Cutting the length of an NSString without splitting the last word - objective-c

Question

I'm trying to cut the length of an NSString without splitting the last word with this method:
// cut a string by words
- (NSString* )stringCutByWords:(NSString *)string toLength:(int)length;
{
// search backwards in the string for the beginning of the last word
while ([string characterAtIndex:length] != ' ' && length > 0) {
length--;
}
// if the last word was the first word of the string search for the end of the word
if (length <= 0){
while ([string characterAtIndex:length] != ' ' && length > string.length-1) {
length++;
}
}
// define the range you're interested in
NSRange stringRange = {0, length};
// adjust the range to include dependent chars
stringRange = [string rangeOfComposedCharacterSequencesForRange:stringRange];
// Now you can create the short string
string = [string substringWithRange:stringRange];
return [NSString stringWithFormat:#"%#...",string];
}
now my question is:
Is there a build-in way in objective-c or cocoa-touch which i did not see or else is there a "nicer" way to do this because iam not very happy with this solution.
greetings and thanks for help
C4rmel

Answer 1

My proposal for a Category method
#interface NSString (Cut)
-(NSString *)stringByCuttingExceptLastWordWithLength:(NSUInteger)length;
#end
#implementation NSString (Cut)
-(NSString *)stringByCuttingExceptLastWordWithLength:(NSUInteger)length
{
__block NSMutableString *newString = [NSMutableString string];
NSArray *components = [self componentsSeparatedByString:#" "];
if ([components count] > 0) {
NSString *lastWord = [components objectAtIndex:[components count]-1];
[components enumerateObjectsUsingBlock:^(NSString *obj, NSUInteger idx, BOOL *stop) {
if (([obj length]+[newString length] + [lastWord length] + 2) < length) {
[newString appendFormat:#" %#", obj];
} else {
[newString appendString:#"…"];
[newString appendFormat:#" %#", lastWord];
*stop = YES;
}
}];
}
return newString;
}
Usage:
NSString *string = #"Hello World! I am standing over here! Can you see me?";
NSLog(#"%#", [string stringByCuttingExceptLastWordWithLength:25]);

Answer 2

Suggestions:
make it a category method;
use NSCharacterSet and the built-in search methods rather than rolling your own.
So:
/* somewhere public */
#interface NSString (CutByWords)
- (NSString *)stringCutByWordsToMaxLength:(int)length
#end
/* in an implementation file, somewhere */
#implementation NSString (CutByWords)
// cut a string by words
- (NSString *)stringCutByWordsToMaxLength:(int)length
{
NSCharacterSet *whitespaceCharacterSet =
[NSCharacterSet whitespaceCharacterSet];
// to consider: a range check on length here?
NSRange relevantRange = NSMakeRange(0, length);
// find beginning of last word
NSRange lastWordRange =
[self rangeOfCharacterFromSet:whitespaceCharacterSet
options:NSBackwardsSearch
range:relevantRange];
// if the last word was the first word of the string,
// consume the whole string; this looks to be the same
// effect as the original scan forward given that the
// assumption is already made in the scan backwards that
// the string doesn't end on a whitespace; if I'm wrong
// then get [whitespaceCharacterSet invertedSet] and do
// a search forwards
if(lastWordRange.location == NSNotFound)
{
lastWordRange = relevantRange;
}
// adjust the range to include dependent chars
stringRange = [self rangeOfComposedCharacterSequencesForRange:stringRange];
// Now you can create the short string
NSString *string = [self substringWithRange:stringRange];
return [NSString stringWithFormat:#"%#...",string];
}
#end
/* subsequently */
NSString *string = ...whatever...;
NSString *cutString = [string stringCutByWordsToMaxLength:100];