SkStream Class Reference

#include <SkStream.h>

Inheritance diagram for SkStream:

Public Member Functions
virtual	~SkStream ()
	SkStream ()
virtual size_t	read (void *buffer, size_t size)=0
size_t	skip (size_t size)
virtual size_t	peek (void *, size_t) const
virtual bool	isAtEnd () const =0
bool	readS8 (int8_t *)
bool	readS16 (int16_t *)
bool	readS32 (int32_t *)
bool	readU8 (uint8_t *i)
bool	readU16 (uint16_t *i)
bool	readU32 (uint32_t *i)
bool	readBool (bool *b)
bool	readScalar (SkScalar *)
bool	readPackedUInt (size_t *)
virtual bool	rewind ()
std::unique_ptr< SkStream >	duplicate () const
std::unique_ptr< SkStream >	fork () const
virtual bool	hasPosition () const
virtual size_t	getPosition () const
virtual bool	seek (size_t)
virtual bool	move (long)
virtual bool	hasLength () const
virtual size_t	getLength () const
virtual const void *	getMemoryBase ()
virtual sk_sp< SkData >	getData () const

Static Public Member Functions
static std::unique_ptr< SkStreamAsset >	MakeFromFile (const char path[])

Private Member Functions
virtual SkStream *	onDuplicate () const
virtual SkStream *	onFork () const

Detailed Description

SkStream – abstraction for a source of bytes. Subclasses can be backed by memory, or a file, or something else.

Definition at line 29 of file SkStream.h.

Constructor & Destructor Documentation

~SkStream()

virtual SkStream::~SkStream ( )

inlinevirtual

Definition at line 31 of file SkStream.h.

{}

SkStream()

SkStream::SkStream ( )

inline

Definition at line 32 of file SkStream.h.

{}

Member Function Documentation

duplicate()

std::unique_ptr< SkStream > SkStream::duplicate ( ) const

inline

Duplicates this stream. If this cannot be done, returns NULL. The returned stream will be positioned at the beginning of its data.

Definition at line 105 of file SkStream.h.

                                              {
        return std::unique_ptr<SkStream>(this->onDuplicate());
    }

fork()

std::unique_ptr< SkStream > SkStream::fork ( ) const

inline

Duplicates this stream. If this cannot be done, returns NULL. The returned stream will be positioned the same as this stream.

Definition at line 111 of file SkStream.h.

                                         {
        return std::unique_ptr<SkStream>(this->onFork());
    }

getData()

virtual sk_sp< SkData > SkStream::getData ( ) const

inlinevirtual

Reimplemented in SkMemoryStream.

Definition at line 142 of file SkStream.h.

{ return nullptr; }

getLength()

virtual size_t SkStream::getLength ( ) const

inlinevirtual

Returns the total length of the stream. If this cannot be done, returns 0.

Reimplemented in SkFILEStream, SkMemoryStream, SkBlockMemoryStream, SkDWriteFontFileStream, HaltingStream, and SkStreamAsset.

Definition at line 137 of file SkStream.h.

{ return 0; }

getMemoryBase()

virtual const void * SkStream::getMemoryBase ( )

inlinevirtual

Returns the starting address for the data. If this cannot be done, returns NULL.

Reimplemented in SkMemoryStream, SkBlockMemoryStream, SkDWriteFontFileStream, and SkStreamMemory.

Definition at line 141 of file SkStream.h.

{ return nullptr; }

getPosition()

virtual size_t SkStream::getPosition ( ) const

inlinevirtual

Returns the current position in the stream. If this cannot be done, returns 0.

Reimplemented in SkFILEStream, SkMemoryStream, SkBlockMemoryStream, SkDWriteFontFileStream, HaltingStream, and SkStreamSeekable.

Definition at line 119 of file SkStream.h.

{ return 0; }

hasLength()

virtual bool SkStream::hasLength ( ) const

inlinevirtual

Returns true if this stream can report its total length.

Reimplemented in SkStreamAsset, NotAssetMemStream, and HaltingStream.

Definition at line 135 of file SkStream.h.

{ return false; }

hasPosition()

virtual bool SkStream::hasPosition ( ) const

inlinevirtual

Returns true if this stream can report its current position.

Reimplemented in SkStreamSeekable, NotAssetMemStream, and HaltingStream.

Definition at line 117 of file SkStream.h.

{ return false; }

isAtEnd()

virtual bool SkStream::isAtEnd ( ) const

pure virtual

Returns true when all the bytes in the stream have been read. As SkStream represents synchronous I/O, isAtEnd returns false when the final stream length isn't known yet, even when all the bytes available so far have been read. This may return true early (when there are no more bytes to be read) or late (after the first unsuccessful read).

Implemented in SkFILEStream, SkMemoryStream, SkBlockMemoryStream, SkDWriteFontFileStream, LimitedPeekingMemStream, LimitedRewindingStream, NotAssetMemStream, and HaltingStream.

MakeFromFile()

std::unique_ptr< SkStreamAsset > SkStream::MakeFromFile ( const char  path[] )

static

Attempts to open the specified file as a stream, returns nullptr on failure.

Definition at line 922 of file SkStream.cpp.

                                                                     {
    auto data(mmap_filename(path));
    if (data) {
        return std::make_unique<SkMemoryStream>(std::move(data));
    }
 
    // If we get here, then our attempt at using mmap failed, so try normal file access.
    auto stream = std::make_unique<SkFILEStream>(path);
    if (!stream->isValid()) {
        return nullptr;
    }
    return stream;
}

move()

virtual bool SkStream::move ( long  )

inlinevirtual

Seeks to an relative offset in the stream. If this cannot be done, returns false. If an attempt is made to move to a position outside the stream, the position will be set to the closest point within the stream (beginning or end).

Reimplemented in SkFILEStream, SkMemoryStream, SkBlockMemoryStream, SkDWriteFontFileStream, HaltingStream, and SkStreamSeekable.

Definition at line 131 of file SkStream.h.

{ return false; }

onDuplicate()

virtual SkStream * SkStream::onDuplicate ( ) const

inlineprivatevirtual

Reimplemented in SkBlockMemoryStream, SkStreamRewindable, SkStreamSeekable, SkStreamAsset, and SkStreamMemory.

Definition at line 145 of file SkStream.h.

{ return nullptr; }

onFork()

virtual SkStream * SkStream::onFork ( ) const

inlineprivatevirtual

Reimplemented in SkBlockMemoryStream, SkStreamSeekable, SkStreamAsset, and SkStreamMemory.

Definition at line 146 of file SkStream.h.

{ return nullptr; }

peek()

virtual size_t SkStream::peek ( void *  , size_t    ) const

inlinevirtual

Attempt to peek at size bytes. If this stream supports peeking, copy min(size, peekable bytes) into buffer, and return the number of bytes copied. If the stream does not support peeking, or cannot peek any bytes, return 0 and leave buffer unchanged. The stream is guaranteed to be in the same visible state after this call, regardless of success or failure.

Parameters

buffer	Must not be NULL, and must be at least size bytes. Destination to copy bytes.
size	Number of bytes to copy.

Returns

The number of bytes peeked/copied.

Reimplemented in LimitedPeekingMemStream, NotAssetMemStream, SkBlockMemoryStream, and SkMemoryStream.

Definition at line 68 of file SkStream.h.

{ return 0; }

read()

virtual size_t SkStream::read ( void *  buffer, size_t  size  )

pure virtual

Reads or skips size number of bytes. If buffer == NULL, skip size bytes, return how many were skipped. If buffer != NULL, copy size bytes into buffer, return how many were copied.

Parameters

buffer	when NULL skip size bytes, otherwise copy size bytes into buffer
size	the number of bytes to skip or copy

Returns

the number of bytes actually read.

Implemented in LimitedPeekingMemStream, NotAssetMemStream, SkBlockMemoryStream, SkFILEStream, SkMemoryStream, SkDWriteFontFileStream, LimitedRewindingStream, and HaltingStream.

readBool()

bool SkStream::readBool ( bool *  b )

inline

Definition at line 87 of file SkStream.h.

                                         {
        uint8_t i;
        if (!this->readU8(&i)) { return false; }
        *b = (i != 0);
        return true;
    }

readPackedUInt()

bool SkStream::readPackedUInt

(

size_t *

i

)

Definition at line 52 of file SkStream.cpp.

                                       {
    uint8_t byte;
    if (!this->read(&byte, 1)) {
        return false;
    }
    if (SK_BYTE_SENTINEL_FOR_U16 == byte) {
        uint16_t i16;
        if (!this->readU16(&i16)) { return false; }
        *i = i16;
    } else if (SK_BYTE_SENTINEL_FOR_U32 == byte) {
        uint32_t i32;
        if (!this->readU32(&i32)) { return false; }
        *i = i32;
    } else {
        *i = byte;
    }
    return true;
}

readS16()

bool SkStream::readS16

(

int16_t *

i

)

Definition at line 36 of file SkStream.cpp.

                                 {
    return this->read(i, sizeof(*i)) == sizeof(*i);
}

readS32()

bool SkStream::readS32

(

int32_t *

i

)

Definition at line 40 of file SkStream.cpp.

                                 {
    return this->read(i, sizeof(*i)) == sizeof(*i);
}

readS8()

bool SkStream::readS8

(

int8_t *

i

)

Definition at line 32 of file SkStream.cpp.

                               {
    return this->read(i, sizeof(*i)) == sizeof(*i);
}

readScalar()

bool SkStream::readScalar

(

SkScalar *

i

)

Definition at line 44 of file SkStream.cpp.

                                     {
    return this->read(i, sizeof(*i)) == sizeof(*i);
}

readU16()

bool SkStream::readU16 ( uint16_t *  i )

inline

Definition at line 84 of file SkStream.h.

{ return this->readS16((int16_t*)i); }

readU32()

bool SkStream::readU32 ( uint32_t *  i )

inline

Definition at line 85 of file SkStream.h.

{ return this->readS32((int32_t*)i); }

readU8()

bool SkStream::readU8 ( uint8_t *  i )

inline

Definition at line 83 of file SkStream.h.

{ return this->readS8((int8_t*)i); }

rewind()

virtual bool SkStream::rewind ( )

inlinevirtual

Rewinds to the beginning of the stream. Returns true if the stream is known to be at the beginning after this call returns.

Reimplemented in SkFILEStream, SkMemoryStream, SkBlockMemoryStream, SkDWriteFontFileStream, LimitedPeekingMemStream, LimitedRewindingStream, NotAssetMemStream, NonseekableStream, HaltingStream, and SkStreamRewindable.

Definition at line 100 of file SkStream.h.

{ return false; }

seek()

virtual bool SkStream::seek ( size_t  )

inlinevirtual

Seeks to an absolute position in the stream. If this cannot be done, returns false. If an attempt is made to seek past the end of the stream, the position will be set to the end of the stream.

Reimplemented in SkFILEStream, SkMemoryStream, SkBlockMemoryStream, SkDWriteFontFileStream, HaltingStream, SkStreamSeekable, and NonseekableStream.

Definition at line 125 of file SkStream.h.

{ return false; }

skip()

size_t SkStream::skip ( size_t  size )

inline

Skip size number of bytes.

Returns

the actual number bytes that could be skipped.

Definition at line 51 of file SkStream.h.

                             {
        return this->read(nullptr, size);
    }

---

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

• third_party/skia/include/core/SkStream.h
• third_party/skia/src/core/SkStream.cpp