SkJpegSegmentScanner Class Reference

#include <SkJpegSegmentScan.h>

Public Member Functions
	SkJpegSegmentScanner (uint8_t stopMarker=kJpegMarkerEndOfImage)
bool	isDone () const
bool	hadError () const
void	onBytes (const void *data, size_t size)
const std::vector< SkJpegSegment > &	getSegments () const

Static Public Member Functions
static sk_sp< SkData >	GetParameters (const SkData *scannedData, const SkJpegSegment &segment)

Detailed Description

Definition at line 39 of file SkJpegSegmentScan.h.

Constructor & Destructor Documentation

SkJpegSegmentScanner()

SkJpegSegmentScanner::SkJpegSegmentScanner

(

uint8_t

stopMarker = kJpegMarkerEndOfImage

)

Definition at line 22 of file SkJpegSegmentScan.cpp.

: fStopMarker(stopMarker) {}

Member Function Documentation

GetParameters()

sk_sp< SkData > SkJpegSegmentScanner::GetParameters ( const SkData *  scannedData, const SkJpegSegment &  segment  )

static

Definition at line 26 of file SkJpegSegmentScan.cpp.

                                                                                {
    return SkData::MakeSubset(
            scannedData,
            segment.offset + kJpegMarkerCodeSize + kJpegSegmentParameterLengthSize,
            segment.parameterLength - kJpegSegmentParameterLengthSize);
}

getSegments()

const std::vector< SkJpegSegment > & SkJpegSegmentScanner::getSegments

(

)

const

Definition at line 24 of file SkJpegSegmentScan.cpp.

{ return fSegments; }

hadError()

bool SkJpegSegmentScanner::hadError ( ) const

inline

Definition at line 44 of file SkJpegSegmentScan.h.

{ return fState == State::kError; }

isDone()

bool SkJpegSegmentScanner::isDone ( ) const

inline

Definition at line 43 of file SkJpegSegmentScan.h.

{ return fState == State::kDone; }

onBytes()

void SkJpegSegmentScanner::onBytes	(	const void *	data,
		size_t	size
	)

Definition at line 34 of file SkJpegSegmentScan.cpp.

                                                                {
    const uint8_t* bytes = reinterpret_cast<const uint8_t*>(data);
    size_t bytesRemaining = size;
 
    while (bytesRemaining > 0) {
        // Process the data byte-by-byte, unless we are in kSegmentParam or kEntropyCodedData, in
        // which case, perform some optimizations to avoid examining every byte.
        size_t bytesToMoveForward = 0;
        switch (fState) {
            case State::kSegmentParam: {
                // Skip forward through payloads.
                SkASSERT(fSegmentParamBytesRemaining > 0);
                bytesToMoveForward = std::min(fSegmentParamBytesRemaining, bytesRemaining);
                fSegmentParamBytesRemaining -= bytesToMoveForward;
                if (fSegmentParamBytesRemaining == 0) {
                    fState = State::kEntropyCodedData;
                }
                break;
            }
            case State::kEntropyCodedData: {
                // Skip through entropy-coded data, only looking at sentinel characters.
                const uint8_t* sentinel =
                        reinterpret_cast<const uint8_t*>(memchr(bytes, 0xFF, bytesRemaining));
                if (sentinel) {
                    bytesToMoveForward = (sentinel - bytes) + 1;
                    fState = State::kEntropyCodedDataSentinel;
                } else {
                    bytesToMoveForward = bytesRemaining;
                }
                break;
            }
            case State::kDone:
                // Skip all data after we have hit our stop marker.
                bytesToMoveForward = bytesRemaining;
                break;
            default: {
                onByte(*bytes);
                bytesToMoveForward = 1;
                break;
            }
        }
        SkASSERT(bytesToMoveForward > 0);
        fOffset += bytesToMoveForward;
        bytes += bytesToMoveForward;
        bytesRemaining -= bytesToMoveForward;
    }
}

---

The documentation for this class was generated from the following files:

• third_party/skia/src/codec/SkJpegSegmentScan.h
• third_party/skia/src/codec/SkJpegSegmentScan.cpp