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gecko-dev/image/decoders/nsICODecoder.cpp

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/* vim:set tw=80 expandtab softtabstop=4 ts=4 sw=4: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* This is a Cross-Platform ICO Decoder, which should work everywhere, including
* Big-Endian machines like the PowerPC. */
#include <stdlib.h>
#include "mozilla/Endian.h"
#include "nsICODecoder.h"
#include "RasterImage.h"
namespace mozilla {
namespace image {
#define ICONCOUNTOFFSET 4
#define DIRENTRYOFFSET 6
#define BITMAPINFOSIZE 40
#define PREFICONSIZE 16
// ----------------------------------------
// Actual Data Processing
// ----------------------------------------
uint32_t
nsICODecoder::CalcAlphaRowSize()
{
// Calculate rowsize in DWORD's and then return in # of bytes
uint32_t rowSize = (GetRealWidth() + 31) / 32; // + 31 to round up
return rowSize * 4; // Return rowSize in bytes
}
// Obtains the number of colors from the bits per pixel
uint16_t
nsICODecoder::GetNumColors()
{
uint16_t numColors = 0;
if (mBPP <= 8) {
switch (mBPP) {
case 1:
numColors = 2;
break;
case 4:
numColors = 16;
break;
case 8:
numColors = 256;
break;
default:
numColors = (uint16_t)-1;
}
}
return numColors;
}
nsICODecoder::nsICODecoder(RasterImage &aImage)
: Decoder(aImage)
{
mPos = mImageOffset = mCurrIcon = mNumIcons = mBPP = mRowBytes = 0;
mIsPNG = false;
mRow = nullptr;
mOldLine = mCurLine = 1; // Otherwise decoder will never start
}
nsICODecoder::~nsICODecoder()
{
if (mRow) {
moz_free(mRow);
}
}
void
nsICODecoder::FinishInternal()
{
// We shouldn't be called in error cases
NS_ABORT_IF_FALSE(!HasError(), "Shouldn't call FinishInternal after error!");
// Finish the internally used decoder as well
if (mContainedDecoder) {
mContainedDecoder->FinishSharedDecoder();
mDecodeDone = mContainedDecoder->GetDecodeDone();
}
}
// Returns a buffer filled with the bitmap file header in little endian:
// Signature 2 bytes 'BM'
// FileSize 4 bytes File size in bytes
// reserved 4 bytes unused (=0)
// DataOffset 4 bytes File offset to Raster Data
// Returns true if successful
bool nsICODecoder::FillBitmapFileHeaderBuffer(int8_t *bfh)
{
memset(bfh, 0, 14);
bfh[0] = 'B';
bfh[1] = 'M';
int32_t dataOffset = 0;
int32_t fileSize = 0;
dataOffset = BFH_LENGTH + BITMAPINFOSIZE;
// The color table is present only if BPP is <= 8
if (mDirEntry.mBitCount <= 8) {
uint16_t numColors = GetNumColors();
if (numColors == (uint16_t)-1) {
return false;
}
dataOffset += 4 * numColors;
fileSize = dataOffset + GetRealWidth() * GetRealHeight();
} else {
fileSize = dataOffset + (mDirEntry.mBitCount * GetRealWidth() *
GetRealHeight()) / 8;
}
NativeEndian::swapToLittleEndianInPlace(&fileSize, 1);
memcpy(bfh + 2, &fileSize, sizeof(fileSize));
NativeEndian::swapToLittleEndianInPlace(&dataOffset, 1);
memcpy(bfh + 10, &dataOffset, sizeof(dataOffset));
return true;
}
// A BMP inside of an ICO has *2 height because of the AND mask
// that follows the actual bitmap. The BMP shouldn't know about
// this difference though.
bool
nsICODecoder::FixBitmapHeight(int8_t *bih)
{
// Get the height from the BMP file information header
int32_t height;
memcpy(&height, bih + 8, sizeof(height));
NativeEndian::swapFromLittleEndianInPlace(&height, 1);
// BMPs can be stored inverted by having a negative height
height = abs(height);
// The bitmap height is by definition * 2 what it should be to account for
// the 'AND mask'. It is * 2 even if the `AND mask` is not present.
height /= 2;
if (height > 256) {
return false;
}
// We should always trust the height from the bitmap itself instead of
// the ICO height. So fix the ICO height.
if (height == 256) {
mDirEntry.mHeight = 0;
} else {
mDirEntry.mHeight = (int8_t)height;
}
// Fix the BMP height in the BIH so that the BMP decoder can work properly
NativeEndian::swapToLittleEndianInPlace(&height, 1);
memcpy(bih + 8, &height, sizeof(height));
return true;
}
// We should always trust the contained resource for the width
// information over our own information.
bool
nsICODecoder::FixBitmapWidth(int8_t *bih)
{
// Get the width from the BMP file information header
int32_t width;
memcpy(&width, bih + 4, sizeof(width));
NativeEndian::swapFromLittleEndianInPlace(&width, 1);
if (width > 256) {
return false;
}
// We should always trust the width from the bitmap itself instead of
// the ICO width.
if (width == 256) {
mDirEntry.mWidth = 0;
} else {
mDirEntry.mWidth = (int8_t)width;
}
return true;
}
// The BMP information header's bits per pixel should be trusted
// more than what we have. Usually the ICO's BPP is set to 0
int32_t
nsICODecoder::ExtractBPPFromBitmap(int8_t *bih)
{
int32_t bitsPerPixel;
memcpy(&bitsPerPixel, bih + 14, sizeof(bitsPerPixel));
NativeEndian::swapFromLittleEndianInPlace(&bitsPerPixel, 1);
return bitsPerPixel;
}
int32_t
nsICODecoder::ExtractBIHSizeFromBitmap(int8_t *bih)
{
int32_t headerSize;
memcpy(&headerSize, bih, sizeof(headerSize));
NativeEndian::swapFromLittleEndianInPlace(&headerSize, 1);
return headerSize;
}
void
nsICODecoder::SetHotSpotIfCursor() {
if (!mIsCursor) {
return;
}
mImageMetadata.SetHotspot(mDirEntry.mXHotspot, mDirEntry.mYHotspot);
}
void
nsICODecoder::WriteInternal(const char* aBuffer, uint32_t aCount, DecodeStrategy aStrategy)
{
NS_ABORT_IF_FALSE(!HasError(), "Shouldn't call WriteInternal after error!");
if (!aCount) {
if (mContainedDecoder) {
WriteToContainedDecoder(aBuffer, aCount, aStrategy);
}
return;
}
while (aCount && (mPos < ICONCOUNTOFFSET)) { // Skip to the # of icons.
if (mPos == 2) { // if the third byte is 1: This is an icon, 2: a cursor
if ((*aBuffer != 1) && (*aBuffer != 2)) {
PostDataError();
return;
}
mIsCursor = (*aBuffer == 2);
}
mPos++; aBuffer++; aCount--;
}
if (mPos == ICONCOUNTOFFSET && aCount >= 2) {
mNumIcons = LittleEndian::readUint16(reinterpret_cast<const uint16_t*>(aBuffer));
aBuffer += 2;
mPos += 2;
aCount -= 2;
}
if (mNumIcons == 0)
return; // Nothing to do.
uint16_t colorDepth = 0;
nsIntSize prefSize = mImage.GetRequestedResolution();
if (prefSize.width == 0 && prefSize.height == 0) {
prefSize.SizeTo(PREFICONSIZE, PREFICONSIZE);
}
// A measure of the difference in size between the entry we've found
// and the requested size. We will choose the smallest image that is
// >= requested size (i.e. we assume it's better to downscale a larger
// icon than to upscale a smaller one).
int32_t diff = INT_MIN;
// Loop through each entry's dir entry
while (mCurrIcon < mNumIcons) {
if (mPos >= DIRENTRYOFFSET + (mCurrIcon * sizeof(mDirEntryArray)) &&
mPos < DIRENTRYOFFSET + ((mCurrIcon + 1) * sizeof(mDirEntryArray))) {
uint32_t toCopy = sizeof(mDirEntryArray) -
(mPos - DIRENTRYOFFSET - mCurrIcon * sizeof(mDirEntryArray));
if (toCopy > aCount) {
toCopy = aCount;
}
memcpy(mDirEntryArray + sizeof(mDirEntryArray) - toCopy, aBuffer, toCopy);
mPos += toCopy;
aCount -= toCopy;
aBuffer += toCopy;
}
if (aCount == 0)
return; // Need more data
IconDirEntry e;
if (mPos == (DIRENTRYOFFSET + ICODIRENTRYSIZE) +
(mCurrIcon * sizeof(mDirEntryArray))) {
mCurrIcon++;
ProcessDirEntry(e);
// We can't use GetRealWidth and GetRealHeight here because those operate
// on mDirEntry, here we are going through each item in the directory.
// Calculate the delta between this image's size and the desired size,
// so we can see if it is better than our current-best option.
// In the case of several equally-good images, we use the last one.
int32_t delta = (e.mWidth == 0 ? 256 : e.mWidth) - prefSize.width +
(e.mHeight == 0 ? 256 : e.mHeight) - prefSize.height;
if (e.mBitCount >= colorDepth &&
((diff < 0 && delta >= diff) || (delta >= 0 && delta <= diff))) {
diff = delta;
mImageOffset = e.mImageOffset;
// ensure mImageOffset is >= size of the direntry headers (bug #245631)
uint32_t minImageOffset = DIRENTRYOFFSET +
mNumIcons * sizeof(mDirEntryArray);
if (mImageOffset < minImageOffset) {
PostDataError();
return;
}
colorDepth = e.mBitCount;
memcpy(&mDirEntry, &e, sizeof(IconDirEntry));
}
}
}
if (mPos < mImageOffset) {
// Skip to (or at least towards) the desired image offset
uint32_t toSkip = mImageOffset - mPos;
if (toSkip > aCount)
toSkip = aCount;
mPos += toSkip;
aBuffer += toSkip;
aCount -= toSkip;
}
// If we are within the first PNGSIGNATURESIZE bytes of the image data,
// then we have either a BMP or a PNG. We use the first PNGSIGNATURESIZE
// bytes to determine which one we have.
if (mCurrIcon == mNumIcons && mPos >= mImageOffset &&
mPos < mImageOffset + PNGSIGNATURESIZE)
{
uint32_t toCopy = PNGSIGNATURESIZE - (mPos - mImageOffset);
if (toCopy > aCount) {
toCopy = aCount;
}
memcpy(mSignature + (mPos - mImageOffset), aBuffer, toCopy);
mPos += toCopy;
aCount -= toCopy;
aBuffer += toCopy;
mIsPNG = !memcmp(mSignature, nsPNGDecoder::pngSignatureBytes,
PNGSIGNATURESIZE);
if (mIsPNG) {
mContainedDecoder = new nsPNGDecoder(mImage);
mContainedDecoder->SetObserver(mObserver);
mContainedDecoder->SetSizeDecode(IsSizeDecode());
mContainedDecoder->InitSharedDecoder(mImageData, mImageDataLength,
mColormap, mColormapSize,
mCurrentFrame);
if (!WriteToContainedDecoder(mSignature, PNGSIGNATURESIZE, aStrategy)) {
return;
}
}
}
// If we have a PNG, let the PNG decoder do all of the rest of the work
if (mIsPNG && mContainedDecoder && mPos >= mImageOffset + PNGSIGNATURESIZE) {
if (!WriteToContainedDecoder(aBuffer, aCount, aStrategy)) {
return;
}
if (!HasSize() && mContainedDecoder->HasSize()) {
PostSize(mContainedDecoder->GetImageMetadata().GetWidth(),
mContainedDecoder->GetImageMetadata().GetHeight());
}
mPos += aCount;
aBuffer += aCount;
aCount = 0;
// Raymond Chen says that 32bpp only are valid PNG ICOs
// http://blogs.msdn.com/b/oldnewthing/archive/2010/10/22/10079192.aspx
if (!IsSizeDecode() &&
!static_cast<nsPNGDecoder*>(mContainedDecoder.get())->IsValidICO()) {
PostDataError();
}
return;
}
// We've processed all of the icon dir entries and are within the
// bitmap info size
if (!mIsPNG && mCurrIcon == mNumIcons && mPos >= mImageOffset &&
mPos >= mImageOffset + PNGSIGNATURESIZE &&
mPos < mImageOffset + BITMAPINFOSIZE) {
// As we were decoding, we did not know if we had a PNG signature or the
// start of a bitmap information header. At this point we know we had
// a bitmap information header and not a PNG signature, so fill the bitmap
// information header with the data it should already have.
memcpy(mBIHraw, mSignature, PNGSIGNATURESIZE);
// We've found the icon.
uint32_t toCopy = sizeof(mBIHraw) - (mPos - mImageOffset);
if (toCopy > aCount)
toCopy = aCount;
memcpy(mBIHraw + (mPos - mImageOffset), aBuffer, toCopy);
mPos += toCopy;
aCount -= toCopy;
aBuffer += toCopy;
}
// If we have a BMP inside the ICO and we have read the BIH header
if (!mIsPNG && mPos == mImageOffset + BITMAPINFOSIZE) {
// Make sure we have a sane value for the bitmap information header
int32_t bihSize = ExtractBIHSizeFromBitmap(reinterpret_cast<int8_t*>(mBIHraw));
if (bihSize != BITMAPINFOSIZE) {
PostDataError();
return;
}
// We are extracting the BPP from the BIH header as it should be trusted
// over the one we have from the icon header
mBPP = ExtractBPPFromBitmap(reinterpret_cast<int8_t*>(mBIHraw));
// Init the bitmap decoder which will do most of the work for us
// It will do everything except the AND mask which isn't present in bitmaps
// bmpDecoder is for local scope ease, it will be freed by mContainedDecoder
nsBMPDecoder *bmpDecoder = new nsBMPDecoder(mImage);
mContainedDecoder = bmpDecoder;
bmpDecoder->SetUseAlphaData(true);
mContainedDecoder->SetObserver(mObserver);
mContainedDecoder->SetSizeDecode(IsSizeDecode());
mContainedDecoder->InitSharedDecoder(mImageData, mImageDataLength,
mColormap, mColormapSize,
mCurrentFrame);
// The ICO format when containing a BMP does not include the 14 byte
// bitmap file header. To use the code of the BMP decoder we need to
// generate this header ourselves and feed it to the BMP decoder.
int8_t bfhBuffer[BMPFILEHEADERSIZE];
if (!FillBitmapFileHeaderBuffer(bfhBuffer)) {
PostDataError();
return;
}
if (!WriteToContainedDecoder((const char*)bfhBuffer, sizeof(bfhBuffer), aStrategy)) {
return;
}
// Setup the cursor hot spot if one is present
SetHotSpotIfCursor();
// Fix the ICO height from the BIH.
// Fix the height on the BIH to be /2 so our BMP decoder will understand.
if (!FixBitmapHeight(reinterpret_cast<int8_t*>(mBIHraw))) {
PostDataError();
return;
}
// Fix the ICO width from the BIH.
if (!FixBitmapWidth(reinterpret_cast<int8_t*>(mBIHraw))) {
PostDataError();
return;
}
// Write out the BMP's bitmap info header
if (!WriteToContainedDecoder(mBIHraw, sizeof(mBIHraw), aStrategy)) {
return;
}
PostSize(mContainedDecoder->GetImageMetadata().GetWidth(),
mContainedDecoder->GetImageMetadata().GetHeight());
// We have the size. If we're doing a size decode, we got what
// we came for.
if (IsSizeDecode())
return;
// Sometimes the ICO BPP header field is not filled out
// so we should trust the contained resource over our own
// information.
mBPP = bmpDecoder->GetBitsPerPixel();
// Check to make sure we have valid color settings
uint16_t numColors = GetNumColors();
if (numColors == (uint16_t)-1) {
PostDataError();
return;
}
}
// If we have a BMP
if (!mIsPNG && mContainedDecoder && mPos >= mImageOffset + BITMAPINFOSIZE) {
uint16_t numColors = GetNumColors();
if (numColors == (uint16_t)-1) {
PostDataError();
return;
}
// Feed the actual image data (not including headers) into the BMP decoder
uint32_t bmpDataOffset = mDirEntry.mImageOffset + BITMAPINFOSIZE;
uint32_t bmpDataEnd = mDirEntry.mImageOffset + BITMAPINFOSIZE +
static_cast<nsBMPDecoder*>(mContainedDecoder.get())->GetCompressedImageSize() +
4 * numColors;
// If we are feeding in the core image data, but we have not yet
// reached the ICO's 'AND buffer mask'
if (mPos >= bmpDataOffset && mPos < bmpDataEnd) {
// Figure out how much data the BMP decoder wants
uint32_t toFeed = bmpDataEnd - mPos;
if (toFeed > aCount) {
toFeed = aCount;
}
if (!WriteToContainedDecoder(aBuffer, toFeed, aStrategy)) {
return;
}
mPos += toFeed;
aCount -= toFeed;
aBuffer += toFeed;
}
// If the bitmap is fully processed, treat any left over data as the ICO's
// 'AND buffer mask' which appears after the bitmap resource.
if (!mIsPNG && mPos >= bmpDataEnd) {
// There may be an optional AND bit mask after the data. This is
// only used if the alpha data is not already set. The alpha data
// is used for 32bpp bitmaps as per the comment in ICODecoder.h
// The alpha mask should be checked in all other cases.
if (static_cast<nsBMPDecoder*>(mContainedDecoder.get())->GetBitsPerPixel() != 32 ||
!static_cast<nsBMPDecoder*>(mContainedDecoder.get())->HasAlphaData()) {
uint32_t rowSize = ((GetRealWidth() + 31) / 32) * 4; // + 31 to round up
if (mPos == bmpDataEnd) {
mPos++;
mRowBytes = 0;
mCurLine = GetRealHeight();
mRow = (uint8_t*)moz_realloc(mRow, rowSize);
if (!mRow) {
PostDecoderError(NS_ERROR_OUT_OF_MEMORY);
return;
}
}
// Ensure memory has been allocated before decoding.
NS_ABORT_IF_FALSE(mRow, "mRow is null");
if (!mRow) {
PostDataError();
return;
}
while (mCurLine > 0 && aCount > 0) {
uint32_t toCopy = std::min(rowSize - mRowBytes, aCount);
if (toCopy) {
memcpy(mRow + mRowBytes, aBuffer, toCopy);
aCount -= toCopy;
aBuffer += toCopy;
mRowBytes += toCopy;
}
if (rowSize == mRowBytes) {
mCurLine--;
mRowBytes = 0;
uint32_t* imageData =
static_cast<nsBMPDecoder*>(mContainedDecoder.get())->GetImageData();
if (!imageData) {
PostDataError();
return;
}
uint32_t* decoded = imageData + mCurLine * GetRealWidth();
uint32_t* decoded_end = decoded + GetRealWidth();
uint8_t* p = mRow;
uint8_t* p_end = mRow + rowSize;
while (p < p_end) {
uint8_t idx = *p++;
for (uint8_t bit = 0x80; bit && decoded<decoded_end; bit >>= 1) {
// Clear pixel completely for transparency.
if (idx & bit) {
*decoded = 0;
}
decoded++;
}
}
}
}
}
}
}
}
bool
nsICODecoder::WriteToContainedDecoder(const char* aBuffer, uint32_t aCount, DecodeStrategy aStrategy)
{
mContainedDecoder->Write(aBuffer, aCount, aStrategy);
if (mContainedDecoder->HasDataError()) {
mDataError = mContainedDecoder->HasDataError();
}
if (mContainedDecoder->HasDecoderError()) {
PostDecoderError(mContainedDecoder->GetDecoderError());
}
return !HasError();
}
void
nsICODecoder::ProcessDirEntry(IconDirEntry& aTarget)
{
memset(&aTarget, 0, sizeof(aTarget));
memcpy(&aTarget.mWidth, mDirEntryArray, sizeof(aTarget.mWidth));
memcpy(&aTarget.mHeight, mDirEntryArray + 1, sizeof(aTarget.mHeight));
memcpy(&aTarget.mColorCount, mDirEntryArray + 2, sizeof(aTarget.mColorCount));
memcpy(&aTarget.mReserved, mDirEntryArray + 3, sizeof(aTarget.mReserved));
memcpy(&aTarget.mPlanes, mDirEntryArray + 4, sizeof(aTarget.mPlanes));
aTarget.mPlanes = LittleEndian::readUint16(&aTarget.mPlanes);
memcpy(&aTarget.mBitCount, mDirEntryArray + 6, sizeof(aTarget.mBitCount));
aTarget.mBitCount = LittleEndian::readUint16(&aTarget.mBitCount);
memcpy(&aTarget.mBytesInRes, mDirEntryArray + 8, sizeof(aTarget.mBytesInRes));
aTarget.mBytesInRes = LittleEndian::readUint32(&aTarget.mBytesInRes);
memcpy(&aTarget.mImageOffset, mDirEntryArray + 12,
sizeof(aTarget.mImageOffset));
aTarget.mImageOffset = LittleEndian::readUint32(&aTarget.mImageOffset);
}
bool
nsICODecoder::NeedsNewFrame() const
{
if (mContainedDecoder) {
return mContainedDecoder->NeedsNewFrame();
}
return Decoder::NeedsNewFrame();
}
nsresult
nsICODecoder::AllocateFrame()
{
if (mContainedDecoder) {
nsresult rv = mContainedDecoder->AllocateFrame();
mCurrentFrame = mContainedDecoder->GetCurrentFrame();
return rv;
}
return Decoder::AllocateFrame();
}
} // namespace image
} // namespace mozilla
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