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<?php
/**
* @package WPSEO\Admin
*/
/**
* Modified (Reduced) TextStatistics Class
*
* Mostly removed functionality that isn't needed within the WordPress SEO plugin.
*
* @link http://code.google.com/p/php-text-statistics/
* @link https://github.com/DaveChild/Text-Statistics (new repo location)
* @license http://www.opensource.org/licenses/bsd-license.php New BSD license
*
* @todo [JRF => whomever] Research if a class/library can be found which will offer
* this functionality to a broader scope of languages/charsets.
* Now basically limited to English.
*/
class Yoast_TextStatistics {
/**
* @var string $strEncoding Used to hold character encoding to be used by object, if set
*/
protected $strEncoding = '';
/**
* @var string $blnMbstring Efficiency: Is the MB String extension loaded ?
*/
protected $blnMbstring = true;
/**
* @var bool $normalize Should the result be normalized ?
*/
public $normalize = true;
/**
* Constructor.
*
* @param string $strEncoding Optional character encoding.
*/
public function __construct( $strEncoding = '' ) {
if ( $strEncoding <> '' ) {
// Encoding is given. Use it!
$this->strEncoding = $strEncoding;
}
$this->blnMbstring = extension_loaded( 'mbstring' );
}
/**
* Gives the Flesch-Kincaid Reading Ease of text entered rounded to one digit
*
* @param string $strText Text to be checked
*
* @return int|float
*/
public function flesch_kincaid_reading_ease( $strText ) {
$strText = $this->clean_text( $strText );
$score = WPSEO_Utils::calc( WPSEO_Utils::calc( 206.835, '-', WPSEO_Utils::calc( 1.015, '*', $this->average_words_per_sentence( $strText ) ) ), '-', WPSEO_Utils::calc( 84.6, '*', $this->average_syllables_per_word( $strText ) ) );
return $this->normalize_score( $score, 0, 100 );
}
/**
* Gives string length.
*
* @param string $strText Text to be measured
*
* @return int
*/
public function text_length( $strText ) {
if ( ! $this->blnMbstring ) {
return strlen( $strText );
}
try {
if ( $this->strEncoding == '' ) {
$intTextLength = mb_strlen( $strText );
}
else {
$intTextLength = mb_strlen( $strText, $this->strEncoding );
}
} catch ( Exception $e ) {
$intTextLength = strlen( $strText );
}
return $intTextLength;
}
/**
* Gives letter count (ignores all non-letters). Tries mb_strlen and if that fails uses regular strlen.
*
* @param string $strText Text to be measured
*
* @return int
*/
public function letter_count( $strText ) {
$strText = $this->clean_text( $strText ); // To clear out newlines etc
$strText = preg_replace( '`[^A-Za-z]+`', '', $strText );
if ( ! $this->blnMbstring ) {
return strlen( $strText );
}
try {
if ( $this->strEncoding == '' ) {
$intTextLength = mb_strlen( $strText );
}
else {
$intTextLength = mb_strlen( $strText, $this->strEncoding );
}
} catch ( Exception $e ) {
$intTextLength = strlen( $strText );
}
return $intTextLength;
}
/**
* Trims, removes line breaks, multiple spaces and generally cleans text before processing.
*
* @param string $strText Text to be transformed
*
* @return string
*/
protected function clean_text( $strText ) {
static $clean = array();
$key = sha1( $strText );
if ( isset( $clean[ $key ] ) ) {
return $clean[ $key ];
}
// all these tags should be preceeded by a full stop.
$fullStopTags = array( 'li', 'p', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'dd' );
foreach ( $fullStopTags as $tag ) {
$strText = str_ireplace( '</' . $tag . '>', '.', $strText );
}
$strText = strip_tags( $strText );
$strText = preg_replace( '`[",:;\(\)-]`', ' ', $strText ); // Replace commas, hyphens etc (count them as spaces)
$strText = preg_replace( '`[\.!?]`', '.', $strText ); // Unify terminators
$strText = trim( $strText ) . '.'; // Add final terminator, just in case it's missing.
$strText = preg_replace( '`[ ]*(\n|\r\n|\r)[ ]*`', ' ', $strText ); // Replace new lines with spaces
$strText = preg_replace( '`([\.])[\. ]+`', '$1', $strText ); // Check for duplicated terminators
$strText = trim( preg_replace( '`[ ]*([\.])`', '$1 ', $strText ) ); // Pad sentence terminators
$strText = preg_replace( '` [0-9]+ `', ' ', ' ' . $strText . ' ' ); // Remove "words" comprised only of numbers
$strText = preg_replace( '`[ ]+`', ' ', $strText ); // Remove multiple spaces
$strText = preg_replace_callback( '`\. [^ ]+?`', create_function( '$matches', 'return strtolower( $matches[0] );' ), $strText ); // Lower case all words following terminators (for gunning fog score)
$strText = trim( $strText );
// Cache it and return
$clean[ $key ] = $strText;
return $strText;
}
/**
* Converts string to lower case. Tries mb_strtolower and if that fails uses regular strtolower.
*
* @param string $strText Text to be transformed
*
* @return string
*/
protected function lower_case( $strText ) {
if ( ! $this->blnMbstring ) {
return strtolower( $strText );
}
try {
if ( $this->strEncoding == '' ) {
$strLowerCaseText = mb_strtolower( $strText );
}
else {
$strLowerCaseText = mb_strtolower( $strText, $this->strEncoding );
}
} catch ( Exception $e ) {
$strLowerCaseText = strtolower( $strText );
}
return $strLowerCaseText;
}
/**
* Converts string to upper case. Tries mb_strtoupper and if that fails uses regular strtoupper.
*
* @param string $strText Text to be transformed
*
* @return string
*/
protected function upper_case( $strText ) {
if ( ! $this->blnMbstring ) {
return strtoupper( $strText );
}
try {
if ( $this->strEncoding == '' ) {
$strUpperCaseText = mb_strtoupper( $strText );
}
else {
$strUpperCaseText = mb_strtoupper( $strText, $this->strEncoding );
}
} catch ( Exception $e ) {
$strUpperCaseText = strtoupper( $strText );
}
return $strUpperCaseText;
}
/**
* Returns sentence count for text.
*
* @param string $strText Text to be measured
*
* @return int
*/
public function sentence_count( $strText ) {
if ( strlen( trim( $strText ) ) == 0 ) {
return 0;
}
$strText = $this->clean_text( $strText );
// Will be tripped up by "Mr." or "U.K.". Not a major concern at this point.
// [JRF] Will also be tripped up by ... or ?!
// @todo [JRF => whomever] May be replace with something along the lines of this - will at least provide better count in ... and ?! situations:
// $intSentences = max( 1, preg_match_all( '`[^\.!?]+[\.!?]+([\s]+|$)`u', $strText, $matches ) ); [/JRF]
$intSentences = max( 1, $this->text_length( preg_replace( '`[^\.!?]`', '', $strText ) ) );
return $intSentences;
}
/**
* Returns word count for text.
*
* @param string $strText Text to be measured
*
* @return int
*/
public function word_count( $strText ) {
if ( strlen( trim( $strText ) ) == 0 ) {
return 0;
}
$strText = $this->clean_text( $strText );
// Will be tripped by em dashes with spaces either side, among other similar characters
$intWords = ( 1 + $this->text_length( preg_replace( '`[^ ]`', '', $strText ) ) ); // Space count + 1 is word count
return $intWords;
}
/**
* Returns average words per sentence for text.
*
* @param string $strText Text to be measured
*
* @return int|float
*/
public function average_words_per_sentence( $strText ) {
$strText = $this->clean_text( $strText );
$intSentenceCount = $this->sentence_count( $strText );
$intWordCount = $this->word_count( $strText );
return ( WPSEO_Utils::calc( $intWordCount, '/', $intSentenceCount ) );
}
/**
* Returns average syllables per word for text.
*
* @param string $strText Text to be measured
*
* @return int|float
*/
public function average_syllables_per_word( $strText ) {
$strText = $this->clean_text( $strText );
$intSyllableCount = 0;
$intWordCount = $this->word_count( $strText );
$arrWords = explode( ' ', $strText );
for ( $i = 0; $i < $intWordCount; $i ++ ) {
$intSyllableCount += $this->syllable_count( $arrWords[ $i ] );
}
return ( WPSEO_Utils::calc( $intSyllableCount, '/', $intWordCount ) );
}
/**
* Returns the number of syllables in the word.
* Based in part on Greg Fast's Perl module Lingua::EN::Syllables
*
* @param string $strWord Word to be measured
*
* @return int
*/
public function syllable_count( $strWord ) {
if ( strlen( trim( $strWord ) ) == 0 ) {
return 0;
}
// Should be no non-alpha characters
$strWord = preg_replace( '`[^A-Za-z]`', '', $strWord );
$intSyllableCount = 0;
$strWord = $this->lower_case( $strWord );
// Specific common exceptions that don't follow the rule set below are handled individually
// Array of problem words (with word as key, syllable count as value)
$arrProblemWords = array(
'simile' => 3,
'forever' => 3,
'shoreline' => 2,
);
if ( isset( $arrProblemWords[ $strWord ] ) ) {
$intSyllableCount = $arrProblemWords[ $strWord ];
}
if ( $intSyllableCount > 0 ) {
return $intSyllableCount;
}
// These syllables would be counted as two but should be one
$arrSubSyllables = array(
'cial',
'tia',
'cius',
'cious',
'giu',
'ion',
'iou',
'sia$',
'[^aeiuoyt]{2,}ed$',
'.ely$',
'[cg]h?e[rsd]?$',
'rved?$',
'[aeiouy][dt]es?$',
'[aeiouy][^aeiouydt]e[rsd]?$',
// Sorts out deal, deign etc
'^[dr]e[aeiou][^aeiou]+$',
// Purse, hearse
'[aeiouy]rse$',
);
// These syllables would be counted as one but should be two
$arrAddSyllables = array(
'ia',
'riet',
'dien',
'iu',
'io',
'ii',
'[aeiouym]bl$',
'[aeiou]{3}',
'^mc',
'ism$',
'([^aeiouy])\1l$',
'[^l]lien',
'^coa[dglx].',
'[^gq]ua[^auieo]',
'dnt$',
'uity$',
'ie(r|st)$',
);
// Single syllable prefixes and suffixes
$arrPrefixSuffix = array(
'`^un`',
'`^fore`',
'`ly$`',
'`less$`',
'`ful$`',
'`ers?$`',
'`ings?$`',
);
// Remove prefixes and suffixes and count how many were taken
$strWord = preg_replace( $arrPrefixSuffix, '', $strWord, - 1, $intPrefixSuffixCount );
// Removed non-word characters from word
$strWord = preg_replace( '`[^a-z]`is', '', $strWord );
$arrWordParts = preg_split( '`[^aeiouy]+`', $strWord );
$intWordPartCount = 0;
foreach ( $arrWordParts as $strWordPart ) {
if ( $strWordPart <> '' ) {
$intWordPartCount ++;
}
}
// Some syllables do not follow normal rules - check for them
// Thanks to Joe Kovar for correcting a bug in the following lines
$intSyllableCount = ( $intWordPartCount + $intPrefixSuffixCount );
foreach ( $arrSubSyllables as $strSyllable ) {
$intSyllableCount -= preg_match( '`' . $strSyllable . '`', $strWord );
}
foreach ( $arrAddSyllables as $strSyllable ) {
$intSyllableCount += preg_match( '`' . $strSyllable . '`', $strWord );
}
$intSyllableCount = ( $intSyllableCount == 0 ) ? 1 : $intSyllableCount;
return $intSyllableCount;
}
/**
* Normalizes score according to min & max allowed. If score larger
* than max, max is returned. If score less than min, min is returned.
* Also rounds result to specified precision.
* Thanks to github.com/lvil.
*
* @param int|float $score Initial score
* @param int $min Minimum score allowed
* @param int $max Maximum score allowed
* @param int $dps Round to # decimals
*
* @return int|float
*/
public function normalize_score( $score, $min, $max, $dps = 1 ) {
$score = WPSEO_Utils::calc( $score, '+', 0, true, $dps ); // Round
if ( ! $this->normalize ) {
return $score;
}
if ( $score > $max ) {
$score = $max;
}
elseif ( $score < $min ) {
$score = $min;
}
return $score;
}
} /* End of class */
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