Ascii85 codecs for Javascript

a85decode_yz.js

/* This decoder supports both space and null byte folding,
    and completely ignores all invalid characters (whitespace, misplaced x's and z's, etc).
    Does not handle Adobe's <~ ~> frame.
    Licensed under CC0. */
function a85decode(ascii85) {
  for (var a = String, b = a.fromCharCode, c = ascii85.length, d = "", e = 0, f = 0, g = 0, h, i; i = a.charCodeAt(ascii85, e++) - 33, e <= c;
    0 <= i && 85 > i ? (g = 85 * g + i, 4 < ++f && (h = b(g & 255), h = b((g >>>= 8) & 255) + h, h = b((g >>= 8) & 255) + h, d += b(g >> 8) + h, f = g = 0)) : f || (d += 88 == i ? "    " : 89 == i ? "\0\0\0\0" : ""));
  if (!f) return d;
  for (e = 5 - f; g = 85 * g + 84, --e;);
  return h = b(g & 255), h = b((g >>>= 8) & 255) + h, h = b((g >>= 8) & 255) + h, (d + b(g >> 8) + h).substring(0, d.length +-- f);
}

a85encode_basic.js

/*This encoder doesn't support space nor null byte folding.
    This is equivalent to base64.a85encode(s).replace(b'z', b'!!!!!') in python.
    This is compatible with Git's implementation.
    Licensed under CC0. */
function a85encode(bytes) {
  for (var a = String, b = a.charCodeAt, c = bytes.length, d = "", e = 0, f = 0; e = (b(bytes, f) << 24) + (++f < c && (b(bytes, f) << 16) + (++f < c && (b(bytes, f) << 8) + (++f < c && b(bytes, f++)))), f <= c; d += g)
    for (var g = "", h = 6; --h; g = a.fromCharCode(e % 85 + 33) + g, e = Math.floor(e / 85));
  return d.substring(0, d.length - (4 - c % 4) % 4);
}

a85encode_yz.js

/* This encoder supports both space and null byte folding and is thus the most compact.
    This is equivalent to base64.a85encode(s, foldspaces=True) in python.
    Adobe's implementation does not support space folding.
    ("    " -> "y", "\0\0\0\0" -> "z")
    Licensed under CC0. */
function a85encode(bytes) {
  for (var a = String, b = a.charCodeAt, c = bytes.length, d = "", e = 0, f = 0, g = (4 - c % 4) % 4; e = (b(bytes, f) << 24) + (++f < c && (b(bytes, f) << 16) + (++f < c && (b(bytes, f) << 8) + (++f < c && b(bytes, f++)))), f <= c; d += h)
    if (e || f > c - g)
      if (538976288 == e)
        h = "y";
      else
        for (var h = "", i = 6; --i; h = a.fromCharCode(e % 85 + 33) + h, e = Math.floor(e / 85));
    else
      h = "z";
  return !h.length - 1 ? d.substring(0, d.length - g) : d;
};

a85encode_z.js

/*This encoder supports null byte folding, but not space folding.
    This is equivalent to base64.a85encode(s) in python.
    This is compatible with Adobe's implementation. (Just add <~ ~>)
    ("\0\0\0\0" -> "z")
    Licensed under CC0. */
function a85encode(bytes) {
  for (var a = String, b = a.charCodeAt, c = bytes.length, d = "", e = 0, f = 0, g = (4 - c % 4) % 4; e = (b(bytes, f) << 24) + (++f < c && (b(bytes, f) << 16) + (++f < c && (b(bytes, f) << 8) + (++f < c && b(bytes, f++)))), f <= c; d += h)
    if (e || f > c - g)
      for (var h = "", i = 6; --i; h = a.fromCharCode(e % 85 + 33) + h, e = Math.floor(e / 85));
    else
      h = "z";
  return "z" != h ? d.substring(0, d.length - g) : d;
};