Module:Md5

Documentation for this module may be created at Module:Md5/doc

-- Lua Module for calculating md5 hash sums
-- Needed in order to get absolute file paths for hosted images from Lua modules.
local md5 = {
  _VERSION     = "md5.lua 1.1.0",
  _DESCRIPTION = "MD5 computation in Lua (5.1-3, LuaJIT)",
  _URL         = "https://github.com/kikito/md5.lua",
  _LICENSE     = [[
    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.
  ]]
}

-- bit lib implementions

local char, byte, format, rep, sub =
  string.char, string.byte, string.format, string.rep, string.sub
local bit_or, bit_and, bit_not, bit_xor, bit_rshift, bit_lshift

local bit = require('bit32')

bit_not = bit.bnot

local tobit = function(n)
  return n <= 0x7fffffff and n or -(bit_not(n) + 1)
end

local normalize = function(f)
  return function(a,b) return tobit(f(tobit(a), tobit(b))) end
end

bit_or, bit_and, bit_xor = normalize(bit.bor), normalize(bit.band), normalize(bit.bxor)
bit_rshift, bit_lshift = normalize(bit.rshift), normalize(bit.lshift)

-- convert little-endian 32-bit int to a 4-char string
local function lei2str(i)
  local f=function (s) return char( bit_and( bit_rshift(i, s), 255)) end
  return f(0)..f(8)..f(16)..f(24)
end

-- convert raw string to big-endian int
local function str2bei(s)
  local v=0
  for i=1, #s do
    v = v * 256 + byte(s, i)
  end
  return v
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 swap = function (w) return str2bei(lei2str(w)) end

-- An MD5 mplementation in Lua, requires bitlib (hacked to use LuaBit from above, ugh)
-- 10/02/2001 jcw@equi4.com

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 bit_or(bit_and(x,y),bit_and(-x-1,z)) end
local g=function (x,y,z) return bit_or(bit_and(x,z),bit_and(y,-z-1)) end
local h=function (x,y,z) return bit_xor(x,bit_xor(y,z)) end
local i=function (x,y,z) return bit_xor(y,bit_or(x,-z-1)) end
local z=function (ff,a,b,c,d,x,s,ac)
  a=bit_and(a+ff(b,c,d)+x+ac,0xFFFFFFFF)
  -- be *very* careful that left shift does not cause rounding!
  return bit_or(bit_lshift(bit_and(a,bit_rshift(0xFFFFFFFF,s)),s),bit_rshift(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 bit_and(A+a,0xFFFFFFFF),bit_and(B+b,0xFFFFFFFF),
         bit_and(C+c,0xFFFFFFFF),bit_and(D+d,0xFFFFFFFF)
end

----------------------------------------------------------------

local function md5_update(self, 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

local function md5_finish(self)
  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(bit_and(8*msgLen, 0xFFFFFFFF)) .. lei2str(math.floor(msgLen/0x20000000))
  md5_update(self, s)

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

----------------------------------------------------------------

function md5.new()
  return { a = CONSTS[65], b = CONSTS[66], c = CONSTS[67], d = CONSTS[68],
           pos = 0,
           buf = '',
           update = md5_update,
           finish = md5_finish }
end

function md5.tohex(s)
  return format("%08x%08x%08x%08x", str2bei(sub(s, 1, 4)), str2bei(sub(s, 5, 8)), str2bei(sub(s, 9, 12)), str2bei(sub(s, 13, 16)))
end

function md5.sum(s)
  return md5.new():update(s):finish()
end

function md5.sumhexa(s)
  return md5.tohex(md5.sum(s))
end

return md5