使用php重新实现PHP脚本引擎内置函数_php实例

// 实在无聊,突发奇想,想把PHP里面部分已经提供封装好的函数重新使用PHP实现一遍,
// 于是便有了下面的代码主要实现了PHP中部分字符串处理函数,同时实现了一些PHP中
// 没有,但是同样有作用的字符串处理函数同样的这些函数,也能够使用其他语言来实
// 现,比如用C/VBScript/Perl等等,那么你就能够有一个自己的函数库.
// 以下函数不一定能够成功运行,只是为了学习而已。
//
// 如果无特别声明,全部是由于heiyeluren原创,要使用任何函数都请保留作者信息


/**
* String Functions Reconstruct
*
* Copyright (c) 2005 heiyeluren
* Author: heiyeluren

* $Id: StringFunctions.php,v 0.1 e 2005-5-29 23:21 heiyeluren Exp $
**/


// {{{ strlen()
/**
* Count string length
*
* @param string $str need count length string variable
* @return int return count result
* @version v0.1
* @create 2005-5-24
* @modified 2005-5-24
* @author heiyeluren
*/
function strlen1($str)
{
if ($str == '')
return 0;

$count = 0;
while (1)
{
if ($str[$count] != NULL)
{
$count++;
continue;
}
else
break;
}
return $count;
}
// }}}


// {{{ substr()
/**
* Get sub string
*
* @param string $str need get sub string variable
* @param int $start start get sub string
* @param int $length need get string length
* @return string return sub string
* @version v0.2
* @create 2005-5-24
* @modified 2005-5-25
* @author heiyeluren
*/
function substr1($str, $start, $length=0)
{
if ($str == '')
return;
if ($start > strlen($str))
return;
if (($length != NULL) && ($start > 0) && ($length > strlen($str)-$start))
return;
if (($length != NULL) && ($start < 0) && ($length > strlen($str)+$start))
return;

if ($length == NULL)
$length = (strlen($str) - $start);

if ($start < 0)
{
for ($i=(strlen($str)+$start); $i<(strlen($str)+$start+$length); $i++)
{
$substr .= $str[$i];
}
}

if ($length > 0)
{
for ($i=$start; $i<($start+$length); $i++)
{
$substr .= $str[$i];
}
}

if ($length < 0)
{
for ($i=$start; $i<(strlen($str)+$length); $i++)
{
$substr .= $str[$i];
}
}
return $substr;
}
// }}}


// {{{ strrev()
/**
* Reversal string order
*
* @param string $str need reversal string variable
* @return string reversal string
* @version v0.1
* @create 2005-5-24
* @modified 2005-5-24
* @author heiyeluren
*/
function strrev1($str)
{
if ($str == '')
return 0;
for ($i=(strlen($str)-1); $i>=0; $i--)
{
$rev_str .= $str[$i];
}
return $rev_str;
}
// }}}


// {{{ strcmp()
/**
* String comparison
*
* @param string $s1 first string
* @param string $s2 second string
* @return int return -1,str1 < str2; return 1, str1 > str2, str1 = str2,
* return 0, other, return false
* @version v0.1
* @create 2005-5-24
* @modified 2005-5-24
* @author heiyeluren
*/
function strcmp1($s1, $s2)
{
if (strlen($s1) < strlen($s2))
return -1;
if (strlen($s1) > strlen($s2))
return 1;

for ($i=0; $i {
if ($s1[$i] == $s2[$i])
continue;
else
return false;
}
return 0;
}
// }}}


// {{{ strchr(), strstr(), strpos()
/**
* Find first occurrence of a string
*
* @param string $str parent string
* @param string $substr need match sub string
* @return int return find sub string at parent string first place,
* f not find, return false
* @version v0.4
* @create 2005-5-24
* @modified 2005-5-29
* @author heiyeluren
*/
function strchr1($str, $substr)
{
$m = strlen($str);
$n = strlen($substr);

if ($m < $n)
return false;

for ($i=0; $i<=($m-$n+1); $i++)
{
$sub = substr($str, $i, $n);
if (strcmp($sub, $substr) == 0)
return $i;
}
return false;
}
// }}}


// {{{ str_replace()
/**
* Replace all occurrences of the search string with the replacement string
*
* @param string $substr need replace sub string variable
* @param string $newsubstr new sub string
* @param string $str operate parent string
* @return string return replace after new parent string
* @version v0.2
* @create 2005-5-24
* @modified 2005-5-29
* @author heiyeluren
*/
function str_replace1($substr, $newsubstr, $str)
{
$m = strlen($str);
$n = strlen($substr);
$x = strlen($newsubstr);

if (strchr($str, $substr) == false)
return false;

for ($i=0; $i<=($m-$n+1); $i++)
{
$i = strchr($str, $substr);
$str = str_delete($str, $i, $n);
$str = str_insert($str, $i, $newstr);
}
return $str;
}
// }}}


/************ 以下串处理函数是PHP中没有的，自己写着玩 ***************/

// {{{ insert_str(), delete_str(), index_str()
/**
* Basic string operate
*
* @param string $str need get sub string variable
* @param int $start start get sub string
* @param int $length need get string length
* @return string return sub string
* @version v0.1
* @create 2005-5-24
* @modified 2005-5-24
* @author heiyeluren
*/
function str_insert($str, $i, $substr)
{

for($j=0; $j<$i; $j++)
{
$startstr .= $str[$j];
}

for ($j=$i; $j {
$laststr .= $str[$j];
}
$str = ($startstr . $substr . $laststr);

return $str;
}


function str_delete($str, $i, $j)
{
for ($c=0; $c<$i; $c++)
{
$startstr .= $str[$c];
}

for ($c=($i+$j); $c {
$laststr .= $str[$c];
}

$str = ($startstr . $laststr);

return $str;
}
// }}}


// {{{ strcpy()
/**
* Use designate sub string replace string
*
* @param string $str need get sub string variable
* @param int $start start get sub string
* @param int $length need get string length
* @return string return sub string
* @version v0.1
* @create 2005-5-27
* @modified 2005-5-27
* @author heiyeluren
*/
function strcpy($s1, $s2)
{
if (strlen($s1) == NULL)
return;
if (!isset($s2))
return;

for ($i=0; $i {
$s2[] = $s1[$i];
}
return $s2;
}
// }}}


// {{{ strcat()
/**
* Use designate sub string replace string
*
* @param string $str need get sub string variable
* @param int $start start get sub string
* @param int $length need get string length
* @return string return sub string
* @version v0.1
* @create 2005-5-27
* @modified 2005-5-27
* @author heiyeluren
*/
function strcat($s1, $s2)
{
if (!isset($s1))
return;
if (!isset($s2))
return;

$newstr = $s1 . $s2;

return $newsstr;
}
// }}}


// {{{ php_encode(), php_decode()
/**
* Simple string encode/decode function
*
* @param string $str need code/encode string variable
* @return string code/encode after string
* @version v0.2
* @create 2005-3-11
* @modified 2005-5-24
* @author heiyeluren
*/

/* String encode function */
function php_encode($str)
{
if ($str=='' && strlen($str)>128)
return false;

for($i=0; $i {
$c = ord($str[$i]);
if ($c>31 && $c<107)
$c += 20;
if ($c>106 && $c<127)
$c -= 75;
$word = chr($c);

$s .= $word;
}
return $s;
}


/* String decode function */
function php_decode($str)
{
if ($str=='' && strlen($str)>128)
return false;

for($i=0; $i {
$c = ord($word);
if ($c>106 && $c<127)
$c = $c-20;
if ($c>31 && $c<107)
$c = $c+75;
$word = chr($c);

$s .= $word;
}
return $s;
}
// }}}


// {{{ php_encrypt(), php_decrypt()
/**
* Simple string encrypt/decrypt function
*
* @param string $str need crypt string variable
* @return string encrypt/decrypt after string
* @version v0.1
* @create 2005-5-27
* @modified 2005-5-29
* @author heiyeluren
*/

/* define crypt key */
$encrypt_key = 'abcdefghijklmnopqrstuvwxyz1234567890';
$decrypt_key = 'ngzqtcobmuhelkpdawxfyivrsj2468021359';

/* String encrypt function */
function php_encrypt($str)
{
global $encrypt_key, $decrypt_key;

if (strlen($str) == 0)
return false;

for ($i=0; $i {
for ($j=0; $j {
if ($str[$i] == $encrypt_key[$j])
{
$enstr .= $decrypt_key[$j];
break;
}
}
}
return $enstr;
}


/* String decrypt function */
function php_decrypt($str)
{
global $encrypt_key, $decrypt_key;

if (strlen($str) == 0)
return false;

for ($i=0; $i {
for ($j=0; $j {
if ($str[$i] == $decrypt_key[$j])
{
$enstr .= $encrypt_key[$j];
break;
}
}
}
return $enstr;
}
// }}}


如果代码不清晰的话，建议查看一下连接，是我在blogchina的博客：

http://heiyeluren.blogchina.com/1741318.html