OC-PsychOS2/lib/liblz16.lua

54 lines
1.2 KiB
Lua

local lz = require "lzss"
local buffer = require "buffer"
lz16 = {}
local function readBuffer(fi)
local stream = {}
if fi:read(4) ~= "lz16" then
return false, "not an lz16 archive"
end
function stream.read()
local len = string.unpack(">I2", fi:read(2) or "\0\0")
if len < 1 then
return nil
end
if os.sleep then os.sleep(0) else coroutine.yield() end
return lz.decompress(fi:read(len))
end
function stream.close()
fi:close()
end
return buffer.new("rb",stream)
end
local function writeBuffer(fo)
local stream = {}
function stream:write(data)
local cblock = lz.compress(data)
fo:write(string.pack(">I2", cblock:len()) .. cblock)
return cblock:len()+2
end
function stream.close()
fo:close()
end
fo:write("lz16") -- write header
return buffer.new("wb",stream)
end
function lz16.buffer(stream) -- table -- table -- Wrap a stream to read or write LZ16.
if stream.mode.w then
return writeBuffer(stream)
end
return readBuffer(stream)
end
function lz16.open(fname, mode) -- string string -- table -- Open file *fname* to read or write LZ16-compressed data depending on *mode*
local f = io.open(fname, mode)
if not f then return false end
f.mode.b = true
return lz16.buffer(f)
end
return lz16