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/*
* probe-buffer.h
* Copyright 2015 John Lindgren
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions, and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions, and the following disclaimer in the documentation
* provided with the distribution.
*
* This software is provided "as is" and without any warranty, express or
* implied. In no event shall the authors be liable for any damages arising from
* the use of this software.
*/
#ifndef LIBAUDCORE_PROBE_BUFFER_H
#define LIBAUDCORE_PROBE_BUFFER_H
/* The buffer is only for the beginning of the file, to allow detecting the file
* type without reading from the file repeatedly. Whenever buffering is active,
* m_at indicates the virtual file position, while the real file position is at
* the end of the buffer. Once it is necessary to read outside the buffer, m_at
* is set to -1, the buffer memory is released, and all file operations are done
* on the real file. Seeking to the beginning of the file activates buffering
* again.
*
* Optionally, reads can be restricted to the bufferable area. In this case,
* reads will stop short at the end of the bufferable area, and seeks outside
* the bufferable area (and any type of SEEK_END) will fail. However, the real
* file size is still reported.
*/
#include "vfs.h"
class ProbeBuffer : public VFSImpl
{
public:
ProbeBuffer (const char * filename, SmartPtr<VFSImpl> && file);
~ProbeBuffer ();
int64_t fread (void * ptr, int64_t size, int64_t nmemb);
int fseek (int64_t offset, VFSSeekType whence);
int64_t ftell ();
int64_t fsize ();
bool feof ();
int64_t fwrite (const void * ptr, int64_t size, int64_t nmemb);
int ftruncate (int64_t length);
int fflush ();
String get_metadata (const char * field);
void set_limit_to_buffer (bool limit)
{ m_limited = limit; }
private:
void increase_buffer (int64_t size);
void release_buffer ();
String m_filename;
SmartPtr<VFSImpl> m_file;
char * m_buffer = nullptr;
int m_filled = 0, m_at = 0;
bool m_limited = false;
};
#endif // LIBAUDCORE_PROBE_BUFFER_H
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