/*
* Copyright 2006 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkStream_DEFINED
#define SkStream_DEFINED
#include "SkData.h"
#include "SkRefCnt.h"
#include "SkScalar.h"
#include <memory.h>
class SkStream;
class SkStreamRewindable;
class SkStreamSeekable;
class SkStreamAsset;
class SkStreamMemory;
/**
* SkStream -- abstraction for a source of bytes. Subclasses can be backed by
* memory, or a file, or something else.
*
* NOTE:
*
* Classic "streams" APIs are sort of async, in that on a request for N
* bytes, they may return fewer than N bytes on a given call, in which case
* the caller can "try again" to get more bytes, eventually (modulo an error)
* receiving their total N bytes.
*
* Skia streams behave differently. They are effectively synchronous, and will
* always return all N bytes of the request if possible. If they return fewer
* (the read() call returns the number of bytes read) then that means there is
* no more data (at EOF or hit an error). The caller should *not* call again
* in hopes of fulfilling more of the request.
*/
class SK_API SkStream : public SkNoncopyable {
public:
virtual ~SkStream() {}
/**
* Attempts to open the specified file as a stream, returns nullptr on failure.
*/
static std::unique_ptr<SkStreamAsset> MakeFromFile(const char path[]);
/** 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.
* @param buffer when NULL skip size bytes, otherwise copy size bytes into buffer
* @param size the number of bytes to skip or copy
* @return the number of bytes actually read.
*/
virtual size_t read(void* buffer, size_t size) = 0;
/** Skip size number of bytes.
* @return the actual number bytes that could be skipped.
*/
size_t skip(size_t size) {
return this->read(nullptr, size);
}
/**
* 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.
* @param buffer Must not be NULL, and must be at least size bytes. Destination
* to copy bytes.
* @param size Number of bytes to copy.
* @return The number of bytes peeked/copied.
*/
virtual size_t peek(void* /*buffer*/, size_t /*size*/) const { return 0; }
/** Returns true when all the bytes in the stream have been read.
* This may return true early (when there are no more bytes to be read)
* or late (after the first unsuccessful read).
*/
virtual bool isAtEnd() const = 0;
int8_t readS8();
int16_t readS16();
int32_t readS32();
uint8_t readU8() { return (uint8_t)this->readS8(); }
uint16_t readU16() { return (uint16_t)this->readS16(); }
uint32_t readU32() { return (uint32_t)this->readS32(); }
bool readBool() { return this->readU8() != 0; }
SkScalar readScalar();
size_t readPackedUInt();
//SkStreamRewindable
/** Rewinds to the beginning of the stream. Returns true if the stream is known
* to be at the beginning after this call returns.
*/
virtual bool rewind() { return false; }
/** Duplicates this stream. If this cannot be done, returns NULL.
* The returned stream will be positioned at the beginning of its data.
*/
std::unique_ptr<SkStream> duplicate() const {
return std::unique_ptr<SkStream>(this->onDuplicate());
}
/** Duplicates this stream. If this cannot be done, returns NULL.
* The returned stream will be positioned the same as this stream.
*/
std::unique_ptr<SkStream> fork() const {
return std::unique_ptr<SkStream>(this->onFork());
}
//SkStreamSeekable
/** Returns true if this stream can report it's current position. */
virtual bool hasPosition() const { return false; }
/** Returns the current position in the stream. If this cannot be done, returns 0. */
virtual size_t getPosition() const { return 0; }
/** 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.
*/
virtual bool seek(size_t /*position*/) { return false; }
/** 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).
*/
virtual bool move(long /*offset*/) { return false; }
//SkStreamAsset
/** Returns true if this stream can report it's total length. */
virtual bool hasLength() const { return false; }
/** Returns the total length of the stream. If this cannot be done, returns 0. */
virtual size_t getLength() const { return 0; }
//SkStreamMemory
/** Returns the starting address for the data. If this cannot be done, returns NULL. */
//TODO: replace with virtual const SkData* getData()
virtual const void* getMemoryBase() { return nullptr; }
private:
virtual SkStream* onDuplicate() const { return nullptr; }
virtual SkStream* onFork() const { return nullptr; }
};
/** SkStreamRewindable is a SkStream for which rewind and duplicate are required. */
class SK_API SkStreamRewindable : public SkStream {
public:
bool rewind() override = 0;
std::unique_ptr<SkStreamRewindable> duplicate() const {
return std::unique_ptr<SkStreamRewindable>(this->onDuplicate());
}
private:
SkStreamRewindable* onDuplicate() const override = 0;
};
/** SkStreamSeekable is a SkStreamRewindable for which position, seek, move, and fork are required. */
class SK_API SkStreamSeekable : public SkStreamRewindable {
public:
std::unique_ptr<SkStreamSeekable> duplicate() const {
return std::unique_ptr<SkStreamSeekable>(this->onDuplicate());
}
bool hasPosition() const override { return true; }
size_t getPosition() const override = 0;
bool seek(size_t position) override = 0;
bool move(long offset) override = 0;
std::unique_ptr<SkStreamSeekable> fork() const {
return std::unique_ptr<SkStreamSeekable>(this->onFork());
}
private:
SkStreamSeekable* onDuplicate() const override = 0;
SkStreamSeekable* onFork() const override = 0;
};
/** SkStreamAsset is a SkStreamSeekable for which getLength is required. */
class SK_API SkStreamAsset : public SkStreamSeekable {
public:
bool hasLength() const override { return true; }
size_t getLength() const override = 0;
std::unique_ptr<SkStreamAsset> duplicate() const {
return std::unique_ptr<SkStreamAsset>(this->onDuplicate());
}
std::unique_ptr<SkStreamAsset> fork() const {
return std::unique_ptr<SkStreamAsset>(this->onFork());
}
private:
SkStreamAsset* onDuplicate() const override = 0;
SkStreamAsset* onFork() const override = 0;
};
/** SkStreamMemory is a SkStreamAsset for which getMemoryBase is required. */
class SK_API SkStreamMemory : public SkStreamAsset {
public:
const void* getMemoryBase() override = 0;
std::unique_ptr<SkStreamMemory> duplicate() const {
return std::unique_ptr<SkStreamMemory>(this->onDuplicate());
}
std::unique_ptr<SkStreamMemory> fork() const {
return std::unique_ptr<SkStreamMemory>(this->onFork());
}
private:
SkStreamMemory* onDuplicate() const override = 0;
SkStreamMemory* onFork() const override = 0;
};
class SK_API SkWStream : SkNoncopyable {
public:
virtual ~SkWStream();
/** Called to write bytes to a SkWStream. Returns true on success
@param buffer the address of at least size bytes to be written to the stream
@param size The number of bytes in buffer to write to the stream
@return true on success
*/
virtual bool write(const void* buffer, size_t size) = 0;
virtual void flush();
virtual size_t bytesWritten() const = 0;
// helpers
bool write8(U8CPU value) {
uint8_t v = SkToU8(value);
return this->write(&v, 1);
}
bool write16(U16CPU value) {
uint16_t v = SkToU16(value);
return this->write(&v, 2);
}
bool write32(uint32_t v) {
return this->write(&v, 4);
}
bool writeText(const char text[]) {
SkASSERT(text);
return this->write(text, strlen(text));
}
bool newline() { return this->write("\n", strlen("\n")); }
bool writeDecAsText(int32_t);
bool writeBigDecAsText(int64_t, int minDigits = 0);
bool writeHexAsText(uint32_t, int minDigits = 0);
bool writeScalarAsText(SkScalar);
bool writeBool(bool v) { return this->write8(v); }
bool writeScalar(SkScalar);
bool writePackedUInt(size_t);
bool writeStream(SkStream* input, size_t length);
/**
* This returns the number of bytes in the stream required to store
* 'value'.
*/
static int SizeOfPackedUInt(size_t value);
};
class SK_API SkNullWStream : public SkWStream {
public:
SkNullWStream() : fBytesWritten(0) {}
bool write(const void*, size_t n) override { fBytesWritten += n; return true; }
void flush() override {}
size_t bytesWritten() const override { return fBytesWritten; }
private:
size_t fBytesWritten;
};
////////////////////////////////////////////////////////////////////////////////////////
#include <stdio.h>
/** A stream that wraps a C FILE* file stream. */
class SK_API SkFILEStream : public SkStreamAsset {
public:
/** Initialize the stream by calling sk_fopen on the specified path.
* This internal stream will be closed in the destructor.
*/
explicit SkFILEStream(const char path[] = nullptr);
/** Initialize the stream with an existing C FILE stream.
* The current position of the C FILE stream will be considered the
* beginning of the SkFILEStream.
* The C FILE stream will be closed in the destructor.
*/
explicit SkFILEStream(FILE* file);
~SkFILEStream() override;
static std::unique_ptr<SkFILEStream> Make(const char path[]) {
std::unique_ptr<SkFILEStream> stream(new SkFILEStream(path));
return stream->isValid() ? std::move(stream) : nullptr;
}
/** Returns true if the current path could be opened. */
bool isValid() const { return fFILE != nullptr; }
/** Close this SkFILEStream. */
void close();
size_t read(void* buffer, size_t size) override;
bool isAtEnd() const override;
bool rewind() override;
std::unique_ptr<SkStreamAsset> duplicate() const {
return std::unique_ptr<SkStreamAsset>(this->onDuplicate());
}
size_t getPosition() const override;
bool seek(size_t position) override;
bool move(long offset) override;
std::unique_ptr<SkStreamAsset> fork() const {
return std::unique_ptr<SkStreamAsset>(this->onFork());
}
size_t getLength() const override;
private:
explicit SkFILEStream(std::shared_ptr<FILE>, size_t size, size_t offset);
explicit SkFILEStream(std::shared_ptr<FILE>, size_t size, size_t offset, size_t originalOffset);
SkStreamAsset* onDuplicate() const override;
SkStreamAsset* onFork() const override;
std::shared_ptr<FILE> fFILE;
// My own council will I keep on sizes and offsets.
size_t fSize;
size_t fOffset;
size_t fOriginalOffset;
typedef SkStreamAsset INHERITED;
};
class SK_API SkMemoryStream : public SkStreamMemory {
public:
SkMemoryStream();
/** We allocate (and free) the memory. Write to it via getMemoryBase() */
SkMemoryStream(size_t length);
/** If copyData is true, the stream makes a private copy of the data. */
SkMemoryStream(const void* data, size_t length, bool copyData = false);
/** Creates the stream to read from the specified data */
SkMemoryStream(sk_sp<SkData>);
/** Returns a stream with a copy of the input data. */
static std::unique_ptr<SkMemoryStream> MakeCopy(const void* data, size_t length);
/** Returns a stream with a bare pointer reference to the input data. */
static std::unique_ptr<SkMemoryStream> MakeDirect(const void* data, size_t length);
/** Returns a stream with a shared reference to the input data. */
static std::unique_ptr<SkMemoryStream> Make(sk_sp<SkData> data);
/** Resets the stream to the specified data and length,
just like the constructor.
if copyData is true, the stream makes a private copy of the data
*/
virtual void setMemory(const void* data, size_t length,
bool copyData = false);
/** Replace any memory buffer with the specified buffer. The caller
must have allocated data with sk_malloc or sk_realloc, since it
will be freed with sk_free.
*/
void setMemoryOwned(const void* data, size_t length);
sk_sp<SkData> asData() const { return fData; }
void setData(sk_sp<SkData>);
void skipToAlign4();
const void* getAtPos();
size_t read(void* buffer, size_t size) override;
bool isAtEnd() const override;
size_t peek(void* buffer, size_t size) const override;
bool rewind() override;
std::unique_ptr<SkMemoryStream> duplicate() const {
return std::unique_ptr<SkMemoryStream>(this->onDuplicate());
}
size_t getPosition() const override;
bool seek(size_t position) override;
bool move(long offset) override;
std::unique_ptr<SkMemoryStream> fork() const {
return std::unique_ptr<SkMemoryStream>(this->onFork());
}
size_t getLength() const override;
const void* getMemoryBase() override;
private:
SkMemoryStream* onDuplicate() const override;
SkMemoryStream* onFork() const override;
sk_sp<SkData> fData;
size_t fOffset;
typedef SkStreamMemory INHERITED;
};
/////////////////////////////////////////////////////////////////////////////////////////////
class SK_API SkFILEWStream : public SkWStream {
public:
SkFILEWStream(const char path[]);
~SkFILEWStream() override;
/** Returns true if the current path could be opened.
*/
bool isValid() const { return fFILE != nullptr; }
bool write(const void* buffer, size_t size) override;
void flush() override;
void fsync();
size_t bytesWritten() const override;
private:
FILE* fFILE;
typedef SkWStream INHERITED;
};
class SK_API SkDynamicMemoryWStream : public SkWStream {
public:
SkDynamicMemoryWStream();
~SkDynamicMemoryWStream() override;
bool write(const void* buffer, size_t size) override;
size_t bytesWritten() const override;
bool read(void* buffer, size_t offset, size_t size);
/** More efficient version of read(dst, 0, bytesWritten()). */
void copyTo(void* dst) const;
bool writeToStream(SkWStream* dst) const;
/** Equivalent to copyTo() followed by reset(), but may save memory use. */
void copyToAndReset(void* dst);
/** Equivalent to writeToStream() followed by reset(), but may save memory use. */
bool writeToAndReset(SkWStream* dst);
/** Return the contents as SkData, and then reset the stream. */
sk_sp<SkData> detachAsData();
/** Reset, returning a reader stream with the current content. */
std::unique_ptr<SkStreamAsset> detachAsStream();
/** Reset the stream to its original, empty, state. */
void reset();
void padToAlign4();
private:
struct Block;
Block* fHead;
Block* fTail;
size_t fBytesWrittenBeforeTail;
#ifdef SK_DEBUG
void validate() const;
#else
void validate() const {}
#endif
// For access to the Block type.
friend class SkBlockMemoryStream;
friend class SkBlockMemoryRefCnt;
typedef SkWStream INHERITED;
};
#endif