-- from https://github.com/kikito/md5.lua

--[[
MIT LICENSE

Copyright (c) 2013 Enrique García Cota + Adam Baldwin + hanzao + Equi 4 Software

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
]]

local char, byte, rep, sub = string.char, string.byte, string.rep, string.sub

-- convert little-endian 32-bit int to a 4-char string
local function lei2str(i)
  return char(i & 255, (i >> 8) & 255, (i >> 16) & 255, (i >> 24) & 255)
end

-- convert raw string to little-endian int
local function str2lei(s)
  local v = 0
  for i = #s, 1, -1 do
    v = (v * 256) + byte(s, i)
  end
  return v
end

-- cut up a string in little-endian ints of given size
local function cut_le_str(s, ...)
  local o, r = 1, {}
  local args = {...}
  for i=1, #args do
    table.insert(r, str2lei(sub(s, o, o + args[i] - 1)))
    o = o + args[i]
  end
  return r
end

local CONSTS = {
  0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee,
  0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
  0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
  0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
  0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa,
  0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
  0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
  0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
  0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c,
  0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
  0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05,
  0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
  0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039,
  0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
  0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
  0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391,
  0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476
}

local f = function(x, y, z)
  return (x & y) | ((-x - 1) & z)
end
local g = function(x, y, z)
  return (x & z) | (y & (-z - 1))
end
local h = function(x, y, z)
  return x ~ (y ~ z)
end
local i = function(x, y, z)
  return y ~ (x | (-z - 1))
end
local z = function(ff, a, b, c, d, x, s, ac)
  a = (a + ff(b, c, d) + x + ac) & 0xFFFFFFFF
  -- be *very* careful that left shift does not cause rounding!
  return (((a & (0xFFFFFFFF >> s)) << s) | (a >> (32 - s))) + b
end
local function transform(A, B, C, D, X)
  local a, b, c, d = A, B, C, D
  local t = CONSTS
  a = z(f, a, b, c, d, X[0], 7, t[1])
  d = z(f, d, a, b, c, X[1], 12, t[2])
  c = z(f, c, d, a, b, X[2], 17, t[3])
  b = z(f, b, c, d, a, X[3], 22, t[4])
  a = z(f, a, b, c, d, X[4], 7, t[5])
  d = z(f, d, a, b, c, X[5], 12, t[6])
  c = z(f, c, d, a, b, X[6], 17, t[7])
  b = z(f, b, c, d, a, X[7], 22, t[8])
  a = z(f, a, b, c, d, X[8], 7, t[9])
  d = z(f, d, a, b, c, X[9], 12, t[10])
  c = z(f, c, d, a, b, X[10], 17, t[11])
  b = z(f, b, c, d, a, X[11], 22, t[12])
  a = z(f, a, b, c, d, X[12], 7, t[13])
  d = z(f, d, a, b, c, X[13], 12, t[14])
  c = z(f, c, d, a, b, X[14], 17, t[15])
  b = z(f, b, c, d, a, X[15], 22, t[16])
  a = z(g, a, b, c, d, X[1], 5, t[17])
  d = z(g, d, a, b, c, X[6], 9, t[18])
  c = z(g, c, d, a, b, X[11], 14, t[19])
  b = z(g, b, c, d, a, X[0], 20, t[20])
  a = z(g, a, b, c, d, X[5], 5, t[21])
  d = z(g, d, a, b, c, X[10], 9, t[22])
  c = z(g, c, d, a, b, X[15], 14, t[23])
  b = z(g, b, c, d, a, X[4], 20, t[24])
  a = z(g, a, b, c, d, X[9], 5, t[25])
  d = z(g, d, a, b, c, X[14], 9, t[26])
  c = z(g, c, d, a, b, X[3], 14, t[27])
  b = z(g, b, c, d, a, X[8], 20, t[28])
  a = z(g, a, b, c, d, X[13], 5, t[29])
  d = z(g, d, a, b, c, X[2], 9, t[30])
  c = z(g, c, d, a, b, X[7], 14, t[31])
  b = z(g, b, c, d, a, X[12], 20, t[32])
  a = z(h, a, b, c, d, X[5], 4, t[33])
  d = z(h, d, a, b, c, X[8], 11, t[34])
  c = z(h, c, d, a, b, X[11], 16, t[35])
  b = z(h, b, c, d, a, X[14], 23, t[36])
  a = z(h, a, b, c, d, X[1], 4, t[37])
  d = z(h, d, a, b, c, X[4], 11, t[38])
  c = z(h, c, d, a, b, X[7], 16, t[39])
  b = z(h, b, c, d, a, X[10], 23, t[40])
  a = z(h, a, b, c, d, X[13], 4, t[41])
  d = z(h, d, a, b, c, X[0], 11, t[42])
  c = z(h, c, d, a, b, X[3], 16, t[43])
  b = z(h, b, c, d, a, X[6], 23, t[44])
  a = z(h, a, b, c, d, X[9], 4, t[45])
  d = z(h, d, a, b, c, X[12], 11, t[46])
  c = z(h, c, d, a, b, X[15], 16, t[47])
  b = z(h, b, c, d, a, X[2], 23, t[48])
  a = z(i, a, b, c, d, X[0], 6, t[49])
  d = z(i, d, a, b, c, X[7], 10, t[50])
  c = z(i, c, d, a, b, X[14], 15, t[51])
  b = z(i, b, c, d, a, X[5], 21, t[52])
  a = z(i, a, b, c, d, X[12], 6, t[53])
  d = z(i, d, a, b, c, X[3], 10, t[54])
  c = z(i, c, d, a, b, X[10], 15, t[55])
  b = z(i, b, c, d, a, X[1], 21, t[56])
  a = z(i, a, b, c, d, X[8], 6, t[57])
  d = z(i, d, a, b, c, X[15], 10, t[58])
  c = z(i, c, d, a, b, X[6], 15, t[59])
  b = z(i, b, c, d, a, X[13], 21, t[60])
  a = z(i, a, b, c, d, X[4], 6, t[61])
  d = z(i, d, a, b, c, X[11], 10, t[62])
  c = z(i, c, d, a, b, X[2], 15, t[63])
  b = z(i, b, c, d, a, X[9], 21, t[64])
  return (A + a) & 0xFFFFFFFF, (B + b) & 0xFFFFFFFF, (C + c) & 0xFFFFFFFF, (D + d) & 0xFFFFFFFF
end

return require('jls.lang.class').create('jls.util.MessageDigest', function(md5)

  function md5:initialize()
    self:reset()
  end

  function md5:update(s)
    self.pos = self.pos + #s
    s = self.buf .. s
    for ii = 1, #s - 63, 64 do
      local X = cut_le_str(sub(s, ii, ii + 63), 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4)
      assert(#X == 16)
      X[0] = table.remove(X,1) -- zero based!
      self.a,self.b,self.c,self.d = transform(self.a,self.b,self.c,self.d,X)
    end
    self.buf = sub(s, math.floor(#s/64)*64 + 1, #s)
    return self
  end

  function md5:digest()
    local msgLen = self.pos
    local padLen = 56 - msgLen % 64

    if msgLen % 64 > 56 then padLen = padLen + 64 end

    if padLen == 0 then padLen = 64 end

    local s = char(128) .. rep(char(0),padLen-1) .. lei2str((8*msgLen) & 0xFFFFFFFF) .. lei2str(math.floor(msgLen/0x20000000))
    self:update(s)

    assert(self.pos % 64 == 0)
    return lei2str(self.a) .. lei2str(self.b) .. lei2str(self.c) .. lei2str(self.d)
  end

  function md5:reset()
    self.a = CONSTS[65]
    self.b = CONSTS[66]
    self.c = CONSTS[67]
    self.d = CONSTS[68]
    self.pos = 0
    self.buf = ''
    return self
  end

  function md5:getAlgorithm()
    return 'MD5'
  end

end)
