//

// ANHTMLParser.m

// ANHTML

//

// Created by Alex Nichol on 11/17/11.

// Copyright (c) 2011 __MyCompanyName__. All rights reserved.

//

#import "ANHTMLParser.h"

@interface ANHTMLParser (Private)

- (BOOL)encounteredTagStart;

- (BOOL)readElementAndCallback:(NSString *)elementDeclaration;

- (BOOL)encounteredEscapeStart;

- (NSString *)unescapeAttributeString:(NSString *)escapedString;

- (unichar)readAndUnescapeNext:(StringFeed *)aFeed;

- (void)delegateInformText:(NSString *)theText;

- (void)delegateInformElementStart:(NSString *)tag attributes:(NSDictionary *)attributes;

- (void)delegateInformElementEnd:(NSString *)tag;

- (unichar)delegateGetEscapeValue:(NSString *)eCode;

@end

@implementation ANHTMLParser

@synthesize delegate;

- (id)initWithDocumentData:(NSData *)data {

if ((self = [super init])) {

feed = [[StringFeed alloc] initWithStringData:data];

if (!feed) {

return nil;

}

}

return self;

}

- (id)initWithDocumentString:(NSString *)string {

if ((self = [super init])) {

feed = [[StringFeed alloc] initWithString:string];

if (!feed) {

return nil;

}

}

return self;

}

- (void)parse {

// reset parsing stats

[feed setOffset:0];

plainBuffer = [[NSMutableString alloc] init];

while (![feed isFinished]) {

unichar c = [feed getCharacter];

if (c == '<') {

[feed pushCurrentOffset];

if (![self encounteredTagStart]) {

[feed restoreOffset];

[plainBuffer appendFormat:@"%C", c];

} else {

[feed skipOffset];

}

} else if (c == '&') {

[feed pushCurrentOffset];

if (![self encounteredEscapeStart]) {

[feed restoreOffset];

[plainBuffer appendFormat:@"%C", c];

} else {

[feed skipOffset];

}

} else {

[plainBuffer appendFormat:@"%C", c];

}

}

if ([plainBuffer length] > 0) {

[self delegateInformText:plainBuffer];

}

}

#pragma mark - Private -

- (BOOL)encounteredTagStart {

if ([feed isFinished]) {

return NO;

}

// different reasons that a '<' might be in our document

if ([feed stringFollows:@"/"]) {

// end of a tag

[feed skipUntil:@"/"]; // skip the / character

NSString * tagContent = [feed readUntil:@">" notEncountering:@"<"];

if (!tagContent) {

return NO;

}

// remove trailing whitespace

NSCharacterSet * whitespace = [NSCharacterSet whitespaceCharacterSet];

NSString * trimmed = [tagContent stringByTrimmingCharactersInSet:whitespace];

if ([trimmed length] == 0) return NO;

// remove stuff after first token (e.g. after element name)

NSRange spaceRange = [trimmed rangeOfCharacterFromSet:whitespace];

if (spaceRange.location != NSNotFound) {

trimmed = [trimmed substringWithRange:NSMakeRange(0, spaceRange.location)];

}

if ([trimmed length] == 0) return NO;

[self delegateInformElementEnd:trimmed];

return YES;

} else if ([feed stringFollows:@"!"]) {

// comment of some sort

if ([feed stringFollows:@"!--"]) {

// long comment

return [feed skipUntil:@"-->"];

} else {

// shorthand comment

return [feed skipUntil:@">"];

}

} else if ([feed stringFollows:@"?"]) {

// PHP, XML info

return [feed skipUntil:@"?>"];

} else {

// beginning of an element

NSString * elementDec = [feed readUntil:@">" notEncountering:@"<"];

if (!elementDec) {

return NO;

}

return [self readElementAndCallback:elementDec];

}

}

- (BOOL)readElementAndCallback:(NSString *)elementDeclaration {

NSCharacterSet * whitespace = [NSCharacterSet whitespaceAndNewlineCharacterSet];

StringFeed * elemFeed = [[StringFeed alloc] initWithString:elementDeclaration];

if ([elemFeed isFinished]) return NO;

// read the element name token

NSString * elementName = [elemFeed readUntilCharacterInSet:whitespace];

if ([elementName length] == 0) {

return NO;

}

NSMutableDictionary * attributes = [NSMutableDictionary dictionary];

// read the attribute tokens

while (![elemFeed isFinished]) {

[elemFeed consumeCharactersInSet:whitespace];

if ([elemFeed isFinished]) break;

NSString * attributeName = [elemFeed readUntil:@"="];

if (!attributeName) break;

if (![elemFeed skipUntil:@"\""]) break;

NSString * attributeValue = [self unescapeAttributeString:[elemFeed readUntil:@"\""]];

if (!attributeValue) break;

[attributes setObject:attributeValue forKey:attributeName];

}

[self delegateInformElementStart:elementName attributes:attributes];

// the <tag ... /> syntax

if ([[elementDeclaration stringByTrimmingCharactersInSet:whitespace] hasSuffix:@"/"]) {

[self delegateInformElementEnd:elementName];

}

return YES;

}

#pragma mark Unescaping

- (BOOL)encounteredEscapeStart {

unichar escapeChar = [self readAndUnescapeNext:feed];

if (escapeChar == 0) {

return NO;

}

[plainBuffer appendFormat:@"%C", escapeChar];

return YES;

}

- (NSString *)unescapeAttributeString:(NSString *)escapedString {

if (!escapedString) return nil;

StringFeed * subFeed = [[StringFeed alloc] initWithString:escapedString];

NSMutableString * unescaped = [[NSMutableString alloc] init];

while (![subFeed isFinished]) {

unichar token = [subFeed getCharacter];

if (token == '&') {

[subFeed pushCurrentOffset];

unichar original = [self readAndUnescapeNext:subFeed];

if (original == 0) {

[subFeed restoreOffset];

[unescaped appendFormat:@"%C", token];

} else {

[subFeed skipOffset];

[unescaped appendFormat:@"%C", original];

}

} else {

[unescaped appendFormat:@"%C", token];

}

}

return [unescaped copy]; // immutable copy

}

- (unichar)readAndUnescapeNext:(StringFeed *)aFeed {

NSString * escBody = [aFeed readUntil:@";" notEncountering:@"&"];

if (!escBody) return 0;

unichar escapeChar = [self delegateGetEscapeValue:escBody];

return escapeChar;

}

#pragma mark Delegate Callbacks

- (void)delegateInformText:(NSString *)theText {

NSCharacterSet * whitespace = [NSCharacterSet whitespaceAndNewlineCharacterSet];

NSCharacterSet * newLines = [NSCharacterSet newlineCharacterSet];

BOOL isJustSpace = YES;

// remove instances where there are two spaces in a row,

// replace with the first space only, deleting the second.

NSMutableString * noRepeats = [[theText stringByTrimmingCharactersInSet:newLines] mutableCopy];

for (NSInteger i = 0; i < (NSInteger)[noRepeats length] - 1; i++) {

unichar current = [noRepeats characterAtIndex:i];

unichar next = [noRepeats characterAtIndex:i + 1];

if ([whitespace characterIsMember:current]) {

if ([whitespace characterIsMember:next]) {

// we have repeating whitespace, remove next character,

// then set i so that we will check this character again

// with the next character

[noRepeats deleteCharactersInRange:NSMakeRange(i + 1, 1)];

i--;

} else {

isJustSpace = NO;

}

} else {

isJustSpace = NO;

}

}

if (isJustSpace) return;

[delegate htmlParser:self didEncounterPlainText:[noRepeats copy]]; // immutable copy

}

- (void)delegateInformElementStart:(NSString *)tag attributes:(NSDictionary *)attributes {

if ([plainBuffer length] > 0) {

[self delegateInformText:plainBuffer];

plainBuffer = [[NSMutableString alloc] init];

}

[delegate htmlParser:self didStartElement:tag attributes:attributes];

}

- (void)delegateInformElementEnd:(NSString *)tag {

if ([plainBuffer length] > 0) {

[self delegateInformText:plainBuffer];

plainBuffer = [[NSMutableString alloc] init];

}

[delegate htmlParser:self didEndElement:tag];

}

- (unichar)delegateGetEscapeValue:(NSString *)eCode {

if (![delegate respondsToSelector:@selector(htmlParser:characterForEscapeCode:)]) {

return 0;

}

return [delegate htmlParser:self characterForEscapeCode:eCode];

}

@end