switch_buffer.c

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/*
 * FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
 * Copyright (C) 2005-2014, Anthony Minessale II <anthm@freeswitch.org>
 *
 * Version: MPL 1.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
 *
 * The Initial Developer of the Original Code is
 * Anthony Minessale II <anthm@freeswitch.org>
 * Portions created by the Initial Developer are Copyright (C)
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Anthony Minessale II <anthm@freeswitch.org>
 *
 *
 * switch_buffer.c -- Data Buffering Code
 *
 */
#include <switch.h>
#include <switch_buffer.h>

static uint32_t buffer_id = 0;

typedef enum {
        SWITCH_BUFFER_FLAG_DYNAMIC = (1 << 0),
        SWITCH_BUFFER_FLAG_PARTITION = (1 << 1)
} switch_buffer_flag_t;

struct switch_buffer {
        switch_byte_t *data;
        switch_byte_t *head;
        switch_size_t used;
        switch_size_t actually_used;
        switch_size_t datalen;
        switch_size_t max_len;
        switch_size_t blocksize;
        switch_mutex_t *mutex;
        uint32_t flags;
        uint32_t id;
        int32_t loops;
};


SWITCH_DECLARE(void *) switch_buffer_get_head_pointer(switch_buffer_t *buffer)
{
        return buffer->head;
}

SWITCH_DECLARE(switch_status_t) switch_buffer_reset_partition_data(switch_buffer_t *buffer)
{
        if (!switch_test_flag(buffer, SWITCH_BUFFER_FLAG_PARTITION)) {
                return SWITCH_STATUS_FALSE;
        }

        buffer->head = buffer->data;
        buffer->used = buffer->actually_used = buffer->datalen;

        return SWITCH_STATUS_SUCCESS;
}

SWITCH_DECLARE(switch_status_t) switch_buffer_set_partition_data(switch_buffer_t *buffer, void *data, switch_size_t datalen)
{
        if (!switch_test_flag(buffer, SWITCH_BUFFER_FLAG_PARTITION)) {
                return SWITCH_STATUS_FALSE;
        }

        buffer->data = data;
        buffer->datalen = datalen;
        return switch_buffer_reset_partition_data(buffer);
}

SWITCH_DECLARE(switch_status_t) switch_buffer_create_partition(switch_memory_pool_t *pool, switch_buffer_t **buffer, void *data, switch_size_t datalen)
{
        switch_buffer_t *new_buffer;

        if ((new_buffer = switch_core_alloc(pool, sizeof(switch_buffer_t))) != 0) {
                new_buffer->id = buffer_id++;
                switch_set_flag(new_buffer, SWITCH_BUFFER_FLAG_PARTITION);
                switch_buffer_set_partition_data(new_buffer, data, datalen);
                *buffer = new_buffer;
                return SWITCH_STATUS_SUCCESS;
        }
        return SWITCH_STATUS_MEMERR;
}

SWITCH_DECLARE(switch_status_t) switch_buffer_create(switch_memory_pool_t *pool, switch_buffer_t **buffer, switch_size_t max_len)
{
        switch_buffer_t *new_buffer;

        if ((new_buffer = switch_core_alloc(pool, sizeof(switch_buffer_t))) != 0 && (new_buffer->data = switch_core_alloc(pool, max_len)) != 0) {
                new_buffer->datalen = max_len;
                new_buffer->id = buffer_id++;
                new_buffer->head = new_buffer->data;
                *buffer = new_buffer;
                return SWITCH_STATUS_SUCCESS;
        }
        return SWITCH_STATUS_MEMERR;
}

SWITCH_DECLARE(switch_status_t) switch_buffer_create_dynamic(switch_buffer_t **buffer, switch_size_t blocksize, switch_size_t start_len,
                                                                                                                         switch_size_t max_len)
{
        switch_buffer_t *new_buffer;

        if ((new_buffer = malloc(sizeof(*new_buffer)))) {
                memset(new_buffer, 0, sizeof(*new_buffer));

                if (!start_len) {
                        start_len = 250;
                }

                if (!blocksize) {
                        blocksize = start_len;
                }
                
                if (!(new_buffer->data = malloc(start_len))) {
                        free(new_buffer);
                        *buffer = NULL;
                        return SWITCH_STATUS_MEMERR;
                }

                memset(new_buffer->data, 0, start_len);

                new_buffer->max_len = max_len;
                new_buffer->datalen = start_len;
                new_buffer->id = buffer_id++;
                new_buffer->blocksize = blocksize;
                new_buffer->head = new_buffer->data;
                switch_set_flag(new_buffer, SWITCH_BUFFER_FLAG_DYNAMIC);

                *buffer = new_buffer;
                return SWITCH_STATUS_SUCCESS;
        }
        *buffer = NULL;
        return SWITCH_STATUS_MEMERR;
}

SWITCH_DECLARE(void) switch_buffer_add_mutex(switch_buffer_t *buffer, switch_mutex_t *mutex)
{
        buffer->mutex = mutex;
}

SWITCH_DECLARE(void) switch_buffer_lock(switch_buffer_t *buffer)
{
        if (buffer->mutex) {
                switch_mutex_lock(buffer->mutex);
        }
}

SWITCH_DECLARE(switch_status_t) switch_buffer_trylock(switch_buffer_t *buffer)
{
        if (buffer->mutex) {
                return switch_mutex_lock(buffer->mutex);
        }
        return SWITCH_STATUS_FALSE;
}

SWITCH_DECLARE(void) switch_buffer_unlock(switch_buffer_t *buffer)
{
        if (buffer->mutex) {
                switch_mutex_unlock(buffer->mutex);
        }
}

SWITCH_DECLARE(switch_size_t) switch_buffer_len(switch_buffer_t *buffer)
{
        return buffer->datalen;
}

SWITCH_DECLARE(switch_size_t) switch_buffer_freespace(switch_buffer_t *buffer)
{
        if (switch_test_flag(buffer, SWITCH_BUFFER_FLAG_DYNAMIC)) {
                if (buffer->max_len) {
                        return (switch_size_t) (buffer->max_len - buffer->used);
                }
                return 1000000;
        }

        return (switch_size_t) (buffer->datalen - buffer->used);
}

SWITCH_DECLARE(switch_size_t) switch_buffer_inuse(switch_buffer_t *buffer)
{
        return buffer->used;
}

SWITCH_DECLARE(switch_size_t) switch_buffer_toss(switch_buffer_t *buffer, switch_size_t datalen)
{
        switch_size_t reading = 0;

        if (buffer->used < 1) {
                buffer->used = 0;
                return 0;
        } else if (buffer->used >= datalen) {
                reading = datalen;
        } else {
                reading = buffer->used;
        }

        buffer->used -= reading;
        buffer->head += reading;

        return buffer->used;
}

SWITCH_DECLARE(void) switch_buffer_set_loops(switch_buffer_t *buffer, int32_t loops)
{
        buffer->loops = loops;
}

SWITCH_DECLARE(switch_size_t) switch_buffer_read_loop(switch_buffer_t *buffer, void *data, switch_size_t datalen)
{
        switch_size_t len;
        if ((len = switch_buffer_read(buffer, data, datalen)) == 0) {
                if (buffer->loops > 0) {
                        buffer->loops--;
                }
                if (buffer->loops == 0) {
                        return 0;
                }
                buffer->head = buffer->data;
                buffer->used = buffer->actually_used;
                len = switch_buffer_read(buffer, data, datalen);
        }
        return len;
}

SWITCH_DECLARE(switch_size_t) switch_buffer_read(switch_buffer_t *buffer, void *data, switch_size_t datalen)
{
        switch_size_t reading = 0;

        if (buffer->used < 1) {
                buffer->used = 0;
                return 0;
        } else if (buffer->used >= datalen) {
                reading = datalen;
        } else {
                reading = buffer->used;
        }

        memcpy(data, buffer->head, reading);
        buffer->used -= reading;
        buffer->head += reading;

        return reading;
}

SWITCH_DECLARE(switch_size_t) switch_buffer_peek(switch_buffer_t *buffer, void *data, switch_size_t datalen)
{
        switch_size_t reading = 0;

        if (buffer->used < 1) {
                buffer->used = 0;
                return 0;
        } else if (buffer->used >= datalen) {
                reading = datalen;
        } else {
                reading = buffer->used;
        }

        memcpy(data, buffer->head, reading);

        return reading;
}

SWITCH_DECLARE(switch_size_t) switch_buffer_peek_zerocopy(switch_buffer_t *buffer, const void **ptr)
{
        switch_size_t reading = 0;

        if (buffer->used < 1) {
                buffer->used = 0;
                *ptr = NULL;
                return 0;
        } else {
                reading = buffer->used;
        }

        *ptr = buffer->head;

        return reading;
}

SWITCH_DECLARE(switch_size_t) switch_buffer_write(switch_buffer_t *buffer, const void *data, switch_size_t datalen)
{
        switch_size_t freespace, actual_freespace;

        if (switch_test_flag(buffer, SWITCH_BUFFER_FLAG_PARTITION)) {
                return 0;
        }

        switch_assert(buffer->data != NULL);

        if (!datalen) {
                return buffer->used;
        }

        actual_freespace = buffer->datalen - buffer->actually_used;

        if (actual_freespace < datalen) {
                memmove(buffer->data, buffer->head, buffer->used);
                buffer->head = buffer->data;
                buffer->actually_used = buffer->used;
        }

        freespace = buffer->datalen - buffer->used;

        if (switch_test_flag(buffer, SWITCH_BUFFER_FLAG_DYNAMIC)) {
                if (freespace < datalen && (!buffer->max_len || (buffer->used + datalen <= buffer->max_len))) {
                        switch_size_t new_size, new_block_size;
                        void *tmp;

                        new_size = buffer->datalen + datalen;
                        new_block_size = buffer->datalen + buffer->blocksize;

                        if (new_block_size > new_size) {
                                new_size = new_block_size;
                        }
                        buffer->head = buffer->data;
                        if (!(tmp = realloc(buffer->data, new_size))) {
                                return 0;
                        }
                        buffer->data = tmp;
                        buffer->head = buffer->data;
                        buffer->datalen = new_size;
                }
        }

        freespace = buffer->datalen - buffer->used;

        if (freespace < datalen) {
                return 0;
        }

        if (data) {
                memcpy(buffer->head + buffer->used, data, datalen);
        } else {
                memset(buffer->head + buffer->used, 0, datalen);
        }

        buffer->used += datalen;
        buffer->actually_used += datalen;
        return buffer->used;
}

SWITCH_DECLARE(void) switch_buffer_zero(switch_buffer_t *buffer)
{
        switch_assert(buffer->data != NULL);

        buffer->used = 0;
        buffer->actually_used = 0;
        buffer->head = buffer->data;
}

SWITCH_DECLARE(switch_size_t) switch_buffer_zwrite(switch_buffer_t *buffer, const void *data, switch_size_t datalen)
{
        switch_size_t w;

        if (switch_test_flag(buffer, SWITCH_BUFFER_FLAG_PARTITION)) {
                return 0;
        }

        if (!(w = switch_buffer_write(buffer, data, datalen))) {
                switch_buffer_zero(buffer);
                return switch_buffer_write(buffer, data, datalen);
        }

        return w;
}

SWITCH_DECLARE(switch_size_t) switch_buffer_slide_write(switch_buffer_t *buffer, const void *data, switch_size_t datalen)
{
        switch_size_t w;

        if (switch_test_flag(buffer, SWITCH_BUFFER_FLAG_PARTITION)) {
                return 0;
        }

        if (!(w = switch_buffer_write(buffer, data, datalen))) {
                switch_buffer_toss(buffer, datalen);
                return switch_buffer_write(buffer, data, datalen);
        }

        return w;
}

SWITCH_DECLARE(void) switch_buffer_destroy(switch_buffer_t **buffer)
{
        if (buffer && *buffer) {
                if ((switch_test_flag((*buffer), SWITCH_BUFFER_FLAG_DYNAMIC))) {
                        switch_safe_free((*buffer)->data);
                        free(*buffer);
                }
                *buffer = NULL;
        }
}

/* For Emacs:
 * Local Variables:
 * mode:c
 * indent-tabs-mode:t
 * tab-width:4
 * c-basic-offset:4
 * End:
 * For VIM:
 * vim:set softtabstop=4 shiftwidth=4 tabstop=4 noet:
 */