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Handle rewinds in SkBmpCodec.

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Factor our BMP code for reading the header, and call it after a rewind.

BUG=skia:3257

Review URL: https://codereview.chromium.org/1057483003
This commit is contained in:
scroggo 2015-04-01 07:39:40 -07:00 committed by Commit bot
parent 8c8f22a3bb
commit 79e378d9b7
3 changed files with 63 additions and 34 deletions
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85
src/codec/SkCodec_libbmp.cpp
View File

@ -105,11 +105,12 @@ SkCodec* SkBmpCodec::NewFromIco(SkStream* stream) {
/*
*
* Creates a bmp decoder
* Reads enough of the stream to determine the image format
* Read enough of the stream to initialize the SkBmpCodec. Returns a bool
* representing success or failure. If it returned true, and codecOut was
* not NULL, it will be set to a new SkBmpCodec.
*
*/
SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool isIco) {
bool SkBmpCodec::ReadHeader(SkStream* stream, bool isIco, SkCodec** codecOut) {
// Header size constants
static const uint32_t kBmpHeaderBytes = 14;
static const uint32_t kBmpHeaderBytesPlusFour = kBmpHeaderBytes + 4;
@ -140,14 +141,14 @@ SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool isIco) {
if (stream->read(hBuffer.get(), kBmpHeaderBytesPlusFour) !=
kBmpHeaderBytesPlusFour) {
SkCodecPrintf("Error: unable to read first bitmap header.\n");
return NULL;
return false;
}
totalBytes = get_int(hBuffer.get(), 2);
offset = get_int(hBuffer.get(), 10);
if (offset < kBmpHeaderBytes + kBmpOS2V1Bytes) {
SkCodecPrintf("Error: invalid starting location for pixel data\n");
return NULL;
return false;
}
// The size of the second (info) header in bytes
@ -156,7 +157,7 @@ SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool isIco) {
infoBytes = get_int(hBuffer.get(), 14);
if (infoBytes < kBmpOS2V1Bytes) {
SkCodecPrintf("Error: invalid second header size.\n");
return NULL;
return false;
}
} else {
// This value is only used by RLE compression. Bmp in Ico files do not
@ -174,12 +175,12 @@ SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool isIco) {
SkNEW_ARRAY(uint8_t, 4));
if (stream->read(hBuffer.get(), 4) != 4) {
SkCodecPrintf("Error: unable to read size of second bitmap header.\n");
return NULL;
return false;
}
infoBytes = get_int(hBuffer.get(), 0);
if (infoBytes < kBmpOS2V1Bytes) {
SkCodecPrintf("Error: invalid second header size.\n");
return NULL;
return false;
}
}
@ -191,7 +192,7 @@ SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool isIco) {
SkNEW_ARRAY(uint8_t, infoBytesRemaining));
if (stream->read(iBuffer.get(), infoBytesRemaining) != infoBytesRemaining) {
SkCodecPrintf("Error: unable to read second bitmap header.\n");
return NULL;
return false;
}
// The number of bits used per pixel in the pixel data
@ -282,7 +283,7 @@ SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool isIco) {
} else {
// There are no valid bmp headers
SkCodecPrintf("Error: second bitmap header size is invalid.\n");
return NULL;
return false;
}
// Check for valid dimensions from header
@ -300,7 +301,7 @@ SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool isIco) {
if (width < 0 || width >= kBmpMaxDim || height >= kBmpMaxDim) {
// TODO: Decide if we want to support really large bmps.
SkCodecPrintf("Error: invalid bitmap dimensions.\n");
return NULL;
return false;
}
// Create mask struct
@ -340,7 +341,7 @@ SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool isIco) {
if (stream->read(mBuffer.get(), kBmpMaskBytes) !=
kBmpMaskBytes) {
SkCodecPrintf("Error: unable to read bit inputMasks.\n");
return NULL;
return false;
}
maskBytes = kBmpMaskBytes;
inputMasks.red = get_int(mBuffer.get(), 0);
@ -366,10 +367,10 @@ SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool isIco) {
// in chromium. I have not come across a test case
// that uses this format.
SkCodecPrintf("Error: huffman format unsupported.\n");
return NULL;
return false;
default:
SkCodecPrintf("Error: invalid bmp bit masks header.\n");
return NULL;
return false;
}
break;
case kJpeg_BitmapCompressionMethod:
@ -383,16 +384,16 @@ SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool isIco) {
// It is unsupported in the previous version and
// in chromium. I think it is used mostly for printers.
SkCodecPrintf("Error: compression format not supported.\n");
return NULL;
return false;
case kCMYK_BitmapCompressionMethod:
case kCMYK8BitRLE_BitmapCompressionMethod:
case kCMYK4BitRLE_BitmapCompressionMethod:
// TODO: Same as above.
SkCodecPrintf("Error: CMYK not supported for bitmap decoding.\n");
return NULL;
return false;
default:
SkCodecPrintf("Error: invalid format for bitmap decoding.\n");
return NULL;
return false;
}
// Most versions of bmps should be rendered as opaque. Either they do
@ -447,7 +448,7 @@ SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool isIco) {
break;
default:
SkCodecPrintf("Error: invalid input value for bits per pixel.\n");
return NULL;
return false;
}
// Check that input bit masks are valid and create the masks object
@ -455,13 +456,13 @@ SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool isIco) {
masks(SkMasks::CreateMasks(inputMasks, bitsPerPixel));
if (NULL == masks) {
SkCodecPrintf("Error: invalid input masks.\n");
return NULL;
return false;
}
// Check for a valid number of total bytes when in RLE mode
if (totalBytes <= offset && kRLE_BitmapInputFormat == inputFormat) {
SkCodecPrintf("Error: RLE requires valid input size.\n");
return NULL;
return false;
}
const size_t RLEBytes = totalBytes - offset;
@ -469,19 +470,37 @@ SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool isIco) {
const uint32_t bytesRead = kBmpHeaderBytes + infoBytes + maskBytes;
if (!isIco && offset < bytesRead) {
SkCodecPrintf("Error: pixel data offset less than header size.\n");
return NULL;
return false;
}
// Return the codec
// We will use ImageInfo to store width, height, and alpha type. We will
// set color type to kN32_SkColorType because that should be the default
// output.
const SkImageInfo& imageInfo = SkImageInfo::Make(width, height,
kN32_SkColorType, alphaType);
return SkNEW_ARGS(SkBmpCodec, (imageInfo, stream, bitsPerPixel,
inputFormat, masks.detach(), numColors,
bytesPerColor, offset - bytesRead,
rowOrder, RLEBytes, isIco));
if (codecOut) {
// Return the codec
// We will use ImageInfo to store width, height, and alpha type. We
// will set color type to kN32_SkColorType because that should be the
// default output.
const SkImageInfo& imageInfo = SkImageInfo::Make(width, height,
kN32_SkColorType, alphaType);
*codecOut = SkNEW_ARGS(SkBmpCodec, (imageInfo, stream, bitsPerPixel,
inputFormat, masks.detach(),
numColors, bytesPerColor,
offset - bytesRead, rowOrder,
RLEBytes, isIco));
}
return true;
}
/*
*
* Creates a bmp decoder
* Reads enough of the stream to determine the image format
*
*/
SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool isIco) {
SkCodec* codec = NULL;
if (ReadHeader(stream, isIco, &codec)) {
return codec;
}
return NULL;
}
/*
@ -523,7 +542,9 @@ SkCodec::Result SkBmpCodec::onGetPixels(const SkImageInfo& dstInfo,
if (rewindState == kCouldNotRewind_RewindState) {
return kCouldNotRewind;
} else if (rewindState == kRewound_RewindState) {
return kCouldNotRewind; // TODO(msarett): handle rewinds
if (!ReadHeader(this->stream(), fIsIco, NULL)) {
return kCouldNotRewind;
}
}
if (dstInfo.dimensions() != this->getInfo().dimensions()) {
SkCodecPrintf("Error: scaling not supported.\n");

9
src/codec/SkCodec_libbmp.h
View File

@ -98,6 +98,15 @@ private:
*/
static SkCodec* NewFromStream(SkStream*, bool isIco);
/*
*
* Read enough of the stream to initialize the SkBmpCodec. Returns a bool
* representing success or failure. If it returned true, and codecOut was
* not NULL, it will be set to a new SkBmpCodec.
*
*/
static bool ReadHeader(SkStream*, bool isIco, SkCodec** codecOut);
/*
*
* Performs the bitmap decoding for bit masks input format

3
tests/CodexTest.cpp
View File

@ -74,8 +74,7 @@ DEF_TEST(Codec, r) {
check(r, "mandrill.wbmp", SkISize::Make(512, 512), true);
// BMP
// TODO (msarett): SkBmpCodec should be able to rewind.
check(r, "randPixels.bmp", SkISize::Make(8, 8), false);
check(r, "randPixels.bmp", SkISize::Make(8, 8), true);
// ICO
// TODO (msarett): SkIcoCodec should be able to rewind.