beetle-lynx-libretro/mednafen/Stream.h

151 lines
3.1 KiB
C++

#ifndef __MDFN_STREAM_H
#define __MDFN_STREAM_H
// TODO/WIP
// TODO?: BufferedStream, no virtual functions, yes inline functions, constructor takes a Stream* argument.
#include "mednafen.h"
#include <errno.h>
#include <stdio.h> // For SEEK_* defines, which we will use in Stream out of FORCE OF HABIT.
class Stream
{
public:
Stream();
virtual ~Stream();
enum
{
ATTRIBUTE_READABLE = 0,
ATTRIBUTE_WRITEABLE,
ATTRIBUTE_SEEKABLE
};
virtual uint64 attributes(void) = 0;
virtual uint64 read(void *data, uint64 count, bool error_on_eos = true) = 0;
virtual void write(const void *data, uint64 count) = 0;
virtual void seek(int64 offset, int whence) = 0;
virtual int64 tell(void) = 0;
virtual int64 size(void) = 0;
virtual void close(void) = 0; // Flushes(in the case of writeable streams) and closes the stream.
// Necessary since this operation can fail(running out of disk space, for instance),
// and throw an exception in the destructor would be a Bad Idea(TM).
//
// Manually calling this function isn't strictly necessary, but recommended when the
// stream is writeable; it will be called automatically from the destructor, with any
// exceptions thrown caught and logged.
//
// Utility functions(TODO):
//
INLINE uint8 get_u8(void)
{
uint8 ret;
read(&ret, sizeof(ret));
return ret;
}
INLINE void put_u8(uint8 c)
{
write(&c, sizeof(c));
}
template<typename T>
INLINE T get_NE(void)
{
T ret;
read(&ret, sizeof(ret));
return ret;
}
template<typename T>
INLINE void put_NE(T c)
{
write(&c, sizeof(c));
}
template<typename T>
INLINE T get_RE(void)
{
uint8 tmp[sizeof(T)];
T ret = 0;
read(tmp, sizeof(tmp));
for(unsigned i = 0; i < sizeof(T); i++)
ret |= (T)tmp[i] << (i * 8);
return ret;
}
template<typename T>
INLINE void put_RE(T c)
{
uint8 tmp[sizeof(T)];
for(unsigned i = 0; i < sizeof(T); i++)
tmp[i] = ((uint8 *)&c)[sizeof(T) - 1 - i];
write(tmp, sizeof(tmp));
}
template<typename T>
INLINE T get_LE(void)
{
#ifdef LSB_FIRST
return get_NE<T>();
#else
return get_RE<T>();
#endif
}
template<typename T>
INLINE void put_LE(T c)
{
#ifdef LSB_FIRST
return put_NE<T>(c);
#else
return put_RE<T>(c);
#endif
}
template<typename T>
INLINE T get_BE(void)
{
#ifndef LSB_FIRST
return get_NE<T>();
#else
return get_RE<T>();
#endif
}
template<typename T>
INLINE void put_BE(T c)
{
#ifndef LSB_FIRST
return put_NE<T>(c);
#else
return put_RE<T>(c);
#endif
}
// Reads a line into "str", overwriting its contents; returns the line-end char('\n' or '\r' or '\0'), or -1 on EOF.
// The line-end char won't be added to "str".
// It's up to the caller to handle extraneous empty lines caused by DOS-format text lines(\r\n).
// ("str" is passed by reference for the possibility of improved performance by reusing alloced memory for the std::string, though part
// of it would be up to the STL implementation).
// Implemented as virtual so that a higher-performance version can be implemented if possible(IE with MemoryStream)
virtual int get_line(std::string &str);
};
#endif