Sha256: 7f2e21404d2931cc93262f8525fe2958032e6e06d5b82281a37f6ee1ac42d8dd
Contents?: true
Size: 1.02 KB
Versions: 396
Compression:
Stored size: 1.02 KB
Contents
local function flatten(tables)
local flattened = {}
for _, t in ipairs(tables) do
for _, v in ipairs(t) do
table.insert(flattened, v)
end
end
return flattened
end
local function correspondences(length, rail_count)
local lines = {}
local line_index = 1
local delta = 1
for i = 1, rail_count do lines[i] = {} end
for i = 1, length do
table.insert(lines[line_index], i)
line_index = line_index + delta
if line_index == rail_count then delta = -1 end
if line_index == 1 then delta = 1 end
end
return ipairs(flatten(lines))
end
local function encode(plaintext, rail_count)
local ciphertext = {}
for i, v in correspondences(#plaintext, rail_count) do
ciphertext[i] = plaintext:sub(v, v)
end
return table.concat(ciphertext)
end
local function decode(ciphertext, rail_count)
local plaintext = {}
for i, v in correspondences(#ciphertext, rail_count) do
plaintext[v] = ciphertext:sub(i, i)
end
return table.concat(plaintext)
end
return { encode = encode, decode = decode }
Version data entries
396 entries across 396 versions & 1 rubygems