Delete SkImageDecoder

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 "SkData.h"
-#include "SkImageDecoder.h"
-#include "SkStream.h"
-#include "SkStreamPriv.h"
-#include "SkTypes.h"
-
-class SkICOImageDecoder : public SkImageDecoder {
-public:
-    SkICOImageDecoder();
-
-    Format getFormat() const override {
-        return kICO_Format;
-    }
-
-protected:
-    Result onDecode(SkStream* stream, SkBitmap* bm, Mode) override;
-
-private:
-    typedef SkImageDecoder INHERITED;
-};
-
-/////////////////////////////////////////////////////////////////////////////////////////
-
-//read bytes starting from the begin-th index in the buffer
-//read in Intel order, and return an integer
-
-#define readByte(buffer,begin) buffer[begin]
-#define read2Bytes(buffer,begin) buffer[begin]+SkLeftShift(buffer[begin+1],8)
-#define read4Bytes(buffer,begin) buffer[begin]+SkLeftShift(buffer[begin+1],8)+SkLeftShift(buffer[begin+2],16)+SkLeftShift(buffer[begin+3],24)
-
-/////////////////////////////////////////////////////////////////////////////////////////
-
-SkICOImageDecoder::SkICOImageDecoder()
-{
-}
-
-//helpers - my function pointer will call one of these, depending on the bitCount, each time through the inner loop
-static void editPixelBit1(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);
-static void editPixelBit4(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);
-static void editPixelBit8(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);
-static void editPixelBit24(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);
-static void editPixelBit32(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);
-
-
-static int calculateRowBytesFor8888(int w, int bitCount)
-{
-    //  Default rowBytes is w << 2 for kARGB_8888
-    //  In the case of a 4 bit image with an odd width, we need to add some
-    //  so we can go off the end of the drawn bitmap.
-    //  Add 4 to ensure that it is still a multiple of 4.
-    if (4 == bitCount && (w & 0x1)) {
-        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) {
-    auto data = SkCopyStreamToData(stream);
-    if (!data) {
-        return kFailure;
-    }
-
-    const size_t length = data->size();
-    // Check that the buffer is large enough to read the directory header
-    if (length < 6) {
-        return kFailure;
-    }
-
-    unsigned char* buf = (unsigned char*) data->data();
-
-    //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.
-    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() != nullptr) {
-            // Disallow nesting ICO files within one another
-            // FIXME: Can ICO files contain other formats besides PNG?
-            if (otherDecoder->getFormat() == SkImageDecoder::kICO_Format) {
-                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) = nullptr;
-    switch (bitCount)
-    {
-        case 1:
-            placePixel = &editPixelBit1;
-            colorCount = 2;
-            break;
-        case 4:
-            placePixel = &editPixelBit4;
-            colorCount = 16;
-            break;
-        case 8:
-            placePixel = &editPixelBit8;
-            colorCount = 256;
-            break;
-        case 24:
-            placePixel = &editPixelBit24;
-            colorCount = 0;
-            break;
-        case 32:
-            placePixel = &editPixelBit32;
-            colorCount = 0;
-            break;
-        default:
-            SkDEBUGF(("Decoding %ibpp is unimplemented\n", bitCount));
-            return kFailure;
-    }
-
-    //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 = nullptr;
-    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?
-            blue = readByte(buf, begin + 4*j);
-            green = readByte(buf, begin + 4*j + 1);
-            red = readByte(buf, begin + 4*j + 2);
-            colors[j] = SkPackARGB32(0xFF, red & 0xFF, green & 0xFF, blue & 0xFF);
-        }
-    }
-    int bitWidth = w*bitCount;
-    int test = bitWidth & 0x1F;
-    int mask = -(((test >> 4) | (test >> 3) | (test >> 2) | (test >> 1) | test) & 0x1);    //either 0xFFFFFFFF or 0
-    int lineBitWidth = (bitWidth & 0xFFFFFFE0) + (0x20 & mask);
-    int lineWidth = lineBitWidth/bitCount;
-
-    int xorOffset = begin + colorCount*4;   //beginning of the color bitmap
-                                            //other read method means we will just be here already
-    int andOffset = xorOffset + ((lineWidth*h*bitCount) >> 3);
-
-    /*int */test = w & 0x1F;   //the low 5 bits - we are rounding up to the next 32 (2^5)
-    /*int */mask = -(((test >> 4) | (test >> 3) | (test >> 2) | (test >> 1) | test) & 0x1);    //either 0xFFFFFFFF or 0
-    int andLineWidth = (w & 0xFFFFFFE0) + (0x20 & mask);
-    //if we allow different Configs, everything is the same til here
-    //change the config, and use different address getter, and place index vs color, and add the color table
-    //FIXME: what is the tradeoff in size?
-    //if the andbitmap (mask) is all zeroes, then we can easily do an index bitmap
-    //however, with small images with large colortables, maybe it's better to still do argb_8888
-
-    bm->setInfo(SkImageInfo::MakeN32Premul(w, h), calculateRowBytesFor8888(w, bitCount));
-
-    if (SkImageDecoder::kDecodeBounds_Mode == mode) {
-        delete[] colors;
-        return kSuccess;
-    }
-
-    if (!this->allocPixelRef(bm, nullptr))
-    {
-        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;
-            //only need to get a new alphaByte when x %8 == 0
-            //but that introduces an if and a mod - probably much slower
-            //that's ok, it's just a read of an array, not a stream
-            int alphaByte = readByte(buf, andOffset + (andPixelNo >> 3));
-            int shift = 7 - (andPixelNo & 0x7);
-            int m = 1 << shift;
-
-            int pixelNo = lineWidth*(h-y-1)+x;
-            placePixel(pixelNo, buf, xorOffset, x, y, w, bm, alphaByte, m, shift, colors);
-
-        }
-    }
-
-    delete [] colors;
-    //ensure we haven't read off the end?
-    //of course this doesn't help us if the andOffset was a lie...
-    //return andOffset + (andLineWidth >> 3) <= length;
-    return kSuccess;
-}   //onDecode
-
-//function to place the pixel, determined by the bitCount
-static void editPixelBit1(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)
-{
-    // note that this should be the same as/similar to the AND bitmap
-    SkPMColor* address = bm->getAddr32(x,y);
-    int byte = readByte(buf, xorOffset + (pixelNo >> 3));
-    int colorBit;
-    int alphaBit;
-    // Read all of the bits in this byte.
-    int i = x + 8;
-    // Pin to the width so we do not write outside the bounds of
-    // our color table.
-    i = i > w ? w : i;
-    // While loop to check all 8 bits individually.
-    while (x < i)
-    {
-
-        colorBit = (byte & m) >> shift;
-        alphaBit = (alphaByte & m) >> shift;
-        *address = (alphaBit-1)&(colors[colorBit]);
-        x++;
-        // setup for the next pixel
-        address = address + 1;
-        m = m >> 1;
-        shift -= 1;
-    }
-    x--;
-}
-static void editPixelBit4(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)
-{
-    SkPMColor* address = bm->getAddr32(x, y);
-    int byte = readByte(buf, xorOffset + (pixelNo >> 1));
-    int pixel = (byte >> 4) & 0xF;
-    int alphaBit = (alphaByte & m) >> shift;
-    *address = (alphaBit-1)&(colors[pixel]);
-    x++;
-    //if w is odd, x may be the same as w, which means we are writing to an unused portion of the bitmap
-    //but that's okay, since i've added an extra rowByte for just this purpose
-    address = address + 1;
-    pixel = byte & 0xF;
-    m = m >> 1;
-    alphaBit = (alphaByte & m) >> (shift-1);
-    //speed up trick here
-    *address = (alphaBit-1)&(colors[pixel]);
-}
-
-static void editPixelBit8(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)
-{
-    SkPMColor* address = bm->getAddr32(x, y);
-    int pixel = readByte(buf, xorOffset + pixelNo);
-    int alphaBit = (alphaByte & m) >> shift;
-    *address = (alphaBit-1)&(colors[pixel]);
-}
-
-static void editPixelBit24(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)
-{
-    SkPMColor* address = bm->getAddr32(x, y);
-    int blue = readByte(buf, xorOffset + 3*pixelNo);
-    int green = readByte(buf, xorOffset + 3*pixelNo + 1);
-    int red = readByte(buf, xorOffset + 3*pixelNo + 2);
-    int alphaBit = (alphaByte & m) >> shift;
-    //alphaBit == 1 => alpha = 0
-    int alpha = (alphaBit-1) & 0xFF;
-    *address = SkPreMultiplyARGB(alpha, red, green, blue);
-}
-
-static void editPixelBit32(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)
-{
-    SkPMColor* address = bm->getAddr32(x, y);
-    int blue = readByte(buf, xorOffset + 4*pixelNo);
-    int green = readByte(buf, xorOffset + 4*pixelNo + 1);
-    int red = readByte(buf, xorOffset + 4*pixelNo + 2);
-    int alphaBit = (alphaByte & m) >> shift;
-#if 1 // don't trust the alphaBit for 32bit images <mrr>
-    alphaBit = 0;
-#endif
-    int alpha = readByte(buf, xorOffset + 4*pixelNo + 3) & ((alphaBit-1)&0xFF);
-    *address = SkPreMultiplyARGB(alpha, red, green, blue);
-}
-
-///////////////////////////////////////////////////////////////////////////////
-DEFINE_DECODER_CREATOR(ICOImageDecoder);
-/////////////////////////////////////////////////////////////////////////////////////////
-
-static bool is_ico(SkStreamRewindable* stream) {
-    // Check to see if the first four bytes are 0,0,1,0
-    // FIXME: Is that required and sufficient?
-    char buf[4];
-    if (stream->read((void*)buf, 4) != 4) {
-        return false;
-    }
-    int reserved = read2Bytes(buf, 0);
-    int type = read2Bytes(buf, 2);
-    return 0 == reserved && 1 == type;
-}
-
-static SkImageDecoder* sk_libico_dfactory(SkStreamRewindable* stream) {
-    if (is_ico(stream)) {
-        return new SkICOImageDecoder;
-    }
-    return nullptr;
-}
-
-static SkImageDecoder_DecodeReg gReg(sk_libico_dfactory);
-
-static SkImageDecoder::Format get_format_ico(SkStreamRewindable* stream) {
-    if (is_ico(stream)) {
-        return SkImageDecoder::kICO_Format;
-    }
-    return SkImageDecoder::kUnknown_Format;
-}
-
-static SkImageDecoder_FormatReg gFormatReg(get_format_ico);