DomDocument::loadXML cannot parse files larger than 1,3 GiB

[pjpawel]

Description

The following code:

<?php
function loadXMLFile($filename) {

    $content = file_get_contents($filename);

    $doc = new DOMDocument();
    
    $success = $doc->loadXML($content);

    if (!$success) {
        echo "Failed to parse $filename\n";
        return null;
    }

    return $doc;
}

function main($filename) {
    $doc = loadXMLFile($filename);

    if ($doc !== null) {
        $root = $doc->documentElement;
        echo "Root element: " . $root->nodeName . "\n";
    } else {
        echo "Empty document or failed to load.\n";
    }
}

if ($argc != 2) {
    echo "Usage: php " . $argv[0] . " <xmlfile>\n";
    exit(1);
}

main($argv[1]);

Resulted in this output:

PHP Warning:  DOMDocument::loadXML(): Memory allocation failed : growing input buffer in domLoadXml.php on line 8

Warning: DOMDocument::loadXML(): Memory allocation failed : growing input buffer in domLoadXml.php on line 8
Root element: tns:JPK

But I expected this output instead:

Root element: tns:JPK

I tried using option LIBXML_PARSEHUGE, but result was the same.
The most curious thing is that DomDocument::load() is loading large files correctly.

PHP Version

8.2.5

Operating System

Windows 11, Ubuntu 22.04

[nielsdos]

My system goes out of memory before I can complete the parse of the file.
The error you're seeing actually comes from libxml, I think it's due to the fact that buffer sizes are stored as 32-bit integers inside libxml, and that 1.3 GiB * 2 (times 2 to grow the buffer) is above the integer limit.
I'd suggest reporting the issue over at libxml.

[pjpawel]

Ok, from libxml2 2.13.1 function xmlreadMemory returns null while loading huge document.

https://gitlab.gnome.org/GNOME/libxml2/-/issues/451

[nielsdos]

Technically I think this can be worked around on by using a custom IO reader.

[nielsdos]

When you say that the load method works fine for large files, that is also a file of roughly 1.3GIB?

[pjpawel]

DomDocument::load() can load files of size at least 3GiB without a problem. Bigger files are out of my range, because loading that file cost my computer 15 GB of RAM