Add b64 encoder

ActionBarSaverReloaded.toc

@@ -5,6 +5,7 @@
 ## Author: Voodoomoose
 ## SavedVariables: ActionBarSaverReloaded
 
+B64.lua
 Constants.lua
 Main.lua
 Actions.lua

B64.lua

@@ -0,0 +1,39 @@
+if not B64 then B64 = {} end
+local encode, decode = {}, { [strbyte("=")] = false }
+for value = 0, 63 do
+	local char = strsub('ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/', value+1, value+1)
+	encode[value] = char
+	decode[strbyte(char)] = value
+end
+
+local t = {}
+function B64.Encode(str)
+	local j = 1
+	for i = 1, strlen(str), 3 do
+		local a, b, c = strbyte(str, i, i+2)
+		t[j] = encode[bit.rshift(a, 2)]
+		t[j+1] = encode[bit.band(bit.lshift(a, 4) + bit.rshift(b or 0, 4), 0x3F)]
+		t[j+2] = b and encode[bit.band(bit.lshift(b, 2) + bit.rshift(c or 0, 6), 0x3F)] or "="
+		t[j+3] = c and encode[bit.band(c, 0x3F)] or "="
+		j = j + 4
+	end
+	return table.concat(t, "", 1, j-1)
+end
+
+function B64Decode(str)
+	local j = 1
+	assert(strlen(str) % 4 == 0, format("invalid data length: %d", strlen(str)))
+	for i = 1, strlen(str), 4 do
+		local ba, bb, bc, bd = strbyte(str, i, i+3)
+		local a, b, c, d = decode[ba], decode[bb], decode[bc], decode[bd]
+		assert(a ~= nil, format("invalid data at position %d: '%s'", i, ba))
+		assert(b ~= nil, format("invalid data at position %d: '%s'", i+1, bb))
+		assert(c ~= nil, format("invalid data at position %d: '%s'", i+2, bc))
+		assert(d ~= nil, format("invalid data at position %d: '%s'", i+3, bd))
+		t[j] = strchar(bit.lshift(a, 2) + bit.rshift(b, 4))
+		t[j+1] = c and strchar(bit.band(bit.lshift(b, 4) + bit.rshift(c, 2), 0xFF)) or ""
+		t[j+2] = d and strchar(bit.band(bit.lshift(c, 6) + d, 0xFF)) or ""
+		j = j + 3
+	end
+	return table.concat(t, "", 1, j-1)
+end