osb/source/core/StarBuffer.hpp

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#pragma once
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#include "StarIODevice.hpp"
#include "StarString.hpp"
namespace Star {
STAR_CLASS(Buffer);
STAR_CLASS(ExternalBuffer);
// Wraps a ByteArray to an IODevice
class Buffer : public IODevice {
public:
// Constructs buffer open ReadWrite
Buffer();
Buffer(size_t initialSize);
Buffer(ByteArray b);
Buffer(Buffer const& buffer);
Buffer(Buffer&& buffer);
StreamOffset pos() override;
void seek(StreamOffset pos, IOSeek mode = IOSeek::Absolute) override;
void resize(StreamOffset size) override;
bool atEnd() override;
size_t read(char* data, size_t len) override;
size_t write(char const* data, size_t len) override;
size_t readAbsolute(StreamOffset readPosition, char* data, size_t len) override;
size_t writeAbsolute(StreamOffset writePosition, char const* data, size_t len) override;
void open(IOMode mode) override;
String deviceName() const override;
StreamOffset size() override;
ByteArray& data();
ByteArray const& data() const;
// If this class holds the underlying data, then this method is cheap, and
// will move the data out of this class into the returned array, otherwise,
// this will incur a copy. Afterwards, this Buffer will be left empty.
ByteArray takeData();
// Returns a pointer to the beginning of the Buffer.
char* ptr();
char const* ptr() const;
// Same thing as size(), just size_t type (since this is in-memory)
size_t dataSize() const;
void reserve(size_t size);
// Clears buffer, moves position to 0.
void clear();
bool empty() const;
// Reset buffer with new contents, moves position to 0.
void reset(size_t newSize);
void reset(ByteArray b);
Buffer& operator=(Buffer const& buffer);
Buffer& operator=(Buffer&& buffer);
private:
size_t doRead(size_t pos, char* data, size_t len);
size_t doWrite(size_t pos, char const* data, size_t len);
size_t m_pos;
ByteArray m_bytes;
};
// Wraps an externally held sequence of bytes to a read-only IODevice
class ExternalBuffer : public IODevice {
public:
// Constructs an empty ReadOnly ExternalBuffer.
ExternalBuffer();
// Constructs a ReadOnly ExternalBuffer pointing to the given external data, which
// must be valid for the lifetime of the ExternalBuffer.
ExternalBuffer(char const* externalData, size_t len);
ExternalBuffer(ExternalBuffer const& buffer) = default;
ExternalBuffer& operator=(ExternalBuffer const& buffer) = default;
StreamOffset pos() override;
void seek(StreamOffset pos, IOSeek mode = IOSeek::Absolute) override;
bool atEnd() override;
size_t read(char* data, size_t len) override;
size_t write(char const* data, size_t len) override;
size_t readAbsolute(StreamOffset readPosition, char* data, size_t len) override;
size_t writeAbsolute(StreamOffset writePosition, char const* data, size_t len) override;
String deviceName() const override;
StreamOffset size() override;
// Returns a pointer to the beginning of the Buffer.
char const* ptr() const;
// Same thing as size(), just size_t type (since this is in-memory)
size_t dataSize() const;
// Clears buffer, moves position to 0.
bool empty() const;
operator bool() const;
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// Reset buffer with new contents, moves position to 0.
void reset(char const* externalData, size_t len);
private:
size_t doRead(size_t pos, char* data, size_t len);
size_t m_pos;
char const* m_bytes;
size_t m_size;
};
}