iOS NSData 和十六进制字符串（HEX）之间的相互转换

其中将十六进制字符串转换成NSData的代码如下:

• - (NSData *)convertHexStrToData:(NSString *)str {

• if (!str || [str length] == 0) {

• return nil;

• }

•  

• NSMutableData *hexData = [[NSMutableData alloc] initWithCapacity:8];

• NSRange range;

• if ([str length] % 2 == 0) {

• range = NSMakeRange(0, 2);

• } else {

• range = NSMakeRange(0, 1);

• }

• for (NSInteger i = range.location; i < [strlength]; i+= 2){

• unsignedintanInt;

• NSString*hexCharStr= [strsubstringWithRange:range];

• NSScanner*scanner= [[NSScanneralloc] initWithString:hexCharStr];

•  

• [scannerscanHexInt:&anInt];

• NSData*entity= [[NSDataalloc] initWithBytes:&anIntlength:1];

• [hexDataappendData:entity];

•  

• range.location+= range.length;

• range.length= 2;

• }

•  

• LEDEBUG(@"hexdata:%@", hexData);

• returnhexData;

• }

 

将NSData转换成十六进制的字符串则可使用如下方式:

• - (NSString *)convertDataToHexStr:(NSData *)data {

• if (!data || [data length] == 0) {

• return @"";

• }

• NSMutableString *string = [[NSMutableString alloc] initWithCapacity:[data length]];

•  

• [data enumerateByteRangesUsingBlock:^(const void *bytes, NSRange byteRange, BOOL *stop) {

• unsigned char *dataBytes = (unsigned char*)bytes;

• for (NSInteger i = 0; i < byteRange.length; i++) {

• NSString*hexStr= [NSStringstringWithFormat:@"%x", (dataBytes[i]) & 0xff];

• if([hexStrlength] == 2){

• [stringappendString:hexStr];

• } else{

• [stringappendFormat:@"0%@", hexStr];

• }

• }

• }];

•  

• returnstring;

• }

•