snes9x/apu/ring_buffer.h

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2010-09-25 15:46:12 +00:00
/* Simple byte-based ring buffer. Licensed under public domain (C) BearOso. */
#ifndef __RING_BUFFER_H
#define __RING_BUFFER_H
#include <string.h>
#undef MIN
#define MIN(a, b) ((a) < (b) ? (a) : (b))
class ring_buffer
{
protected:
int size;
int buffer_size;
int start;
unsigned char *buffer;
public:
ring_buffer (int buffer_size)
{
this->buffer_size = buffer_size;
buffer = new unsigned char[this->buffer_size];
memset (buffer, 0, this->buffer_size);
size = 0;
start = 0;
}
~ring_buffer (void)
{
delete[] buffer;
}
bool
push (unsigned char *src, int bytes)
{
if (space_empty () < bytes)
return false;
int end = (start + size) % buffer_size;
int first_write_size = MIN (bytes, buffer_size - end);
memcpy (buffer + end, src, first_write_size);
if (bytes > first_write_size)
memcpy (buffer, src + first_write_size, bytes - first_write_size);
size += bytes;
return true;
}
bool
pull (unsigned char *dst, int bytes)
{
if (space_filled () < bytes)
return false;
memcpy (dst, buffer + start, MIN (bytes, buffer_size - start));
if (bytes > (buffer_size - start))
memcpy (dst + (buffer_size - start), buffer, bytes - (buffer_size - start));
start = (start + bytes) % buffer_size;
size -= bytes;
return true;
}
inline int
space_empty (void) const
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{
return buffer_size - size;
}
inline int
space_filled (void) const
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{
return size;
}
void
clear (void)
{
start = 0;
size = 0;
memset (buffer, 0, buffer_size);
}
void
resize (int size)
{
delete[] buffer;
buffer_size = size;
buffer = new unsigned char[buffer_size];
memset (buffer, 0, this->buffer_size);
this->size = 0;
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start = 0;
}
inline void
cache_silence (void)
{
clear ();
size = buffer_size;
}
};
#endif