byte

问题 C++17 introduced a new type, std::byte , so now we finally have a first-class citizen type to represent bytes in memory. Besides being a novelty in the standard, the C++ rules for object creation, start and end of life, aliasing etc. are fairly complicated an unintuitive most of the times, so whenever I feel std::byte is the right tool I also get nervous and reluctant to use it, for fear of unintentionally summoning the Undefined Behavior Balrogs. One such case is a buffer to be used with

问题 C++17 introduced a new type, std::byte , so now we finally have a first-class citizen type to represent bytes in memory. Besides being a novelty in the standard, the C++ rules for object creation, start and end of life, aliasing etc. are fairly complicated an unintuitive most of the times, so whenever I feel std::byte is the right tool I also get nervous and reluctant to use it, for fear of unintentionally summoning the Undefined Behavior Balrogs. One such case is a buffer to be used with

问题 What's the correct way to handle two distinct values being stored in one byte of data. I have a byte that contains two nibbles each containing their own data. I want to read the top nibble and the bottom nibble into their own variables. 11110000 = High 4 bits throttle, to be read into $throttle , and should be a value from 0 to 15. 00001111 = Low 4 bits brake, to be read into $brake , and should be a value from 0 to 15. Don't forget , drivers can apply the throttle and the brake at the same

问题 When I print a program such as this in Python: x = b'francis' The output is b'francis' . If bytes is in 0 's and 1 's why is it not printing it out? 回答1: You seem to be fundamentally confused, in a very common way. The data itself is a distinct concept from its representation , i.e. what you see when you attempt to print it out or otherwise display it. There may be multiple ways to represent the same data. This is just like how if I write 23 (in decimal) or 0x17 (hexadecimal) or 0o27 (octal)

问题 I am trying to convert a std::vector of BYTES (or unsigned char) to a std::string. The problem I have is when the first element of the vector is a 0, then this returns an empty string after the conversion. I have tried the 2 methods below. Both string1 and string2 return an empty string. The result I am expecting is a string that starts with 2 x 0s followed by several other characters. // vector of BYTE, contains these 7 elements for example: (0,30,85,160,155,93,0) std::vector<BYTE> data; //

问题 Surprisingly (to me), this code does not do what I want: fun ByteArray.toHexString() : String { return this.joinToString("") { it.toString(16) } } Turns out Byte is signed , so you get negative hex representations for individual bytes, which leads to a completely bogus end result. Also, Byte.toString won't pad leading zeroes, which you'd want here. What is the simplest (no additional libraries, ideally no extensions) resp. most efficient fix? 回答1: As I am on Kotlin 1.3 you may also be

问题 Surprisingly (to me), this code does not do what I want: fun ByteArray.toHexString() : String { return this.joinToString("") { it.toString(16) } } Turns out Byte is signed , so you get negative hex representations for individual bytes, which leads to a completely bogus end result. Also, Byte.toString won't pad leading zeroes, which you'd want here. What is the simplest (no additional libraries, ideally no extensions) resp. most efficient fix? 回答1: As I am on Kotlin 1.3 you may also be

问题 I am trying to do some serial input and output operations, and one of those is to send an 8x8 array to an external device (Arduino). The pySerial library requires that the information that I send be a byte. However, in my python code, the 8x8 matrix is made up of types <class 'str'> . Here's my sending function: import serial import Matrix width = 8 height = 8 portName = 'COM3' def sendMatrix(matrix): try: port = serial.Serial(portName, 9600, timeout = 1000000) port.setDTR(0) print("Opened

问题 I am trying to do some serial input and output operations, and one of those is to send an 8x8 array to an external device (Arduino). The pySerial library requires that the information that I send be a byte. However, in my python code, the 8x8 matrix is made up of types <class 'str'> . Here's my sending function: import serial import Matrix width = 8 height = 8 portName = 'COM3' def sendMatrix(matrix): try: port = serial.Serial(portName, 9600, timeout = 1000000) port.setDTR(0) print("Opened

问题 I start with a signed byte array and convert to unsigned.. so is the printed result correct? byte[] unsigned = new byte[] {10,100,120,180,200,220,240}; sbyte[] signed = Utils.toSignedByteArray(unsigned); And the print (I just append them with a StringBuilder): signed: [10,100,120,-76,-56,-36,-16] unsigned : [10,100,120,180,200,220,240] where: public static sbyte[] toSignedByteArray(byte[] unsigned){ sbyte[] signed = new sbyte[unsigned.Length]; Buffer.BlockCopy(unsigned, 0, signed, 0, unsigned