added type annotations and function documentation to liblz16 and pkgfs

README.md

@@ -6,16 +6,25 @@ A lightweight, multi-user operating system for OpenComputers
 
 ### The kernel
 
-The kernel can be built using luapreproc:
+The kernel is composed of a number of modules, found in the *module/* directory. Which modules are included can be customised by changing the include statements in *module/init.lua*; copying it and customizing that is recommended, so you can *git pull* later without having to stash or reset your changes.
 
-    ./luapreproc.lua module/init.lua kernel.lua
+#### Unix-like systems
+
+The kernel can be built using the preproc library and provided scripts:
+
+    lua build.lua module/init.lua kernel.lua
+
+#### PsychOS
+
+The kernel can be built from inside PsychOS using the preproc library, assuming you have the kernel source available:
+
+    preproc("module/init.lua","kernel.lua")
 
 ### The boot filesystem
 
 A boot filesystem contains several things:
 
  - The kernel, as init.lua
- - The exec/ directory, as this contains all executables
  - The lib/ directory, containing libraries
  - The service/ directory, containing system services
 
@@ -23,6 +32,4 @@ This has been automated in the form of build.sh, pending a real makefile.
 
 ## Documentation
 
-To generate function documentation, run:
+Documentation is generated as the system is built with build.sh; a set of markdown files will be placed into *doc/*, as well as an all-in-one *apidoc.md*. If pandoc is installed, an *apidoc.pdf* will also be generated.
-
-    ./finddesc.lua module/* lib/* > apidoc.md

lib/liblz16.lua

@@ -0,0 +1,71 @@
+local lz = require "lzss"
+local buffer = require "buffer"
+
+lz16 = {}
+
+local function cint(n,l)
+ local t={}
+ for i = 0, 7 do
+  t[i+1] = (n >> (i * 8)) & 0xFF
+ end
+ return string.reverse(string.char(table.unpack(t)):sub(1,l))
+end
+local function toint(s)
+ local n = 0
+ local i = 1
+ for p in s:gmatch(".") do
+  n = n << 8
+  n = n | string.byte(p)
+  i=i+1
+ end
+ return n
+end
+
+local function readBuffer(fi)
+ local stream = {}
+ if fi:read(4) ~= "lz16" then
+  return false, "not an lz16 archive"
+ end
+ function stream.read()
+  local len = toint(fi:read(2) or "\0\0")
+  if len < 1 then
+   return nil
+  end
+  coroutine.yield()
+  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(cint(cblock:len(),2)..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

lib/lzss.lua

@@ -0,0 +1,123 @@
+--[[----------------------------------------------------------------------------
+
+	LZSS - encoder / decoder
+
+	This is free and unencumbered software released into the public domain.
+
+	Anyone is free to copy, modify, publish, use, compile, sell, or
+	distribute this software, either in source code form or as a compiled
+	binary, for any purpose, commercial or non-commercial, and by any
+	means.
+
+	In jurisdictions that recognize copyright laws, the author or authors
+	of this software dedicate any and all copyright interest in the
+	software to the public domain. We make this dedication for the benefit
+	of the public at large and to the detriment of our heirs and
+	successors. We intend this dedication to be an overt act of
+	relinquishment in perpetuity of all present and future rights to this
+	software under copyright law.
+
+	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+	EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+	MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+	IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+	OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+	ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+	OTHER DEALINGS IN THE SOFTWARE.
+
+	For more information, please refer to <http://unlicense.org/>
+
+--]]----------------------------------------------------------------------------
+--------------------------------------------------------------------------------
+local M = {}
+local string, table = string, table
+
+--------------------------------------------------------------------------------
+local POS_BITS = 12
+local LEN_BITS = 16 - POS_BITS
+local POS_SIZE = 1 << POS_BITS
+local LEN_SIZE = 1 << LEN_BITS
+local LEN_MIN = 3
+
+--------------------------------------------------------------------------------
+function M.compress(input)
+	local offset, output = 1, {}
+	local window = ''
+
+	local function search()
+		for i = LEN_SIZE + LEN_MIN - 1, LEN_MIN, -1 do
+			local str = string.sub(input, offset, offset + i - 1)
+			local pos = string.find(window, str, 1, true)
+			if pos then
+				return pos, str
+			end
+		end
+	end
+
+	while offset <= #input do
+		local flags, buffer = 0, {}
+
+		for i = 0, 7 do
+			if offset <= #input then
+				local pos, str = search()
+				if pos and #str >= LEN_MIN then
+					local tmp = ((pos - 1) << LEN_BITS) | (#str - LEN_MIN)
+					buffer[#buffer + 1] = string.pack('>I2', tmp)
+				else
+					flags = flags | (1 << i)
+					str = string.sub(input, offset, offset)
+					buffer[#buffer + 1] = str
+				end
+				window = string.sub(window .. str, -POS_SIZE)
+				offset = offset + #str
+			else
+				break
+			end
+		end
+
+		if #buffer > 0 then
+			output[#output + 1] = string.char(flags)
+			output[#output + 1] = table.concat(buffer)
+		end
+	end
+
+	return table.concat(output)
+end
+
+--------------------------------------------------------------------------------
+function M.decompress(input)
+	local offset, output = 1, {}
+	local window = ''
+
+	while offset <= #input do
+		local flags = string.byte(input, offset)
+		offset = offset + 1
+
+		for i = 1, 8 do
+			local str = nil
+			if (flags & 1) ~= 0 then
+				if offset <= #input then
+					str = string.sub(input, offset, offset)
+					offset = offset + 1
+				end
+			else
+				if offset + 1 <= #input then
+					local tmp = string.unpack('>I2', input, offset)
+					offset = offset + 2
+					local pos = (tmp >> LEN_BITS) + 1
+					local len = (tmp & (LEN_SIZE - 1)) + LEN_MIN
+					str = string.sub(window, pos, pos + len - 1)
+				end
+			end
+			flags = flags >> 1
+			if str then
+				output[#output + 1] = str
+				window = string.sub(window .. str, -POS_SIZE)
+			end
+		end
+	end
+
+	return table.concat(output)
+end
+
+return M

lib/pkgfs.lua

@@ -98,8 +98,10 @@ function pkgfs.component.close(handle)
  return true
 end
 
-function pkgfs.add(fname,comp)
+function pkgfs.add(fname,comp) -- string boolean -- -- Add a package as specified in *fname* to the pkgfs component. If *comp* is true, read it as a LZ16-compressed package.
- local fname = "/"..fnormalize(os.getenv("PWD").."/"..fname)
+ if fname:sub(1,1) ~= "/" then
+  fname = "/"..fnormalize(os.getenv("PWD").."/"..fname)
+ end
  local f = fopen(fname,comp)
  if not fname then error("unable to open file") end
  print(fname)