PHP Classes
elePHPant
Icontem

File: example.php

Recommend this page to a friend!
  Classes of Christian Vigh  >  PHP Bit String  >  example.php  >  Download  
File: example.php
Role: Example script
Content type: text/plain
Description: Example script
Class: PHP Bit String
Manipulate strings of sequences of binary digits
Author: By
Last change:
Date: 2 years ago
Size: 2,897 bytes
 

Contents

Class file image Download
<?php
   
/*************************************************************************************************

        This example demonstrates the use of the BitString and BitStringIterator classes on a
        simple example string, "ABCDEF", which will be considered as a string of bits.

     *************************************************************************************************/

   
require_once ( 'BitString.phpclass' ) ;

    if (
php_sapi_name ( ) != 'cli' )
        echo
'<pre>' ;

   
// getbits -
    // This function simply outputs bits from the specified value, up to $count.
   
function getbits ( $value, $count )
       {
       
$result = '' ;

        for (
$i = 0 ; $i < $count ; $i ++, $value >>= 1 )
           
$result .= ( $value & 1 ) ? '1' : '0' ;

        return (
$result ) ;
        }

   
// Our example string
   
$data = "ABCDEF" ;

   
// Create a bit string from it
   
$bs = new BitString ( $data ) ;

   
// Try the ToHex() and ToBin() functions. Note that ToBin (0) will print the bits in exactly the same order
    // as they are stored (least significant bit first), while ToBin(1) will print them in the order they are
    // printed by ToHex()
   
echo "ToHex() : " ; print_r ( $bs -> ToHex ( ) ) ; echo "\n" ;
    echo
"ToBin(1) : " ; print_r ( $bs -> ToBin ( 1 ) ) ; echo "\n" ;
    echo
"ToBin(0) : " ; print_r ( $bs -> ToBin ( 0 ) ) ; echo "\n" ;

   
// Use the ArrayAccess interface to retrieve and display each individual bit
   
echo "Bit per bit (for) : " ;

    for (
$i = 0 ; $i < count ( $bs ) ; $i ++ )
        echo
$bs [$i] ;

   
// Use the Iterator interface to display each individual bit
   
echo "\nBit per bit (foreach) : " ;

    foreach (
$bs as $bit )
        echo
$bit ;

   
// Now, use the BitString::GetBits() function to display bits by group of x bits, from 1 to 32.
    // Note that the getbits() function defined here will add trailing zeroes for bit counts that are
    // not a denominator of the machine's word size - this is not a bug, this inconvenience was aimed
    // at making this example simpler
   
for ( $bit_count = 1 ; $bit_count <= 32 ; $bit_count ++ )
       {
        echo
sprintf ( "\nTaking by %2d bits : ", $bit_count ) ;
       
        for (
$i = 0 ; $i < count ( $bs ) ; $i += $bit_count )
           {
           
$value = $bs -> GetBits ( $i, $bit_count ) ;

            if (
$value === false )
               
output ( "FALSE for offset $i, count $bit_count" ) ;

            echo
getbits ( $value, $bit_count ) ;
            }
        }

   
// Now use a BitStringIterator object : extract bits from the bit string by groups of
    // 3 components having 8 bits each. It should display the hexadecimal translation of
    // "ABCDEF" which is : "414243444546"
   
echo "\nBitStringIterator(8,3) : " ;

    foreach ( new
BitStringIterator ( $bs, 8, 3 ) as $values )
       {
        foreach (
$values as $value )
            echo (
sprintf ( "%02X", $value ) ) ;
        }