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#ifndef AUDIO_SCOPE_H
#define AUDIO_SCOPE_H
 
#include "SDL.h"
 
class Audio_Scope {
public:
    typedef const char* error_t;
    
    // Initialize scope window of specified size. Height must be 256 or less.
    error_t init( int width, int height );
    
    // Draw at most 'count' samples from 'in', skipping 'step' samples after
    // each sample drawn. Step can be less than 1.0.
    error_t draw( const short* in, long count, double step = 1.0 );
    
    Audio_Scope();
    ~Audio_Scope();
    
private:
    typedef unsigned char byte;
    SDL_Surface* screen;
    SDL_Surface* surface;
    byte* buf;
    int buf_size;
    int sample_shift;
    int low_y;
    int high_y;
    int v_offset;
    
    void render( short const* in, long count, long step );
};
 
#endif

#include "Audio_Scope.h"
#include <assert.h>
#include <stdlib.h>
 
// ...
Audio_Scope::~Audio_Scope()
{
    free( buf );
    
    if ( surface )
        SDL_FreeSurface( surface );
}
// ...