iska
51 lines
1.3 KiB
Objective-C
51 lines
1.3 KiB
Objective-C
//
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// CSSNthExpression.m
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// HTMLKit
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//
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// Created by Iska on 10/10/15.
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// Copyright © 2015 BrainCookie. All rights reserved.
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//
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#import "CSSNthExpressionParser.h"
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#import "CSSCodePoints.h"
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#import "NSString+HTMLKit.h"
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#import "NSCharacterSet+HTMLKit.h"
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@implementation CSSNthExpressionParser
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+ (CSSNthExpression)parseExpression:(NSString *)expression
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{
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NSCharacterSet *whitespace = [NSCharacterSet whitespaceAndNewlineCharacterSet];
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NSString *string = [expression.lowercaseString copy];
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string = [[string stringByTrimmingCharactersInSet:whitespace] copy];
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if ([string isEqualToStringIgnoringCase:@"odd"]) {
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return CSSNthExpressionOdd;
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} else if ([string isEqualToStringIgnoringCase:@"even"]) {
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return CSSNthExpressionEven;
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}
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NSCharacterSet *set = [[NSCharacterSet CSSNthExpressionCharacterSet] invertedSet];
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if ([string rangeOfCharacterFromSet:set].location != NSNotFound) {
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return CSSNthExpressionMake(0, 0);
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}
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NSArray *parts = [string componentsSeparatedByString:@"n"];
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if (parts.count == 1) {
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NSInteger b = [parts[0] integerValue];
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return CSSNthExpressionMake(0, b);
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} else if (parts.count == 2) {
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NSInteger a = [parts[0] integerValue];
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if (a == 0) {
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a = [parts[0] isEqualToString:@"-"] ? -1 : 1;
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}
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NSInteger b = [parts[1] integerValue];
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return CSSNthExpressionMake(a, b);
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} else {
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return CSSNthExpressionMake(0, 0);
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}
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}
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@end
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