~roger-booth/mysql-proxy/laminator

/* $%BEGINLICENSE%$

 Copyright (C) 2007-2008 MySQL AB, 2008 Sun Microsystems, Inc

 This program is free software; you can redistribute it and/or modify

 it under the terms of the GNU General Public License as published by

 the Free Software Foundation; version 2 of the License.

 This program 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 General Public License for more details.

 You should have received a copy of the GNU General Public License

 along with this program; if not, write to the Free Software

 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 $%ENDLICENSE%$ */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include "network-queue.h"

#ifndef DISABLE_DEPRECATED_DECL

network_queue *network_queue_init() {

	return network_queue_new();

}

#endif

network_queue *network_queue_new() {

	network_queue *queue;

	queue = g_new0(network_queue, 1);

	queue->chunks = g_queue_new();

	return queue;

}

void network_queue_free(network_queue *queue) {

	GString *packet;

	if (!queue) return;

	while ((packet = g_queue_pop_head(queue->chunks))) g_string_free(packet, TRUE);

	g_queue_free(queue->chunks);

	g_free(queue);

}

int network_queue_append(network_queue *queue, GString *s) {

	queue->len += s->len;

	g_queue_push_tail(queue->chunks, s);

	return 0;

}

/**

 * get a string from the head of the queue and leave the queue unchanged 

 *

 * @param  queue the queue to read from

 * @param  peek_len  bytes to collect

 * @param  dest      GString to write it. If NULL, we allow a new one and return it

 * @return NULL if not enough data

 *         if dest is not NULL, dest, otherwise a new GString containing the data

 */

GString *network_queue_peek_string(network_queue *queue, gsize peek_len, GString *dest) {

	gsize we_want = peek_len;

	GList *node;

/* TODO: convert to DTrace probe

	g_debug("[%s] looking for %d bytes, queue has %d", G_STRLOC, peek_len, queue->len); */

	if (queue->len < peek_len) {

		return NULL;

	}

	if (!dest) {

		/* no define */

		dest = g_string_sized_new(peek_len);

	}

	g_assert_cmpint(dest->allocated_len, >, peek_len);

	for (node = queue->chunks->head; node && we_want; node = node->next) {

		GString *chunk = node->data;

		if (node == queue->chunks->head) {

			gsize we_have = we_want < (chunk->len - queue->offset) ? we_want : (chunk->len - queue->offset);

			g_string_append_len(dest, chunk->str + queue->offset, we_have);

			we_want -= we_have;

		} else {

			gsize we_have = we_want < chunk->len ? we_want : chunk->len;

			g_string_append_len(dest, chunk->str, we_have);

			we_want -= we_have;

		}

	}

	return dest;

}

/**

 * get a string from the head of the queue and remove the chunks from the queue 

 */

GString *network_queue_pop_string(network_queue *queue, gsize steal_len, GString *dest) {

	gsize we_want = steal_len;

	GString *chunk;

	if (queue->len < steal_len) {

		return NULL;

	}

	while ((chunk = g_queue_peek_head(queue->chunks))) {

		gsize we_have = we_want < (chunk->len - queue->offset) ? we_want : (chunk->len - queue->offset);

		if (!dest && (queue->offset == 0) && (chunk->len == steal_len)) {

			/* optimize the common case that we want to have to full chunk

			 *

			 * if dest is null, we can remove the GString from the queue and return it directly without

			 * copying it

			 */

			dest = g_queue_pop_head(queue->chunks);

			queue->len -= we_have;

			return dest;

		}

		if (!dest) {

			/* if we don't have a dest-buffer yet, create one */

			dest = g_string_sized_new(steal_len);

		}

		g_string_append_len(dest, chunk->str + queue->offset, we_have);

		queue->offset += we_have;

		queue->len    -= we_have;

		we_want -= we_have;

		if (chunk->len == queue->offset) {

			/* the chunk is done, remove it */

			g_string_free(g_queue_pop_head(queue->chunks), TRUE);

			queue->offset = 0;

		} else {

			break;

		}

	}

	return dest;

}