UUID.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 #ifndef __UUID_H__
00018 #define __UUID_H__
00019 
00020 #include <stdint.h>
00021 #include <string.h>
00022 #include <algorithm>
00023 
00024 #include "blecommon.h"
00025 
00026 /**
00027  * A trivial converter for single hexadecimal character to unsigned-int.
00028  * @param  c hexadecimal character.
00029  * @return   the corresponding value as unsigned int.
00030  */
00031 static uint8_t char2int(char c) {
00032     if ((c >= '0') && (c <= '9')) {
00033         return c - '0';
00034     } else if ((c >= 'a') && (c <= 'f')) {
00035         return c - 'a' + 10;
00036     } else if ((c >= 'A') && (c <= 'F')) {
00037         return c - 'A' + 10;
00038     } else {
00039         return 0;
00040     }
00041 }
00042 
00043 class UUID {
00044 public:
00045     enum UUID_Type_t {
00046         UUID_TYPE_SHORT = 0,    // Short BLE UUID.
00047         UUID_TYPE_LONG  = 1     // Full 128-bit UUID.
00048     };
00049 
00050     /**
00051      * An enumeration to specify byte ordering of the long version of the UUID.
00052      */
00053     typedef enum {
00054         MSB, /*!< Most-significant byte first (at the smallest address) */
00055         LSB  /*!< least-significant byte first (at the smallest address) */
00056     } ByteOrder_t;
00057 
00058     typedef uint16_t      ShortUUIDBytes_t;
00059 
00060     static const unsigned LENGTH_OF_LONG_UUID = 16;
00061     typedef uint8_t       LongUUIDBytes_t[LENGTH_OF_LONG_UUID];
00062 
00063     static const unsigned MAX_UUID_STRING_LENGTH = LENGTH_OF_LONG_UUID * 2 + 4;
00064 
00065 public:
00066 
00067     /**
00068      * Creates a new 128-bit UUID.
00069      *
00070      * @note   The UUID is a unique 128-bit (16 byte) ID used to identify
00071      *         different service or characteristics on the BLE device.
00072      *
00073      * @param  stringUUID
00074      *          The 128-bit (16-byte) UUID as a human readable const-string.
00075      *          Format: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
00076      *          Upper and lower case supported. Hyphens are optional, but only
00077      *          upto four of them. The UUID is stored internally as a 16 byte
00078      *          array, LSB (little endian), which is opposite from the string.
00079      */
00080     UUID(const char* stringUUID) : type(UUID_TYPE_LONG), baseUUID(), shortUUID(0) {
00081         bool nibble = false;
00082         uint8_t byte = 0;
00083         size_t baseIndex = 0;
00084         uint8_t tempUUID[LENGTH_OF_LONG_UUID];
00085 
00086         // Iterate through string, abort if NULL is encountered prematurely.
00087         // Ignore upto four hyphens.
00088         for (size_t index = 0; (index < MAX_UUID_STRING_LENGTH) && (baseIndex < LENGTH_OF_LONG_UUID); index++) {
00089             if (stringUUID[index] == '\0') {
00090                 // error abort
00091                 break;
00092             } else if (stringUUID[index] == '-') {
00093                 // ignore hyphen
00094                 continue;
00095             } else if (nibble) {
00096                 // got second nibble
00097                 byte |= char2int(stringUUID[index]);
00098                 nibble = false;
00099 
00100                 // store copy
00101                 tempUUID[baseIndex++] = byte;
00102             } else {
00103                 // got first nibble
00104                 byte = char2int(stringUUID[index]) << 4;
00105                 nibble = true;
00106             }
00107         }
00108 
00109         // populate internal variables if string was successfully parsed
00110         if (baseIndex == LENGTH_OF_LONG_UUID) {
00111             setupLong(tempUUID, UUID::MSB);
00112         } else {
00113             const uint8_t sig[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x00,
00114                                     0x80, 0x00, 0x00, 0x80, 0x5F, 0x9B, 0x34, 0xFB };
00115             setupLong(sig, UUID::MSB);
00116         }
00117     }
00118 
00119     /**
00120      * Creates a new 128-bit UUID.
00121      *
00122      * @note   The UUID is a unique 128-bit (16 byte) ID used to identify
00123      *         different service or characteristics on the BLE device.
00124      *
00125      * @param longUUID
00126      *          The 128-bit (16-byte) UUID value.
00127      * @param order
00128      *          The bit order of the UUID, MSB by default.
00129      */
00130     UUID(const LongUUIDBytes_t longUUID, ByteOrder_t order = UUID::MSB) : type(UUID_TYPE_LONG), baseUUID(), shortUUID(0) {
00131         setupLong(longUUID, order);
00132     }
00133 
00134     /**
00135      * Creates a new 16-bit UUID.
00136      *
00137      * @note The UUID is a unique 16-bit (2 byte) ID used to identify
00138      *       different service or characteristics on the BLE device.
00139      *
00140      * For efficiency, and because 16 bytes would take a large chunk of the
00141      * 27-byte data payload length of the Link Layer, the BLE specification adds
00142      * two additional UUID formats: 16-bit and 32-bit UUIDs. These shortened
00143      * formats can be used only with UUIDs that are defined in the Bluetooth
00144      * specification (listed by the Bluetooth SIG as standard
00145      * Bluetooth UUIDs).
00146      *
00147      * To reconstruct the full 128-bit UUID from the shortened version, insert
00148      * the 16-bit short value (indicated by xxxx, including leading zeros) into
00149      * the Bluetooth Base UUID:
00150      *
00151      *  0000xxxx-0000-1000-8000-00805F9B34FB
00152      *
00153      * @note Shortening is not available for UUIDs that are not derived from the
00154      *       Bluetooth Base UUID. Such non-standard UUIDs are commonly called
00155      *       vendor-specific UUIDs. In these cases, you’ll need to use the full
00156      *       128-bit UUID value at all times.
00157      *
00158      * @note We don't yet support 32-bit shortened UUIDs.
00159      */
00160     UUID(ShortUUIDBytes_t _shortUUID) : type(UUID_TYPE_SHORT), baseUUID(), shortUUID(_shortUUID) {
00161         /* Empty */
00162     }
00163 
00164     UUID(const UUID &source) {
00165         type      = source.type;
00166         shortUUID = source.shortUUID;
00167         memcpy(baseUUID, source.baseUUID, LENGTH_OF_LONG_UUID);
00168     }
00169 
00170     UUID(void) : type(UUID_TYPE_SHORT), shortUUID(BLE_UUID_UNKNOWN) {
00171         /* empty */
00172     }
00173 
00174     /**
00175      * Fill in a 128-bit UUID; this is useful when the UUID isn't known at the time of the object construction.
00176      */
00177     void setupLong(const LongUUIDBytes_t longUUID, ByteOrder_t order = UUID::MSB) {
00178         type      = UUID_TYPE_LONG;
00179         if (order == UUID::MSB) {
00180             // Switch endian. Input is big-endian, internal representation is little endian.
00181             std::reverse_copy(longUUID, longUUID + LENGTH_OF_LONG_UUID, baseUUID);
00182         } else {
00183             std::copy(longUUID, longUUID + LENGTH_OF_LONG_UUID, baseUUID);
00184         }
00185         shortUUID = (uint16_t)((baseUUID[13] << 8) | (baseUUID[12]));
00186     }
00187 
00188 public:
00189     UUID_Type_t       shortOrLong(void)  const {return type;     }
00190     const uint8_t    *getBaseUUID(void)  const {
00191         if (type == UUID_TYPE_SHORT) {
00192             return (const uint8_t*)&shortUUID;
00193         } else {
00194             return baseUUID;
00195         }
00196     }
00197 
00198     ShortUUIDBytes_t  getShortUUID(void) const {return shortUUID;}
00199     uint8_t           getLen(void)       const {
00200         return ((type == UUID_TYPE_SHORT) ? sizeof(ShortUUIDBytes_t) : LENGTH_OF_LONG_UUID);
00201     }
00202 
00203     bool operator== (const UUID &other) const {
00204         if ((this->type == UUID_TYPE_SHORT) && (other.type == UUID_TYPE_SHORT) &&
00205             (this->shortUUID == other.shortUUID)) {
00206             return true;
00207         }
00208 
00209         if ((this->type == UUID_TYPE_LONG) && (other.type == UUID_TYPE_LONG) &&
00210             (memcmp(this->baseUUID, other.baseUUID, LENGTH_OF_LONG_UUID) == 0)) {
00211             return true;
00212         }
00213 
00214         return false;
00215     }
00216 
00217     bool operator!= (const UUID &other) const {
00218         return !(*this == other);
00219     }
00220 
00221 private:
00222     UUID_Type_t      type;      // UUID_TYPE_SHORT or UUID_TYPE_LONG
00223     LongUUIDBytes_t  baseUUID;  // The long UUID
00224     ShortUUIDBytes_t shortUUID; // 16 bit UUID
00225 };
00226 
00227 #endif // ifndef __UUID_H__