Below we together to see and an article about PHP BCD code compression-The decimal number compressed into hexadecimal data instances, I hope that the article to help you students oh.
Example, PHP BCD compression-Compress decimal numbers into hexadecimal data
| The code is as follows |
Copy Code |
/*
PHP BCD compression-Compress decimal numbers into hexadecimal data
For example 0091 after compression 0x00 0x91
*/
$string = ' 0091 ';
$bytes = Bytes::getbytes ($string);
Print_r ($bytes);
/*
Array
(
[0] = 48
[1] = 48
[2] = 57
[3] = 49
)
*/
$asc =bytes::asctohex ($bytes, 4);
4-bit compression into 2-bit
Print_r ($ASC);
/*
Array
(
[0] = 0
[1] = 145
)
*/
echo Bytes::tostr ($ASC);
/*
0091
*/
$hex =bytes::hextoasc ($ASC, 2);
Anti-operation 2-bit revert to 4-bit
Print_r ($hex);
/*
Array
(
[0] = 48
[1] = 48
[2] = 57
[3] = 49
)
*/
?> |
example, compressing decimal numbers into hexadecimal data
| The code is as follows |
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/**
* PHP BCD Code compression
* Compress decimal numbers into hexadecimal data
* @author phpff.com
* Created on 2011-7-15
*/
Class Bytes {
/**
* Convert a string string to a byte array
* @param $str strings that need to be converted
* @param $bytes Target byte array
* @author phpff.com
*/
public static function GetBytes ($string) {
$bytes = Array ();
for ($i = 0; $i < strlen ($string); $i + +) {
$bytes [] = Ord ($string [$i]);
}
return $bytes;
}
/**
* Converts a byte array to a string type of data
* @param $bytes byte array
* @param $str Target string
* @return A String type of data
*/
public static function Tostr ($bytes) {
$str = ";
foreach ($bytes as $ch) {
$str. = Bin2Hex (Chr ($ch));
}
return $str;
}
/**
* ASC code turns into 16 binary data
* @param $asc ASC Numeric string
* @param $AscLen the length of the string to convert
* @return 16 binary array
* @author phpff.com
*/
public static function Asctohex ($ASC, $AscLen) {
$i = 0;
$Hex =array ();
for ($i = 0; $i < $AscLen; $i + +)
{
/*a:0x41 (0100 0001), a:0x61 (0110 0001), 4-bit right shift after 0001, plus 0x90, etc. 0xa*/
$Hex [$i] = (Chr ($asc [$i]) << 4);
if (! ( Chr ($ASC [$i]) >= ' 0 ' && chr ($ASC [$i]) <= ' 9 ') {
$Hex [$i] + = 0x90;
}
if ($i +1 >= $AscLen) {
Break
}
$Hex [$i] |= (Chr ($ASC [$i +1]) & 0x0f);
if (! ( Chr ($ASC [$i +1]) >= ' 0 ' && chr ($asc [$i +1]) <= ' 9 ') {
$Hex [$i] + = 0x09;
}
}
return $Hex;
}
/**
* Convert 16 binary data into ASC code
* @param $Hex 16 binary array
* @param $HexLen 16 binary array length
* @return ASC Array
* @author phpff.com
*/
public static function Hextoasc ($Hex, $HexLen) {
$i = 0;
$Temp = 0;
for ($i = 0; $i < $HexLen; $i + +)
{
$Temp = ($Hex [$i] & 0xf0) >> 4;
if ($Temp < 10) {
$ASC [$i] = (0x30 + $Temp);
}else{
$ASC [$i] = (0x37 + $Temp);
}
$Temp = $Hex [$i] & 0x0f;
if ($Temp < 10) {
$ASC [$i +1] = (0x30 + $Temp);
}else{
$ASC [$i +1] = (0x37 + $Temp);
}
}
return $ASC;
}
}
?> |
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