/* * 
 * This file is part of bufferpool
 *
 * Copyright (C) 2007 by LScube team <team@streaming.polito.it>
 * See AUTHORS for more details
 * 
 * bufferpool is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * bufferpool is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with bufferpool; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 
 *
 */


#include <bufferpool.h>

#define BPNEWBUFF_RET_ERR \
    do { \
            free(slots); \
            free(buffer); \
            free(control); \
            return NULL; \
        } while (0)

BPBuffer *bp_new(uint32_t buffer_size)
{
    BPSlot *slots = NULL;
    BPBuffer *buffer = NULL;
    BPControl *control = NULL;
    uint32_t index;
    pthread_mutexattr_t mutex_attr;

    if (!buffer_size)
        return NULL;

    if (!(slots = (BPSlot *) calloc(buffer_size, sizeof(BPSlot))))
        BPNEWBUFF_RET_ERR;
    // *** slots initialization
    for (index = 0; index < buffer_size - 1; index++)
        (slots[index]).next = index + 1;
    (slots[index]).next = 0;    /*end of the list back to the head */

    // control struct allocation
    if (!(control = malloc(sizeof(BPControl))))
        BPNEWBUFF_RET_ERR;

    control->write_pos = buffer_size - 1;

    control->refs = 0;
    control->nslots = buffer_size;

    if (pthread_mutexattr_init(&mutex_attr))
        BPNEWBUFF_RET_ERR;

    if (pthread_mutex_init(&control->syn, &mutex_attr))
        BPNEWBUFF_RET_ERR;

    if (!(buffer = (BPBuffer *) malloc(sizeof(BPBuffer))))
        BPNEWBUFF_RET_ERR;

    buffer->type = buff_local;
    *buffer->filename = '\0';
    buffer->known_slots = buffer_size;

    // link all allocated structs
    buffer->slots = slots;
    buffer->control = control;

    return buffer;
}

#undef BPNEWBUFF_RET_ERR