Convert Hex to ASCII number on Objective-c

Question

I have an one hexa decimal number

535443326663315634524877795678586b536854535530342f44526a795744716133353942704359697a6b736e446953677171555473

I want to convert this number to ASCII format which will look like this

STC2fc1V4RHwyVxXkShTSU04/DRjyWDqa359BpCYizksnDiSgqqUTsYUOcHKHNMJOdqR1/TQywpD9a9xhri

i have seen solutions here but none of them is useful to me NSString containing hex convert to ascii equivalent

i checked here but they give different result. Any help

have you tried the solution on the other thread? If yes, could you include that code here? — Puneet Sharma, Sep 16 '13 at 12:18
It seems like you want Base64 encoding. Check out http://stackoverflow.com/questions/882277/how-to-base64-encode-on-the-iphone — robbie_c, Sep 16 '13 at 12:23
@robbie_c tried that last one , but result is different what iam getting here in http://www.branah.com/ascii-converter — Prateek sharma, Sep 16 '13 at 12:32
NTM1NDQzMzI2NjYzMzE1NjM0NTI0ODc3Nzk1Njc4NTg2YjUzNjg1NDUzNTUzMDM0MmY0NDUyNmE3OTU3NDQ3MTYxMzMzNTM5NDI3MDQzNTk2OTdhNmI3MzZlNDQ2OTUzNjc3MTcxNTU1NDczN , its coming like this .. it should start with STC — Prateek sharma, Sep 16 '13 at 12:38
Ah fair enough, that website seems to just convert one byte of the hex number to one ASCII character, the answer given should work. — robbie_c, Sep 16 '13 at 13:09

score 1 · Answer 1 · edited Sep 16 '13 at 13:10

This works perfectly

- (NSString *)stringFromHexString:(NSString *)hexString {


    // The hex codes should all be two characters.
    if (([hexString length] % 2) != 0)
        return nil;

    NSMutableString *string = [NSMutableString string];

    for (NSInteger i = 0; i < [hexString length]; i += 2) {

        NSString *hex = [hexString substringWithRange:NSMakeRange(i, 2)];
        NSInteger decimalValue = 0;
        sscanf([hex UTF8String], "%x", &decimalValue);
        [string appendFormat:@"%c", decimalValue];
        NSLog(@"string--%@",string);
    }
    _hexString1=string;

    NSLog(@"string ---%@",_hexString1);
    return string;
}

score 1 · Answer 2 · answered Nov 11 '20 at 00:30

1

If you're starting with NSData * you could get the ASCII string this way:

NSData *someData = [NSData dataWithHexString:@"ABC123"];

NSString *asciiString = [[NSString alloc] initWithData: someData encoding:NSASCIIStringEncoding];

answered Nov 11 '20 at 00:30

TT--

2,956
1
27
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That doesn't work out of the box because dataWithHexString is not a function provided by Foundation. You need to add the code from `NSData+HexString.m` (https://opensource.apple.com/source/Security/Security-55471/libsecurity_transform/NSData+HexString.m.auto.html) – Thomas Tempelmann Mar 12 '22 at 20:31
Ok, good point. Btw why does the link have comment `// Not efficent` ? – TT-- Mar 13 '22 at 23:10
Perhaps because of the use of subroutines such as `strtol()` and the way the source string is indexed. One could access the input as a raw char array instead, which is probably faster, and convert the nibbles thru a table or a few comparisons, additions and shifts. But it's fast enough for most uses as you'll probably not convert millions of these per second. – Thomas Tempelmann Mar 14 '22 at 15:33

Convert Hex to ASCII number on Objective-c

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