CODEWITHSUNDEEP
phpunicode-string
Transistor
Transistor

Reputation: 213

PHP find a word in a Unicode string

I am searching for the string version in text read from a Unicode little-endian file.

With the $text 'version (apostrophe intended) I get

echo strpos($text, "r");          // Returns 7.
echo strpos($text, "version");    // Returns null.

I suspect that I need to convert either the needle or the haystack into the same format.

Any ideas?

Update after cmbuckley's answer.

$var = iconv('UTF-16LE', 'UTF-8', $fields[0]); 
// Returns Notice: iconv(): Detected an incomplete multibyte character in ...input string in

So I checked the existing encoding and find

echo mb_detect_encoding($fields[0], mb_detect_order(), false);  // Returns 'ASCII'.

This is confusing. If the string is ASCII why was I having trouble with the original strpos function?

Update 2

The hex encoding of 'version is 2700 5600 6500 7200 7300 6900 6f00 6e00.

What encoding is that?

Upvotes: 2

Views: 1327

Answers (2)

Marco
Marco

Reputation: 7287

I created a file with the hex contents you provided and managed to find a solution:

<?php

$text = file_get_contents(__DIR__.'/test');

$text = mb_convert_encoding($text, 'UTF-8', 'UTF-16LE');

var_dump(strpos($text, "r"));          // int(3)
var_dump(strpos($text, "Version"));    // int(1)

Contents of test (viewed in Hex Fiend):

enter image description here

Version of PHP used: PHP 5.6.36

Upvotes: 1

cmbuckley
cmbuckley

Reputation: 42507

Even if you're using mb_strpos, you'd need to make sure $needle and $haystack are the same encoding anyway.

I'd suggest you use UTF-8 as much and as soon as possible, which means that I'd convert the UTF-16LE content to UTF-8 using iconv:

$text = file_get_contents('test.txt'); // contains 'version in UTF-16LE

var_dump(strpos($text, 'r'));          // 6
var_dump(strpos($text, 'version'));    // false

$text = iconv('UTF-16LE', 'UTF-8', $text);

var_dump(strpos($text, 'r'));          // 3
var_dump(strpos($text, 'version'));    // 1

Remember to do a strict !== false check (not null, as you mention in your post) as the file contents may start with the string version, in which case strpos would return 0.

Upvotes: 2

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