reading unicode from sqlite and creating a NSString - sqlite

Question

Im working on an iOS app where I need to store and retrieve from an SQLite DB, a representation of a NSString that has subscripts. I can create a NSString at compile time with a constant:
#"Br\u2082_CCl\u2084"
\u2082 is a 2 subscript, \u2084 is a 4 subscript. What im storing in the SQLite db is:
"Br\u2082_CCl\u2084"
But what I can not figure out how to do, is reconvert that back into an NSString. The data comes back from the db as a char * "Br\\u2082_CCl\\u2084" Stripping out the extra slash has made no difference in my feeble experiments. I need a way get that back into an NSString - Thanks!

Answer 1

You need one of the NSString stringWithCString class methods or the corresponding initWithCString instance methods.

Answer 2

I solved the problem like this - error checking removed for clarity -
the unicode string comes into the parameter stringEncoded from the db like:
"MgBr\u2082_CH\u2082Cl\u2082"
+(NSString *)decodeUnicodeBytes:(char *)stringEncoded {
unsigned int unicodeValue;
char *p, buff[5];
NSMutableString *theString;
NSString *hexString;
NSScanner *pScanner;
theString = [[[NSMutableString alloc] init] autorelease];
p = stringEncoded;
buff[4] = 0x00;
while (*p != 0x00) {
if (*p == '\\') {
p++;
if (*p == 'u') {
memmove(buff, ++p, 4);
hexString = [NSString stringWithUTF8String:buff];
pScanner = [NSScanner scannerWithString: hexString];
[pScanner scanHexInt: &unicodeValue];
[theString appendFormat:#"%C", unicodeValue];
p += 4;
continue;
}
}
[theString appendFormat:#"%c", *p];
p++;
}
return [NSString stringWithString:theString];
}