return (function()
local builders = {}
local function register(name, f)
builders[name] = f
end
register('advent.compat', function(myrequire)
-- Compatibility functions
-- (Things present in Lua 5.3 that are missing in Lua 5.1)
local compat = {}
local string = myrequire('string')
local table = myrequire('table')
function compat.len(v)
-- the length metamethod is only available starting in Lua 5.2
if type(v) == 'table' then
local mt = getmetatable(v)
if mt ~= nil then
local len = mt.__len
if len ~= nil then
return len(v)
end
end
end
return #v
end
function compat.combineBytes(msb, lsb)
-- (msb << 8) | lsb
return (msb * 256) + lsb
end
function compat.splitBytes(u16)
-- u16 >> 8, u16 & 0xFF
local lsb = math.fmod(u16, 256)
local msb = (u16 - lsb) / 256
return msb, lsb
end
function compat.rshift(x, disp)
-- x >> disp
return math.floor(x/(2^disp))
end
function compat.idiv(a, b)
local tya, tyb = type(a), type(b)
if tya ~= 'number' or tyb ~= 'number' then
local op = nil
local mt = getmetatable(a)
if mt ~= nil then op = mt.__idiv end
if op == nil then
mt = getmetatable(b)
if mt ~= nil then op = mt.__idiv end
end
if op ~= nil then
return op(a, b)
end
end
return math.floor(a / b)
end
function compat.utf8codes(s)
local len = #s
local f = function(state, _)
local pos = state.nextpos
if pos > len then
return nil, nil
end
local c1 = string.byte(s, pos)
if c1 <= 0x7F then
state.nextpos = pos + 1
return pos, c1
end
local c2 = string.byte(s, pos + 1)
if c1 <= 0xDF then
state.nextpos = pos + 2
return pos, ((c1 % 0x20 ) * 0x40) + (c2 % 0x40)
end
local c3 = string.byte(s, pos + 2)
if c1 <= 0xEF then
state.nextpos = pos + 3
return pos, (((c1 % 0x10) * 0x40) + (c2 % 0x40)) * 0x40 + (c3 % 0x40)
end
local c4 = string.byte(s, pos + 3)
if c1 <= 0xF7 then
state.nextpos = pos + 4
return pos, ((((c1 % 0x08) * 0x40) + (c2 % 0x40)) * 0x40 + (c3 % 0x40)) * 0x40 + (c4 % 0x40)
end
error("bad utf-8")
end
return f, { nextpos = 1 }, 0
end
function compat.utf8char(...)
-- utf8.char(c)
local result = {}
for _,c in ipairs{...} do
local s
if c <= 0x7F then
s = string.char(c)
else
local c1 = c % 0x40
local cN = (c - c1) / 0x40
if c <= 0x7FF then
s = string.char(
cN + 0xC0,
c1 + 0x80
)
else
local c2 = cN % 0x40
cN = (cN - c2) / 0x40
if c <= 0xFFFF then
s = string.char(
cN + 0xE0,
c2 + 0x80,
c1 + 0x80
)
else
local c3 = cN % 0x40
cN = (cN - c3) / 0x40
if c <= 0x10FFFF then
s = string.char(
cN + 0xF0,
c3 + 0x80,
c2 + 0x80,
c1 + 0x80
)
else
error()
end
end
end
end
table.insert(result, s)
end
return table.concat(result)
end
-- unpack is a global function for Lua 5.1, otherwise use table.unpack
compat.unpack = table.unpack or function(tbl, i, j)
local unpack = rawget(_G, "unpack")
-- we also need to use compat.len to get the length of this table!
if i == nil then i = 1 end
if j == nil then j = compat.len(tbl) end
return unpack(tbl, i, j)
end
-- table.pack was added in Lua 5.2
compat.pack = table.pack or function(...)
local t = { ... }
t.n = select("#",...)
return t
end
-- table.move was added in Lua 5.3
compat.move = table.move or function(a1, f, e, t, a2)
if a2 == nil then a2 = a1 end
local tmp = {}
for i=f,e do
tmp[1+i-f] = a1[i]
end
for i=f,e do
a2[t+i-f] = tmp[1+i-f]
end
return a2
end
return compat
end)
local modules = {}
modules['bit32'] = require('bit32')
modules['string'] = require('string')
modules['strict'] = {}
modules['table'] = require('table')
local function myrequire(name)
if modules[name] == nil then
modules[name] = true
modules[name] = (builders[name])(myrequire)
end
return modules[name]
end
return myrequire('advent.compat')
end)()
