From ccc97d8c96c6e679891cc85d29e75cf8c032ea0d Mon Sep 17 00:00:00 2001
From: "Roger A. Light" <roger@atchoo.org>
Date: Thu, 30 Aug 2018 22:49:32 +0100
Subject: [PATCH] Function for reading variable length ints from packet.

---
 lib/packet_mosq.c | 25 +++++++++++++++++++++++++
 lib/packet_mosq.h |  1 +
 2 files changed, 26 insertions(+)

diff --git a/lib/packet_mosq.c b/lib/packet_mosq.c
index ddfaef49..78916568 100644
--- a/lib/packet_mosq.c
+++ b/lib/packet_mosq.c
@@ -280,6 +280,31 @@ void packet__write_uint32(struct mosquitto__packet *packet, uint32_t word)
 }
 
 
+int packet__read_varint(struct mosquitto__packet *packet, uint32_t *word)
+{
+	int i;
+	int remaining_mult = 1;
+	uint8_t byte;
+
+	*word = 0;
+
+	for(i=0; i<4; i++){
+		if(packet->pos < packet->remaining_length){
+			byte = packet->payload[packet->pos];
+			word += (byte & 127) * remaining_mult;
+			remaining_mult *= 128;
+			packet->pos++;
+			if((byte & 128) == 0){
+				return MOSQ_ERR_SUCCESS;
+			}
+		}else{
+			return MOSQ_ERR_PROTOCOL;
+		}
+	}
+	return MOSQ_ERR_PROTOCOL;
+}
+
+
 int packet__write(struct mosquitto *mosq)
 {
 	ssize_t write_length;
diff --git a/lib/packet_mosq.h b/lib/packet_mosq.h
index 915605d5..56e27e2d 100644
--- a/lib/packet_mosq.h
+++ b/lib/packet_mosq.h
@@ -32,6 +32,7 @@ int packet__read_bytes(struct mosquitto__packet *packet, void *bytes, uint32_t c
 int packet__read_string(struct mosquitto__packet *packet, char **str, int *length);
 int packet__read_uint16(struct mosquitto__packet *packet, uint16_t *word);
 int packet__read_uint32(struct mosquitto__packet *packet, uint32_t *word);
+int packet__read_varint(struct mosquitto__packet *packet, uint32_t *word);
 
 void packet__write_byte(struct mosquitto__packet *packet, uint8_t byte);
 void packet__write_bytes(struct mosquitto__packet *packet, const void *bytes, uint32_t count);