Replace sha256.lua with sha1.lua (no need for 5.2 bit32)

Fixes #6, version bump

cat_osc.json

@@ -4,7 +4,7 @@
 		"src/license_blurb.lua",
 		"<version>",
 		"lib/helpers.lua",
-		"lib/sha256.lua",
+		"lib/sha1.lua",
 		"src/options.lua",
 		"src/thumbnailer_shared.lua",
 		"src/patched_osc.lua"
@@ -15,4 +15,4 @@
 
 	"header_prefix" : "--[ ",
 	"header_suffix" : " ]--"
-}
+}

lib/sha1.lua

@@ -0,0 +1,332 @@
+-- $Revision: 1.5 $
+-- $Date: 2014-09-10 16:54:25 $
+
+-- This module was originally taken from http://cube3d.de/uploads/Main/sha1.txt.
+
+-------------------------------------------------------------------------------
+-- SHA-1 secure hash computation, and HMAC-SHA1 signature computation,
+-- in pure Lua (tested on Lua 5.1)
+-- License: MIT
+--
+-- Usage:
+-- local hashAsHex = sha1.hex(message) -- returns a hex string
+-- local hashAsData = sha1.bin(message) -- returns raw bytes
+--
+-- local hmacAsHex = sha1.hmacHex(key, message) -- hex string
+-- local hmacAsData = sha1.hmacBin(key, message) -- raw bytes
+--
+--
+-- Pass sha1.hex() a string, and it returns a hash as a 40-character hex string.
+-- For example, the call
+--
+-- local hash = sha1.hex("iNTERFACEWARE")
+--
+-- puts the 40-character string
+--
+-- "e76705ffb88a291a0d2f9710a5471936791b4819"
+--
+-- into the variable 'hash'
+--
+-- Pass sha1.hmacHex() a key and a message, and it returns the signature as a
+-- 40-byte hex string.
+--
+--
+-- The two "bin" versions do the same, but return the 20-byte string of raw
+-- data that the 40-byte hex strings represent.
+--
+-------------------------------------------------------------------------------
+--
+-- Description
+-- Due to the lack of bitwise operations in 5.1, this version uses numbers to
+-- represents the 32bit words that we combine with binary operations. The basic
+-- operations of byte based "xor", "or", "and" are all cached in a combination
+-- table (several 64k large tables are built on startup, which
+-- consumes some memory and time). The caching can be switched off through
+-- setting the local cfg_caching variable to false.
+-- For all binary operations, the 32 bit numbers are split into 8 bit values
+-- that are combined and then merged again.
+--
+-- Algorithm: http://www.itl.nist.gov/fipspubs/fip180-1.htm
+--
+-------------------------------------------------------------------------------
+
+local sha1 = (function()
+local sha1 = {}
+
+-- set this to false if you don't want to build several 64k sized tables when
+-- loading this file (takes a while but grants a boost of factor 13)
+local cfg_caching = false
+-- local storing of global functions (minor speedup)
+local floor,modf = math.floor,math.modf
+local char,format,rep = string.char,string.format,string.rep
+
+-- merge 4 bytes to an 32 bit word
+local function bytes_to_w32 (a,b,c,d) return a*0x1000000+b*0x10000+c*0x100+d end
+-- split a 32 bit word into four 8 bit numbers
+local function w32_to_bytes (i)
+   return floor(i/0x1000000)%0x100,floor(i/0x10000)%0x100,floor(i/0x100)%0x100,i%0x100
+end
+
+-- shift the bits of a 32 bit word. Don't use negative values for "bits"
+local function w32_rot (bits,a)
+   local b2 = 2^(32-bits)
+   local a,b = modf(a/b2)
+   return a+b*b2*(2^(bits))
+end
+
+-- caching function for functions that accept 2 arguments, both of values between
+-- 0 and 255. The function to be cached is passed, all values are calculated
+-- during loading and a function is returned that returns the cached values (only)
+local function cache2arg (fn)
+   if not cfg_caching then return fn end
+   local lut = {}
+   for i=0,0xffff do
+      local a,b = floor(i/0x100),i%0x100
+      lut[i] = fn(a,b)
+   end
+   return function (a,b)
+      return lut[a*0x100+b]
+   end
+end
+
+-- splits an 8-bit number into 8 bits, returning all 8 bits as booleans
+local function byte_to_bits (b)
+   local b = function (n)
+      local b = floor(b/n)
+      return b%2==1
+   end
+   return b(1),b(2),b(4),b(8),b(16),b(32),b(64),b(128)
+end
+
+-- builds an 8bit number from 8 booleans
+local function bits_to_byte (a,b,c,d,e,f,g,h)
+   local function n(b,x) return b and x or 0 end
+   return n(a,1)+n(b,2)+n(c,4)+n(d,8)+n(e,16)+n(f,32)+n(g,64)+n(h,128)
+end
+
+-- debug function for visualizing bits in a string
+local function bits_to_string (a,b,c,d,e,f,g,h)
+   local function x(b) return b and "1" or "0" end
+   return ("%s%s%s%s %s%s%s%s"):format(x(a),x(b),x(c),x(d),x(e),x(f),x(g),x(h))
+end
+
+-- debug function for converting a 8-bit number as bit string
+local function byte_to_bit_string (b)
+   return bits_to_string(byte_to_bits(b))
+end
+
+-- debug function for converting a 32 bit number as bit string
+local function w32_to_bit_string(a)
+   if type(a) == "string" then return a end
+   local aa,ab,ac,ad = w32_to_bytes(a)
+   local s = byte_to_bit_string
+   return ("%s %s %s %s"):format(s(aa):reverse(),s(ab):reverse(),s(ac):reverse(),s(ad):reverse()):reverse()
+end
+
+-- bitwise "and" function for 2 8bit number
+local band = cache2arg (function(a,b)
+      local A,B,C,D,E,F,G,H = byte_to_bits(b)
+      local a,b,c,d,e,f,g,h = byte_to_bits(a)
+      return bits_to_byte(
+         A and a, B and b, C and c, D and d,
+         E and e, F and f, G and g, H and h)
+   end)
+
+-- bitwise "or" function for 2 8bit numbers
+local bor = cache2arg(function(a,b)
+      local A,B,C,D,E,F,G,H = byte_to_bits(b)
+      local a,b,c,d,e,f,g,h = byte_to_bits(a)
+      return bits_to_byte(
+         A or a, B or b, C or c, D or d,
+         E or e, F or f, G or g, H or h)
+   end)
+
+-- bitwise "xor" function for 2 8bit numbers
+local bxor = cache2arg(function(a,b)
+      local A,B,C,D,E,F,G,H = byte_to_bits(b)
+      local a,b,c,d,e,f,g,h = byte_to_bits(a)
+      return bits_to_byte(
+         A ~= a, B ~= b, C ~= c, D ~= d,
+         E ~= e, F ~= f, G ~= g, H ~= h)
+   end)
+
+-- bitwise complement for one 8bit number
+local function bnot (x)
+   return 255-(x % 256)
+end
+
+-- creates a function to combine to 32bit numbers using an 8bit combination function
+local function w32_comb(fn)
+   return function (a,b)
+      local aa,ab,ac,ad = w32_to_bytes(a)
+      local ba,bb,bc,bd = w32_to_bytes(b)
+      return bytes_to_w32(fn(aa,ba),fn(ab,bb),fn(ac,bc),fn(ad,bd))
+   end
+end
+
+-- create functions for and, xor and or, all for 2 32bit numbers
+local w32_and = w32_comb(band)
+local w32_xor = w32_comb(bxor)
+local w32_or = w32_comb(bor)
+
+-- xor function that may receive a variable number of arguments
+local function w32_xor_n (a,...)
+   local aa,ab,ac,ad = w32_to_bytes(a)
+   for i=1,select('#',...) do
+      local ba,bb,bc,bd = w32_to_bytes(select(i,...))
+      aa,ab,ac,ad = bxor(aa,ba),bxor(ab,bb),bxor(ac,bc),bxor(ad,bd)
+   end
+   return bytes_to_w32(aa,ab,ac,ad)
+end
+
+-- combining 3 32bit numbers through binary "or" operation
+local function w32_or3 (a,b,c)
+   local aa,ab,ac,ad = w32_to_bytes(a)
+   local ba,bb,bc,bd = w32_to_bytes(b)
+   local ca,cb,cc,cd = w32_to_bytes(c)
+   return bytes_to_w32(
+      bor(aa,bor(ba,ca)), bor(ab,bor(bb,cb)), bor(ac,bor(bc,cc)), bor(ad,bor(bd,cd))
+   )
+end
+
+-- binary complement for 32bit numbers
+local function w32_not (a)
+   return 4294967295-(a % 4294967296)
+end
+
+-- adding 2 32bit numbers, cutting off the remainder on 33th bit
+local function w32_add (a,b) return (a+b) % 4294967296 end
+
+-- adding n 32bit numbers, cutting off the remainder (again)
+local function w32_add_n (a,...)
+   for i=1,select('#',...) do
+      a = (a+select(i,...)) % 4294967296
+   end
+   return a
+end
+-- converting the number to a hexadecimal string
+local function w32_to_hexstring (w) return format("%08x",w) end
+
+-- calculating the SHA1 for some text
+function sha1.hex(msg)
+   local H0,H1,H2,H3,H4 = 0x67452301,0xEFCDAB89,0x98BADCFE,0x10325476,0xC3D2E1F0
+   local msg_len_in_bits = #msg * 8
+
+   local first_append = char(0x80) -- append a '1' bit plus seven '0' bits
+
+   local non_zero_message_bytes = #msg +1 +8 -- the +1 is the appended bit 1, the +8 are for the final appended length
+   local current_mod = non_zero_message_bytes % 64
+   local second_append = current_mod>0 and rep(char(0), 64 - current_mod) or ""
+
+   -- now to append the length as a 64-bit number.
+   local B1, R1 = modf(msg_len_in_bits / 0x01000000)
+   local B2, R2 = modf( 0x01000000 * R1 / 0x00010000)
+   local B3, R3 = modf( 0x00010000 * R2 / 0x00000100)
+   local B4 = 0x00000100 * R3
+
+   local L64 = char( 0) .. char( 0) .. char( 0) .. char( 0) -- high 32 bits
+   .. char(B1) .. char(B2) .. char(B3) .. char(B4) -- low 32 bits
+
+   msg = msg .. first_append .. second_append .. L64
+
+   assert(#msg % 64 == 0)
+
+   local chunks = #msg / 64
+
+   local W = { }
+   local start, A, B, C, D, E, f, K, TEMP
+   local chunk = 0
+
+   while chunk < chunks do
+      --
+      -- break chunk up into W[0] through W[15]
+      --
+      start,chunk = chunk * 64 + 1,chunk + 1
+
+      for t = 0, 15 do
+         W[t] = bytes_to_w32(msg:byte(start, start + 3))
+         start = start + 4
+      end
+
+      --
+      -- build W[16] through W[79]
+      --
+      for t = 16, 79 do
+         -- For t = 16 to 79 let Wt = S1(Wt-3 XOR Wt-8 XOR Wt-14 XOR Wt-16).
+         W[t] = w32_rot(1, w32_xor_n(W[t-3], W[t-8], W[t-14], W[t-16]))
+      end
+
+      A,B,C,D,E = H0,H1,H2,H3,H4
+
+      for t = 0, 79 do
+         if t <= 19 then
+            -- (B AND C) OR ((NOT B) AND D)
+            f = w32_or(w32_and(B, C), w32_and(w32_not(B), D))
+            K = 0x5A827999
+         elseif t <= 39 then
+            -- B XOR C XOR D
+            f = w32_xor_n(B, C, D)
+            K = 0x6ED9EBA1
+         elseif t <= 59 then
+            -- (B AND C) OR (B AND D) OR (C AND D
+            f = w32_or3(w32_and(B, C), w32_and(B, D), w32_and(C, D))
+            K = 0x8F1BBCDC
+         else
+            -- B XOR C XOR D
+            f = w32_xor_n(B, C, D)
+            K = 0xCA62C1D6
+         end
+
+         -- TEMP = S5(A) + ft(B,C,D) + E + Wt + Kt;
+         A,B,C,D,E = w32_add_n(w32_rot(5, A), f, E, W[t], K),
+         A, w32_rot(30, B), C, D
+      end
+      -- Let H0 = H0 + A, H1 = H1 + B, H2 = H2 + C, H3 = H3 + D, H4 = H4 + E.
+      H0,H1,H2,H3,H4 = w32_add(H0, A),w32_add(H1, B),w32_add(H2, C),w32_add(H3, D),w32_add(H4, E)
+   end
+   local f = w32_to_hexstring
+   return f(H0) .. f(H1) .. f(H2) .. f(H3) .. f(H4)
+end
+
+local function hex_to_binary(hex)
+   return hex:gsub('..', function(hexval)
+         return string.char(tonumber(hexval, 16))
+      end)
+end
+
+function sha1.bin(msg)
+   return hex_to_binary(sha1.hex(msg))
+end
+
+local xor_with_0x5c = {}
+local xor_with_0x36 = {}
+-- building the lookuptables ahead of time (instead of littering the source code
+-- with precalculated values)
+for i=0,0xff do
+   xor_with_0x5c[char(i)] = char(bxor(i,0x5c))
+   xor_with_0x36[char(i)] = char(bxor(i,0x36))
+end
+
+local blocksize = 64 -- 512 bits
+
+function sha1.hmacHex(key, text)
+   assert(type(key) == 'string', "key passed to hmacHex should be a string")
+   assert(type(text) == 'string', "text passed to hmacHex should be a string")
+
+   if #key > blocksize then
+      key = sha1.bin(key)
+   end
+
+   local key_xord_with_0x36 = key:gsub('.', xor_with_0x36) .. string.rep(string.char(0x36), blocksize - #key)
+   local key_xord_with_0x5c = key:gsub('.', xor_with_0x5c) .. string.rep(string.char(0x5c), blocksize - #key)
+
+   return sha1.hex(key_xord_with_0x5c .. sha1.bin(key_xord_with_0x36 .. text))
+end
+
+function sha1.hmacBin(key, text)
+   return hex_to_binary(sha1.hmacHex(key, text))
+end
+
+return sha1
+end)()
+