Files
lib_xua/lib_xua/src/midi/queue.h
2024-04-30 08:21:46 +01:00

75 lines
1.7 KiB
C

// Copyright 2013-2024 XMOS LIMITED.
// This Software is subject to the terms of the XMOS Public Licence: Version 1.
#ifndef QUEUE_H_
#define QUEUE_H_
#include "midioutparse.h"
#include "xassert.h"
typedef struct queue_t {
/// Read index.
unsigned rdptr;
/// Write index.
unsigned wrptr;
unsigned size;
unsigned mask;
} queue_t;
#ifdef __XC__
inline int is_power_of_2(unsigned x) {
return x != 0 && (x & (x - 1)) == 0;
}
inline void queue_init(queue_t &q, unsigned size) {
xassert(is_power_of_2(size) && "MIDI FIFO size must be a power of 2"); // Keep this enabled as will be discovered duirng dev time
q.rdptr = 0;
q.wrptr = 0;
q.size = size;
q.mask = size - 1; // Assumes power of two.
}
inline int queue_is_empty(const queue_t &q) {
return q.wrptr == q.rdptr;
}
inline int queue_is_full(const queue_t &q) {
return q.wrptr - q.rdptr == q.size;
}
inline void queue_push_word(queue_t &q, unsigned array[], unsigned data)
{
if(queue_is_full(q)) {
xassert(0 && "Unexpected push to MIDI queue when full");
// Silently drop message if asserts not enabled
return;
}
array[q.wrptr++ & q.mask] = data;
}
inline unsigned queue_pop_word(queue_t &q, unsigned array[]) {
if(queue_is_empty(q)){
xassert(0 && "Unexpected pop from MIDI queue when empty");
// Return NULL messaqe if asserts not enabled
return MIDI_OUT_NULL_MESSAGE;
}
return array[q.rdptr++ & q.mask];
}
inline unsigned queue_items(const queue_t &q) {
return q.wrptr - q.rdptr;
}
inline unsigned queue_space(const queue_t &q) {
return q.size - queue_items(q);
}
#endif // __XC__
#endif /* QUEUE_H_ */