Diff: ble/UUID.h

Revision:

1134:d540a48f650d

Parent:

1131:692ddf04fc42

Child:

1170:e8f2db0e8e11

--- a/ble/UUID.h	Wed Apr 06 19:13:50 2016 +0100
+++ b/ble/UUID.h	Wed Apr 06 19:13:52 2016 +0100
@@ -19,9 +19,27 @@
 
 #include <stdint.h>
 #include <string.h>
+#include <algorithm>
 
 #include "blecommon.h"
 
+/**
+ * A trivial converter for single hexadecimal character to unsigned-int.
+ * @param  c hexadecimal character.
+ * @return   the corresponding value as unsigned int.
+ */
+static uint8_t char2int(char c) {
+    if ((c >= '0') && (c <= '9')) {
+        return c - '0';
+    } else if ((c >= 'a') && (c <= 'f')) {
+        return c - 'a' + 10;
+    } else if ((c >= 'A') && (c <= 'F')) {
+        return c - 'A' + 10;
+    } else {
+        return 0;
+    }
+}
+
 class UUID {
 public:
     enum UUID_Type_t {
@@ -29,12 +47,75 @@
         UUID_TYPE_LONG  = 1     // Full 128-bit UUID.
     };
 
+    /**
+     * An enumeration to specify byte ordering of the long version of the UUID.
+     */
+    typedef enum {
+        MSB, /*!< Most-significant byte first (at the smallest address) */
+        LSB  /*!< least-significant byte first (at the smallest address) */
+    } ByteOrder_t;
+
     typedef uint16_t      ShortUUIDBytes_t;
 
     static const unsigned LENGTH_OF_LONG_UUID = 16;
     typedef uint8_t       LongUUIDBytes_t[LENGTH_OF_LONG_UUID];
 
+    static const unsigned MAX_UUID_STRING_LENGTH = LENGTH_OF_LONG_UUID * 2 + 4;
+
 public:
+
+    /**
+     * Creates a new 128-bit UUID.
+     *
+     * @note   The UUID is a unique 128-bit (16 byte) ID used to identify
+     *         different service or characteristics on the BLE device.
+     *
+     * @param  stringUUID
+     *          The 128-bit (16-byte) UUID as a human readable const-string.
+     *          Format: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
+     *          Upper and lower case supported. Hyphens are optional, but only
+     *          upto four of them. The UUID is stored internally as a 16 byte
+     *          array, LSB (little endian), which is opposite from the string.
+     */
+    UUID(const char* stringUUID) : type(UUID_TYPE_LONG), baseUUID(), shortUUID(0) {
+        bool nibble = false;
+        uint8_t byte = 0;
+        size_t baseIndex = 0;
+        uint8_t tempUUID[LENGTH_OF_LONG_UUID];
+
+        // Iterate through string, abort if NULL is encountered prematurely.
+        // Ignore upto four hyphens.
+        for (size_t index = 0; (index < MAX_UUID_STRING_LENGTH) && (baseIndex < LENGTH_OF_LONG_UUID); index++) {
+            if (stringUUID[index] == '\0') {
+                // error abort
+                break;
+            } else if (stringUUID[index] == '-') {
+                // ignore hyphen
+                continue;
+            } else if (nibble) {
+                // got second nibble
+                byte |= char2int(stringUUID[index]);
+                nibble = false;
+
+                // store copy
+                tempUUID[baseIndex++] = byte;
+            } else {
+                // got first nibble
+                byte = char2int(stringUUID[index]) << 4;
+                nibble = true;
+            }
+        }
+
+        // populate internal variables if string was successfully parsed
+        if (baseIndex == LENGTH_OF_LONG_UUID) {
+            setupLong(tempUUID, UUID::MSB);
+        } else {
+            const uint8_t sig[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x00,
+                                    0x80, 0x00, 0x00, 0x80, 0x5F, 0x9B, 0x34, 0xFB };
+            setupLong(sig, UUID::MSB);
+        }
+    }
+
     /**
      * Creates a new 128-bit UUID.
      *
@@ -42,10 +123,12 @@
      *         different service or characteristics on the BLE device.
      *
      * @param longUUID
-     *          The 128-bit (16-byte) UUID value, MSB first (big-endian).
+     *          The 128-bit (16-byte) UUID value.
+     * @param order
+     *          The bit order of the UUID, MSB by default.
      */
-    UUID(const LongUUIDBytes_t longUUID) : type(UUID_TYPE_LONG), baseUUID(), shortUUID(0) {
-        setupLong(longUUID);
+    UUID(const LongUUIDBytes_t longUUID, ByteOrder_t order = UUID::MSB) : type(UUID_TYPE_LONG), baseUUID(), shortUUID(0) {
+        setupLong(longUUID, order);
     }
 
     /**
@@ -91,10 +174,15 @@
     /**
      * Fill in a 128-bit UUID; this is useful when the UUID isn't known at the time of the object construction.
      */
-    void setupLong(const LongUUIDBytes_t longUUID) {
+    void setupLong(const LongUUIDBytes_t longUUID, ByteOrder_t order = UUID::MSB) {
         type      = UUID_TYPE_LONG;
-        memcpy(baseUUID, longUUID, LENGTH_OF_LONG_UUID);
-        shortUUID = (uint16_t)((longUUID[2] << 8) | (longUUID[3]));
+        if (order == UUID::MSB) {
+            // Switch endian. Input is big-endian, internal representation is little endian.
+            std::reverse_copy(longUUID, longUUID + LENGTH_OF_LONG_UUID, baseUUID);
+        } else {
+            std::copy(longUUID, longUUID + LENGTH_OF_LONG_UUID, baseUUID);
+        }
+        shortUUID = (uint16_t)((baseUUID[13] << 8) | (baseUUID[12]));
     }
 
 public:
@@ -132,12 +220,8 @@
 
 private:
     UUID_Type_t      type;      // UUID_TYPE_SHORT or UUID_TYPE_LONG
-    LongUUIDBytes_t  baseUUID;  /* The base of the long UUID (if
-                            * used). Note: bytes 12 and 13 (counting from LSB)
-                            * are zeroed out to allow comparison with other long
-                            * UUIDs, which differ only in the 16-bit relative
-                            * part.*/
-    ShortUUIDBytes_t shortUUID; // 16 bit UUID (byte 2-3 using with base).
+    LongUUIDBytes_t  baseUUID;  // The long UUID
+    ShortUUIDBytes_t shortUUID; // 16 bit UUID
 };
 
 #endif // ifndef __UUID_H__
\ No newline at end of file