<?php
/**
* I18N: WP_Translation_File_MO class.
*
* @package WordPress
* @subpackage I18N
* @since 6.5.0
*/

/**
* Class WP_Translation_File_MO.
*
* @since 6.5.0
*/
class WP_Translation_File_MO extends WP_Translation_File {
/**
* Endian value.
*
* V for little endian, N for big endian, or false.
*
* Used for unpack().
*
* @since 6.5.0
* @var false|'V'|'N'
*/
protected $uint32 = false;

/**
* The magic number of the GNU message catalog format.
*
* @since 6.5.0
* @var int
*/
const MAGIC_MARKER = 0x950412de;

/**
* Detects endian and validates file.
*
* @since 6.5.0
*
* @param string $header File contents.
* @return false|'V'|'N' V for little endian, N for big endian, or false on failure.
*/
protected function detect_endian_and_validate_file( string $header ) {
$big = unpack( 'N', $header );

if ( false === $big ) {
return false;
}

$big = reset( $big );

if ( false === $big ) {
return false;
}

$little = unpack( 'V', $header );

if ( false === $little ) {
return false;
}

$little = reset( $little );

if ( false === $little ) {
return false;
}

// Force cast to an integer as it can be a float on x86 systems. See https://core.trac.wordpress.org/ticket/60678.
if ( (int) self::MAGIC_MARKER === $big ) {
return 'N';
}

// Force cast to an integer as it can be a float on x86 systems. See https://core.trac.wordpress.org/ticket/60678.
if ( (int) self::MAGIC_MARKER === $little ) {
return 'V';
}

$this->error = 'Magic marker does not exist';
return false;
}

/**
* Parses the file.
*
* @since 6.5.0
*
* @return bool True on success, false otherwise.
*/
protected function parse_file(): bool {
$this->parsed = true;

$file_contents = file_get_contents( $this->file ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents

if ( false === $file_contents ) {
return false;
}

$file_length = strlen( $file_contents );

if ( $file_length < 24 ) {
$this->error = 'Invalid data';
return false;
}

$this->uint32 = $this->detect_endian_and_validate_file( substr( $file_contents, 0, 4 ) );

if ( false === $this->uint32 ) {
return false;
}

$offsets = substr( $file_contents, 4, 24 );

if ( false === $offsets ) {
return false;
}

$offsets = unpack( "{$this->uint32}rev/{$this->uint32}total/{$this->uint32}originals_addr/{$this->uint32}translations_addr/{$this->uint32}hash_length/{$this->uint32}hash_addr", $offsets );

if ( false === $offsets ) {
return false;
}

$offsets['originals_length'] = $offsets['translations_addr'] - $offsets['originals_addr'];
$offsets['translations_length'] = $offsets['hash_addr'] - $offsets['translations_addr'];

if ( $offsets['rev'] > 0 ) {
$this->error = 'Unsupported revision';
return false;
}

if ( $offsets['translations_addr'] > $file_length || $offsets['originals_addr'] > $file_length ) {
$this->error = 'Invalid data';
return false;
}

// Load the Originals.
$original_data = str_split( substr( $file_contents, $offsets['originals_addr'], $offsets['originals_length'] ), 8 );
$translations_data = str_split( substr( $file_contents, $offsets['translations_addr'], $offsets['translations_length'] ), 8 );

foreach ( array_keys( $original_data ) as $i ) {
$o = unpack( "{$this->uint32}length/{$this->uint32}pos", $original_data[ $i ] );
$t = unpack( "{$this->uint32}length/{$this->uint32}pos", $translations_data[ $i ] );

if ( false === $o || false === $t ) {
continue;
}

$original = substr( $file_contents, $o['pos'], $o['length'] );
$translation = substr( $file_contents, $t['pos'], $t['length'] );
// GlotPress bug.
$translation = rtrim( $translation, "\0" );

// Metadata about the MO file is stored in the first translation entry.
if ( '' === $original ) {
foreach ( explode( "\n", $translation ) as $meta_line ) {
if ( '' === $meta_line || ! str_contains( $meta_line, ':' ) ) {
continue;
}

list( $name, $value ) = array_map( 'trim', explode( ':', $meta_line, 2 ) );

$this->headers[ strtolower( $name ) ] = $value;
}
} else {
/*
* In MO files, the key normally contains both singular and plural versions.
* However, this just adds the singular string for lookup,
* which caters for cases where both __( 'Product' ) and _n( 'Product', 'Products' )
* are used and the translation is expected to be the same for both.
*/
$parts = explode( "\0", (string) $original );

$this->entries[ $parts[0] ] = $translation;
}
}

return true;
}

/**
* Exports translation contents as a string.
*
* @since 6.5.0
*
* @return string Translation file contents.
*/
public function export(): string {
// Prefix the headers as the first key.
$headers_string = '';
foreach ( $this->headers as $header => $value ) {
$headers_string .= "{$header}: $value\n";
}
$entries = array_merge( array( '' => $headers_string ), $this->entries );
$entry_count = count( $entries );

if ( false === $this->uint32 ) {
$this->uint32 = 'V';
}

$bytes_for_entries = $entry_count * 4 * 2;
// Pair of 32bit ints per entry.
$originals_addr = 28; /* header */
$translations_addr = $originals_addr + $bytes_for_entries;
$hash_addr = $translations_addr + $bytes_for_entries;
$entry_offsets = $hash_addr;

$file_header = pack(
$this->uint32 . '*',
// Force cast to an integer as it can be a float on x86 systems. See https://core.trac.wordpress.org/ticket/60678.
(int) self::MAGIC_MARKER,
0, /* rev */
$entry_count,
$originals_addr,
$translations_addr,
0, /* hash_length */
$hash_addr
);

$o_entries = '';
$t_entries = '';
$o_addr = '';
$t_addr = '';

foreach ( array_keys( $entries ) as $original ) {
$o_addr .= pack( $this->uint32 . '*', strlen( $original ), $entry_offsets );
$entry_offsets += strlen( $original ) + 1;
$o_entries .= $original . "\0";
}

foreach ( $entries as $translations ) {
$t_addr .= pack( $this->uint32 . '*', strlen( $translations ), $entry_offsets );
$entry_offsets += strlen( $translations ) + 1;
$t_entries .= $translations . "\0";
}

return $file_header . $o_addr . $t_addr . $o_entries . $t_entries;
}
}