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File: example.php

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  Classes of Christian Vigh  >  Random Access File  >  example.php  >  Download  
File: example.php
Role: Example script
Content type: text/plain
Description: Example script
Class: Random Access File
Store data fixed record length data in files
Author: By
Last change: Updated the example to take into account the addition of a $header_size parameter in the class constructor
Date: 6 years ago
Size: 1,792 bytes
 

Contents

Class file image Download
<?php
   
require ( "RandomAccessFile.phpclass" ) ;

   
$random_file = "random.dat" ;

   
// Initialize a file containing the numbers 0 through 100, written with 3 digits
    // and terminated by a newline (each record will occupy 4 bytes)
    // This file will be used as our example case for testing random file access.
   
$fp = fopen ( $random_file, "w" ) ;

    for (
$i = 1 ; $i < 100 ; $i ++ )
       
fwrite ( $fp, sprintf ( "%03d", $i ) . "\n" ) ;

   
fwrite ( $fp, "100" ) ; // Note that the last record will be incomplete (no terminating newline)
   
fclose ( $fp ) ;

   
// Instantiate a random access file and open it in read/write mode.
    // "4" is the record size, "1024" the number of records to be cached, and "\n" the filler character to be
    // used when inserting empty records
   
$rf = new RandomAccessFile ( $random_file, 4, 0, 1024, "\n" ) ;
   
$rf -> Open ( ) ;

   
// Show the number of records that this file holds (should be 100)
   
echo ( "Count = " . count ( $rf ) . "\n" ) ;

   
// Swap 10 records (3d parameter) from record #0 with record #10
    // The file should now have the following values (one per line) :
    // Records 0 to 9 : 011..020
    // Records 10 to 19 : 001..010
    // Records 20 to 99 : 021..099
   
$rf -> Swap ( 0, 10, 10 ) ;

   
// Now copy 20 records from record #0 to record #100 (which is past the end of file)
    // The new contents should have 20 more records, with values in the range 011..020 and 001..010
   
$rf -> Copy ( 0, 100, 20 ) ;

   
// Note that you can use the for() and foreach() constructs to loop through each record
   
foreach ( $rf as $entry )
        echo (
"[" . trim ( $entry ) . "]\n") ;

   
// There is also a small (and dumb) cache that store a few statistics
   
echo ( "Hits : {$rf -> CacheHits}, misses = {$rf -> CacheMisses}\n" ) ;

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