framework/i18n/GettextPoFile.php
public function load($filePath, $context)
    {
        $pattern = '/(msgctxt\s+"(.*?(?<!\\\\))")?\s+' // context
            . 'msgid\s+((?:".*(?<!\\\\)"\s*)+)\s+' // message ID, i.e. original string
            . 'msgstr\s+((?:".*(?<!\\\\)"\s*)+)/'; // translated string
        $content = file_get_contents($filePath);
        $matches = [];
        $matchCount = preg_match_all($pattern, $content, $matches);

        $messages = [];
        for ($i = 0; $i < $matchCount; ++$i) {
            if ($matches[2][$i] === $context) {
                $id = $this->decode($matches[3][$i]);
                $message = $this->decode($matches[4][$i]);
                $messages[$id] = $message;
            }
        }

        return $messages;
    }
public function load($filePath, $context)
    {
        $pattern = '/(msgctxt\s+"(.*?(?<!\\\\))")?\s+' // context
            . 'msgid\s+((?:".*(?<!\\\\)"\s*)+)\s+' // message ID, i.e. original string
            . 'msgstr\s+((?:".*(?<!\\\\)"\s*)+)/'; // translated string
        $content = file_get_contents($filePath);
        $matches = [];
        $matchCount = preg_match_all($pattern, $content, $matches);

        $messages = [];
        for ($i = 0; $i < $matchCount; ++$i) {
            if ($matches[2][$i] === $context) {
                $id = $this->decode($matches[3][$i]);
                $message = $this->decode($matches[4][$i]);
                $messages[$id] = $message;
            }
        }

        return $messages;
    }
Loads messages from a PO file.
@param string $filePath file path
@param string $context message context
@return array message translations. Array keys are source messages and array values are translated messages:
source message => translated message.