root/branches/1.5/wp-includes/wp-l10n.php

<?php

if ( defined('WPLANG') && '' != constant('WPLANG') ) {
    include_once(ABSPATH . 'wp-includes/streams.php');
    include_once(ABSPATH . 'wp-includes/gettext.php');
}

function get_locale() {
    global $locale;

    if (isset($locale))
        return $locale;

    // WPLANG is defined in wp-config.
    if (defined('WPLANG')) {
    $locale = WPLANG;
    }
    
    if (empty($locale)) {
    $locale = 'en_US';
    }

    $locale = apply_filters('locale', $locale);

    return $locale;
}

// Return a translated string.    
function __($text, $domain = 'default') {
    global $l10n;

    if (isset($l10n[$domain])) {
        return $l10n[$domain]->translate($text);
    } else {
        return $text;
    }
}

// Echo a translated string.
function _e($text, $domain = 'default') {
    global $l10n;

    if (isset($l10n[$domain])) {
        echo $l10n[$domain]->translate($text);
    } else {
        echo $text;
    }
}

// Return the plural form.
function __ngettext($single, $plural, $number, $domain = 'default') {
    global $l10n;

    if (isset($l10n[$domain])) {
        return $l10n[$domain]->ngettext($single, $plural, $number);
    } else {
        if ($number != 1)
            return $plural;
        else
            return $single;
    }
}

function load_textdomain($domain, $mofile) {
    global $l10n;

    if (isset($l10n[$domain])) {
        return;
    }

    if ( is_readable($mofile)) {
    $input = new CachedFileReader($mofile);
    }    else {
        return;
    }

    $l10n[$domain] = new gettext_reader($input);
}

function load_default_textdomain() {
    global $l10n;

    $locale = get_locale();
    $mofile = ABSPATH . "wp-includes/languages/$locale.mo";
    
    load_textdomain('default', $mofile);
}

function load_plugin_textdomain($domain) {
    $locale = get_locale();
    
    $mofile = ABSPATH . "wp-content/plugins/$domain-$locale.mo";
    load_textdomain($domain, $mofile);
}

function load_theme_textdomain($domain) {
    $locale = get_locale();
    
    $mofile = get_template_directory() . "/$locale.mo";
    load_textdomain($domain, $mofile);
}

?>