beetle-psx-libretro/mednafen/Stream.h

#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.

#define MODE_READ          0
#define MODE_WRITE         1
#define MODE_WRITE_SAFE    2
#define MODE_WRITE_INPLACE 3

class Stream
{
   public:

      Stream();
      virtual ~Stream();

      enum
      {
         ATTRIBUTE_READABLE = 0,
         ATTRIBUTE_WRITEABLE,
         ATTRIBUTE_SEEKABLE
      };
      virtual uint64_t attributes(void) = 0;

      virtual uint64_t read(void *data, uint64_t count, bool error_on_eos = true) = 0;
      virtual void write(const void *data, uint64_t count) = 0;

      virtual void truncate(uint64 length) = 0;	/* Should have ftruncate()-like semantics; but avoid using it to extend files. */
      virtual void flush(void) = 0;

      virtual void seek(int64_t offset, int whence) = 0;
      virtual uint64_t tell(void) = 0;
      virtual uint64_t 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_t get_u8(void)
      {
         uint8_t ret;

         read(&ret, sizeof(ret));

         return ret;
      }

      INLINE void put_u8(uint8_t 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_t 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_t tmp[sizeof(T)];

            for(unsigned i = 0; i < sizeof(T); i++)
               tmp[i] = ((uint8_t *)&c)[sizeof(T) - 1 - i];

            write(tmp, sizeof(tmp));
         }

      template<typename T>
         INLINE T get_LE(void)
         {
#ifdef MSB_FIRST
            return get_RE<T>();
#else
            return get_NE<T>();
#endif
         }

      template<typename T>
         INLINE void put_LE(T c)
         {
#ifdef MSB_FIRST
            return put_RE<T>(c);
#else
            return put_NE<T>(c);
#endif
         }

      template<typename T>
         INLINE T get_BE(void)
         {
#ifdef MSB_FIRST
            return get_NE<T>();
#else
            return get_RE<T>();
#endif
         }

      template<typename T>
         INLINE void put_BE(T c)
         {
#ifdef MSB_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