athena/include/Athena/MemoryReader.hpp

137 lines
4.2 KiB
C++

#ifndef MEMORYREADER_HPP
#define MEMORYREADER_HPP
#include <string>
#include <memory>
#include <functional>
#include "Athena/IStreamReader.hpp"
namespace Athena
{
namespace io
{
/*! \class MemoryReader
* \brief A Stream class for reading data from a memory position
*
* A Class for reading binary data from a file or memory stream,
* all work is done using a memory buffer, and not read directly from the disk
* this allows for fast, flexible code as well as the ability to quickly modify data
* \sa Stream
*/
class MemoryReader : public IStreamReader
{
public:
virtual ~MemoryReader();
/*! \brief This constructor references an existing buffer to read from.
*
* \param data The existing buffer
* \param length The length of the existing buffer
* \param takeOwnership Memory will be freed with the reader if set
*/
MemoryReader(const atUint8* data, atUint64 length, bool takeOwnership=false);
/*! \brief Sets the buffers position relative to the specified position.<br />
* It seeks relative to the current position by default.
* \param position where in the buffer to seek
* \param origin The Origin to seek \sa SeekOrigin
*/
void seek(atInt64 pos, SeekOrigin origin = SeekOrigin::Current);
/*! \brief Returns the current position in the stream.
*
* \return Int64 The current position in the stream.
*/
inline atUint64 position() const
{return m_position;}
/*! \brief Returns whether or not the stream is at the end.
*
* \return bool True if at end; False otherwise.
*/
inline atUint64 length() const
{return m_length;}
/*! \brief Sets the buffer to the given one, deleting the current one.<br />
* <b>BEWARE:</b> As this deletes the current buffer it WILL cause a loss of data
* if that was not the intent.<br />
* Once you pass the data to setData <b>DO NOT</b> delete the buffer
* as Stream now owns the address, this is done to keep memory usage down.
* \param data The new buffer.
* \param length The length of the new buffer.
* \param takeOwnership Memory will be freed with the reader if set
* \throw IOException
*/
void setData(const atUint8* data, atUint64 length, bool takeOwnership=false);
/*! \brief Returns a copy of the current buffer.<br />
* Changes to the copy do not affect the buffer so it's perfectly safe to
* directly edit the buffer and use setData to set the new information.<br />
* However once you pass the data to setData <b>DO NOT</b> delete the buffer
* as Stream now owns the address, this is done to keep memory usage down.
* \return Uint8* The copy of the buffer.
*/
atUint8* data() const;
/*! \brief Reads a specified number of bytes to user-allocated buffer
* \param buf User-allocated buffer pointer
* \param len Length to read
* \return Number of bytes read
*/
atUint64 readUBytesToBuf(void* buf, atUint64 len);
protected:
const atUint8* m_data;
atUint64 m_length;
atUint64 m_position;
bool m_owns;
};
class MemoryCopyReader : public MemoryReader
{
public:
/*! \brief This constructor copies an existing buffer to read from.
*
* \param data The existing buffer
* \param length The length of the existing buffer
*/
MemoryCopyReader(const atUint8* data, atUint64 length);
/*! \brief This constructor creates an instance from a file on disk.
*
* \param filename The file to create the stream from
*/
MemoryCopyReader(const std::string& filename)
: MemoryReader(NULL, 0),
m_filepath(filename)
{loadData();}
void setData(const atUint8* data, atUint64 length);
protected:
void loadData();
std::unique_ptr<atUint8[]> m_dataCopy;
std::string m_filepath; //!< Path to the target file
};
} // io
} // Athena
#ifndef MEMORYREADER_BASE
#define MEMORYREADER_BASE() \
private: \
typedef Athena::io::MemoryReader base
#endif // MEMORYREADER_BASE
#ifndef MEMORYCOPYREADER_BASE
#define MEMORYCOPYREADER_BASE() \
private: \
typedef Athena::io::MemoryCopyReader base
#endif // MEMORYCOPYREADER_BASE
#endif // MEMORYREADER_HPP