NSString+SSToolkitAdditions.m

//
//  NSString+SSToolkitAdditions.m
//  SSToolkit
//
//  Created by Sam Soffes on 6/22/09.
//  Copyright 2009-2011 Sam Soffes. All rights reserved.
//

#import "NSString+SSToolkitAdditions.h"
#import "NSData+SSToolkitAdditions.h"
#import <CommonCrypto/CommonDigest.h>

@implementation NSString (SSToolkitAdditions)

- (BOOL)containsString:(NSString *)string {
	return !NSEqualRanges([self rangeOfString:string], NSMakeRange(NSNotFound, 0));
}

- (NSString *)MD5Sum {
	const char *cstr = [self cStringUsingEncoding:NSUTF8StringEncoding];
	NSData *data = [NSData dataWithBytes:cstr length:self.length];
	return [data MD5Sum];
}


- (NSString *)SHA1Sum {
	const char *cstr = [self cStringUsingEncoding:NSUTF8StringEncoding];
	NSData *data = [NSData dataWithBytes:cstr length:self.length];
	return [data SHA1Sum];
}


// Adapted from http://snipplr.com/view/2771/compare-two-version-strings
- (NSComparisonResult)compareToVersionString:(NSString *)version {
	// Break version into fields (separated by '.')
	NSMutableArray *leftFields  = [[NSMutableArray alloc] initWithArray:[self  componentsSeparatedByString:@"."]];
	NSMutableArray *rightFields = [[NSMutableArray alloc] initWithArray:[version componentsSeparatedByString:@"."]];
	
	// Implict ".0" in case version doesn't have the same number of '.'
	if ([leftFields count] < [rightFields count]) {
		while ([leftFields count] != [rightFields count]) {
			[leftFields addObject:@"0"];
		}
	} else if ([leftFields count] > [rightFields count]) {
		while ([leftFields count] != [rightFields count]) {
			[rightFields addObject:@"0"];
		}
	}
	
	// Do a numeric comparison on each field
	for (NSUInteger i = 0; i < [leftFields count]; i++) {
		NSComparisonResult result = [[leftFields objectAtIndex:i] compare:[rightFields objectAtIndex:i] options:NSNumericSearch];
		if (result != NSOrderedSame) {
			return result;
		}
	}
	
	return NSOrderedSame;
}


#pragma mark - HTML Methods

- (NSString *)escapeHTML {
	NSMutableString *s = [NSMutableString string];
	
	NSUInteger start = 0;
	NSUInteger len = [self length];
	NSCharacterSet *chs = [NSCharacterSet characterSetWithCharactersInString:@"<>&\""];
	
	while (start < len) {
		NSRange r = [self rangeOfCharacterFromSet:chs options:0 range:NSMakeRange(start, len-start)];
		if (r.location == NSNotFound) {
			[s appendString:[self substringFromIndex:start]];
			break;
		}
		
		if (start < r.location) {
			[s appendString:[self substringWithRange:NSMakeRange(start, r.location-start)]];
		}
		
		switch ([self characterAtIndex:r.location]) {
			case '<':
				[s appendString:@"&lt;"];
				break;
			case '>':
				[s appendString:@"&gt;"];
				break;
			case '"':
				[s appendString:@"&quot;"];
				break;
//			case '…':
//				[s appendString:@"&hellip;"];
//				break;
			case '&':
				[s appendString:@"&amp;"];
				break;
		}
		
		start = r.location + 1;
	}
	
	return s;
}


- (NSString *)unescapeHTML {
	NSMutableString *s = [NSMutableString string];
	NSMutableString *target = [self mutableCopy];
	NSCharacterSet *chs = [NSCharacterSet characterSetWithCharactersInString:@"&"];
	
	while ([target length] > 0) {
		NSRange r = [target rangeOfCharacterFromSet:chs];
		if (r.location == NSNotFound) {
			[s appendString:target];
			break;
		}
		
		if (r.location > 0) {
			[s appendString:[target substringToIndex:r.location]];
			[target deleteCharactersInRange:NSMakeRange(0, r.location)];
		}
		
		if ([target hasPrefix:@"&lt;"]) {
			[s appendString:@"<"];
			[target deleteCharactersInRange:NSMakeRange(0, 4)];
		} else if ([target hasPrefix:@"&gt;"]) {
			[s appendString:@">"];
			[target deleteCharactersInRange:NSMakeRange(0, 4)];
		} else if ([target hasPrefix:@"&quot;"]) {
			[s appendString:@"\""];
			[target deleteCharactersInRange:NSMakeRange(0, 6)];
		} else if ([target hasPrefix:@"&#39;"]) {
			[s appendString:@"'"];
			[target deleteCharactersInRange:NSMakeRange(0, 5)];
		} else if ([target hasPrefix:@"&amp;"]) {
			[s appendString:@"&"];
			[target deleteCharactersInRange:NSMakeRange(0, 5)];
		} else if ([target hasPrefix:@"&hellip;"]) {
			[s appendString:@"…"];
			[target deleteCharactersInRange:NSMakeRange(0, 8)];
		} else {
			[s appendString:@"&"];
			[target deleteCharactersInRange:NSMakeRange(0, 1)];
		}
	}
	
	return s;
}


#pragma mark - URL Escaping and Unescaping

- (NSString *)stringByEscapingForURLQuery {
	NSString *result = self;

	static CFStringRef leaveAlone = CFSTR(" ");
	static CFStringRef toEscape = CFSTR("\n\r:/=,!$&'()*+;[]@#?%");

	CFStringRef escapedStr = CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault, (__bridge CFStringRef)self, leaveAlone,
																	 toEscape, kCFStringEncodingUTF8);

	if (escapedStr) {
		NSMutableString *mutable = [NSMutableString stringWithString:(__bridge NSString *)escapedStr];
		CFRelease(escapedStr);

		[mutable replaceOccurrencesOfString:@" " withString:@"+" options:0 range:NSMakeRange(0, [mutable length])];
		result = mutable;
	}
	return result;  
}


- (NSString *)stringByUnescapingFromURLQuery {
	NSString *deplussed = [self stringByReplacingOccurrencesOfString:@"+" withString:@" "];
    return [deplussed stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
}


#pragma mark - URL Encoding and Unencoding (Deprecated)

- (NSString *)URLEncodedString {
	static CFStringRef toEscape = CFSTR(":/=,!$&'()*+;[]@#?%");
	return (__bridge_transfer NSString *)CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
																				 (__bridge CFStringRef)self,
																				 NULL,
																				 toEscape,
																				 kCFStringEncodingUTF8);
}


- (NSString *)URLEncodedParameterString {
	static CFStringRef toEscape = CFSTR(":/=,!$&'()*+;[]@#?");
    return (__bridge_transfer NSString *)CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
																				 (__bridge CFStringRef)self,
																				 NULL,
																				 toEscape,
																				 kCFStringEncodingUTF8);
}


- (NSString *)URLDecodedString {
	return (__bridge_transfer NSString *)CFURLCreateStringByReplacingPercentEscapesUsingEncoding(kCFAllocatorDefault,
																								 (__bridge CFStringRef)self,
																								 CFSTR(""),
																								 kCFStringEncodingUTF8);
}


#pragma mark - Base64 Encoding

- (NSString *)base64EncodedString  {
    if ([self length] == 0) {
        return nil;
	}
	
	return [[self dataUsingEncoding:NSUTF8StringEncoding] base64EncodedString];
}


+ (NSString *)stringWithBase64String:(NSString *)base64String {
	return [[NSString alloc] initWithData:[NSData dataWithBase64String:base64String] encoding:NSUTF8StringEncoding];
}



#pragma mark - Generating a UUID

+ (NSString *)stringWithUUID {
	CFUUIDRef uuid = CFUUIDCreate(NULL);
	CFStringRef string = CFUUIDCreateString(NULL, uuid);
	CFRelease(uuid);
	return (__bridge_transfer NSString *)string;
}


#pragma mark - Trimming

- (NSString *)stringByTrimmingLeadingAndTrailingCharactersInSet:(NSCharacterSet *)characterSet {
	return [[self stringByTrimmingLeadingCharactersInSet:characterSet]
			stringByTrimmingTrailingCharactersInSet:characterSet];
}


- (NSString *)stringByTrimmingLeadingAndTrailingWhitespaceAndNewlineCharacters {
	return [[self stringByTrimmingLeadingWhitespaceAndNewlineCharacters]
			stringByTrimmingTrailingWhitespaceAndNewlineCharacters];
}


- (NSString *)stringByTrimmingLeadingCharactersInSet:(NSCharacterSet *)characterSet {
    NSRange rangeOfFirstWantedCharacter = [self rangeOfCharacterFromSet:[characterSet invertedSet]];
    if (rangeOfFirstWantedCharacter.location == NSNotFound) {
        return @"";
    }
    return [self substringFromIndex:rangeOfFirstWantedCharacter.location];
}


- (NSString *)stringByTrimmingLeadingWhitespaceAndNewlineCharacters {
    return [self stringByTrimmingLeadingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
}


- (NSString *)stringByTrimmingTrailingCharactersInSet:(NSCharacterSet *)characterSet {
    NSRange rangeOfLastWantedCharacter = [self rangeOfCharacterFromSet:[characterSet invertedSet]
                                                               options:NSBackwardsSearch];
    if (rangeOfLastWantedCharacter.location == NSNotFound) {
        return @"";
    }
    return [self substringToIndex:rangeOfLastWantedCharacter.location + 1]; // Non-inclusive
}


- (NSString *)stringByTrimmingTrailingWhitespaceAndNewlineCharacters {
    return [self stringByTrimmingTrailingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
}

@end