NSString+HTMLEntities

NSString+HTMLEntities.h

//
//  NSString+HTMLEntities.h
//
//  Created by Adam Swinden on 10/10/2014.
//  Copyright (c) 2014 Adam Swinden. All rights reserved.
//

#import <Foundation/Foundation.h>


@interface NSString (HTMLEntities)


- (NSString *)stringByStrippingHTMLEntities;


@end

NSString+HTMLEntities.m

//
//  NSString+HTMLEntities.m
//
//  Created by Adam Swinden on 10/10/2014.
//  Copyright (c) 2014 Adam Swinden. All rights reserved.
//

#import "NSString+HTMLEntities.h"


@implementation NSString (HTMLEntities)


- (NSString *)stringByStrippingHTMLEntities {
	
	static NSDictionary *htmlEntitiesMappings = nil;
	
	static dispatch_once_t onceToken;
	dispatch_once(&onceToken, ^{
		
		htmlEntitiesMappings = @{@"quot": @(0x0022),
								 @"amp": @(0x0026),
								 @"apos": @(0x0027),
								 @"lt": @(0x003C),
								 @"gt": @(0x003E),
								 @"nbsp": @(0x00A0),
								 @"iexcl": @(0x00A1),
								 @"cent": @(0x00A2),
								 @"pound": @(0x00A3),
								 @"curren": @(0x00A4),
								 @"yen": @(0x00A5),
								 @"brvbar": @(0x00A6),
								 @"sect": @(0x00A7),
								 @"uml": @(0x00A8),
								 @"copy": @(0x00A9),
								 @"ordf": @(0x00AA),
								 @"laquo": @(0x00AB),
								 @"not": @(0x00AC),
								 @"shy": @(0x00AD),
								 @"reg": @(0x00AE),
								 @"macr": @(0x00AF),
								 @"deg": @(0x00B0),
								 @"plusmn": @(0x00B1),
								 @"sup2": @(0x00B2),
								 @"sup3": @(0x00B3),
								 @"acute": @(0x00B4),
								 @"micro": @(0x00B5),
								 @"para": @(0x00B6),
								 @"middot": @(0x00B7),
								 @"cedil": @(0x00B8),
								 @"sup1": @(0x00B9),
								 @"ordm": @(0x00BA),
								 @"raquo": @(0x00BB),
								 @"frac14": @(0x00BC),
								 @"frac12": @(0x00BD),
								 @"frac34": @(0x00BE),
								 @"iquest": @(0x00BF),
								 @"Agrave": @(0x00C0),
								 @"Aacute": @(0x00C1),
								 @"Acirc": @(0x00C2),
								 @"Atilde": @(0x00C3),
								 @"Auml": @(0x00C4),
								 @"Aring": @(0x00C5),
								 @"AElig": @(0x00C6),
								 @"Ccedil": @(0x00C7),
								 @"Egrave": @(0x00C8),
								 @"Eacute": @(0x00C9),
								 @"Ecirc": @(0x00CA),
								 @"Euml": @(0x00CB),
								 @"Igrave": @(0x00CC),
								 @"Iacute": @(0x00CD),
								 @"Icirc": @(0x00CE),
								 @"Iuml": @(0x00CF),
								 @"ETH": @(0x00D0),
								 @"Ntilde": @(0x00D1),
								 @"Ograve": @(0x00D2),
								 @"Oacute": @(0x00D3),
								 @"Ocirc": @(0x00D4),
								 @"Otilde": @(0x00D5),
								 @"Ouml": @(0x00D6),
								 @"times": @(0x00D7),
								 @"Oslash": @(0x00D8),
								 @"Ugrave": @(0x00D9),
								 @"Uacute": @(0x00DA),
								 @"Ucirc": @(0x00DB),
								 @"Uuml": @(0x00DC),
								 @"Yacute": @(0x00DD),
								 @"THORN": @(0x00DE),
								 @"szlig": @(0x00DF),
								 @"agrave": @(0x00E0),
								 @"aacute": @(0x00E1),
								 @"acirc": @(0x00E2),
								 @"atilde": @(0x00E3),
								 @"auml": @(0x00E4),
								 @"aring": @(0x00E5),
								 @"aelig": @(0x00E6),
								 @"ccedil": @(0x00E7),
								 @"egrave": @(0x00E8),
								 @"eacute": @(0x00E9),
								 @"ecirc": @(0x00EA),
								 @"euml": @(0x00EB),
								 @"igrave": @(0x00EC),
								 @"iacute": @(0x00ED),
								 @"icirc": @(0x00EE),
								 @"iuml": @(0x00EF),
								 @"eth": @(0x00F0),
								 @"ntilde": @(0x00F1),
								 @"ograve": @(0x00F2),
								 @"oacute": @(0x00F3),
								 @"ocirc": @(0x00F4),
								 @"otilde": @(0x00F5),
								 @"ouml": @(0x00F6),
								 @"divide": @(0x00F7),
								 @"oslash": @(0x00F8),
								 @"ugrave": @(0x00F9),
								 @"uacute": @(0x00FA),
								 @"ucirc": @(0x00FB),
								 @"uuml": @(0x00FC),
								 @"yacute": @(0x00FD),
								 @"thorn": @(0x00FE),
								 @"yuml": @(0x00FF),
								 @"OElig": @(0x0152),
								 @"oelig": @(0x0153),
								 @"Scaron": @(0x0160),
								 @"scaron": @(0x0161),
								 @"Yuml": @(0x0178),
								 @"fnof": @(0x0192),
								 @"circ": @(0x02C6),
								 @"tilde": @(0x02DC),
								 @"Alpha": @(0x0391),
								 @"Beta": @(0x0392),
								 @"Gamma": @(0x0393),
								 @"Delta": @(0x0394),
								 @"Epsilon": @(0x0395),
								 @"Zeta": @(0x0396),
								 @"Eta": @(0x0397),
								 @"Theta": @(0x0398),
								 @"Iota": @(0x0399),
								 @"Kappa": @(0x039A),
								 @"Lambda": @(0x039B),
								 @"Mu": @(0x039C),
								 @"Nu": @(0x039D),
								 @"Xi": @(0x039E),
								 @"Omicron": @(0x039F),
								 @"Pi": @(0x03A0),
								 @"Rho": @(0x03A1),
								 @"Sigma": @(0x03A3),
								 @"Tau": @(0x03A4),
								 @"Upsilon": @(0x03A5),
								 @"Phi": @(0x03A6),
								 @"Chi": @(0x03A7),
								 @"Psi": @(0x03A8),
								 @"Omega": @(0x03A9),
								 @"alpha": @(0x03B1),
								 @"beta": @(0x03B2),
								 @"gamma": @(0x03B3),
								 @"delta": @(0x03B4),
								 @"epsilon": @(0x03B5),
								 @"zeta": @(0x03B6),
								 @"eta": @(0x03B7),
								 @"theta": @(0x03B8),
								 @"iota": @(0x03B9),
								 @"kappa": @(0x03BA),
								 @"lambda": @(0x03BB),
								 @"mu": @(0x03BC),
								 @"nu": @(0x03BD),
								 @"xi": @(0x03BE),
								 @"omicron": @(0x03BF),
								 @"pi": @(0x03C0),
								 @"rho": @(0x03C1),
								 @"sigmaf": @(0x03C2),
								 @"sigma": @(0x03C3),
								 @"tau": @(0x03C4),
								 @"upsilon": @(0x03C5),
								 @"phi": @(0x03C6),
								 @"chi": @(0x03C7),
								 @"psi": @(0x03C8),
								 @"omega": @(0x03C9),
								 @"thetasym": @(0x03D1),
								 @"upsih": @(0x03D2),
								 @"piv": @(0x03D6),
								 @"ensp": @(0x2002),
								 @"emsp": @(0x2003),
								 @"thinsp": @(0x2009),
								 @"zwnj": @(0x200C),
								 @"zwj": @(0x200D),
								 @"lrm": @(0x200E),
								 @"rlm": @(0x200F),
								 @"ndash": @(0x2013),
								 @"mdash": @(0x2014),
								 @"lsquo": @(0x2018),
								 @"rsquo": @(0x2019),
								 @"sbquo": @(0x201A),
								 @"ldquo": @(0x201C),
								 @"rdquo": @(0x201D),
								 @"bdquo": @(0x201E),
								 @"dagger": @(0x2020),
								 @"Dagger": @(0x2021),
								 @"bull": @(0x2022),
								 @"hellip": @(0x2026),
								 @"permil": @(0x2030),
								 @"prime": @(0x2032),
								 @"Prime": @(0x2033),
								 @"lsaquo": @(0x2039),
								 @"rsaquo": @(0x203A),
								 @"oline": @(0x203E),
								 @"frasl": @(0x2044),
								 @"euro": @(0x20AC),
								 @"image": @(0x2111),
								 @"weierp": @(0x2118),
								 @"real": @(0x211C),
								 @"trade": @(0x2122),
								 @"alefsym": @(0x2135),
								 @"larr": @(0x2190),
								 @"uarr": @(0x2191),
								 @"rarr": @(0x2192),
								 @"darr": @(0x2193),
								 @"harr": @(0x2194),
								 @"crarr": @(0x21B5),
								 @"lArr": @(0x21D0),
								 @"uArr": @(0x21D1),
								 @"rArr": @(0x21D2),
								 @"dArr": @(0x21D3),
								 @"hArr": @(0x21D4),
								 @"forall": @(0x2200),
								 @"part": @(0x2202),
								 @"exist": @(0x2203),
								 @"empty": @(0x2205),
								 @"nabla": @(0x2207),
								 @"isin": @(0x2208),
								 @"notin": @(0x2209),
								 @"ni": @(0x220B),
								 @"prod": @(0x220F),
								 @"sum": @(0x2211),
								 @"minus": @(0x2212),
								 @"lowast": @(0x2217),
								 @"radic": @(0x221A),
								 @"prop": @(0x221D),
								 @"infin": @(0x221E),
								 @"ang": @(0x2220),
								 @"and": @(0x2227),
								 @"or": @(0x2228),
								 @"cap": @(0x2229),
								 @"cup": @(0x222A),
								 @"int": @(0x222B),
								 @"there4": @(0x2234),
								 @"sim": @(0x223C),
								 @"cong": @(0x2245),
								 @"asymp": @(0x2248),
								 @"ne": @(0x2260),
								 @"equiv": @(0x2261),
								 @"le": @(0x2264),
								 @"ge": @(0x2265),
								 @"sub": @(0x2282),
								 @"sup": @(0x2283),
								 @"nsub": @(0x2284),
								 @"sube": @(0x2286),
								 @"supe": @(0x2287),
								 @"oplus": @(0x2295),
								 @"otimes": @(0x2297),
								 @"perp": @(0x22A5),
								 @"sdot": @(0x22C5),
								 @"vellip": @(0x22EE),
								 @"lceil": @(0x2308),
								 @"rceil": @(0x2309),
								 @"lfloor": @(0x230A),
								 @"rfloor": @(0x230B),
								 @"lang": @(0x2329),
								 @"rang": @(0x232A),
								 @"loz": @(0x25CA),
								 @"spades": @(0x2660),
								 @"clubs": @(0x2663),
								 @"hearts": @(0x2665),
								 @"diams": @(0x2666)};
	});
	
	NSError *error = nil;
	NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"&([A-Za-z0-9]+);" options:0 error:&error];
	if (error) return self;
	
	NSArray *matches = [regex matchesInString:self options:kNilOptions range:NSMakeRange(0, self.length)];
	NSMutableString *mutableString = [self mutableCopy];
	
	[matches enumerateObjectsWithOptions:NSEnumerationReverse usingBlock:^(NSTextCheckingResult *match, NSUInteger idx, BOOL *stop) {
		
		NSString *code = [mutableString substringWithRange:[match rangeAtIndex:1]];
		NSString *unicodeString = htmlEntitiesMappings[code] ? [NSString stringWithFormat:@"%C", (unsigned short)[htmlEntitiesMappings[code] intValue]] : @"";
		
		[mutableString replaceCharactersInRange:[match rangeAtIndex:0] withString:unicodeString];
	}];
	
	return [mutableString copy];
}


@end