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Up to [ELWIX - Embedded LightWeight unIX -] / mqtt / src

add subscribe variable helpers

#include "global.h"


/* ------------------------------------------------------------------- */

int
mqtt_msgSUBSCRIBE(mqtt_msg_t * __restrict buf, const char *csTopic, u_short msgID, 
		u_char Dup, u_char QOS)
{
	int siz = 0;
	struct mqtthdr *hdr;
	mqtthdr_var_t *topic;
	mqtt_v_t *mid;

	if (!buf || !csTopic)
		return -1;
	if (QOS > MQTT_QOS_EXACTLY) {
		mqtt_SetErr(EINVAL, "Error:: invalid QoS parameter");
		return -1;
	}
	if (!msgID && QOS != MQTT_QOS_ONCE) {
		mqtt_SetErr(EINVAL, "Error:: invalid MessageID parameter must be >0");
		return -1;
	}

	if (mqtt_msgRealloc(buf, MQTTMSG_MAX) == -1)
		return -1;
	else {
		hdr = (struct mqtthdr *) (buf->msg_base + siz);
		siz += sizeof(struct mqtthdr);
	}

	/* variable header */

	mid = (mqtt_v_t*) (buf->msg_base + siz);
	mid->val = htons(msgID);
	siz += sizeof(mqtt_v_t);

	topic = (mqtthdr_var_t*) (buf->msg_base + siz);
	topic->var_sb.val = htons(strlen(csTopic));
	memcpy(topic->var_data, csTopic, ntohs(topic->var_sb.val));
	siz += MQTTHDR_VAR_SIZEOF(topic);

	/* fixed header */

	hdr->mqtt_msg.type = MQTT_TYPE_SUBSCRIBE;
	hdr->mqtt_msg.qos = QOS;
	hdr->mqtt_msg.dup = Dup ? 1 : 0;
	hdr->mqtt_msg.retain = 0;
	*hdr->mqtt_len = mqtt_encodeLen(siz - sizeof(struct mqtthdr));

	mqtt_msgRealloc(buf, siz);
	return siz;
}