third_party/WebKit/Source/core/html/track/WebVTTParser.cpp - chromium/src - Git at Google

 /*
  * Copyright (C) 2011 Google Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "config.h"
 #include "core/html/track/WebVTTParser.h"

 #include "core/dom/Document.h"
 #include "core/dom/ProcessingInstruction.h"
 #include "core/dom/Text.h"
 #include "core/html/track/WebVTTElement.h"
 #include "platform/text/SegmentedString.h"
 #include "wtf/text/WTFString.h"

 namespace WebCore {

 const double secondsPerHour = 3600;
 const double secondsPerMinute = 60;
 const double secondsPerMillisecond = 0.001;
 const double malformedTime = -1;
 const unsigned fileIdentifierLength = 6;

 String WebVTTParser::collectDigits(const String& input, unsigned* position)
 {
     StringBuilder digits;
     while (*position < input.length() && isASCIIDigit(input[*position]))
         digits.append(input[(*position)++]);
     return digits.toString();
 }

 String WebVTTParser::collectWord(const String& input, unsigned* position)
 {
     StringBuilder string;
     while (*position < input.length() && !isASpace(input[*position]))
         string.append(input[(*position)++]);
     return string.toString();
 }

 float WebVTTParser::parseFloatPercentageValue(const String& value, bool& isValidSetting)
 {
     // '%' must be present and at the end of the setting value.
     if (value.find('%', 1) != value.length() - 1) {
         isValidSetting = false;
         return 0;
     }

     unsigned position = 0;

     StringBuilder floatNumberAsString;
     floatNumberAsString.append(WebVTTParser::collectDigits(value, &position));

     if (value[position] == '.') {
         floatNumberAsString.append(".");
         position++;

         floatNumberAsString.append(WebVTTParser::collectDigits(value, &position));
     }
     float number = floatNumberAsString.toString().toFloat(&isValidSetting);

     if (isValidSetting && (number <= 0 || number >= 100))
         isValidSetting = false;

     return number;
 }

 FloatPoint WebVTTParser::parseFloatPercentageValuePair(const String& value, char delimiter, bool& isValidSetting)
 {
     // The delimiter can't be the first or second value because a pair of
     // percentages (x%,y%) implies that at least the first two characters
     // are the first percentage value.
     size_t delimiterOffset = value.find(delimiter, 2);
     if (delimiterOffset == kNotFound || delimiterOffset == value.length() - 1) {
         isValidSetting = false;
         return FloatPoint(0, 0);
     }

     bool isFirstValueValid;
     float firstCoord = parseFloatPercentageValue(value.substring(0, delimiterOffset), isFirstValueValid);

     bool isSecondValueValid;
     float secondCoord = parseFloatPercentageValue(value.substring(delimiterOffset + 1, value.length() - 1), isSecondValueValid);

     isValidSetting = isFirstValueValid && isSecondValueValid;
     return FloatPoint(firstCoord, secondCoord);
 }

 WebVTTParser::WebVTTParser(WebVTTParserClient* client, Document& document)
     : m_document(&document)
     , m_state(Initial)
     , m_decoder(TextResourceDecoder::create("text/plain", UTF8Encoding()))
     , m_currentStartTime(0)
     , m_currentEndTime(0)
     , m_client(client)
 {
 }

 void WebVTTParser::getNewCues(Vector<RefPtr<VTTCue> >& outputCues)
 {
     outputCues = m_cuelist;
     m_cuelist.clear();
 }

 void WebVTTParser::getNewRegions(Vector<RefPtr<VTTRegion> >& outputRegions)
 {
     outputRegions = m_regionList;
     m_regionList.clear();
 }

 void WebVTTParser::parseBytes(const char* data, unsigned length)
 {
     String textData = m_decoder->decode(data, length);
     m_lineReader.append(textData);
     parse();
 }

 void WebVTTParser::flush()
 {
     String textData = m_decoder->flush();
     m_lineReader.append(textData);
     m_lineReader.setEndOfStream();
     parse();
     flushPendingCue();
 }

 void WebVTTParser::parse()
 {
     // WebVTT parser algorithm. (5.1 WebVTT file parsing.)
     // Steps 1 - 3 - Initial setup.

     String line;
     while (m_lineReader.getLine(line)) {
         switch (m_state) {
         case Initial:
             // Steps 4 - 9 - Check for a valid WebVTT signature.
             if (!hasRequiredFileIdentifier(line)) {
                 if (m_client)
                     m_client->fileFailedToParse();
                 return;
             }

             m_state = Header;
             break;

         case Header:
             // Steps 10 - 14 - Allow a header (comment area) under the WEBVTT line.
             collectMetadataHeader(line);

             if (line.isEmpty()) {
                 if (m_client && m_regionList.size())
                     m_client->newRegionsParsed();

                 m_state = Id;
                 break;
             }

             // Step 16 - Line is not the empty string and does not contain "-->".
             break;

         case Id:
             // Steps 17 - 20 - Allow any number of line terminators, then initialize new cue values.
             if (line.isEmpty())
                 break;

             // Step 21 - Cue creation (start a new cue).
             resetCueValues();

             // Steps 22 - 25 - Check if this line contains an optional identifier or timing data.
             m_state = collectCueId(line);
             break;

         case TimingsAndSettings:
             // Steps 26 - 27 - Discard current cue if the line is empty.
             if (line.isEmpty()) {
                 m_state = Id;
                 break;
             }

             // Steps 28 - 29 - Collect cue timings and settings.
             m_state = collectTimingsAndSettings(line);
             break;

         case CueText:
             // Steps 31 - 41 - Collect the cue text, create a cue, and add it to the output.
             m_state = collectCueText(line);
             break;

         case BadCue:
             // Steps 42 - 48 - Discard lines until an empty line or a potential timing line is seen.
             m_state = ignoreBadCue(line);
             break;
         }
     }
 }

 void WebVTTParser::flushPendingCue()
 {
     ASSERT(m_lineReader.isAtEndOfStream());
     // If we're in the CueText state when we run out of data, we emit the pending cue.
     if (m_state == CueText)
         createNewCue();
 }

 bool WebVTTParser::hasRequiredFileIdentifier(const String& line)
 {
     // A WebVTT file identifier consists of an optional BOM character,
     // the string "WEBVTT" followed by an optional space or tab character,
     // and any number of characters that are not line terminators ...
     if (!line.startsWith("WEBVTT", fileIdentifierLength))
         return false;
     if (line.length() > fileIdentifierLength && !isASpace(line[fileIdentifierLength]))
         return false;

     return true;
 }

 void WebVTTParser::collectMetadataHeader(const String& line)
 {
     // WebVTT header parsing (WebVTT parser algorithm step 12)
     DEFINE_STATIC_LOCAL(const AtomicString, regionHeaderName, ("Region", AtomicString::ConstructFromLiteral));

     // Step 12.4 If line contains the character ":" (A U+003A COLON), then set metadata's
     // name to the substring of line before the first ":" character and
     // metadata's value to the substring after this character.
     if (!RuntimeEnabledFeatures::webVTTRegionsEnabled() || !line.contains(":"))
         return;

     unsigned colonPosition = line.find(":");
     String headerName = line.substring(0, colonPosition);

     // Steps 12.5 If metadata's name equals "Region":
     if (headerName == regionHeaderName) {
         String headerValue = line.substring(colonPosition + 1);
         // Steps 12.5.1 - 12.5.11 Region creation: Let region be a new text track region [...]
         createNewRegion(headerValue);
     }
 }

 WebVTTParser::ParseState WebVTTParser::collectCueId(const String& line)
 {
     if (line.contains("-->"))
         return collectTimingsAndSettings(line);
     m_currentId = line;
     return TimingsAndSettings;
 }

 WebVTTParser::ParseState WebVTTParser::collectTimingsAndSettings(const String& line)
 {
     // Collect WebVTT cue timings and settings. (5.3 WebVTT cue timings and settings parsing.)
     // Steps 1 - 3 - Let input be the string being parsed and position be a pointer into input.
     unsigned position = 0;
     skipWhiteSpace(line, &position);

     // Steps 4 - 5 - Collect a WebVTT timestamp. If that fails, then abort and return failure. Otherwise, let cue's text track cue start time be the collected time.
     m_currentStartTime = collectTimeStamp(line, &position);
     if (m_currentStartTime == malformedTime)
         return BadCue;
     if (position >= line.length())
         return BadCue;

     skipWhiteSpace(line, &position);

     // Steps 6 - 9 - If the next three characters are not "-->", abort and return failure.
     if (line.find("-->", position) == kNotFound)
         return BadCue;
     position += 3;
     if (position >= line.length())
         return BadCue;

     skipWhiteSpace(line, &position);

     // Steps 10 - 11 - Collect a WebVTT timestamp. If that fails, then abort and return failure. Otherwise, let cue's text track cue end time be the collected time.
     m_currentEndTime = collectTimeStamp(line, &position);
     if (m_currentEndTime == malformedTime)
         return BadCue;
     skipWhiteSpace(line, &position);

     // Step 12 - Parse the WebVTT settings for the cue (conducted in TextTrackCue).
     m_currentSettings = line.substring(position, line.length()-1);
     return CueText;
 }

 WebVTTParser::ParseState WebVTTParser::collectCueText(const String& line)
 {
     if (line.isEmpty()) {
         createNewCue();
         return Id;
     }
     if (!m_currentContent.isEmpty())
         m_currentContent.append("\n");
     m_currentContent.append(line);

     return CueText;
 }

 WebVTTParser::ParseState WebVTTParser::ignoreBadCue(const String& line)
 {
     if (!line.isEmpty())
         return BadCue;
     return Id;
 }

 // A helper class for the construction of a "cue fragment" from the cue text.
 class WebVTTTreeBuilder {
 public:
     WebVTTTreeBuilder(Document& document)
         : m_document(document) { }

     PassRefPtr<DocumentFragment> buildFromString(const String& cueText);

 private:
     void constructTreeFromToken(Document&);

     WebVTTToken m_token;
     RefPtr<ContainerNode> m_currentNode;
     Vector<AtomicString> m_languageStack;
     Document& m_document;
 };

 PassRefPtr<DocumentFragment> WebVTTTreeBuilder::buildFromString(const String& cueText)
 {
     // Cue text processing based on
     // 5.4 WebVTT cue text parsing rules, and
     // 5.5 WebVTT cue text DOM construction rules

     RefPtr<DocumentFragment> fragment = DocumentFragment::create(m_document);

     if (cueText.isEmpty()) {
         fragment->parserAppendChild(Text::create(m_document, ""));
         return fragment;
     }

     m_currentNode = fragment;

     OwnPtr<WebVTTTokenizer> tokenizer(WebVTTTokenizer::create());
     m_token.clear();
     m_languageStack.clear();

     SegmentedString content(cueText);
     while (tokenizer->nextToken(content, m_token))
         constructTreeFromToken(m_document);

     return fragment.release();
 }

 PassRefPtr<DocumentFragment> WebVTTParser::createDocumentFragmentFromCueText(Document& document, const String& cueText)
 {
     WebVTTTreeBuilder treeBuilder(document);
     return treeBuilder.buildFromString(cueText);
 }

 void WebVTTParser::createNewCue()
 {
     RefPtr<VTTCue> cue = VTTCue::create(*m_document, m_currentStartTime, m_currentEndTime, m_currentContent.toString());
     cue->setId(m_currentId);
     cue->setCueSettings(m_currentSettings);

     m_cuelist.append(cue);
     if (m_client)
         m_client->newCuesParsed();
 }

 void WebVTTParser::resetCueValues()
 {
     m_currentId = emptyString();
     m_currentSettings = emptyString();
     m_currentStartTime = 0;
     m_currentEndTime = 0;
     m_currentContent.clear();
 }

 void WebVTTParser::createNewRegion(const String& headerValue)
 {
     if (headerValue.isEmpty())
         return;

     // Steps 12.5.1 - 12.5.9 - Construct and initialize a WebVTT Region object.
     RefPtr<VTTRegion> region = VTTRegion::create();
     region->setRegionSettings(headerValue);

     // Step 12.5.10 If the text track list of regions regions contains a region
     // with the same region identifier value as region, remove that region.
     for (size_t i = 0; i < m_regionList.size(); ++i)
         if (m_regionList[i]->id() == region->id()) {
             m_regionList.remove(i);
             break;
         }

     // Step 12.5.11
     m_regionList.append(region);
 }

 double WebVTTParser::collectTimeStamp(const String& line, unsigned* position)
 {
     // Collect a WebVTT timestamp (5.3 WebVTT cue timings and settings parsing.)
     // Steps 1 - 4 - Initial checks, let most significant units be minutes.
     enum Mode { minutes, hours };
     Mode mode = minutes;
     if (*position >= line.length() || !isASCIIDigit(line[*position]))
         return malformedTime;

     // Steps 5 - 6 - Collect a sequence of characters that are 0-9.
     String digits1 = collectDigits(line, position);
     int value1 = digits1.toInt();

     // Step 7 - If not 2 characters or value is greater than 59, interpret as hours.
     if (digits1.length() != 2 || value1 > 59)
         mode = hours;

     // Steps 8 - 11 - Collect the next sequence of 0-9 after ':' (must be 2 chars).
     if (*position >= line.length() || line[(*position)++] != ':')
         return malformedTime;
     if (*position >= line.length() || !isASCIIDigit(line[(*position)]))
         return malformedTime;
     String digits2 = collectDigits(line, position);
     int value2 = digits2.toInt();
     if (digits2.length() != 2)
         return malformedTime;

     // Step 12 - Detect whether this timestamp includes hours.
     int value3;
     if (mode == hours || (*position < line.length() && line[*position] == ':')) {
         if (*position >= line.length() || line[(*position)++] != ':')
             return malformedTime;
         if (*position >= line.length() || !isASCIIDigit(line[*position]))
             return malformedTime;
         String digits3 = collectDigits(line, position);
         if (digits3.length() != 2)
             return malformedTime;
         value3 = digits3.toInt();
     } else {
         value3 = value2;
         value2 = value1;
         value1 = 0;
     }

     // Steps 13 - 17 - Collect next sequence of 0-9 after '.' (must be 3 chars).
     if (*position >= line.length() || line[(*position)++] != '.')
         return malformedTime;
     if (*position >= line.length() || !isASCIIDigit(line[*position]))
         return malformedTime;
     String digits4 = collectDigits(line, position);
     if (digits4.length() != 3)
         return malformedTime;
     int value4 = digits4.toInt();
     if (value2 > 59 || value3 > 59)
         return malformedTime;

     // Steps 18 - 19 - Calculate result.
     return (value1 * secondsPerHour) + (value2 * secondsPerMinute) + value3 + (value4 * secondsPerMillisecond);
 }

 static WebVTTNodeType tokenToNodeType(WebVTTToken& token)
 {
     switch (token.name().size()) {
     case 1:
         if (token.name()[0] == 'c')
             return WebVTTNodeTypeClass;
         if (token.name()[0] == 'v')
             return WebVTTNodeTypeVoice;
         if (token.name()[0] == 'b')
             return WebVTTNodeTypeBold;
         if (token.name()[0] == 'i')
             return WebVTTNodeTypeItalic;
         if (token.name()[0] == 'u')
             return WebVTTNodeTypeUnderline;
         break;
     case 2:
         if (token.name()[0] == 'r' && token.name()[1] == 't')
             return WebVTTNodeTypeRubyText;
         break;
     case 4:
         if (token.name()[0] == 'r' && token.name()[1] == 'u' && token.name()[2] == 'b' && token.name()[3] == 'y')
             return WebVTTNodeTypeRuby;
         if (token.name()[0] == 'l' && token.name()[1] == 'a' && token.name()[2] == 'n' && token.name()[3] == 'g')
             return WebVTTNodeTypeLanguage;
         break;
     }
     return WebVTTNodeTypeNone;
 }

 void WebVTTTreeBuilder::constructTreeFromToken(Document& document)
 {
     QualifiedName tagName(nullAtom, AtomicString(m_token.name()), xhtmlNamespaceURI);

     // http://dev.w3.org/html5/webvtt/#webvtt-cue-text-dom-construction-rules

     switch (m_token.type()) {
     case WebVTTTokenTypes::Character: {
         String content(m_token.characters()); // FIXME: This should be 8bit if possible.
         RefPtr<Text> child = Text::create(document, content);
         m_currentNode->parserAppendChild(child);
         break;
     }
     case WebVTTTokenTypes::StartTag: {
         RefPtr<WebVTTElement> child;
         WebVTTNodeType nodeType = tokenToNodeType(m_token);
         if (nodeType != WebVTTNodeTypeNone)
             child = WebVTTElement::create(nodeType, &document);
         if (child) {
             if (m_token.classes().size() > 0)
                 child->setAttribute(classAttr, AtomicString(m_token.classes()));

             if (child->webVTTNodeType() == WebVTTNodeTypeVoice)
                 child->setAttribute(WebVTTElement::voiceAttributeName(), AtomicString(m_token.annotation()));
             else if (child->webVTTNodeType() == WebVTTNodeTypeLanguage) {
                 m_languageStack.append(AtomicString(m_token.annotation()));
                 child->setAttribute(WebVTTElement::langAttributeName(), m_languageStack.last());
             }
             if (!m_languageStack.isEmpty())
                 child->setLanguage(m_languageStack.last());
             m_currentNode->parserAppendChild(child);
             m_currentNode = child;
         }
         break;
     }
     case WebVTTTokenTypes::EndTag: {
         WebVTTNodeType nodeType = tokenToNodeType(m_token);
         if (nodeType != WebVTTNodeTypeNone) {
             if (nodeType == WebVTTNodeTypeLanguage && m_currentNode->isWebVTTElement() && toWebVTTElement(m_currentNode.get())->webVTTNodeType() == WebVTTNodeTypeLanguage)
                 m_languageStack.removeLast();
             if (m_currentNode->parentNode())
                 m_currentNode = m_currentNode->parentNode();
         }
         break;
     }
     case WebVTTTokenTypes::TimestampTag: {
         unsigned position = 0;
         String charactersString(StringImpl::create8BitIfPossible(m_token.characters()));
         double time = WebVTTParser::collectTimeStamp(charactersString, &position);
         if (time != malformedTime)
             m_currentNode->parserAppendChild(ProcessingInstruction::create(document, "timestamp", charactersString));
         break;
     }
     default:
         break;
     }
     m_token.clear();
 }

 void WebVTTParser::skipWhiteSpace(const String& line, unsigned* position)
 {
     while (*position < line.length() && isASpace(line[*position]))
         (*position)++;
 }

 }
	/*
	* Copyright (C) 2011 Google Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met:
	*
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above
	* copyright notice, this list of conditions and the following disclaimer
	* in the documentation and/or other materials provided with the
	* distribution.
	* * Neither the name of Google Inc. nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "config.h"
	#include "core/html/track/WebVTTParser.h"

	#include "core/dom/Document.h"
	#include "core/dom/ProcessingInstruction.h"
	#include "core/dom/Text.h"
	#include "core/html/track/WebVTTElement.h"
	#include "platform/text/SegmentedString.h"
	#include "wtf/text/WTFString.h"

	namespace WebCore {

	const double secondsPerHour = 3600;
	const double secondsPerMinute = 60;
	const double secondsPerMillisecond = 0.001;
	const double malformedTime = -1;
	const unsigned fileIdentifierLength = 6;

	String WebVTTParser::collectDigits(const String& input, unsigned* position)
	{
	StringBuilder digits;
	while (position < input.length() && isASCIIDigit(input[position]))
	digits.append(input[(*position)++]);
	return digits.toString();
	}

	String WebVTTParser::collectWord(const String& input, unsigned* position)
	{
	StringBuilder string;
	while (position < input.length() && !isASpace(input[position]))
	string.append(input[(*position)++]);
	return string.toString();
	}

	float WebVTTParser::parseFloatPercentageValue(const String& value, bool& isValidSetting)
	{
	// '%' must be present and at the end of the setting value.
	if (value.find('%', 1) != value.length() - 1) {
	isValidSetting = false;
	return 0;
	}

	unsigned position = 0;

	StringBuilder floatNumberAsString;
	floatNumberAsString.append(WebVTTParser::collectDigits(value, &position));

	if (value[position] == '.') {
	floatNumberAsString.append(".");
	position++;

	floatNumberAsString.append(WebVTTParser::collectDigits(value, &position));
	}
	float number = floatNumberAsString.toString().toFloat(&isValidSetting);

	if (isValidSetting && (number <= 0 \|\| number >= 100))
	isValidSetting = false;

	return number;
	}

	FloatPoint WebVTTParser::parseFloatPercentageValuePair(const String& value, char delimiter, bool& isValidSetting)
	{
	// The delimiter can't be the first or second value because a pair of
	// percentages (x%,y%) implies that at least the first two characters
	// are the first percentage value.
	size_t delimiterOffset = value.find(delimiter, 2);
	if (delimiterOffset == kNotFound \|\| delimiterOffset == value.length() - 1) {
	isValidSetting = false;
	return FloatPoint(0, 0);
	}

	bool isFirstValueValid;
	float firstCoord = parseFloatPercentageValue(value.substring(0, delimiterOffset), isFirstValueValid);

	bool isSecondValueValid;
	float secondCoord = parseFloatPercentageValue(value.substring(delimiterOffset + 1, value.length() - 1), isSecondValueValid);

	isValidSetting = isFirstValueValid && isSecondValueValid;
	return FloatPoint(firstCoord, secondCoord);
	}

	WebVTTParser::WebVTTParser(WebVTTParserClient* client, Document& document)
	: m_document(&document)
	, m_state(Initial)
	, m_decoder(TextResourceDecoder::create("text/plain", UTF8Encoding()))
	, m_currentStartTime(0)
	, m_currentEndTime(0)
	, m_client(client)
	{
	}

	void WebVTTParser::getNewCues(Vector<RefPtr<VTTCue> >& outputCues)
	{
	outputCues = m_cuelist;
	m_cuelist.clear();
	}

	void WebVTTParser::getNewRegions(Vector<RefPtr<VTTRegion> >& outputRegions)
	{
	outputRegions = m_regionList;
	m_regionList.clear();
	}

	void WebVTTParser::parseBytes(const char* data, unsigned length)
	{
	String textData = m_decoder->decode(data, length);
	m_lineReader.append(textData);
	parse();
	}

	void WebVTTParser::flush()
	{
	String textData = m_decoder->flush();
	m_lineReader.append(textData);
	m_lineReader.setEndOfStream();
	parse();
	flushPendingCue();
	}

	void WebVTTParser::parse()
	{
	// WebVTT parser algorithm. (5.1 WebVTT file parsing.)
	// Steps 1 - 3 - Initial setup.

	String line;
	while (m_lineReader.getLine(line)) {
	switch (m_state) {
	case Initial:
	// Steps 4 - 9 - Check for a valid WebVTT signature.
	if (!hasRequiredFileIdentifier(line)) {
	if (m_client)
	m_client->fileFailedToParse();
	return;
	}

	m_state = Header;
	break;

	case Header:
	// Steps 10 - 14 - Allow a header (comment area) under the WEBVTT line.
	collectMetadataHeader(line);

	if (line.isEmpty()) {
	if (m_client && m_regionList.size())
	m_client->newRegionsParsed();

	m_state = Id;
	break;
	}

	// Step 16 - Line is not the empty string and does not contain "-->".
	break;

	case Id:
	// Steps 17 - 20 - Allow any number of line terminators, then initialize new cue values.
	if (line.isEmpty())
	break;

	// Step 21 - Cue creation (start a new cue).
	resetCueValues();

	// Steps 22 - 25 - Check if this line contains an optional identifier or timing data.
	m_state = collectCueId(line);
	break;

	case TimingsAndSettings:
	// Steps 26 - 27 - Discard current cue if the line is empty.
	if (line.isEmpty()) {
	m_state = Id;
	break;
	}

	// Steps 28 - 29 - Collect cue timings and settings.
	m_state = collectTimingsAndSettings(line);
	break;

	case CueText:
	// Steps 31 - 41 - Collect the cue text, create a cue, and add it to the output.
	m_state = collectCueText(line);
	break;

	case BadCue:
	// Steps 42 - 48 - Discard lines until an empty line or a potential timing line is seen.
	m_state = ignoreBadCue(line);
	break;
	}
	}
	}

	void WebVTTParser::flushPendingCue()
	{
	ASSERT(m_lineReader.isAtEndOfStream());
	// If we're in the CueText state when we run out of data, we emit the pending cue.
	if (m_state == CueText)
	createNewCue();
	}

	bool WebVTTParser::hasRequiredFileIdentifier(const String& line)
	{
	// A WebVTT file identifier consists of an optional BOM character,
	// the string "WEBVTT" followed by an optional space or tab character,
	// and any number of characters that are not line terminators ...
	if (!line.startsWith("WEBVTT", fileIdentifierLength))
	return false;
	if (line.length() > fileIdentifierLength && !isASpace(line[fileIdentifierLength]))
	return false;

	return true;
	}

	void WebVTTParser::collectMetadataHeader(const String& line)
	{
	// WebVTT header parsing (WebVTT parser algorithm step 12)
	DEFINE_STATIC_LOCAL(const AtomicString, regionHeaderName, ("Region", AtomicString::ConstructFromLiteral));

	// Step 12.4 If line contains the character ":" (A U+003A COLON), then set metadata's
	// name to the substring of line before the first ":" character and
	// metadata's value to the substring after this character.
	if (!RuntimeEnabledFeatures::webVTTRegionsEnabled() \|\| !line.contains(":"))
	return;

	unsigned colonPosition = line.find(":");
	String headerName = line.substring(0, colonPosition);

	// Steps 12.5 If metadata's name equals "Region":
	if (headerName == regionHeaderName) {
	String headerValue = line.substring(colonPosition + 1);
	// Steps 12.5.1 - 12.5.11 Region creation: Let region be a new text track region [...]
	createNewRegion(headerValue);
	}
	}

	WebVTTParser::ParseState WebVTTParser::collectCueId(const String& line)
	{
	if (line.contains("-->"))
	return collectTimingsAndSettings(line);
	m_currentId = line;
	return TimingsAndSettings;
	}

	WebVTTParser::ParseState WebVTTParser::collectTimingsAndSettings(const String& line)
	{
	// Collect WebVTT cue timings and settings. (5.3 WebVTT cue timings and settings parsing.)
	// Steps 1 - 3 - Let input be the string being parsed and position be a pointer into input.
	unsigned position = 0;
	skipWhiteSpace(line, &position);

	// Steps 4 - 5 - Collect a WebVTT timestamp. If that fails, then abort and return failure. Otherwise, let cue's text track cue start time be the collected time.
	m_currentStartTime = collectTimeStamp(line, &position);
	if (m_currentStartTime == malformedTime)
	return BadCue;
	if (position >= line.length())
	return BadCue;

	skipWhiteSpace(line, &position);

	// Steps 6 - 9 - If the next three characters are not "-->", abort and return failure.
	if (line.find("-->", position) == kNotFound)
	return BadCue;
	position += 3;
	if (position >= line.length())
	return BadCue;

	skipWhiteSpace(line, &position);

	// Steps 10 - 11 - Collect a WebVTT timestamp. If that fails, then abort and return failure. Otherwise, let cue's text track cue end time be the collected time.
	m_currentEndTime = collectTimeStamp(line, &position);
	if (m_currentEndTime == malformedTime)
	return BadCue;
	skipWhiteSpace(line, &position);

	// Step 12 - Parse the WebVTT settings for the cue (conducted in TextTrackCue).
	m_currentSettings = line.substring(position, line.length()-1);
	return CueText;
	}

	WebVTTParser::ParseState WebVTTParser::collectCueText(const String& line)
	{
	if (line.isEmpty()) {
	createNewCue();
	return Id;
	}
	if (!m_currentContent.isEmpty())
	m_currentContent.append("\n");
	m_currentContent.append(line);

	return CueText;
	}

	WebVTTParser::ParseState WebVTTParser::ignoreBadCue(const String& line)
	{
	if (!line.isEmpty())
	return BadCue;
	return Id;
	}

	// A helper class for the construction of a "cue fragment" from the cue text.
	class WebVTTTreeBuilder {
	public:
	WebVTTTreeBuilder(Document& document)
	: m_document(document) { }

	PassRefPtr<DocumentFragment> buildFromString(const String& cueText);

	private:
	void constructTreeFromToken(Document&);

	WebVTTToken m_token;
	RefPtr<ContainerNode> m_currentNode;
	Vector<AtomicString> m_languageStack;
	Document& m_document;
	};

	PassRefPtr<DocumentFragment> WebVTTTreeBuilder::buildFromString(const String& cueText)
	{
	// Cue text processing based on
	// 5.4 WebVTT cue text parsing rules, and
	// 5.5 WebVTT cue text DOM construction rules

	RefPtr<DocumentFragment> fragment = DocumentFragment::create(m_document);

	if (cueText.isEmpty()) {
	fragment->parserAppendChild(Text::create(m_document, ""));
	return fragment;
	}

	m_currentNode = fragment;

	OwnPtr<WebVTTTokenizer> tokenizer(WebVTTTokenizer::create());
	m_token.clear();
	m_languageStack.clear();

	SegmentedString content(cueText);
	while (tokenizer->nextToken(content, m_token))
	constructTreeFromToken(m_document);

	return fragment.release();
	}

	PassRefPtr<DocumentFragment> WebVTTParser::createDocumentFragmentFromCueText(Document& document, const String& cueText)
	{
	WebVTTTreeBuilder treeBuilder(document);
	return treeBuilder.buildFromString(cueText);
	}

	void WebVTTParser::createNewCue()
	{
	RefPtr<VTTCue> cue = VTTCue::create(*m_document, m_currentStartTime, m_currentEndTime, m_currentContent.toString());
	cue->setId(m_currentId);
	cue->setCueSettings(m_currentSettings);

	m_cuelist.append(cue);
	if (m_client)
	m_client->newCuesParsed();
	}

	void WebVTTParser::resetCueValues()
	{
	m_currentId = emptyString();
	m_currentSettings = emptyString();
	m_currentStartTime = 0;
	m_currentEndTime = 0;
	m_currentContent.clear();
	}

	void WebVTTParser::createNewRegion(const String& headerValue)
	{
	if (headerValue.isEmpty())
	return;

	// Steps 12.5.1 - 12.5.9 - Construct and initialize a WebVTT Region object.
	RefPtr<VTTRegion> region = VTTRegion::create();
	region->setRegionSettings(headerValue);

	// Step 12.5.10 If the text track list of regions regions contains a region
	// with the same region identifier value as region, remove that region.
	for (size_t i = 0; i < m_regionList.size(); ++i)
	if (m_regionList[i]->id() == region->id()) {
	m_regionList.remove(i);
	break;
	}

	// Step 12.5.11
	m_regionList.append(region);
	}

	double WebVTTParser::collectTimeStamp(const String& line, unsigned* position)
	{
	// Collect a WebVTT timestamp (5.3 WebVTT cue timings and settings parsing.)
	// Steps 1 - 4 - Initial checks, let most significant units be minutes.
	enum Mode { minutes, hours };
	Mode mode = minutes;
	if (position >= line.length() \|\| !isASCIIDigit(line[position]))
	return malformedTime;

	// Steps 5 - 6 - Collect a sequence of characters that are 0-9.
	String digits1 = collectDigits(line, position);
	int value1 = digits1.toInt();

	// Step 7 - If not 2 characters or value is greater than 59, interpret as hours.
	if (digits1.length() != 2 \|\| value1 > 59)
	mode = hours;

	// Steps 8 - 11 - Collect the next sequence of 0-9 after ':' (must be 2 chars).
	if (position >= line.length() \|\| line[(position)++] != ':')
	return malformedTime;
	if (position >= line.length() \|\| !isASCIIDigit(line[(position)]))
	return malformedTime;
	String digits2 = collectDigits(line, position);
	int value2 = digits2.toInt();
	if (digits2.length() != 2)
	return malformedTime;

	// Step 12 - Detect whether this timestamp includes hours.
	int value3;
	if (mode == hours \|\| (position < line.length() && line[position] == ':')) {
	if (position >= line.length() \|\| line[(position)++] != ':')
	return malformedTime;
	if (position >= line.length() \|\| !isASCIIDigit(line[position]))
	return malformedTime;
	String digits3 = collectDigits(line, position);
	if (digits3.length() != 2)
	return malformedTime;
	value3 = digits3.toInt();
	} else {
	value3 = value2;
	value2 = value1;
	value1 = 0;
	}

	// Steps 13 - 17 - Collect next sequence of 0-9 after '.' (must be 3 chars).
	if (position >= line.length() \|\| line[(position)++] != '.')
	return malformedTime;
	if (position >= line.length() \|\| !isASCIIDigit(line[position]))
	return malformedTime;
	String digits4 = collectDigits(line, position);
	if (digits4.length() != 3)
	return malformedTime;
	int value4 = digits4.toInt();
	if (value2 > 59 \|\| value3 > 59)
	return malformedTime;

	// Steps 18 - 19 - Calculate result.
	return (value1 * secondsPerHour) + (value2 * secondsPerMinute) + value3 + (value4 * secondsPerMillisecond);
	}

	static WebVTTNodeType tokenToNodeType(WebVTTToken& token)
	{
	switch (token.name().size()) {
	case 1:
	if (token.name()[0] == 'c')
	return WebVTTNodeTypeClass;
	if (token.name()[0] == 'v')
	return WebVTTNodeTypeVoice;
	if (token.name()[0] == 'b')
	return WebVTTNodeTypeBold;
	if (token.name()[0] == 'i')
	return WebVTTNodeTypeItalic;
	if (token.name()[0] == 'u')
	return WebVTTNodeTypeUnderline;
	break;
	case 2:
	if (token.name()[0] == 'r' && token.name()[1] == 't')
	return WebVTTNodeTypeRubyText;
	break;
	case 4:
	if (token.name()[0] == 'r' && token.name()[1] == 'u' && token.name()[2] == 'b' && token.name()[3] == 'y')
	return WebVTTNodeTypeRuby;
	if (token.name()[0] == 'l' && token.name()[1] == 'a' && token.name()[2] == 'n' && token.name()[3] == 'g')
	return WebVTTNodeTypeLanguage;
	break;
	}
	return WebVTTNodeTypeNone;
	}

	void WebVTTTreeBuilder::constructTreeFromToken(Document& document)
	{
	QualifiedName tagName(nullAtom, AtomicString(m_token.name()), xhtmlNamespaceURI);

	// http://dev.w3.org/html5/webvtt/#webvtt-cue-text-dom-construction-rules

	switch (m_token.type()) {
	case WebVTTTokenTypes::Character: {
	String content(m_token.characters()); // FIXME: This should be 8bit if possible.
	RefPtr<Text> child = Text::create(document, content);
	m_currentNode->parserAppendChild(child);
	break;
	}
	case WebVTTTokenTypes::StartTag: {
	RefPtr<WebVTTElement> child;
	WebVTTNodeType nodeType = tokenToNodeType(m_token);
	if (nodeType != WebVTTNodeTypeNone)
	child = WebVTTElement::create(nodeType, &document);
	if (child) {
	if (m_token.classes().size() > 0)
	child->setAttribute(classAttr, AtomicString(m_token.classes()));

	if (child->webVTTNodeType() == WebVTTNodeTypeVoice)
	child->setAttribute(WebVTTElement::voiceAttributeName(), AtomicString(m_token.annotation()));
	else if (child->webVTTNodeType() == WebVTTNodeTypeLanguage) {
	m_languageStack.append(AtomicString(m_token.annotation()));
	child->setAttribute(WebVTTElement::langAttributeName(), m_languageStack.last());
	}
	if (!m_languageStack.isEmpty())
	child->setLanguage(m_languageStack.last());
	m_currentNode->parserAppendChild(child);
	m_currentNode = child;
	}
	break;
	}
	case WebVTTTokenTypes::EndTag: {
	WebVTTNodeType nodeType = tokenToNodeType(m_token);
	if (nodeType != WebVTTNodeTypeNone) {
	if (nodeType == WebVTTNodeTypeLanguage && m_currentNode->isWebVTTElement() && toWebVTTElement(m_currentNode.get())->webVTTNodeType() == WebVTTNodeTypeLanguage)
	m_languageStack.removeLast();
	if (m_currentNode->parentNode())
	m_currentNode = m_currentNode->parentNode();
	}
	break;
	}
	case WebVTTTokenTypes::TimestampTag: {
	unsigned position = 0;
	String charactersString(StringImpl::create8BitIfPossible(m_token.characters()));
	double time = WebVTTParser::collectTimeStamp(charactersString, &position);
	if (time != malformedTime)
	m_currentNode->parserAppendChild(ProcessingInstruction::create(document, "timestamp", charactersString));
	break;
	}
	default:
	break;
	}
	m_token.clear();
	}

	void WebVTTParser::skipWhiteSpace(const String& line, unsigned* position)
	{
	while (position < line.length() && isASpace(line[position]))
	(*position)++;
	}

	}