add a comment to UUID constructor to explain MSB byte ordering.

This commit is contained in:
Rohit Grover 2015-05-26 10:01:08 +01:00
parent dc406f5b23
commit 273ed9e69f
1 changed files with 129 additions and 129 deletions

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@ -1,129 +1,129 @@
/* mbed Microcontroller Library
* Copyright (c) 2006-2013 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef __UUID_H__
#define __UUID_H__
#include <string.h>
#include "blecommon.h"
class UUID {
public:
enum UUID_Type_t {
UUID_TYPE_SHORT = 0, // Short BLE UUID
UUID_TYPE_LONG = 1 // Full 128-bit UUID
};
static const unsigned LENGTH_OF_LONG_UUID = 16;
typedef uint16_t ShortUUIDBytes_t;
typedef uint8_t LongUUIDBytes_t[LENGTH_OF_LONG_UUID];
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 longUUID
* The 128-bit (16-byte) UUID value.
*/
UUID(const LongUUIDBytes_t longUUID) : type(UUID_TYPE_LONG), baseUUID(), shortUUID(0) {
memcpy(baseUUID, longUUID, LENGTH_OF_LONG_UUID);
shortUUID = (uint16_t)((longUUID[2] << 8) | (longUUID[3]));
}
/**
* Creates a new 16-bit UUID
*
* @note The UUID is a unique 16-bit (2 byte) ID used to identify
* different service or characteristics on the BLE device.
*
* For efficiency, and because 16 bytes would take a large chunk of the
* 27-byte data payload length of the Link Layer, the BLE specification adds
* two additional UUID formats: 16-bit and 32-bit UUIDs. These shortened
* formats can be used only with UUIDs that are defined in the Bluetooth
* specification (i.e., that are listed by the Bluetooth SIG as standard
* Bluetooth UUIDs).
*
* To reconstruct the full 128-bit UUID from the shortened version, insert
* the 16-bit short value (indicated by xxxx, including leading zeros) into
* the Bluetooth Base UUID:
*
* 0000xxxx-0000-1000-8000-00805F9B34FB
*
* @note Shortening is not available for UUIDs that are not derived from the
* Bluetooth Base UUID. Such non-standard UUIDs are commonly called
* vendor-specific UUIDs. In these cases, youll need to use the full
* 128-bit UUID value at all times.
*
* @note we don't yet support 32-bit shortened UUIDs.
*/
UUID(ShortUUIDBytes_t shortUUID) : type(UUID_TYPE_SHORT), baseUUID(), shortUUID(shortUUID) {
/* empty */
}
UUID(const UUID &source) {
type = source.type;
shortUUID = source.shortUUID;
memcpy(baseUUID, source.baseUUID, LENGTH_OF_LONG_UUID);
}
UUID(void) : type(UUID_TYPE_SHORT), shortUUID(BLE_UUID_UNKNOWN) {
/* empty */
}
public:
UUID_Type_t shortOrLong(void) const {return type; }
const uint8_t *getBaseUUID(void) const {
if (type == UUID_TYPE_SHORT) {
return (const uint8_t*)&shortUUID;
} else {
return baseUUID;
}
}
ShortUUIDBytes_t getShortUUID(void) const {return shortUUID;}
uint8_t getLen(void) const {
return ((type == UUID_TYPE_SHORT) ? sizeof(ShortUUIDBytes_t) : LENGTH_OF_LONG_UUID);
}
bool operator== (const UUID &other) const {
if ((this->type == UUID_TYPE_SHORT) && (other.type == UUID_TYPE_SHORT) &&
(this->shortUUID == other.shortUUID)) {
return true;
}
if ((this->type == UUID_TYPE_LONG) && (other.type == UUID_TYPE_LONG) &&
(memcmp(this->baseUUID, other.baseUUID, LENGTH_OF_LONG_UUID) == 0)) {
return true;
}
return false;
}
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)
};
#endif // ifndef __UUID_H__
/* mbed Microcontroller Library
* Copyright (c) 2006-2013 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef __UUID_H__
#define __UUID_H__
#include <string.h>
#include "blecommon.h"
class UUID {
public:
enum UUID_Type_t {
UUID_TYPE_SHORT = 0, // Short BLE UUID
UUID_TYPE_LONG = 1 // Full 128-bit UUID
};
static const unsigned LENGTH_OF_LONG_UUID = 16;
typedef uint16_t ShortUUIDBytes_t;
typedef uint8_t LongUUIDBytes_t[LENGTH_OF_LONG_UUID];
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 longUUID
* The 128-bit (16-byte) UUID value, MSB first (big-endian).
*/
UUID(const LongUUIDBytes_t longUUID) : type(UUID_TYPE_LONG), baseUUID(), shortUUID(0) {
memcpy(baseUUID, longUUID, LENGTH_OF_LONG_UUID);
shortUUID = (uint16_t)((longUUID[2] << 8) | (longUUID[3]));
}
/**
* Creates a new 16-bit UUID
*
* @note The UUID is a unique 16-bit (2 byte) ID used to identify
* different service or characteristics on the BLE device.
*
* For efficiency, and because 16 bytes would take a large chunk of the
* 27-byte data payload length of the Link Layer, the BLE specification adds
* two additional UUID formats: 16-bit and 32-bit UUIDs. These shortened
* formats can be used only with UUIDs that are defined in the Bluetooth
* specification (i.e., that are listed by the Bluetooth SIG as standard
* Bluetooth UUIDs).
*
* To reconstruct the full 128-bit UUID from the shortened version, insert
* the 16-bit short value (indicated by xxxx, including leading zeros) into
* the Bluetooth Base UUID:
*
* 0000xxxx-0000-1000-8000-00805F9B34FB
*
* @note Shortening is not available for UUIDs that are not derived from the
* Bluetooth Base UUID. Such non-standard UUIDs are commonly called
* vendor-specific UUIDs. In these cases, youll need to use the full
* 128-bit UUID value at all times.
*
* @note we don't yet support 32-bit shortened UUIDs.
*/
UUID(ShortUUIDBytes_t shortUUID) : type(UUID_TYPE_SHORT), baseUUID(), shortUUID(shortUUID) {
/* empty */
}
UUID(const UUID &source) {
type = source.type;
shortUUID = source.shortUUID;
memcpy(baseUUID, source.baseUUID, LENGTH_OF_LONG_UUID);
}
UUID(void) : type(UUID_TYPE_SHORT), shortUUID(BLE_UUID_UNKNOWN) {
/* empty */
}
public:
UUID_Type_t shortOrLong(void) const {return type; }
const uint8_t *getBaseUUID(void) const {
if (type == UUID_TYPE_SHORT) {
return (const uint8_t*)&shortUUID;
} else {
return baseUUID;
}
}
ShortUUIDBytes_t getShortUUID(void) const {return shortUUID;}
uint8_t getLen(void) const {
return ((type == UUID_TYPE_SHORT) ? sizeof(ShortUUIDBytes_t) : LENGTH_OF_LONG_UUID);
}
bool operator== (const UUID &other) const {
if ((this->type == UUID_TYPE_SHORT) && (other.type == UUID_TYPE_SHORT) &&
(this->shortUUID == other.shortUUID)) {
return true;
}
if ((this->type == UUID_TYPE_LONG) && (other.type == UUID_TYPE_LONG) &&
(memcmp(this->baseUUID, other.baseUUID, LENGTH_OF_LONG_UUID) == 0)) {
return true;
}
return false;
}
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)
};
#endif // ifndef __UUID_H__