php 字符串之模式匹配

<?php
/**  
* @description: 获取模式串在主字符串中的所有首字母出现索引位置(递归版)  
* @author: cutefrog(injection.mail@gmail.com)  
* @parameter: $mainstr 主字符串(必要参数)  
* @parameter: $modestr 模式串(必要参数)
* @parameter: $mainpos 主字符串起始索引(可选参数)  
* @parameter: $modepos 模式串起始索引(可选参数)
* @parameter: $matcheds 匹配到的索引数组(不需传入的参数，只作为递归时函数传递参数之用)   
* @return: $matcheds 如果非空返回匹配到的索引数组，否则返回-1  
*/ 

function myStrPos_recursive( $mainstr, $modestr, $mainpos = 0, $modepos = 0, $matcheds = array() ) {   

  //若数组为空则返回-1,否则返回匹配到的数组
 if( !isset( $mainstr[$mainpos] ) ) {

      return empty($matcheds)?-1:$matcheds;
 }

  //如果匹配到了就继续与模式串的下一个字符比较
  if ( $modestr[$modepos] == $mainstr[$mainpos] ) {   

    if ( !isset($modestr[$modepos+1]) ){   

     //将匹配结果加入数组
     array_push( $matcheds, $mainpos - $modepos );  

     return myStrPos_recursive ( $mainstr, $modestr, ++$mainpos, 0, $matcheds );   

    }   

    return myStrPos_recursive ( $mainstr, $modestr, ++$mainpos, ++$modepos, $matcheds );   

  }
  //否则回溯主串字符数组索引
  else {   

    return myStrPos_recursive ( $mainstr, $modestr, $mainpos-=$modepos-1, 0, $matcheds );   

  }

}
/**
* @description: 获取模式串在主字符串中的所有首字母出现索引位置(迭代版)
* @author: cutefrog(injection.mail@gmail.com)
* @parameter: $mainstr 主字符串(必要参数)
* @parameter: $modestr 模式串(必要参数)
* @return: $matcheds 如果非空返回匹配到的索引数组，否则返回-1
*/
function myStrPos_iteration( $mainstr, $modestr ) {

 $mainlen = strlen( $mainstr );

 $modelen = strlen( $modestr );
 $matchedpos = -1;
 $limit = 0;
 $matcheds = array();
 for ( $mainpos = 0; $mainpos < $mainlen; $mainpos++ ){
  for ( $modepos = 0; $modepos < $modelen; $modepos++ )

   if ( $modestr[$modepos] == $mainstr[$mainpos] ){

    if ( $modepos == ( $modelen - 1 ) ){
     $matcheds[$limit++] = $mainpos - $modepos;
     break;
    }
    $mainpos++;

   }
   else {
    $mainpos = $mainpos - $modepos;
    break;

   }
 }

 return empty($matcheds)?-1:$matcheds;
}

$mainstr = 'dccabsccadsacca';
$modestr = 'cca';
print_r( myStrPos_recursive( $mainstr, $modestr ) );
print_r( myStrPos_iteration( $mainstr, $modestr ) );
?>
//该片段来自于http://outofmemory.cn