giuliomoro@338: /*
giuliomoro@338:  *  Copyright (c) 2012 Peter Brinkmann (peter.brinkmann@gmail.com)
giuliomoro@338:  *
giuliomoro@338:  *  For information on usage and redistribution, and for a DISCLAIMER OF ALL
giuliomoro@338:  *  WARRANTIES, see the file, "LICENSE.txt," in this distribution.
giuliomoro@338:  *
giuliomoro@338:  * See https://github.com/libpd/libpd/wiki for documentation
giuliomoro@338:  *
giuliomoro@338:  */
giuliomoro@338: 
giuliomoro@338: #ifndef __OPENSL_RING_BUFFER_H__
giuliomoro@338: #define __OPENSL_RING_BUFFER_H__
giuliomoro@338: 
giuliomoro@338: // Simple lock-free ring buffer implementation for one writer thread and one
giuliomoro@338: // consumer thread.
giuliomoro@338: typedef struct ring_buffer {
giuliomoro@338:     int size;
giuliomoro@338:     char *buf_ptr;
giuliomoro@338:     int write_idx;
giuliomoro@338:     int read_idx;
giuliomoro@338: } ring_buffer;
giuliomoro@338: 
giuliomoro@338: // Creates a ring buffer (returns NULL on failure).
giuliomoro@338: ring_buffer *rb_create(int size);
giuliomoro@338: 
giuliomoro@338: // Deletes a ring buffer.
giuliomoro@338: void rb_free(ring_buffer *buffer);
giuliomoro@338: 
giuliomoro@338: // Returns the number of bytes that can currently be written; safe to be called
giuliomoro@338: // from any thread.
giuliomoro@338: int rb_available_to_write(ring_buffer *buffer);
giuliomoro@338: 
giuliomoro@338: // Returns the number of bytes that can currently be read; safe to be called
giuliomoro@338: // from any thread.
giuliomoro@338: int rb_available_to_read(ring_buffer *buffer);
giuliomoro@338: 
giuliomoro@338: // Writes bytes from n sources to the ring buffer (if the ring buffer has
giuliomoro@338: // enough space). The varargs are pairs of type (const char*, int) giving a
giuliomoro@338: // pointer to a buffer and the number of bytes to be copied. Only to be called
giuliomoro@338: // from a single writer thread.
giuliomoro@338: // Returns 0 on success.
giuliomoro@338: int rb_write_to_buffer(ring_buffer *buffer, int n, ...);
giuliomoro@338: 
giuliomoro@338: // Reads the given number of bytes fromthe ring buffer to dest if the ring
giuliomoro@338: // buffer has enough data. Only to be called from a single reader thread.
giuliomoro@338: // Returns 0 on success.
giuliomoro@338: int rb_read_from_buffer(ring_buffer *buffer, char *dest, int len);
giuliomoro@338: 
giuliomoro@338: #endif