<?php

/**
 * Parses string hash files. File format is as such:
 *
 *      DefaultKeyValue
 *      KEY: Value
 *      KEY2: Value2
 *      --MULTILINE-KEY--
 *      Multiline
 *      value.
 *
 * Which would output something similar to:
 *
 *      array(
 *          'ID' => 'DefaultKeyValue',
 *          'KEY' => 'Value',
 *          'KEY2' => 'Value2',
 *          'MULTILINE-KEY' => "Multiline\nvalue.\n",
 *      )
 *
 * We use this as an easy to use file-format for configuration schema
 * files, but the class itself is usage agnostic.
 *
 * You can use ---- to forcibly terminate parsing of a single string-hash;
 * this marker is used in multi string-hashes to delimit boundaries.
 */
class HTMLPurifier_StringHashParser {
	
	/**
	 * @type string
	 */
	public $default = 'ID';
	
	/**
	 * Parses a file that contains a single string-hash.
	 * 
	 * @param string $file        	
	 * @return array
	 */
	public function parseFile($file) {
		if (! file_exists ( $file )) {
			return false;
		}
		$fh = fopen ( $file, 'r' );
		if (! $fh) {
			return false;
		}
		$ret = $this->parseHandle ( $fh );
		fclose ( $fh );
		return $ret;
	}
	
	/**
	 * Parses a file that contains multiple string-hashes delimited by '----'
	 * 
	 * @param string $file        	
	 * @return array
	 */
	public function parseMultiFile($file) {
		if (! file_exists ( $file )) {
			return false;
		}
		$ret = array ();
		$fh = fopen ( $file, 'r' );
		if (! $fh) {
			return false;
		}
		while ( ! feof ( $fh ) ) {
			$ret [] = $this->parseHandle ( $fh );
		}
		fclose ( $fh );
		return $ret;
	}
	
	/**
	 * Internal parser that acepts a file handle.
	 * @note While it's possible to simulate in-memory parsing by using
	 * custom stream wrappers, if such a use-case arises we should
	 * factor out the file handle into its own class.
	 * 
	 * @param resource $fh
	 *        	File handle with pointer at start of valid string-hash
	 *        	block.
	 * @return array
	 */
	protected function parseHandle($fh) {
		$state = false;
		$single = false;
		$ret = array ();
		do {
			$line = fgets ( $fh );
			if ($line === false) {
				break;
			}
			$line = rtrim ( $line, "\n\r" );
			if (! $state && $line === '') {
				continue;
			}
			if ($line === '----') {
				break;
			}
			if (strncmp ( '--#', $line, 3 ) === 0) {
				// Comment
				continue;
			} elseif (strncmp ( '--', $line, 2 ) === 0) {
				// Multiline declaration
				$state = trim ( $line, '- ' );
				if (! isset ( $ret [$state] )) {
					$ret [$state] = '';
				}
				continue;
			} elseif (! $state) {
				$single = true;
				if (strpos ( $line, ':' ) !== false) {
					// Single-line declaration
					list ( $state, $line ) = explode ( ':', $line, 2 );
					$line = trim ( $line );
				} else {
					// Use default declaration
					$state = $this->default;
				}
			}
			if ($single) {
				$ret [$state] = $line;
				$single = false;
				$state = false;
			} else {
				$ret [$state] .= "$line\n";
			}
		} while ( ! feof ( $fh ) );
		return $ret;
	}
}

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