How to convert HEX to NSString in Objective-C j? - ios

Question

I have a NSString with hex string like "&# x62a;&# x631;&# x642;&# x628;" which means "ترقب".
Now I want to convert the hex string into another NSString object which shows "ترقب". How to do that ?

Answer 1

- (NSMutableString *) hextostring:(NSString *) str{
//ت
NSMutableString *string = [[NSMutableString alloc]init];
str = [str stringByReplacingOccurrencesOfString:#"&#" withString:#"0"];
str = [str stringByReplacingOccurrencesOfString:#" " withString:#"z;"];
NSArray *arr = [str componentsSeparatedByString:#";"];
for (int i =0; i<[arr count]; i++) {
if ([[arr objectAtIndex:i] isEqualToString:#"z"]) {
[string appendString:#" "];
} else {
unsigned x;
[[NSScanner scannerWithString: [arr objectAtIndex:i]] scanHexInt: &x];
[string appendFormat:#"%C",(unichar)x];
}
}
NSLog(#"%#",string);
return string;
}

Answer 2

Your string looks like HTML escape sequences, except for the spaces after the #'s. If this is really what you have (check something isn't just displaying Unicode as escapes) then there is a myriad of ways to convert it. You can just process the string picking out the hex chars and producing UniChar values from them, etc.
If you want a high-level, maybe somewhat long-winded approach, you and try:
- (NSString *)decodeHTMLescapes:(NSString *)raw
{
NSString *nospaces = [raw stringByReplacingOccurrencesOfString:#" " withString:#""]; // one way to remove the spaces
const char *cString = [nospaces UTF8String]; // C string
NSData *bytes = [[NSData alloc] initWithBytesNoCopy:(void *)cString length:strlen(cString) freeWhenDone:NO]; // as bytes
NSAttributedString *attributed = [[NSAttributedString alloc] initWithHTML:bytes documentAttributes:nil]; // interpret as HTML
NSString *decoded = attributed.string; // and finally as plain text
return decoded;
}
That (a) strips the spaces, (b) creates a C string and (c) creates a byte buffer, all that so we can (d) interpret that byte buffer as HTML, and (e) finally gets the string back. The use of initWithBytesNoCopy:length:freeWhenDone: is to reduce the copying all this does.
Use it like:
NSString *raw = #"&# x62a;&# x631;&# x642;&# x628;";
NSString *decoded = [self decodeHTMLescapes:raw];
NSLog(#"%# -> %#", raw, decoded);
HTH