/* SPDX-License-Identifier: Apache-2.0 */
/**       
 * @file        duplexqueue.c
 *
 * @brief       Code file for Duplex Queue library
 *   
 * @copyright   Copyright (C) 2024 Jackrabbit Founders LLC. All rights reserved.
 *       
 * @date        Feb 2024
 * @author      Barrett Edwards <code@jrlabs.io>
 *          
 */

/* INCLUDES ==================================================================*/

/* free()
 */
#include <stdlib.h>

/* printf()
 */
#include <stdio.h>

/* errno 
 */
#include <errno.h>

/* memset()
 */
#include <string.h>

/* __u32
 * __s32
 */
#include <linux/types.h>

#include <ptrqueue.h>

#include "main.h"


/* MACROS ====================================================================*/

/* ENUMERATIONS ==============================================================*/

/* STRUCTS ===================================================================*/

/* GLOBAL VARIABLES ==========================================================*/

/* PROTOTYPES ================================================================*/

/* FUNCTIONS =================================================================*/

/* 
 * Relese allocated memory
 *
 * Return 0 upon success, 1 otherwise and set errno
 */
int dq_free(struct duplex_queue *dq)
{
	/* STEPS
	 * 1: Validate inputs 
	 * 2: Free data buffer 
	 * 3: Free ring buffer pointer 
	 */
	 if (dq == NULL) {
		errno = EINVAL;
		goto end;
	 }

	pq_free(dq->tx);
	pq_free(dq->rx);
	free(dq->data);
	free(dq);

	return 0;

end:
	return 1;
}

/*
 * Create and initialize a duplex queue
 * Param: 
 *	count   : This is the number of buffer entries in each direction of the queue pair
 * 
 * Returns a pointer to a struct duplex_queue upon success. Upon error, returns NULL and sets errno 
 */
struct duplex_queue *dq_init(size_t count, size_t obj_size)
{
	struct duplex_queue *dq;

	/* STEPS
	 * 1. Validate inputs
	 * 2. Allocate memory for duplex_queue struct 
	 * 3. Init the rx and tx ptr_queues
	 * 4. Allocate memory for data buffers
	 * 5: Add pointers into rx queue
	 */

	// STEP 1. Validate inputs
	if ( (count == 0) || (obj_size == 0) ) {
		errno = EINVAL;
		goto end;
	}
	
	// STEP 2. Allocate memory for duplex_queue struct 
	dq = (struct duplex_queue*) malloc (sizeof(struct duplex_queue));
	if (dq == 0) {
		errno = ENOMEM;
		goto end;
	}
	memset(dq, 0, sizeof(struct duplex_queue));

	dq->count = count;
	dq->obj_size = obj_size;

	// STEP 3. Init the rx and tx ptr_queues
	dq->rx = pq_init(count, 0);
	dq->tx = pq_init(count, 0);

	// STEP 4. Allocate memory for data buffer 
	dq->data = (__u8*) malloc (count * obj_size); 
	if (dq->data == 0) {
		errno = ENOMEM;
		goto end_free;;
	}
	memset(dq->data, 0, count * obj_size);

	// STEP 5: Add pointers into rx queue
	for ( size_t i = 0 ; i < count ; i++ )
		pq_push(dq->rx, &dq->data[i*obj_size]);	

	return dq;

end_free:
	dq_free(dq);

end:
	return NULL;
}