Linear TSV encode/decode for PHP

ltsv.php

<?php

function ltsv_decode($data){
    // From parse_field (https://github.com/solidsnack/tsv/blob/master/tsv.py#L90)
    $stack = [];
    $replaces = ['t' => "\t", 'n' => "\n", 'r' => "\r", '\\' => "\\"];
    
    $tmp = explode("\\", $data, 2);
    while (count($tmp) >= 2){
        $stack[] = $tmp[0];
        $next = substr($tmp[1], 0, 1);
        if (isset($replaces[$next])){
            $stack[] = $replaces[$next];
            $tmp = explode("\\", substr($tmp[1], 1), 2);
        }else{
            $tmp = explode("\\", $tmp[1], 2);
        }
    }
    $stack[] = $tmp[0];
    
    return implode('', $stack);
}

function ltsv_encode($data){
    // From format_field (https://github.com/solidsnack/tsv/blob/master/tsv.py#L138)
    return str_replace(["\\","\n","\t","\r"],["\\\\", "\\n","\\t","\\r"], $data);
}

Reference implementation in Python at https://github.com/solidsnack/tsv
Spec at http://specs.okfnlabs.org/linear-tsv/

Does:

• To include newlines, tabs, carriage returns and backslashes in field data, the following escape sequences must be used: \n for newline, \t for tab, \r for carriage return, \\ for backslash.
• If a backslash precedes another character but does not form one of the escape sequences above, it is a “superfluous backslash” and is removed from the field on read.
  • Remark: if your original content is encoded into LTSV properly, then this does not impact you / will not mangle your input

Does not do:

• To indicate missing data for a field, the character sequence \N (bytes 0x5c and 0x4e) is used.
• If a single backslash is encountered at the end of a field, it is an error.