Fix BLEUUID toString

[tanakamasayuki]

uuid16 is Missing first 4 characters.
uuid is Missing last 2 characters.

UUID string format: AABBCCDD-EEFF-GGHH-IIJJ-KKLLMMNNOOPP 123456789012345678901234567890123456 < 36 characters + null 

Test code

#include"BLEDevice.h"voidsetup(){Serial.begin(115200); delay(1000); BLEUUIDuuid("00001812-0000-1000-8000-00805F9B34FB"); Serial.printf("uuid : %s\n", uuid.toString().c_str()); BLEUUIDuuid16("1812"); Serial.printf("uuid16 : %s\n", uuid16.toString().c_str()); BLEUUIDuuid16_2(uuid16.toString().c_str()); Serial.printf("uuid16_2 : %s\n", uuid16_2.toString().c_str()); BLEUUIDuuid32("00001812"); Serial.printf("uuid32 : %s\n", uuid32.toString().c_str())} voidloop(){}

1.0.3 Run

uuid : 00001812-0000-1000-8000-00805f9b34 uuid16 : 1812-0000-1000-8000-00805f9b34fb uuid16_2 : <NULL> uuid32 : 00001812-0000-1000-8000-00805f9b34fb 

uuid -> Missing last 2 characters
uuid16 -> Missing first 4 characters
uuid32 -> Good

This patch

uuid : 00001812-0000-1000-8000-00805f9b34fb uuid16 : 00001812-0000-1000-8000-00805f9b34fb uuid16_2 : 00001812-0000-1000-8000-00805f9b34fb uuid32 : 00001812-0000-1000-8000-00805f9b34fb 

[me-no-dev]

what is the purpose of those 4 leading zeroes? I have never seen them printed or discussed before.

[tanakamasayuki]

The UUID format is specified.

https://en.wikipedia.org/wiki/Universally_unique_identifier

123e4567-e89b-12d3-a456-426655440000 xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx 

in the form 8-4-4-4-12 for a total of 36 characters (32 alphanumeric characters and 4 hyphens).

https://www.bluetooth.com/specifications/assigned-numbers/service-discovery/

BASE_UUID | 00000000-0000-1000-8000-00805F9B34FB 

/libraries/BLE/src/BLEUUID.cpp

/** * @brief Create a UUID from a string. * * Create a UUID from a string. There will be two possible stories here. Either the string represents * a binary data field or the string represents a hex encoding of a UUID. * For the hex encoding, here is an example: * * ``` * "beb5483e-36e1-4688-b7f5-ea07361b26a8" * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 * 12345678-90ab-cdef-1234-567890abcdef * ``` * * This has a length of 36 characters. We need to parse this into 16 bytes. * * @param [in] value The string to build a UUID from. */BLEUUID::BLEUUID(std::stringvalue){m_valueSet= true; if (value.length() ==4){m_uuid.len=ESP_UUID_LEN_16; m_uuid.uuid.uuid16=0; for(inti=0;i<value.length();){uint8_tMSB=value.c_str()[i]; uint8_tLSB=value.c_str()[i+1]; if(MSB>'9') MSB-=7; if(LSB>'9') LSB-=7; m_uuid.uuid.uuid16+= (((MSB&0x0F) <<4) | (LSB&0x0F))<<(2-i)*4; i+=2} } elseif (value.length() ==8){m_uuid.len=ESP_UUID_LEN_32; m_uuid.uuid.uuid32=0; for(inti=0;i<value.length();){uint8_tMSB=value.c_str()[i]; uint8_tLSB=value.c_str()[i+1]; if(MSB>'9') MSB-=7; if(LSB>'9') LSB-=7; m_uuid.uuid.uuid32+= (((MSB&0x0F) <<4) | (LSB&0x0F))<<(6-i)*4; i+=2} } elseif (value.length() ==16){// how we can have 16 byte length string reprezenting 128 bit uuid??? needs to be investigated (lack of time)m_uuid.len=ESP_UUID_LEN_128; memrcpy(m_uuid.uuid.uuid128, (uint8_t*)value.data(), 16)} elseif (value.length() ==36){// If the length of the string is 36 bytes then we will assume it is a long hex string in// UUID format.m_uuid.len=ESP_UUID_LEN_128; intn=0; for(inti=0;i<value.length();){if(value.c_str()[i] =='-') i++; uint8_tMSB=value.c_str()[i]; uint8_tLSB=value.c_str()[i+1]; if(MSB>'9') MSB-=7; if(LSB>'9') LSB-=7; m_uuid.uuid.uuid128[15-n++] = ((MSB&0x0F) <<4) | (LSB&0x0F); i+=2} } else{log_e("ERROR: UUID value not 2, 4, 16 or 36 bytes"); m_valueSet= false} } //BLEUUID(std::string)

*Thishasalengthof36characters. Weneedtoparsethisinto16bytes.

elseif (value.length() ==36){

If it is 32 characters, an input error occurs.