/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkCodec.h"
#include "SkJpegCodec.h"
#include "SkJpegDecoderMgr.h"
#include "SkCodecPriv.h"
#include "SkColorData.h"
#include "SkStream.h"
#include "SkTemplates.h"
#include "SkTypes.h"
// stdio is needed for libjpeg-turbo
#include <stdio.h>
#include "SkJpegUtility.h"
// This warning triggers false postives way too often in here.
#if defined(__GNUC__) && !defined(__clang__)
#pragma GCC diagnostic ignored "-Wclobbered"
#endif
extern "C" {
#include "jerror.h"
#include "jpeglib.h"
}
bool SkJpegCodec::IsJpeg(const void* buffer, size_t bytesRead) {
constexpr uint8_t jpegSig[] = { 0xFF, 0xD8, 0xFF };
return bytesRead >= 3 && !memcmp(buffer, jpegSig, sizeof(jpegSig));
}
static uint32_t get_endian_int(const uint8_t* data, bool littleEndian) {
if (littleEndian) {
return (data[3] << 24) | (data[2] << 16) | (data[1] << 8) | (data[0]);
}
return (data[0] << 24) | (data[1] << 16) | (data[2] << 8) | (data[3]);
}
const uint32_t kExifHeaderSize = 14;
const uint32_t kExifMarker = JPEG_APP0 + 1;
static bool is_orientation_marker(jpeg_marker_struct* marker, SkEncodedOrigin* orientation) {
if (kExifMarker != marker->marker || marker->data_length < kExifHeaderSize) {
return false;
}
constexpr uint8_t kExifSig[] { 'E', 'x', 'i', 'f', '\0' };
if (memcmp(marker->data, kExifSig, sizeof(kExifSig))) {
return false;
}
// Account for 'E', 'x', 'i', 'f', '\0', '<fill byte>'.
constexpr size_t kOffset = 6;
return is_orientation_marker(marker->data + kOffset, marker->data_length - kOffset,
orientation);
}
bool is_orientation_marker(const uint8_t* data, size_t data_length, SkEncodedOrigin* orientation) {
bool littleEndian;
if (!is_valid_endian_marker(data, &littleEndian)) {
return false;
}
// Get the offset from the start of the marker.
// Though this only reads four bytes, use a larger int in case it overflows.
uint64_t offset = get_endian_int(data + 4, littleEndian);
// Require that the marker is at least large enough to contain the number of entries.
if (data_length < offset + 2) {
return false;
}
uint32_t numEntries = get_endian_short(data + offset, littleEndian);
// Tag (2 bytes), Datatype (2 bytes), Number of elements (4 bytes), Data (4 bytes)
const uint32_t kEntrySize = 12;
const auto max = SkTo<uint32_t>((data_length - offset - 2) / kEntrySize);
numEntries = SkTMin(numEntries, max);
// Advance the data to the start of the entries.
data += offset + 2;
const uint16_t kOriginTag = 0x112;
const uint16_t kOriginType = 3;
for (uint32_t i = 0; i < numEntries; i++, data += kEntrySize) {
uint16_t tag = get_endian_short(data, littleEndian);
uint16_t type = get_endian_short(data + 2, littleEndian);
uint32_t count = get_endian_int(data + 4, littleEndian);
if (kOriginTag == tag && kOriginType == type && 1 == count) {
uint16_t val = get_endian_short(data + 8, littleEndian);
if (0 < val && val <= kLast_SkEncodedOrigin) {
*orientation = (SkEncodedOrigin) val;
return true;
}
}
}
return false;
}
static SkEncodedOrigin get_exif_orientation(jpeg_decompress_struct* dinfo) {
SkEncodedOrigin orientation;
for (jpeg_marker_struct* marker = dinfo->marker_list; marker; marker = marker->next) {
if (is_orientation_marker(marker, &orientation)) {
return orientation;
}
}
return kDefault_SkEncodedOrigin;
}
static bool is_icc_marker(jpeg_marker_struct* marker) {
if (kICCMarker != marker->marker || marker->data_length < kICCMarkerHeaderSize) {
return false;
}
return !memcmp(marker->data, kICCSig, sizeof(kICCSig));
}
/*
* ICC profiles may be stored using a sequence of multiple markers. We obtain the ICC profile
* in two steps:
* (1) Discover all ICC profile markers and verify that they are numbered properly.
* (2) Copy the data from each marker into a contiguous ICC profile.
*/
static sk_sp<SkColorSpace> read_color_space(jpeg_decompress_struct* dinfo) {
// Note that 256 will be enough storage space since each markerIndex is stored in 8-bits.
jpeg_marker_struct* markerSequence[256];
memset(markerSequence, 0, sizeof(markerSequence));
uint8_t numMarkers = 0;
size_t totalBytes = 0;
// Discover any ICC markers and verify that they are numbered properly.
for (jpeg_marker_struct* marker = dinfo->marker_list; marker; marker = marker->next) {
if (is_icc_marker(marker)) {
// Verify that numMarkers is valid and consistent.
if (0 == numMarkers) {
numMarkers = marker->data[13];
if (0 == numMarkers) {
SkCodecPrintf("ICC Profile Error: numMarkers must be greater than zero.\n");
return nullptr;
}
} else if (numMarkers != marker->data[13]) {
SkCodecPrintf("ICC Profile Error: numMarkers must be consistent.\n");
return nullptr;
}
// Verify that the markerIndex is valid and unique. Note that zero is not
// a valid index.
uint8_t markerIndex = marker->data[12];
if (markerIndex == 0 || markerIndex > numMarkers) {
SkCodecPrintf("ICC Profile Error: markerIndex is invalid.\n");
return nullptr;
}
if (markerSequence[markerIndex]) {
SkCodecPrintf("ICC Profile Error: Duplicate value of markerIndex.\n");
return nullptr;
}
markerSequence[markerIndex] = marker;
SkASSERT(marker->data_length >= kICCMarkerHeaderSize);
totalBytes += marker->data_length - kICCMarkerHeaderSize;
}
}
if (0 == totalBytes) {
// No non-empty ICC profile markers were found.
return nullptr;
}
// Combine the ICC marker data into a contiguous profile.
sk_sp<SkData> iccData = SkData::MakeUninitialized(totalBytes);
void* dst = iccData->writable_data();
for (uint32_t i = 1; i <= numMarkers; i++) {
jpeg_marker_struct* marker = markerSequence[i];
if (!marker) {
SkCodecPrintf("ICC Profile Error: Missing marker %d of %d.\n", i, numMarkers);
return nullptr;
}
void* src = SkTAddOffset<void>(marker->data, kICCMarkerHeaderSize);
size_t bytes = marker->data_length - kICCMarkerHeaderSize;
memcpy(dst, src, bytes);
dst = SkTAddOffset<void>(dst, bytes);
}
return SkColorSpace::MakeICC(iccData->data(), iccData->size());
}
SkCodec::Result SkJpegCodec::ReadHeader(SkStream* stream, SkCodec** codecOut,
JpegDecoderMgr** decoderMgrOut, sk_sp<SkColorSpace> defaultColorSpace) {
// Create a JpegDecoderMgr to own all of the decompress information
std::unique_ptr<JpegDecoderMgr> decoderMgr(new JpegDecoderMgr(stream));
// libjpeg errors will be caught and reported here
skjpeg_error_mgr::AutoPushJmpBuf jmp(decoderMgr->errorMgr());
if (setjmp(jmp)) {
return decoderMgr->returnFailure("ReadHeader", kInvalidInput);
}
// Initialize the decompress info and the source manager
decoderMgr->init();
// Instruct jpeg library to save the markers that we care about. Since
// the orientation and color profile will not change, we can skip this
// step on rewinds.
if (codecOut) {
jpeg_save_markers(decoderMgr->dinfo(), kExifMarker, 0xFFFF);
jpeg_save_markers(decoderMgr->dinfo(), kICCMarker, 0xFFFF);
}
// Read the jpeg header
switch (jpeg_read_header(decoderMgr->dinfo(), true)) {
case JPEG_HEADER_OK:
break;
case JPEG_SUSPENDED:
return decoderMgr->returnFailure("ReadHeader", kIncompleteInput);
default:
return decoderMgr->returnFailure("ReadHeader", kInvalidInput);
}
if (codecOut) {
// Get the encoded color type
SkEncodedInfo::Color color;
if (!decoderMgr->getEncodedColor(&color)) {
return kInvalidInput;
}
// Create image info object and the codec
SkEncodedInfo info = SkEncodedInfo::Make(color, SkEncodedInfo::kOpaque_Alpha, 8);
SkEncodedOrigin orientation = get_exif_orientation(decoderMgr->dinfo());
sk_sp<SkColorSpace> colorSpace = read_color_space(decoderMgr->dinfo());
if (colorSpace) {
switch (decoderMgr->dinfo()->jpeg_color_space) {
case JCS_CMYK:
case JCS_YCCK:
if (colorSpace->type() != SkColorSpace::kCMYK_Type) {
colorSpace = nullptr;
}
break;
case JCS_GRAYSCALE:
if (colorSpace->type() != SkColorSpace::kGray_Type &&
colorSpace->type() != SkColorSpace::kRGB_Type)
{
colorSpace = nullptr;
}
break;
default:
if (colorSpace->type() != SkColorSpace::kRGB_Type) {
colorSpace = nullptr;
}
break;
}
}
if (!colorSpace) {
colorSpace = defaultColorSpace;
}
const int width = decoderMgr->dinfo()->image_width;
const int height = decoderMgr->dinfo()->image_height;
SkJpegCodec* codec = new SkJpegCodec(width, height, info, std::unique_ptr<SkStream>(stream),
decoderMgr.release(), std::move(colorSpace),
orientation);
*codecOut = codec;
} else {
SkASSERT(nullptr != decoderMgrOut);
*decoderMgrOut = decoderMgr.release();
}
return kSuccess;
}
std::unique_ptr<SkCodec> SkJpegCodec::MakeFromStream(std::unique_ptr<SkStream> stream,
Result* result) {
return SkJpegCodec::MakeFromStream(std::move(stream), result, SkColorSpace::MakeSRGB());
}
std::unique_ptr<SkCodec> SkJpegCodec::MakeFromStream(std::unique_ptr<SkStream> stream,
Result* result,
sk_sp<SkColorSpace> defaultColorSpace) {
SkCodec* codec = nullptr;
*result = ReadHeader(stream.get(), &codec, nullptr, std::move(defaultColorSpace));
if (kSuccess == *result) {
// Codec has taken ownership of the stream, we do not need to delete it
SkASSERT(codec);
stream.release();
return std::unique_ptr<SkCodec>(codec);
}
return nullptr;
}
SkJpegCodec::SkJpegCodec(int width, int height, const SkEncodedInfo& info,
std::unique_ptr<SkStream> stream, JpegDecoderMgr* decoderMgr,
sk_sp<SkColorSpace> colorSpace, SkEncodedOrigin origin)
: INHERITED(width, height, info, SkColorSpaceXform::kRGBA_8888_ColorFormat, std::move(stream),
std::move(colorSpace), origin)
, fDecoderMgr(decoderMgr)
, fReadyState(decoderMgr->dinfo()->global_state)
, fSwizzleSrcRow(nullptr)
, fColorXformSrcRow(nullptr)
, fSwizzlerSubset(SkIRect::MakeEmpty())
{}
/*
* Return the row bytes of a particular image type and width
*/
static size_t get_row_bytes(const j_decompress_ptr dinfo) {
const size_t colorBytes = (dinfo->out_color_space == JCS_RGB565) ? 2 :
dinfo->out_color_components;
return dinfo->output_width * colorBytes;
}
/*
* Calculate output dimensions based on the provided factors.
*
* Not to be used on the actual jpeg_decompress_struct used for decoding, since it will
* incorrectly modify num_components.
*/
void calc_output_dimensions(jpeg_decompress_struct* dinfo, unsigned int num, unsigned int denom) {
dinfo->num_components = 0;
dinfo->scale_num = num;
dinfo->scale_denom = denom;
jpeg_calc_output_dimensions(dinfo);
}
/*
* Return a valid set of output dimensions for this decoder, given an input scale
*/
SkISize SkJpegCodec::onGetScaledDimensions(float desiredScale) const {
// libjpeg-turbo supports scaling by 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 7/8, and 1/1, so we will
// support these as well
unsigned int num;
unsigned int denom = 8;
if (desiredScale >= 0.9375) {
num = 8;
} else if (desiredScale >= 0.8125) {
num = 7;
} else if (desiredScale >= 0.6875f) {
num = 6;
} else if (desiredScale >= 0.5625f) {
num = 5;
} else if (desiredScale >= 0.4375f) {
num = 4;
} else if (desiredScale >= 0.3125f) {
num = 3;
} else if (desiredScale >= 0.1875f) {
num = 2;
} else {
num = 1;
}
// Set up a fake decompress struct in order to use libjpeg to calculate output dimensions
jpeg_decompress_struct dinfo;
sk_bzero(&dinfo, sizeof(dinfo));
dinfo.image_width = this->getInfo().width();
dinfo.image_height = this->getInfo().height();
dinfo.global_state = fReadyState;
calc_output_dimensions(&dinfo, num, denom);
// Return the calculated output dimensions for the given scale
return SkISize::Make(dinfo.output_width, dinfo.output_height);
}
bool SkJpegCodec::onRewind() {
JpegDecoderMgr* decoderMgr = nullptr;
if (kSuccess != ReadHeader(this->stream(), nullptr, &decoderMgr, nullptr)) {
return fDecoderMgr->returnFalse("onRewind");
}
SkASSERT(nullptr != decoderMgr);
fDecoderMgr.reset(decoderMgr);
fSwizzler.reset(nullptr);
fSwizzleSrcRow = nullptr;
fColorXformSrcRow = nullptr;
fStorage.reset();
return true;
}
/*
* Checks if the conversion between the input image and the requested output
* image has been implemented
* Sets the output color space
*/
bool SkJpegCodec::setOutputColorSpace(const SkImageInfo& dstInfo) {
if (kUnknown_SkAlphaType == dstInfo.alphaType()) {
return false;
}
if (kOpaque_SkAlphaType != dstInfo.alphaType()) {
SkCodecPrintf("Warning: an opaque image should be decoded as opaque "
"- it is being decoded as non-opaque, which will draw slower\n");
}
J_COLOR_SPACE encodedColorType = fDecoderMgr->dinfo()->jpeg_color_space;
// Check for valid color types and set the output color space
switch (dstInfo.colorType()) {
case kRGBA_8888_SkColorType:
fDecoderMgr->dinfo()->out_color_space = JCS_EXT_RGBA;
break;
case kBGRA_8888_SkColorType:
if (this->colorXform()) {
// Always using RGBA as the input format for color xforms makes the
// implementation a little simpler.
fDecoderMgr->dinfo()->out_color_space = JCS_EXT_RGBA;
} else {
fDecoderMgr->dinfo()->out_color_space = JCS_EXT_BGRA;
}
break;
case kRGB_565_SkColorType:
if (this->colorXform()) {
fDecoderMgr->dinfo()->out_color_space = JCS_EXT_RGBA;
} else {
fDecoderMgr->dinfo()->dither_mode = JDITHER_NONE;
fDecoderMgr->dinfo()->out_color_space = JCS_RGB565;
}
break;
case kGray_8_SkColorType:
if (this->colorXform() || JCS_GRAYSCALE != encodedColorType) {
return false;
}
fDecoderMgr->dinfo()->out_color_space = JCS_GRAYSCALE;
break;
case kRGBA_F16_SkColorType:
SkASSERT(this->colorXform());
if (!dstInfo.colorSpace()->gammaIsLinear()) {
return false;
}
fDecoderMgr->dinfo()->out_color_space = JCS_EXT_RGBA;
break;
default:
return false;
}
// Check if we will decode to CMYK. libjpeg-turbo does not convert CMYK to RGBA, so
// we must do it ourselves.
if (JCS_CMYK == encodedColorType || JCS_YCCK == encodedColorType) {
fDecoderMgr->dinfo()->out_color_space = JCS_CMYK;
}
return true;
}
/*
* Checks if we can natively scale to the requested dimensions and natively scales the
* dimensions if possible
*/
bool SkJpegCodec::onDimensionsSupported(const SkISize& size) {
skjpeg_error_mgr::AutoPushJmpBuf jmp(fDecoderMgr->errorMgr());
if (setjmp(jmp)) {
return fDecoderMgr->returnFalse("onDimensionsSupported");
}
const unsigned int dstWidth = size.width();
const unsigned int dstHeight = size.height();
// Set up a fake decompress struct in order to use libjpeg to calculate output dimensions
// FIXME: Why is this necessary?
jpeg_decompress_struct dinfo;
sk_bzero(&dinfo, sizeof(dinfo));
dinfo.image_width = this->getInfo().width();
dinfo.image_height = this->getInfo().height();
dinfo.global_state = fReadyState;
// libjpeg-turbo can scale to 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 7/8, and 1/1
unsigned int num = 8;
const unsigned int denom = 8;
calc_output_dimensions(&dinfo, num, denom);
while (dinfo.output_width != dstWidth || dinfo.output_height != dstHeight) {
// Return a failure if we have tried all of the possible scales
if (1 == num || dstWidth > dinfo.output_width || dstHeight > dinfo.output_height) {
return false;
}
// Try the next scale
num -= 1;
calc_output_dimensions(&dinfo, num, denom);
}
fDecoderMgr->dinfo()->scale_num = num;
fDecoderMgr->dinfo()->scale_denom = denom;
return true;
}
int SkJpegCodec::readRows(const SkImageInfo& dstInfo, void* dst, size_t rowBytes, int count,
const Options& opts) {
// Set the jump location for libjpeg-turbo errors
skjpeg_error_mgr::AutoPushJmpBuf jmp(fDecoderMgr->errorMgr());
if (setjmp(jmp)) {
return 0;
}
// When fSwizzleSrcRow is non-null, it means that we need to swizzle. In this case,
// we will always decode into fSwizzlerSrcRow before swizzling into the next buffer.
// We can never swizzle "in place" because the swizzler may perform sampling and/or
// subsetting.
// When fColorXformSrcRow is non-null, it means that we need to color xform and that
// we cannot color xform "in place" (many times we can, but not when the dst is F16).
// In this case, we will color xform from fColorXformSrcRow into the dst.
JSAMPLE* decodeDst = (JSAMPLE*) dst;
uint32_t* swizzleDst = (uint32_t*) dst;
size_t decodeDstRowBytes = rowBytes;
size_t swizzleDstRowBytes = rowBytes;
int dstWidth = opts.fSubset ? opts.fSubset->width() : dstInfo.width();
if (fSwizzleSrcRow && fColorXformSrcRow) {
decodeDst = (JSAMPLE*) fSwizzleSrcRow;
swizzleDst = fColorXformSrcRow;
decodeDstRowBytes = 0;
swizzleDstRowBytes = 0;
dstWidth = fSwizzler->swizzleWidth();
} else if (fColorXformSrcRow) {
decodeDst = (JSAMPLE*) fColorXformSrcRow;
swizzleDst = fColorXformSrcRow;
decodeDstRowBytes = 0;
swizzleDstRowBytes = 0;
} else if (fSwizzleSrcRow) {
decodeDst = (JSAMPLE*) fSwizzleSrcRow;
decodeDstRowBytes = 0;
dstWidth = fSwizzler->swizzleWidth();
}
for (int y = 0; y < count; y++) {
uint32_t lines = jpeg_read_scanlines(fDecoderMgr->dinfo(), &decodeDst, 1);
if (0 == lines) {
return y;
}
if (fSwizzler) {
fSwizzler->swizzle(swizzleDst, decodeDst);
}
if (this->colorXform()) {
this->applyColorXform(dst, swizzleDst, dstWidth, kOpaque_SkAlphaType);
dst = SkTAddOffset<void>(dst, rowBytes);
}
decodeDst = SkTAddOffset<JSAMPLE>(decodeDst, decodeDstRowBytes);
swizzleDst = SkTAddOffset<uint32_t>(swizzleDst, swizzleDstRowBytes);
}
return count;
}
/*
* This is a bit tricky. We only need the swizzler to do format conversion if the jpeg is
* encoded as CMYK.
* And even then we still may not need it. If the jpeg has a CMYK color space and a color
* xform, the color xform will handle the CMYK->RGB conversion.
*/
static inline bool needs_swizzler_to_convert_from_cmyk(J_COLOR_SPACE jpegColorType,
const SkImageInfo& srcInfo, bool hasColorSpaceXform) {
if (JCS_CMYK != jpegColorType) {
return false;
}
bool hasCMYKColorSpace = SkColorSpace::kCMYK_Type == srcInfo.colorSpace()->type();
return !hasCMYKColorSpace || !hasColorSpaceXform;
}
/*
* Performs the jpeg decode
*/
SkCodec::Result SkJpegCodec::onGetPixels(const SkImageInfo& dstInfo,
void* dst, size_t dstRowBytes,
const Options& options,
int* rowsDecoded) {
if (options.fSubset) {
// Subsets are not supported.
return kUnimplemented;
}
// Get a pointer to the decompress info since we will use it quite frequently
jpeg_decompress_struct* dinfo = fDecoderMgr->dinfo();
// Set the jump location for libjpeg errors
skjpeg_error_mgr::AutoPushJmpBuf jmp(fDecoderMgr->errorMgr());
if (setjmp(jmp)) {
return fDecoderMgr->returnFailure("setjmp", kInvalidInput);
}
// Check if we can decode to the requested destination and set the output color space
if (!this->setOutputColorSpace(dstInfo)) {
return fDecoderMgr->returnFailure("setOutputColorSpace", kInvalidConversion);
}
if (!jpeg_start_decompress(dinfo)) {
return fDecoderMgr->returnFailure("startDecompress", kInvalidInput);
}
// The recommended output buffer height should always be 1 in high quality modes.
// If it's not, we want to know because it means our strategy is not optimal.
SkASSERT(1 == dinfo->rec_outbuf_height);
if (needs_swizzler_to_convert_from_cmyk(dinfo->out_color_space, this->getInfo(),
this->colorXform())) {
this->initializeSwizzler(dstInfo, options, true);
}
this->allocateStorage(dstInfo);
int rows = this->readRows(dstInfo, dst, dstRowBytes, dstInfo.height(), options);
if (rows < dstInfo.height()) {
*rowsDecoded = rows;
return fDecoderMgr->returnFailure("Incomplete image data", kIncompleteInput);
}
return kSuccess;
}
void SkJpegCodec::allocateStorage(const SkImageInfo& dstInfo) {
int dstWidth = dstInfo.width();
size_t swizzleBytes = 0;
if (fSwizzler) {
swizzleBytes = get_row_bytes(fDecoderMgr->dinfo());
dstWidth = fSwizzler->swizzleWidth();
SkASSERT(!this->colorXform() || SkIsAlign4(swizzleBytes));
}
size_t xformBytes = 0;
if (this->colorXform() && (kRGBA_F16_SkColorType == dstInfo.colorType() ||
kRGB_565_SkColorType == dstInfo.colorType())) {
xformBytes = dstWidth * sizeof(uint32_t);
}
size_t totalBytes = swizzleBytes + xformBytes;
if (totalBytes > 0) {
fStorage.reset(totalBytes);
fSwizzleSrcRow = (swizzleBytes > 0) ? fStorage.get() : nullptr;
fColorXformSrcRow = (xformBytes > 0) ?
SkTAddOffset<uint32_t>(fStorage.get(), swizzleBytes) : nullptr;
}
}
void SkJpegCodec::initializeSwizzler(const SkImageInfo& dstInfo, const Options& options,
bool needsCMYKToRGB) {
SkEncodedInfo swizzlerInfo = this->getEncodedInfo();
if (needsCMYKToRGB) {
swizzlerInfo = SkEncodedInfo::Make(SkEncodedInfo::kInvertedCMYK_Color,
swizzlerInfo.alpha(),
swizzlerInfo.bitsPerComponent());
}
Options swizzlerOptions = options;
if (options.fSubset) {
// Use fSwizzlerSubset if this is a subset decode. This is necessary in the case
// where libjpeg-turbo provides a subset and then we need to subset it further.
// Also, verify that fSwizzlerSubset is initialized and valid.
SkASSERT(!fSwizzlerSubset.isEmpty() && fSwizzlerSubset.x() <= options.fSubset->x() &&
fSwizzlerSubset.width() == options.fSubset->width());
swizzlerOptions.fSubset = &fSwizzlerSubset;
}
SkImageInfo swizzlerDstInfo = dstInfo;
if (this->colorXform()) {
// The color xform will be expecting RGBA 8888 input.
swizzlerDstInfo = swizzlerDstInfo.makeColorType(kRGBA_8888_SkColorType);
}
fSwizzler.reset(SkSwizzler::CreateSwizzler(swizzlerInfo, nullptr, swizzlerDstInfo,
swizzlerOptions, nullptr, !needsCMYKToRGB));
SkASSERT(fSwizzler);
}
SkSampler* SkJpegCodec::getSampler(bool createIfNecessary) {
if (!createIfNecessary || fSwizzler) {
SkASSERT(!fSwizzler || (fSwizzleSrcRow && fStorage.get() == fSwizzleSrcRow));
return fSwizzler.get();
}
bool needsCMYKToRGB = needs_swizzler_to_convert_from_cmyk(
fDecoderMgr->dinfo()->out_color_space, this->getInfo(), this->colorXform());
this->initializeSwizzler(this->dstInfo(), this->options(), needsCMYKToRGB);
this->allocateStorage(this->dstInfo());
return fSwizzler.get();
}
SkCodec::Result SkJpegCodec::onStartScanlineDecode(const SkImageInfo& dstInfo,
const Options& options) {
// Set the jump location for libjpeg errors
skjpeg_error_mgr::AutoPushJmpBuf jmp(fDecoderMgr->errorMgr());
if (setjmp(jmp)) {
SkCodecPrintf("setjmp: Error from libjpeg\n");
return kInvalidInput;
}
// Check if we can decode to the requested destination and set the output color space
if (!this->setOutputColorSpace(dstInfo)) {
return fDecoderMgr->returnFailure("setOutputColorSpace", kInvalidConversion);
}
if (!jpeg_start_decompress(fDecoderMgr->dinfo())) {
SkCodecPrintf("start decompress failed\n");
return kInvalidInput;
}
bool needsCMYKToRGB = needs_swizzler_to_convert_from_cmyk(
fDecoderMgr->dinfo()->out_color_space, this->getInfo(), this->colorXform());
if (options.fSubset) {
uint32_t startX = options.fSubset->x();
uint32_t width = options.fSubset->width();
// libjpeg-turbo may need to align startX to a multiple of the IDCT
// block size. If this is the case, it will decrease the value of
// startX to the appropriate alignment and also increase the value
// of width so that the right edge of the requested subset remains
// the same.
jpeg_crop_scanline(fDecoderMgr->dinfo(), &startX, &width);
SkASSERT(startX <= (uint32_t) options.fSubset->x());
SkASSERT(width >= (uint32_t) options.fSubset->width());
SkASSERT(startX + width >= (uint32_t) options.fSubset->right());
// Instruct the swizzler (if it is necessary) to further subset the
// output provided by libjpeg-turbo.
//
// We set this here (rather than in the if statement below), so that
// if (1) we don't need a swizzler for the subset, and (2) we need a
// swizzler for CMYK, the swizzler will still use the proper subset
// dimensions.
//
// Note that the swizzler will ignore the y and height parameters of
// the subset. Since the scanline decoder (and the swizzler) handle
// one row at a time, only the subsetting in the x-dimension matters.
fSwizzlerSubset.setXYWH(options.fSubset->x() - startX, 0,
options.fSubset->width(), options.fSubset->height());
// We will need a swizzler if libjpeg-turbo cannot provide the exact
// subset that we request.
if (startX != (uint32_t) options.fSubset->x() ||
width != (uint32_t) options.fSubset->width()) {
this->initializeSwizzler(dstInfo, options, needsCMYKToRGB);
}
}
// Make sure we have a swizzler if we are converting from CMYK.
if (!fSwizzler && needsCMYKToRGB) {
this->initializeSwizzler(dstInfo, options, true);
}
this->allocateStorage(dstInfo);
return kSuccess;
}
int SkJpegCodec::onGetScanlines(void* dst, int count, size_t dstRowBytes) {
int rows = this->readRows(this->dstInfo(), dst, dstRowBytes, count, this->options());
if (rows < count) {
// This allows us to skip calling jpeg_finish_decompress().
fDecoderMgr->dinfo()->output_scanline = this->dstInfo().height();
}
return rows;
}
bool SkJpegCodec::onSkipScanlines(int count) {
// Set the jump location for libjpeg errors
skjpeg_error_mgr::AutoPushJmpBuf jmp(fDecoderMgr->errorMgr());
if (setjmp(jmp)) {
return fDecoderMgr->returnFalse("onSkipScanlines");
}
return (uint32_t) count == jpeg_skip_scanlines(fDecoderMgr->dinfo(), count);
}
static bool is_yuv_supported(jpeg_decompress_struct* dinfo) {
// Scaling is not supported in raw data mode.
SkASSERT(dinfo->scale_num == dinfo->scale_denom);
// I can't imagine that this would ever change, but we do depend on it.
static_assert(8 == DCTSIZE, "DCTSIZE (defined in jpeg library) should always be 8.");
if (JCS_YCbCr != dinfo->jpeg_color_space) {
return false;
}
SkASSERT(3 == dinfo->num_components);
SkASSERT(dinfo->comp_info);
// It is possible to perform a YUV decode for any combination of
// horizontal and vertical sampling that is supported by
// libjpeg/libjpeg-turbo. However, we will start by supporting only the
// common cases (where U and V have samp_factors of one).
//
// The definition of samp_factor is kind of the opposite of what SkCodec
// thinks of as a sampling factor. samp_factor is essentially a
// multiplier, and the larger the samp_factor is, the more samples that
// there will be. Ex:
// U_plane_width = image_width * (U_h_samp_factor / max_h_samp_factor)
//
// Supporting cases where the samp_factors for U or V were larger than
// that of Y would be an extremely difficult change, given that clients
// allocate memory as if the size of the Y plane is always the size of the
// image. However, this case is very, very rare.
if ((1 != dinfo->comp_info[1].h_samp_factor) ||
(1 != dinfo->comp_info[1].v_samp_factor) ||
(1 != dinfo->comp_info[2].h_samp_factor) ||
(1 != dinfo->comp_info[2].v_samp_factor))
{
return false;
}
// Support all common cases of Y samp_factors.
// TODO (msarett): As mentioned above, it would be possible to support
// more combinations of samp_factors. The issues are:
// (1) Are there actually any images that are not covered
// by these cases?
// (2) How much complexity would be added to the
// implementation in order to support these rare
// cases?
int hSampY = dinfo->comp_info[0].h_samp_factor;
int vSampY = dinfo->comp_info[0].v_samp_factor;
return (1 == hSampY && 1 == vSampY) ||
(2 == hSampY && 1 == vSampY) ||
(2 == hSampY && 2 == vSampY) ||
(1 == hSampY && 2 == vSampY) ||
(4 == hSampY && 1 == vSampY) ||
(4 == hSampY && 2 == vSampY);
}
bool SkJpegCodec::onQueryYUV8(SkYUVSizeInfo* sizeInfo, SkYUVColorSpace* colorSpace) const {
jpeg_decompress_struct* dinfo = fDecoderMgr->dinfo();
if (!is_yuv_supported(dinfo)) {
return false;
}
jpeg_component_info * comp_info = dinfo->comp_info;
for (auto i : { SkYUVSizeInfo::kY, SkYUVSizeInfo::kU, SkYUVSizeInfo::kV }) {
sizeInfo->fSizes[i].set(comp_info[i].downsampled_width, comp_info[i].downsampled_height);
sizeInfo->fWidthBytes[i] = comp_info[i].width_in_blocks * DCTSIZE;
}
if (colorSpace) {
*colorSpace = kJPEG_SkYUVColorSpace;
}
return true;
}
SkCodec::Result SkJpegCodec::onGetYUV8Planes(const SkYUVSizeInfo& sizeInfo, void* planes[3]) {
SkYUVSizeInfo defaultInfo;
// This will check is_yuv_supported(), so we don't need to here.
bool supportsYUV = this->onQueryYUV8(&defaultInfo, nullptr);
if (!supportsYUV ||
sizeInfo.fSizes[SkYUVSizeInfo::kY] != defaultInfo.fSizes[SkYUVSizeInfo::kY] ||
sizeInfo.fSizes[SkYUVSizeInfo::kU] != defaultInfo.fSizes[SkYUVSizeInfo::kU] ||
sizeInfo.fSizes[SkYUVSizeInfo::kV] != defaultInfo.fSizes[SkYUVSizeInfo::kV] ||
sizeInfo.fWidthBytes[SkYUVSizeInfo::kY] < defaultInfo.fWidthBytes[SkYUVSizeInfo::kY] ||
sizeInfo.fWidthBytes[SkYUVSizeInfo::kU] < defaultInfo.fWidthBytes[SkYUVSizeInfo::kU] ||
sizeInfo.fWidthBytes[SkYUVSizeInfo::kV] < defaultInfo.fWidthBytes[SkYUVSizeInfo::kV]) {
return fDecoderMgr->returnFailure("onGetYUV8Planes", kInvalidInput);
}
// Set the jump location for libjpeg errors
skjpeg_error_mgr::AutoPushJmpBuf jmp(fDecoderMgr->errorMgr());
if (setjmp(jmp)) {
return fDecoderMgr->returnFailure("setjmp", kInvalidInput);
}
// Get a pointer to the decompress info since we will use it quite frequently
jpeg_decompress_struct* dinfo = fDecoderMgr->dinfo();
dinfo->raw_data_out = TRUE;
if (!jpeg_start_decompress(dinfo)) {
return fDecoderMgr->returnFailure("startDecompress", kInvalidInput);
}
// A previous implementation claims that the return value of is_yuv_supported()
// may change after calling jpeg_start_decompress(). It looks to me like this
// was caused by a bug in the old code, but we'll be safe and check here.
SkASSERT(is_yuv_supported(dinfo));
// Currently, we require that the Y plane dimensions match the image dimensions
// and that the U and V planes are the same dimensions.
SkASSERT(sizeInfo.fSizes[SkYUVSizeInfo::kU] == sizeInfo.fSizes[SkYUVSizeInfo::kV]);
SkASSERT((uint32_t) sizeInfo.fSizes[SkYUVSizeInfo::kY].width() == dinfo->output_width &&
(uint32_t) sizeInfo.fSizes[SkYUVSizeInfo::kY].height() == dinfo->output_height);
// Build a JSAMPIMAGE to handle output from libjpeg-turbo. A JSAMPIMAGE has
// a 2-D array of pixels for each of the components (Y, U, V) in the image.
// Cheat Sheet:
// JSAMPIMAGE == JSAMPLEARRAY* == JSAMPROW** == JSAMPLE***
JSAMPARRAY yuv[3];
// Set aside enough space for pointers to rows of Y, U, and V.
JSAMPROW rowptrs[2 * DCTSIZE + DCTSIZE + DCTSIZE];
yuv[0] = &rowptrs[0]; // Y rows (DCTSIZE or 2 * DCTSIZE)
yuv[1] = &rowptrs[2 * DCTSIZE]; // U rows (DCTSIZE)
yuv[2] = &rowptrs[3 * DCTSIZE]; // V rows (DCTSIZE)
// Initialize rowptrs.
int numYRowsPerBlock = DCTSIZE * dinfo->comp_info[0].v_samp_factor;
for (int i = 0; i < numYRowsPerBlock; i++) {
rowptrs[i] = SkTAddOffset<JSAMPLE>(planes[SkYUVSizeInfo::kY],
i * sizeInfo.fWidthBytes[SkYUVSizeInfo::kY]);
}
for (int i = 0; i < DCTSIZE; i++) {
rowptrs[i + 2 * DCTSIZE] = SkTAddOffset<JSAMPLE>(planes[SkYUVSizeInfo::kU],
i * sizeInfo.fWidthBytes[SkYUVSizeInfo::kU]);
rowptrs[i + 3 * DCTSIZE] = SkTAddOffset<JSAMPLE>(planes[SkYUVSizeInfo::kV],
i * sizeInfo.fWidthBytes[SkYUVSizeInfo::kV]);
}
// After each loop iteration, we will increment pointers to Y, U, and V.
size_t blockIncrementY = numYRowsPerBlock * sizeInfo.fWidthBytes[SkYUVSizeInfo::kY];
size_t blockIncrementU = DCTSIZE * sizeInfo.fWidthBytes[SkYUVSizeInfo::kU];
size_t blockIncrementV = DCTSIZE * sizeInfo.fWidthBytes[SkYUVSizeInfo::kV];
uint32_t numRowsPerBlock = numYRowsPerBlock;
// We intentionally round down here, as this first loop will only handle
// full block rows. As a special case at the end, we will handle any
// remaining rows that do not make up a full block.
const int numIters = dinfo->output_height / numRowsPerBlock;
for (int i = 0; i < numIters; i++) {
JDIMENSION linesRead = jpeg_read_raw_data(dinfo, yuv, numRowsPerBlock);
if (linesRead < numRowsPerBlock) {
// FIXME: Handle incomplete YUV decodes without signalling an error.
return kInvalidInput;
}
// Update rowptrs.
for (int i = 0; i < numYRowsPerBlock; i++) {
rowptrs[i] += blockIncrementY;
}
for (int i = 0; i < DCTSIZE; i++) {
rowptrs[i + 2 * DCTSIZE] += blockIncrementU;
rowptrs[i + 3 * DCTSIZE] += blockIncrementV;
}
}
uint32_t remainingRows = dinfo->output_height - dinfo->output_scanline;
SkASSERT(remainingRows == dinfo->output_height % numRowsPerBlock);
SkASSERT(dinfo->output_scanline == numIters * numRowsPerBlock);
if (remainingRows > 0) {
// libjpeg-turbo needs memory to be padded by the block sizes. We will fulfill
// this requirement using a dummy row buffer.
// FIXME: Should SkCodec have an extra memory buffer that can be shared among
// all of the implementations that use temporary/garbage memory?
SkAutoTMalloc<JSAMPLE> dummyRow(sizeInfo.fWidthBytes[SkYUVSizeInfo::kY]);
for (int i = remainingRows; i < numYRowsPerBlock; i++) {
rowptrs[i] = dummyRow.get();
}
int remainingUVRows = dinfo->comp_info[1].downsampled_height - DCTSIZE * numIters;
for (int i = remainingUVRows; i < DCTSIZE; i++) {
rowptrs[i + 2 * DCTSIZE] = dummyRow.get();
rowptrs[i + 3 * DCTSIZE] = dummyRow.get();
}
JDIMENSION linesRead = jpeg_read_raw_data(dinfo, yuv, numRowsPerBlock);
if (linesRead < remainingRows) {
// FIXME: Handle incomplete YUV decodes without signalling an error.
return kInvalidInput;
}
}
return kSuccess;
}