shithub: werc

ref: 94488206bdf9439045d61afe0f16f533397f4474
dir: /bin/contrib/rc-httpd/lib/urldecode.awk/

# taken from werc
BEGIN {
    hextab ["0"] = 0; hextab ["8"] = 8;
    hextab ["1"] = 1; hextab ["9"] = 9;
    hextab ["2"] = 2; hextab ["A"] = hextab ["a"] = 10
    hextab ["3"] = 3; hextab ["B"] = hextab ["b"] = 11;
    hextab ["4"] = 4; hextab ["C"] = hextab ["c"] = 12;
    hextab ["5"] = 5; hextab ["D"] = hextab ["d"] = 13;
    hextab ["6"] = 6; hextab ["E"] = hextab ["e"] = 14;
    hextab ["7"] = 7; hextab ["F"] = hextab ["f"] = 15;
}
{
    decoded = ""
    i = 1
    len = length ($0)
    while ( i <= len ) {
        c = substr ($0, i, 1)
        if ( c == "%" ) {
            if ( i+2 <= len ) {
                c1 = substr ($0, i+1, 1)
                c2 = substr ($0, i+2, 1)
                if ( hextab [c1] == "" || hextab [c2] == "" ) {
                    print "WARNING: invalid hex encoding: %" c1 c2 | "cat >&2"
                } else {
                    code = 0 + hextab [c1] * 16 + hextab [c2] + 0
                    c = sprintf ("%c", code)
                    i = i + 2
                }
            } else {
                print "WARNING: invalid % encoding: " substr ($0, i, len - i)
            }
        } else if ( c == "+" ) {
            c = " "
        }
        decoded = decoded c
        ++i
    }
    printf "%s", decoded
}