local n = 619155
local t = {}
for i = 1, n do t[i] = string.char((i * 37) % 256) end
local data = table.concat(t)
local key = "0123456789abcdef0123456789abcdef"

print("data", #data, "buffer", type(buffer), "crypt", type(crypt))

local enc = crypt.base64encode(data)
print("enc", #enc)
local t0 = os.clock()
local dec = crypt.base64decode(enc)
print("native_b64", string.format("%.3f", os.clock() - t0), #dec, dec == data)

-- reference keystream table
local KS = {}
for i = 0, 511 do
    KS[i + 1] = string.char(bit32.bxor(string.byte(key, (i % #key) + 1), (i + 1) % 256))
end
local KSS = table.concat(KS)

-- buffer 4-byte version
local t1 = os.clock()
local src = buffer.fromstring(data)
local dst = buffer.create(n)
local ksb = buffer.fromstring(KSS)
local i = 0
while i <= n - 4 do
    local a = buffer.readu32(src, i)
    local k = buffer.readu32(ksb, i % 256)
    local hi = math.floor((i + 1) / 256) % 256
    local hi4 = hi + hi * 256 + hi * 65536 + hi * 16777216
    buffer.writeu32(dst, i, bit32.bxor(a, k, hi4))
    i = i + 4
end
local out = buffer.tostring(dst)
print("buffer_dec", string.format("%.3f", os.clock() - t1), #out)

-- string.unpack 4-byte version
local t2 = os.clock()
local parts = {}
local j = 0
while j <= n - 4 do
    local a = string.unpack("<I4", data, j + 1)
    local k = string.unpack("<I4", KSS, (j % 256) + 1)
    local hi = math.floor((j + 1) / 256) % 256
    local hi4 = hi + hi * 256 + hi * 65536 + hi * 16777216
    parts[#parts + 1] = string.pack("<I4", bit32.bxor(a, k, hi4))
    j = j + 4
end
local out2 = table.concat(parts)
print("unpack_dec", string.format("%.3f", os.clock() - t2), #out2)

-- verify first mismatch against a reference byte-at-a-time on a small prefix
local function refbyte(pos)
    local c = string.byte(data, pos)
    local k = string.byte(key, ((pos - 1) % #key) + 1)
    local x = bit32.bxor(c, k, pos % 256, math.floor(pos / 256) % 256)
    return string.char(x)
end
local ok = true
for p = 1, 64 do
    if string.byte(out, p) ~= string.byte(refbyte(p)) then ok = false print("mismatch", p, string.byte(out,p), string.byte(refbyte(p))) break end
end
print("prefix_ok", ok)

-- native crypt roundtrip shape
local e = crypt.encrypt("hello world", "key")
print("crypt_enc", type(e), #tostring(e), tostring(e))
local d2 = crypt.decrypt(e, "key")
print("crypt_round", tostring(d2))