Objective C 中的 unsigned long , unsigned char 到 Swift

Question

I am changing my Objective C project to Swift project. In objective CI used unsigned long, Unsigned char.

const char * bytesIn = [self bytes];
unsigned long bytesLength = range.location + range.length;
unsigned long   bytesOffset = range.location;
NSMutableData * dataOut = [NSMutableData data];

BOOL currIsEOF = NO;
unsigned char currChar;         /* current character */
unsigned char charBuf[MAX_READ];    /* buffer of already read characters */
int count;                       /* number of characters in a run */

/* prime the read loop */
currChar = bytesIn[bytesOffset];
bytesOffset = bytesOffset + skip;
count = 0;

The above is the code. Can Anybody help to change this to a Swift one. In Swift to my understanding there is no const char

Answer 1

Your code snippet looks like part of a larger function that is extracting some bytes out of an NSData object. Swift providesData which bridges to NSData and provides a whole slew of functions to manipulate byte buffers Swift collections. You should look at the larger function your snippet is from and recast the algorithm using the functions provided by Data .

BTW Swift provides unsigned types, for some reason it views them as Special-Use Numeric Types and also provides type aliases named after C types, see C Interoperability . So if you have algorithms which use unsigned types and/or Objective-C code for them, you can write/translate them into Swift – indeed it seems the result will be "special" to Swift folk when of course unsigned numbers are really natural ;-)