Objective-C中是否有将十六进制字符串转换为字节的方法?例如,连接到unsigned char array {0x11, 0x56, 0xFF, ...}
的@"1156FFCD3430AA22"
。
发布于 2013-07-07 19:05:31
我能想到的最快的NSString类别实现(一些例子的鸡尾酒):
- (NSData *)dataFromHexString {
const char *chars = [self UTF8String];
int i = 0, len = self.length;
NSMutableData *data = [NSMutableData dataWithCapacity:len / 2];
char byteChars[3] = {'\0','\0','\0'};
unsigned long wholeByte;
while (i < len) {
byteChars[0] = chars[i++];
byteChars[1] = chars[i++];
wholeByte = strtoul(byteChars, NULL, 16);
[data appendBytes:&wholeByte length:1];
}
return data;
}
它比wookay的解决方案快近8倍。NSScanner相当慢。
发布于 2010-03-24 13:31:57
@interface NSString (NSStringHexToBytes)
-(NSData*) hexToBytes ;
@end
@implementation NSString (NSStringHexToBytes)
-(NSData*) hexToBytes {
NSMutableData* data = [NSMutableData data];
int idx;
for (idx = 0; idx+2 <= self.length; idx+=2) {
NSRange range = NSMakeRange(idx, 2);
NSString* hexStr = [self substringWithRange:range];
NSScanner* scanner = [NSScanner scannerWithString:hexStr];
unsigned int intValue;
[scanner scanHexInt:&intValue];
[data appendBytes:&intValue length:1];
}
return data;
}
@end
/// example
unsigned char bytes[] = { 0x11, 0x56, 0xFF, 0xCD, 0x34, 0x30, 0xAA, 0x22 };
NSData* expectedData = [NSData dataWithBytes:bytes length:sizeof(bytes)];
NSLog(@"data %@", [@"1156FFCD3430AA22" hexToBytes]);
NSLog(@"expectedData isEqual:%d", [expectedData isEqual:[@"1156FFCD3430AA22" hexToBytes]]);
发布于 2010-03-23 23:24:22
NSScanner
的scanHexInt:
和类似方法可能有助于完成您想要的操作,但您可能需要首先将字符串拆分成更小的块,在这种情况下,手动执行转换可能比使用NSScanner
更简单。
https://stackoverflow.com/questions/2501033
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