Text.php
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<?php
namespace Faker\Provider;
abstract class Text extends Base
{
protected static $baseText = '';
protected static $separator = ' ';
protected static $separatorLen = 1;
protected $explodedText;
protected $consecutiveWords = array();
protected static $textStartsWithUppercase = true;
/**
* Generate a text string by the Markov chain algorithm.
*
* Depending on the $maxNbChars, returns a random valid looking text. The algorithm
* generates a weighted table with the specified number of words as the index and the
* possible following words as the value.
*
* @example 'Alice, swallowing down her flamingo, and began by taking the little golden key'
* @param integer $maxNbChars Maximum number of characters the text should contain (minimum: 10)
* @param integer $indexSize Determines how many words are considered for the generation of the next word.
* The minimum is 1, and it produces the higher level of randomness, although the
* generated text usually doesn't make sense. Higher index sizes (up to 5)
* produce more correct text, at the price of less randomness.
* @return string
*/
public function realText($maxNbChars = 200, $indexSize = 2)
{
if ($maxNbChars < 10) {
throw new \InvalidArgumentException('maxNbChars must be at least 10');
}
if ($indexSize < 1) {
throw new \InvalidArgumentException('indexSize must be at least 1');
}
if ($indexSize > 5) {
throw new \InvalidArgumentException('indexSize must be at most 5');
}
$words = $this->getConsecutiveWords($indexSize);
$result = array();
$resultLength = 0;
// take a random starting point
$next = static::randomKey($words);
while ($resultLength < $maxNbChars && isset($words[$next])) {
// fetch a random word to append
$word = static::randomElement($words[$next]);
// calculate next index
$currentWords = static::explode($next);
$currentWords[] = $word;
array_shift($currentWords);
$next = static::implode($currentWords);
// ensure text starts with an uppercase letter
if ($resultLength == 0 && !static::validStart($word)) {
continue;
}
// append the element
$result[] = $word;
$resultLength += static::strlen($word) + static::$separatorLen;
}
// remove the element that caused the text to overflow
array_pop($result);
// build result
$result = static::implode($result);
return static::appendEnd($result);
}
protected function getConsecutiveWords($indexSize)
{
if (!isset($this->consecutiveWords[$indexSize])) {
$parts = $this->getExplodedText();
$words = array();
$index = array();
for ($i = 0; $i < $indexSize; $i++) {
$index[] = array_shift($parts);
}
for ($i = 0, $count = count($parts); $i < $count; $i++) {
$stringIndex = static::implode($index);
if (!isset($words[$stringIndex])) {
$words[$stringIndex] = array();
}
$word = $parts[$i];
$words[$stringIndex][] = $word;
array_shift($index);
$index[] = $word;
}
// cache look up words for performance
$this->consecutiveWords[$indexSize] = $words;
}
return $this->consecutiveWords[$indexSize];
}
protected function getExplodedText()
{
if ($this->explodedText === null) {
$this->explodedText = static::explode(preg_replace('/\s+/u', ' ', static::$baseText));
}
return $this->explodedText;
}
protected static function explode($text)
{
return explode(static::$separator, $text);
}
protected static function implode($words)
{
return implode(static::$separator, $words);
}
protected static function strlen($text)
{
return function_exists('mb_strlen') ? mb_strlen($text, 'UTF-8') : strlen($text);
}
protected static function validStart($word)
{
$isValid = true;
if (static::$textStartsWithUppercase) {
$isValid = preg_match('/^\p{Lu}/u', $word);
}
return $isValid;
}
protected static function appendEnd($text)
{
return preg_replace("/([ ,-:;\x{2013}\x{2014}]+$)/us", '', $text).'.';
}
}