NSString, trim

우째 이런 기본적인 것이 없을까나..
NSString에 카테고리로 trim 관련 메소드를 추가해봤습니다. 

NSString_Trim.h

@interface NSString(Trim)

- (NSString *)ltrim;

- (NSString *)rtrim;

- (NSString *)trim;
@end 

NSString_Trim.m

@implementation NSString(Trim)

- (NSString *)ltrim

{

NSCharacterSet *cs = [NSCharacterSet whitespaceAndNewlineCharacterSet];

NSUInteger len = [self length];

int i;

for (i=0; i < len; i++)

{

unichar c = [self characterAtIndex:i];

if ( [cs characterIsMember:c] == NO ) break;

}

NSString *trimmed = [self substringFromIndex:i];

return trimmed;

}

- (NSString *)rtrim

{

NSCharacterSet *cs = [NSCharacterSet whitespaceAndNewlineCharacterSet];

NSUInteger len = [self length];

int i;

for (i=(len-1); i >= 0; i--)

{

unichar c = [self characterAtIndex:i];

if ( [cs characterIsMember:c] == NO ) break;

}

NSString *trimmed = [self substringToIndex:i+1];

return trimmed;

}

- (NSString *)trim

{

NSCharacterSet *cs = [NSCharacterSet whitespaceAndNewlineCharacterSet];

NSUInteger len = [self length];

int start, end;

unichar c;

for (start=0; start < len; start++)

{

c = [self characterAtIndex:start];

if ( [cs characterIsMember:c] == NO ) break;

}

for (end=(len-1); end >= start; end--)

{

c = [self characterAtIndex:end];

if ( [cs characterIsMember:c] == NO ) break;

}

NSRange r = NSMakeRange(start, end-start+1);

NSString *trimmed = [self substringWithRange:r];

return trimmed;

}

@end