php字符串和ascii码互转

有时候中文字符在不同的平台上传输存储容易乱码，这时候可以把有中文的字符串转化为ascii码传输，然后还可以再转化回来

1. [代码][PHP]代码    

//把字符串转化为asscii码
function  Binary2String($pIn){
	$str = '';
	$iOut=0;
	for($i = 0 ;$i<strlen($pIn);$i++){

		$str .= Value2Ascii((ord($pIn[$i])&0xF0)>>4);

		$str .= Value2Ascii(ord($pIn[$i])&0x0F);
	}
	return $str;
}
function Value2Ascii($in){
	
	switch($in){
		case 0:
			return '0';
			break;
		case 1:
			return '1';
			break;
		case 2:
			return '2';
			break;
		case 3:
			return '3';
			break;
		case 4:
			return '4';
			break;
		case 5:
			return '5';
			break;
		case 6:
			return '6';
			break;
		case 7:
			return '7';
			break;
		case 8:
			return '8';
			break;
		case 9:
			return '9';
			break;
		case 10:
			return 'A';
			break;
		case 11:
			return 'B';
			break;
		case 12:
			return 'C';
			break;
		case 13:
			return 'D';
			break;
		case 14:
			return 'E';
			break;
		case 15:
			return 'F';
			break;
		default:
			
			return '?';
			break;
	}
	return '?';
}

//把asscii码转化为字符串
function DBStr2Binary($pIn){

	$iOut = 0;
	$pOut = '';
	for( $i = 0 ;$i<strlen($pIn)-1;){
		if($pIn[$i]=='\0'|| $pIn[$i+1]=='\0'){
			break;
		}
		$pOut	.=	chr((Ascii2Value($pIn[$i])<<4) + (Ascii2Value($pIn[$i+1])));
		$iOut++;
		$i+=2;
		
	}
	return $pOut;
}
function Ascii2Value($in){
	
		switch($in){
		case '0':
			return 0;
			break;
		case '1':
			return 1;
			break;
		case '2':
			return 2;
			break;
		case '3':
			return 3;
			break;
		case '4':
			return 4;
			break;
		case '5':
			return 5;
			break;
		case '6':
			return 6;
			break;
		case '7':
			return 7;
			break;
		case '8':
			return 8;
			break;
		case '9':
			return 9;
			break;
		case 'A':
			return 10;
			break;
		case 'B':
			return 11;
			break;
		case 'C':
			return 12;
			break;
		case 'D':
			return 13;
			break;
		case 'E':
			return 14;
			break;
		case 'F':
			return 15;
			break;
		default:
			
			return '?';
			break;
	}
		return '?';
}

$str = '伟大的中国程序猿!';
$bin = Binary2String($str);
echo $bin.'<br />';
$new_str = DBStr2Binary($bin);
echo $new_str;