1 files changed, 13 insertions, 8 deletions
diff --git a/src/venus_api.c b/src/venus_api.c
index 04ad78d..40a52ea 100644
--- a/src/venus_api.c
+++ b/src/venus_api.c
@@ -267,19 +267,24 @@ int venus_write_msg_read_ack(int fd, struct venus_msg *msg)
 
 ssize_t venus_read_nmea_sentence(int fd, void *buf, size_t count)
 {
-	int err;
-	char c;
 	ssize_t total = 0;
 	char *cp = buf;
-
 	int start = 0;
+	char c;
+	int err;
 
-	while (1) {
+	if (!count) {
+		return 0;
+	}
+	count--;
+
+	while (count > 0) {
 		err = safe_read(fd, &c, 1);
 		if (err <= 0) {
 			log_error("read from gps failed: %m");
 			return -1;
 		}
+
 		if (!start) {
 			if (c != '$') {
 				continue;
@@ -287,16 +292,16 @@ ssize_t venus_read_nmea_sentence(int fd, void *buf, size_t count)
 			start = 1;
 		}
 
-		if (total < count) {
-			*cp++ = c;
-			total++;
-		}
+		cp[total++] = c;
+		count--;
 
 		if (c == '\n') {
 			break;
 		}
 	}
 
+	cp[total] = '\0';
+
 	return total;
 }