
 public:
     SkICOImageDecoder();
 
-    Format getFormat() const SK_OVERRIDE {
-        return kICO_Format;
+    SkEncodedFormat getFormat() const SK_OVERRIDE {
+        return kICO_SkEncodedFormat;
     }
 
 protected:
     Result onDecode(SkStream* stream, SkBitmap* bm, Mode) SK_OVERRIDE;
 
 private:
     typedef SkImageDecoder INHERITED;
 };
 
 /////////////////////////////////////////////////////////////////////////////////////////
@@ skipping 39 matching lines @@
         return (w + 1) << 2;
     }
     //  Otherwise return 0, which will allow it to be calculated automatically.
     return 0;
 }
 
 SkImageDecoder::Result SkICOImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode)
 {
     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;
     }
 
     unsigned char* buf = (unsigned char*)autoMal.get();
 
     //these should always be the same - should i use for error checking? - what about files that have some
     //incorrect values, but still decode properly?
     int reserved = read2Bytes(buf, 0);    // 0
     int type = read2Bytes(buf, 2);        // 1
     if (reserved != 0 || type != 1) {
         return kFailure;
     }
 
     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;
     }
 
     //skip ahead to the correct header
     //commented out lines are not used, but if i switch to other read method, need to know how many to skip
     //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
     //int fakeBitCount = read2Bytes(buf, 12 + choice*16); //should be real - usually 0
     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;
     }
 
     // Check to see if this is a PNG image inside the ICO
     {
         SkMemoryStream subStream(buf + offset, size, false);
         SkAutoTDelete<SkImageDecoder> otherDecoder(SkImageDecoder::Factory(&subStream));
         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.
             this->copyFieldsToOther(otherDecoder.get());
             const Result result = otherDecoder->decode(&subStream, bm, this->getDefaultPref(),
                                                        mode);
             // FIXME: Should we just return result here? Is it possible that data that looked like
             // a subimage was not, but was actually a valid ICO?
             if (result != kFailure) {
                 return result;
             }
         }
     }
 
     //int infoSize = read4Bytes(buf, offset);             //40
     //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,
         const int xorOffset, int& x, int y, const int w,
         SkBitmap* bm, int alphaByte, int m, int shift, SkPMColor* colors) = NULL;
     switch (bitCount)
     {
         case 1:
             placePixel = &editPixelBit1;
             colorCount = 2;
@@ skipping 21 matching lines @@
 
     //these should all be zero, but perhaps are not - need to check
     //int compression = read4Bytes(buf, offset+16);       //0
     //int imageSize = read4Bytes(buf, offset+20);         //0 - sometimes has a value
     //int xPixels = read4Bytes(buf, offset+24);           //0
     //int yPixels = read4Bytes(buf, offset+28);           //0
     //int colorsUsed = read4Bytes(buf, offset+32)         //0 - might have an actual value though
     //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;
     int blue, green, red;
     if (colorCount)
     {
         colors = new SkPMColor[colorCount];
         for (int j = 0; j < colorCount; j++)
         {
             //should this be a function - maybe a #define?
@@ skipping 28 matching lines @@
         delete[] colors;
         return kSuccess;
     }
 
     if (!this->allocPixelRef(bm, NULL))
     {
         delete[] colors;
         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++)
     {
         for (int x = 0; x < w; x++)
         {
             //U32* address = bm->getAddr32(x, y);
 
             //check the alpha bit first, but pass it along to the function to figure out how to deal with it
             int andPixelNo = andLineWidth*(h-y-1)+x;
@@ skipping 125 matching lines @@
 
 static SkImageDecoder* sk_libico_dfactory(SkStreamRewindable* stream) {
     if (is_ico(stream)) {
         return SkNEW(SkICOImageDecoder);
     }
     return NULL;
 }
 
 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);