From becaf02ab63a67d584fcaa64fe649b69bb7a931f Mon Sep 17 00:00:00 2001
From: Jef Driesen <jefdriesen@users.sourceforge.net>
Date: Thu, 15 Feb 2018 08:25:28 +0100
Subject: [PATCH] Add functions for converting bluetooth addresses

---
 src/bluetooth.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 src/bluetooth.h | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+)

diff --git a/src/bluetooth.c b/src/bluetooth.c
index e6dc09d..08347d5 100644
--- a/src/bluetooth.c
+++ b/src/bluetooth.c
@@ -24,6 +24,7 @@
 #endif
 
 #include <stdlib.h> // malloc, free
+#include <stdio.h>
 
 #include "socket.h"
 
@@ -223,6 +224,54 @@ error:
 #endif
 #endif
 
+char *
+dc_bluetooth_addr2str(dc_bluetooth_address_t address, char *str, size_t size)
+{
+	if (str == NULL || size < DC_BLUETOOTH_SIZE)
+		return NULL;
+
+	int n = snprintf(str, size, "%02X:%02X:%02X:%02X:%02X:%02X",
+		(unsigned char)((address >> 40) & 0xFF),
+		(unsigned char)((address >> 32) & 0xFF),
+		(unsigned char)((address >> 24) & 0xFF),
+		(unsigned char)((address >> 16) & 0xFF),
+		(unsigned char)((address >>  8) & 0xFF),
+		(unsigned char)((address >>  0) & 0xFF));
+	if (n < 0 || (size_t) n >= size)
+		return NULL;
+
+	return str;
+}
+
+dc_bluetooth_address_t
+dc_bluetooth_str2addr(const char *str)
+{
+	dc_bluetooth_address_t address = 0;
+
+	if (str == NULL)
+		return 0;
+
+	unsigned char c = 0;
+	while ((c = *str++) != '\0') {
+		if (c == ':') {
+			continue;
+		} else if (c >= '0' && c <= '9') {
+			c -= '0';
+		} else if (c >= 'A' && c <= 'F') {
+			c -= 'A' - 10;
+		} else if (c >= 'a' && c <= 'f') {
+			c -= 'a' - 10;
+		} else {
+			return 0; /* Invalid character! */
+		}
+
+		address <<= 4;
+		address |= c;
+	}
+
+	return address;
+}
+
 dc_bluetooth_address_t
 dc_bluetooth_device_get_address (dc_bluetooth_device_t *device)
 {
diff --git a/src/bluetooth.h b/src/bluetooth.h
index bc5bb2a..5b443a4 100644
--- a/src/bluetooth.h
+++ b/src/bluetooth.h
@@ -32,6 +32,12 @@
 extern "C" {
 #endif /* __cplusplus */
 
+/**
+ * The minimum number of bytes (including the terminating null byte) for
+ * formatting a bluetooth address as a string.
+ */
+#define DC_BLUETOOTH_SIZE 18
+
 /**
  * Bluetooth address (48 bits).
  */
@@ -41,6 +47,34 @@ typedef unsigned __int64 dc_bluetooth_address_t;
 typedef unsigned long long dc_bluetooth_address_t;
 #endif
 
+/**
+ * Convert a bluetooth address to a string.
+ *
+ * The bluetooth address is formatted as XX:XX:XX:XX:XX:XX, where each
+ * XX is a hexadecimal number specifying an octet of the 48-bit address.
+ * The minimum size for the buffer is #DC_BLUETOOTH_SIZE bytes.
+ *
+ * @param[in]  address  A bluetooth address.
+ * @param[in]  str      The memory buffer to store the result.
+ * @param[in]  size     The size of the memory buffer.
+ * @returns The null-terminated string on success, or NULL on failure.
+ */
+char *
+dc_bluetooth_addr2str(dc_bluetooth_address_t address, char *str, size_t size);
+
+/**
+ * Convert a string to a bluetooth address.
+ *
+ * The string is expected to be in the format XX:XX:XX:XX:XX:XX, where
+ * each XX is a hexadecimal number specifying an octet of the 48-bit
+ * address.
+ *
+ * @param[in]  address  A null-terminated string.
+ * @returns The bluetooth address on success, or zero on failure.
+ */
+dc_bluetooth_address_t
+dc_bluetooth_str2addr(const char *address);
+
 /**
  * Opaque object representing a bluetooth device.
  */