AutoCleanPng Class Reference

Inheritance diagram for AutoCleanPng:

Public Member Functions
	AutoCleanPng (png_structp png_ptr, SkStream *stream, SkPngChunkReader *reader, SkCodec **codecPtr)
	~AutoCleanPng ()
void	setInfoPtr (png_infop info_ptr)
bool	decodeBounds ()
Public Member Functions inherited from SkNoncopyable
	SkNoncopyable ()=default
	SkNoncopyable (SkNoncopyable &&)=default
SkNoncopyable &	operator= (SkNoncopyable &&)=default

Detailed Description

Definition at line 88 of file SkPngCodec.cpp.

Constructor & Destructor Documentation

AutoCleanPng()

AutoCleanPng::AutoCleanPng ( png_structp  png_ptr, SkStream *  stream, SkPngChunkReader *  reader, SkCodec **  codecPtr  )

inline

Definition at line 96 of file SkPngCodec.cpp.

        : fPng_ptr(png_ptr)
        , fInfo_ptr(nullptr)
        , fStream(stream)
        , fChunkReader(reader)
        , fOutCodec(codecPtr)
    {}

~AutoCleanPng()

AutoCleanPng::~AutoCleanPng ( )

inline

Definition at line 105 of file SkPngCodec.cpp.

                    {
        // fInfo_ptr will never be non-nullptr unless fPng_ptr is.
        if (fPng_ptr) {
            png_infopp info_pp = fInfo_ptr ? &fInfo_ptr : nullptr;
            png_destroy_read_struct(&fPng_ptr, info_pp, nullptr);
        }
    }

Member Function Documentation

decodeBounds()

bool AutoCleanPng::decodeBounds

(

)

Reads enough of the input stream to decode the bounds.

Returns

false if the stream is not a valid PNG (or too short). true if it read enough of the stream to determine the bounds. In the latter case, the stream may have been read beyond the point to determine the bounds, and the png_ptr will have saved any extra data. Further, if the codecPtr supplied to the constructor was not NULL, it will now point to a new SkCodec, which owns (or refs, in the case of the SkPngChunkReader) the inputs. If codecPtr was NULL, the png_ptr and info_ptr are unowned, and it is up to the caller to destroy them.

Definition at line 165 of file SkPngCodec.cpp.

                                {
    SkASSERT(fStream);
    if (setjmp(PNG_JMPBUF(fPng_ptr))) {
        return false;
    }
 
    png_set_progressive_read_fn(fPng_ptr, nullptr, nullptr, nullptr, nullptr);
 
    // Arbitrary buffer size, though note that it matches (below)
    // SkPngCodec::processData(). FIXME: Can we better suit this to the size of
    // the PNG header?
    constexpr size_t kBufferSize = 4096;
    char buffer[kBufferSize];
 
    {
        // Parse the signature.
        if (fStream->read(buffer, 8) < 8) {
            return false;
        }
 
        png_process_data(fPng_ptr, fInfo_ptr, (png_bytep) buffer, 8);
    }
 
    while (true) {
        // Parse chunk length and type.
        if (fStream->read(buffer, 8) < 8) {
            // We have read to the end of the input without decoding bounds.
            break;
        }
 
        png_byte* chunk = reinterpret_cast<png_byte*>(buffer);
        const size_t length = png_get_uint_32(chunk);
 
        if (is_chunk(chunk, "IDAT")) {
            this->infoCallback(length);
            return true;
        }
 
        png_process_data(fPng_ptr, fInfo_ptr, chunk, 8);
        // Process the full chunk + CRC.
        if (!process_data(fPng_ptr, fInfo_ptr, fStream, buffer, kBufferSize, length + 4)) {
            return false;
        }
    }
 
    return false;
}

setInfoPtr()

void AutoCleanPng::setInfoPtr ( png_infop  info_ptr )

inline

Definition at line 113 of file SkPngCodec.cpp.

                                        {
        SkASSERT(nullptr == fInfo_ptr);
        fInfo_ptr = info_ptr;
    }

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

• third_party/skia/src/codec/SkPngCodec.cpp