phone_number.php

<?php

$carriers_number = array(
    '096'  => 'Viettel',
    '097'  => 'Viettel',
    '098'  => 'Viettel',
    '0162' => 'Viettel',
    '0163' => 'Viettel',
    '0164' => 'Viettel',
    '0165' => 'Viettel',
    '0166' => 'Viettel',
    '0167' => 'Viettel',
    '0168' => 'Viettel',
    '0169' => 'Viettel',
    
    '090'  => 'Mobifone',
    '093'  => 'Mobifone',
    '0120' => 'Mobifone',
    '0121' => 'Mobifone',
    '0122' => 'Mobifone',
    '0126' => 'Mobifone',
    '0128' => 'Mobifone',
    
    '091'  => 'Vinaphone',
    '094'  => 'Vinaphone',
    '0123' => 'Vinaphone',
    '0124' => 'Vinaphone',
    '0125' => 'Vinaphone',
    '0127' => 'Vinaphone',
    '0129' => 'Vinaphone',
    
    '0993' => 'Gmobile',
    '0994' => 'Gmobile',
    '0995' => 'Gmobile',
    '0996' => 'Gmobile',
    '0997' => 'Gmobile',
    '0199' => 'Gmobile',
    
    '092'  => 'Vietnamobile',
    '0186' => 'Vietnamobile',
    '0188' => 'Vietnamobile',
    
    '095'  => 'SFone'
);

/*
 * Check if a string is started with another string
 *
 * @param (string) ($needle) The string being searched for.
 * @param (string) ($haystack) The string being searched
 * @return (boolean) true if $haystack is started with $needle
 */
function start_with($needle, $haystack) {
    $length = strlen($needle);
    return (substr($haystack, 0, $length) === $needle);
}

/*
 * Detect carrier name by phone number
 *
 * @param (string) ($number) The input phone number
 * @return (mixed) Name of the carrier, false if not found
 */
function detect_number ($number) {
	$number = str_replace(array('-', '.', ' '), '', $number);
	
    // $number is not a phone number
    if (!preg_match('/^(01[2689]|09)[0-9]{8}$/', $number)) return false;

	// Store all start number in an array to search
    $start_numbers = array_keys($carriers_number);
    
    foreach ($start_numbers as $start_number) {
        // if $start number found in $number then return value of $carriers_number array as carrier name
    	if (start_with($start_number, $number) {
        	return $carriers_number[$start_number];
        }
    }
    
    // if not found, return false
    return false;
}