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 an unsigned integer.
00028  *
00029  * @param  c
00030  *          Hexadecimal character.
00031  *
00032  * @return The corresponding value as unsigned integer.
00033  */
00034 static uint8_t char2int(char c) {
00035     if ((c >= '0') && (c <= '9')) {
00036         return c - '0';
00037     } else if ((c >= 'a') && (c <= 'f')) {
00038         return c - 'a' + 10;
00039     } else if ((c >= 'A') && (c <= 'F')) {
00040         return c - 'A' + 10;
00041     } else {
00042         return 0;
00043     }
00044 }
00045 
00046 /**
00047  * An instance of this class represents a Universally Unique Identifier (UUID)
00048  * in the BLE API.
00049  */
00050 class UUID {
00051 public:
00052     /**
00053      * Enumeration of the possible types of UUIDs in BLE with regards to length.
00054      */
00055     enum UUID_Type_t {
00056         UUID_TYPE_SHORT = 0,    /**< Short 16-bit UUID. */
00057         UUID_TYPE_LONG  = 1     /**< Full 128-bit UUID. */
00058     };
00059 
00060     /**
00061      * Enumeration to specify byte ordering of the long version of the UUID.
00062      */
00063     typedef enum {
00064         MSB, /**< Most-significant byte first (at the smallest address) */
00065         LSB  /**< least-significant byte first (at the smallest address) */
00066     } ByteOrder_t;
00067 
00068     /**
00069      * Type for a 16-bit UUID.
00070      */
00071     typedef uint16_t      ShortUUIDBytes_t;
00072 
00073     /**
00074      * Length of a long UUID in bytes.
00075      */
00076     static const unsigned LENGTH_OF_LONG_UUID = 16;
00077     /**
00078      * Type for a 128-bit UUID.
00079      */
00080     typedef uint8_t       LongUUIDBytes_t[LENGTH_OF_LONG_UUID];
00081 
00082     /**
00083      * Maximum length of a string representation of a UUID not including the
00084      * null termination ('\0'): two characters per
00085      * byte plus four '-' characters.
00086      */
00087     static const unsigned MAX_UUID_STRING_LENGTH = LENGTH_OF_LONG_UUID * 2 + 4;
00088 
00089 public:
00090 
00091     /**
00092      * Creates a new 128-bit UUID.
00093      *
00094      * @note   The UUID is a unique 128-bit (16 byte) ID used to identify
00095      *         different service or characteristics on the BLE device.
00096      *
00097      * @param  stringUUID
00098      *          The 128-bit (16-byte) UUID as a human readable const-string.
00099      *          Format: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
00100      *          Upper and lower case supported. Hyphens are optional, but only
00101      *          upto four of them. The UUID is stored internally as a 16 byte
00102      *          array, LSB (little endian), which is opposite from the string.
00103      */
00104     UUID(const char* stringUUID) : type(UUID_TYPE_LONG), baseUUID(), shortUUID(0) {
00105         bool nibble = false;
00106         uint8_t byte = 0;
00107         size_t baseIndex = 0;
00108         uint8_t tempUUID[LENGTH_OF_LONG_UUID];
00109 
00110         /*
00111          * Iterate through string, abort if NULL is encountered prematurely.
00112          * Ignore upto four hyphens.
00113          */
00114         for (size_t index = 0; (index < MAX_UUID_STRING_LENGTH) && (baseIndex < LENGTH_OF_LONG_UUID); index++) {
00115             if (stringUUID[index] == '\0') {
00116                 /* Error abort */
00117                 break;
00118             } else if (stringUUID[index] == '-') {
00119                 /* Ignore hyphen */
00120                 continue;
00121             } else if (nibble) {
00122                 /* Got second nibble */
00123                 byte |= char2int(stringUUID[index]);
00124                 nibble = false;
00125 
00126                 /* Store copy */
00127                 tempUUID[baseIndex++] = byte;
00128             } else {
00129                 /* Got first nibble */
00130                 byte = char2int(stringUUID[index]) << 4;
00131                 nibble = true;
00132             }
00133         }
00134 
00135         /* Populate internal variables if string was successfully parsed */
00136         if (baseIndex == LENGTH_OF_LONG_UUID) {
00137             setupLong(tempUUID, UUID::MSB);
00138         } else {
00139             const uint8_t sig[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x00,
00140                                     0x80, 0x00, 0x00, 0x80, 0x5F, 0x9B, 0x34, 0xFB };
00141             setupLong(sig, UUID::MSB);
00142         }
00143     }
00144 
00145     /**
00146      * Creates a new 128-bit UUID.
00147      *
00148      * @param[in] longUUID
00149      *              The 128-bit (16-byte) UUID value.
00150      * @param[in] order
00151      *              The bit order of the UUID, MSB by default.
00152      *
00153      * @note   The UUID is a unique 128-bit (16 byte) ID used to identify
00154      *         different service or characteristics on the BLE device.
00155      */
00156     UUID(const LongUUIDBytes_t longUUID, ByteOrder_t order = UUID::MSB) : type(UUID_TYPE_LONG), baseUUID(), shortUUID(0) {
00157         setupLong(longUUID, order);
00158     }
00159 
00160     /**
00161      * Creates a new 16-bit UUID.
00162      *
00163      * For efficiency, and because 16 bytes would take a large chunk of the
00164      * 27-byte data payload length of the Link Layer, the BLE specification adds
00165      * two additional UUID formats: 16-bit and 32-bit UUIDs. These shortened
00166      * formats can be used only with UUIDs that are defined in the Bluetooth
00167      * specification (listed by the Bluetooth SIG as standard
00168      * Bluetooth UUIDs).
00169      *
00170      * To reconstruct the full 128-bit UUID from the shortened version, insert
00171      * the 16-bit short value (indicated by xxxx, including leading zeros) into
00172      * the Bluetooth Base UUID:
00173      *
00174      *  0000xxxx-0000-1000-8000-00805F9B34FB
00175      *
00176      * @param[in] _shortUUID
00177      *              The short UUID value.
00178      *
00179      * @note Shortening is not available for UUIDs that are not derived from the
00180      *       Bluetooth Base UUID. Such non-standard UUIDs are commonly called
00181      *       vendor-specific UUIDs. In these cases, you’ll need to use the full
00182      *       128-bit UUID value at all times.
00183      *
00184      * @note The UUID is a unique 16-bit (2 byte) ID used to identify
00185      *       different service or characteristics on the BLE device.
00186      *
00187      * @note We do not yet support 32-bit shortened UUIDs.
00188      */
00189     UUID(ShortUUIDBytes_t _shortUUID) : type(UUID_TYPE_SHORT), baseUUID(), shortUUID(_shortUUID) {
00190         /* Empty */
00191     }
00192 
00193     /**
00194      * Copy constructor.
00195      *
00196      * @param[in] source
00197      *              The UUID to copy.
00198      */
00199     UUID(const UUID &source) {
00200         type      = source.type;
00201         shortUUID = source.shortUUID;
00202         memcpy(baseUUID, source.baseUUID, LENGTH_OF_LONG_UUID);
00203     }
00204 
00205     /**
00206      * The empty constructor.
00207      *
00208      * @note The type of the resulting UUID instance is UUID_TYPE_SHORT and the
00209      *       value BLE_UUID_UNKNOWN.
00210      */
00211     UUID(void) : type(UUID_TYPE_SHORT), shortUUID(BLE_UUID_UNKNOWN) {
00212         /* empty */
00213     }
00214 
00215     /**
00216      * Fill in a 128-bit UUID; this is useful when the UUID is not known at the
00217      * time of the object construction.
00218      *
00219      * @param[in] longUUID
00220      *              The UUID value to copy.
00221      * @param[in]  order
00222      *              The byte ordering of the UUID at @p longUUID.
00223      */
00224     void setupLong(const LongUUIDBytes_t longUUID, ByteOrder_t order = UUID::MSB) {
00225         type      = UUID_TYPE_LONG;
00226         if (order == UUID::MSB) {
00227             /*
00228              * Switch endian. Input is big-endian, internal representation
00229              * is little endian.
00230              */
00231             std::reverse_copy(longUUID, longUUID + LENGTH_OF_LONG_UUID, baseUUID);
00232         } else {
00233             std::copy(longUUID, longUUID + LENGTH_OF_LONG_UUID, baseUUID);
00234         }
00235         shortUUID = (uint16_t)((baseUUID[13] << 8) | (baseUUID[12]));
00236     }
00237 
00238 public:
00239     /**
00240      * Check whether this UUID is short or long.
00241      *
00242      * @return UUID_TYPE_SHORT if the UUID is short, UUID_TYPE_LONG otherwise.
00243      */
00244     UUID_Type_t shortOrLong(void) const {
00245         return type;
00246     }
00247 
00248     /**
00249      * Get a pointer to the UUID value based on the current UUID type.
00250      *
00251      * @return A pointer to the short UUID if the type is set to
00252      *         UUID_TYPE_SHORT. Otherwise, a pointer to the long UUID if the
00253      *         type is set to UUID_TYPE_LONG.
00254      */
00255     const uint8_t *getBaseUUID(void) const {
00256         if (type == UUID_TYPE_SHORT) {
00257             return (const uint8_t*)&shortUUID;
00258         } else {
00259             return baseUUID;
00260         }
00261     }
00262 
00263     /**
00264      * Get the short UUID.
00265      *
00266      * @return The short UUID.
00267      */
00268     ShortUUIDBytes_t getShortUUID(void) const {
00269         return shortUUID;
00270     }
00271 
00272     /**
00273      * Get the length (in bytes) of the UUID based on its type.
00274      *
00275      * @retval sizeof(ShortUUIDBytes_t) if the UUID type is UUID_TYPE_SHORT.
00276      * @retval LENGTH_OF_LONG_UUID if the UUID type is UUID_TYPE_LONG.
00277      */
00278     uint8_t getLen(void) const {
00279         return ((type == UUID_TYPE_SHORT) ? sizeof(ShortUUIDBytes_t) : LENGTH_OF_LONG_UUID);
00280     }
00281 
00282     /**
00283      * Overload == operator to enable UUID comparisons.
00284      *
00285      * @param[in] other
00286      *              The other UUID in the comparison.
00287      *
00288      * @return true if this == @p other, false otherwise.
00289      */
00290     bool operator== (const UUID &other) const {
00291         if ((this->type == UUID_TYPE_SHORT) && (other.type == UUID_TYPE_SHORT) &&
00292             (this->shortUUID == other.shortUUID)) {
00293             return true;
00294         }
00295 
00296         if ((this->type == UUID_TYPE_LONG) && (other.type == UUID_TYPE_LONG) &&
00297             (memcmp(this->baseUUID, other.baseUUID, LENGTH_OF_LONG_UUID) == 0)) {
00298             return true;
00299         }
00300 
00301         return false;
00302     }
00303 
00304     /**
00305      * Overload != operator to enable UUID comparisons.
00306      *
00307      * @param[in] other
00308      *              The other UUID in the comparison.
00309      *
00310      * @return true if this != @p other, false otherwise.
00311      */
00312     bool operator!= (const UUID &other) const {
00313         return !(*this == other);
00314     }
00315 
00316 private:
00317     /**
00318      * The UUID type. Refer to UUID_Type_t.
00319      */
00320     UUID_Type_t      type;
00321     /**
00322      * The long UUID value.
00323      */
00324     LongUUIDBytes_t  baseUUID;
00325     /**
00326      * The short UUID value.
00327      */
00328     ShortUUIDBytes_t shortUUID;
00329 };
00330 
00331 #endif // ifndef __UUID_H__