//
// Created by rick on 30-01-21.
//

#include <stdlib.h>
#include <string.h>
#include <myke/libc/ringqueue.h>

#define calc_pos(buffer, index) ((buffer->object_size) * (index))

typedef struct {
    int object_size;
    int count;
    int read_pos;
    int write_pos;
    void *mem;
} ring_buffer_t;

void *create_buffer(int count, int object_size) {
    ring_buffer_t *buffer = malloc(sizeof(ring_buffer_t));
    if (buffer == NULL) {
        return NULL;
    }
    buffer->object_size = object_size;
    buffer->count = count;
    buffer->read_pos = 0;
    buffer->write_pos = 0;
    buffer->mem = calloc(object_size, count);
    if (buffer->mem == NULL) {
        free(buffer);
        return NULL;
    }
    return buffer;
};

void free_buffer(void *buffer) {
    free(((ring_buffer_t *) buffer)->mem);
    free(buffer);
}

void ring_buffer_put(void *buffer, void *item) {
    ring_buffer_t *ring_buffer = (ring_buffer_t *) buffer;
    // todo check if this write would overwrite the current reading pos
    // todo handle the above case
    memcpy(ring_buffer->mem + calc_pos(ring_buffer, ring_buffer->write_pos), item, ring_buffer->object_size);
    ring_buffer->write_pos++;
};

bool ring_buffer_get(void *buffer, void *target) {
    ring_buffer_t *ring_buffer = (ring_buffer_t *) buffer;
    if (ring_buffer->read_pos == ring_buffer->write_pos) {
        // nothing to read
        return false;
    }
    memcpy(target, ring_buffer->mem + calc_pos(ring_buffer, ring_buffer->read_pos++), ring_buffer->object_size);
    return true;
};