Objective-C:将 NSData 转换为 int 或 char

Question

NSData * data;
NSFileHandle * file;

file = [NSFileHandle fileHandleForReadingAtPath: @"script.txt"]; //this is wrong, as I have to provide a full pathname, but disregard for now

[file seekToFileOffset: i]; //i not mentioned here, as this is only a snippet of code. Suffice to know that in the file it falls at the beginning of an integer I want to read

data = [file readDataOfLength: 5]; //5-digit integer that I want to read

现在我该如何将数据转换为我可以使用的 int(即执行算术运算)？

Answer 1

由于您是从文本文件中读取整数，因此可以像这样转换它:

char buf[6];
[data getBytes:buf length:5];
buf[5] = '\0';
NSInteger res = atoi(buf);

这假设一个编码每个字符使用一个字节，这与您提供的代码片段中的 [file readDataOfLength: 5] 调用一致。

如果事先不知道位数，您可以这样做:

char buf[11]; // Max 10 digits in a 32-bit number + 1 for null terminator
bzero(buf, 11);
[data getBytes:buf length:variableLength];
NSInteger res = atoi(buf);