OCL [Operating System Compatibility Layer] 0.4

-- CC BIOS

local function write(sText)
    local w, h = term.getSize()
    local x, y = term.getCursorPos()
    local nLinesPrinted = 0
    local function newLine()
        if y + 1 <= h then
            term.setCursorPos(1, y + 1)
        else
            term.scroll(1)
            term.setCursorPos(1, h)
        end
        x, y = term.getCursorPos()
        nLinesPrinted = nLinesPrinted + 1
    end
    -- Print the line with proper word wrapping
    while string.len(sText) > 0 do
        local whitespace = string.match( sText, "^[ t]+" )
        if whitespace then
            -- Print whitespace
            term.write( whitespace )
            x,y = term.getCursorPos()
            sText = string.sub( sText, string.len(whitespace) + 1 )
        end
        
        local newline = string.match( sText, "^n" )
        if newline then
            -- Print newlines
            newLine()
            sText = string.sub( sText, 2 )
        end
        
        local text = string.match( sText, "^[^ tn]+" )
        if text then
            sText = string.sub( sText, string.len(text) + 1 )
            if string.len(text) > w then
                -- Print a multiline word                
                while string.len( text ) > 0 do
                if x > w then
                    newLine()
                end
                    term.write( text )
                    text = string.sub( text, (w-x) + 2 )
                    x,y = term.getCursorPos()
                end
            else
                -- Print a word normally
                if x + string.len(text) > w then
                    newLine()
                end
                term.write( text )
                x,y = term.getCursorPos()
            end
        end
    end
    
    return nLinesPrinted
end

local function print( ... )
    local nLinesPrinted = 0
    for n,v in ipairs( { ... } ) do
        nLinesPrinted = nLinesPrinted + write( tostring( v ) )
    end
    nLinesPrinted = nLinesPrinted + write( "n" )
    return nLinesPrinted
end

local sBoot = "rom/CraftOS_1_3.startup"

if fs.exists("boot") then
    if fs.isDir("boot") then
        if fs.exists("boot/loader") and not fs.isDir("boot/loader") then
            sBoot = "boot/loader"
        end
    else
        sBoot = "boot"
    end
end

local function boot()
    local file = fs.open(sBoot, "r")
    if file then
        local func, err = loadstring(file.readAll(), fs.getName(sBoot))
        file.close()
        if func then
            return pcall(func)
        else
            return false, err
        end
    else
        return false, "Error opening file "..sBoot
    end
end

local ok, err = boot()
if not ok then
    term.clear()
    term.setCursorPos(1, 1)
    term.setCursorBlink(false)
    print(err)
    print("Press any key to continue")
    repeat
        local evt = coroutine.yield()
    until evt == "key"
end

os.shutdown()

-- Version string
local sVersion = "CC Boot Loader 0.1"

-- Paths to search for boot files
local tBootPaths = {
"/rom/boot",
"/boot"
}
-- Wheter to load boot files from disks or not
local bBootFromDisk = true
-- The boot files extension
local sBootExt = "boot"

-- clear function:
-- clears the screen and sets the cursor to the top-left corner
local function clear()
	term.clear()
	term.setCursorPos(1, 1)
end

-- print function:
-- writes the given text to the screen
local function print(s)
	-- get the current cursor position
	local x, y = term.getCursorPos()
	-- get the screen size
	local w, h = term.getSize()
	-- write the text
	term.write(s)
	if y >= h then
		-- scroll the screen
		term.scroll((h - y) + 1)
	else
		-- move the cursor down
		term.setCursorPos(1, y + 1)
	end
end

-- boot function:
-- loads a boot file as a function and then calls it
local function boot(sPath)
	-- open the file
	local file = fs.open(sPath, "r")
	-- if the file is open
	if file then
		-- read the file contents and load the function
		local func, err = loadstring(file.readAll(), fs.getName(sPath))
		-- close the file handle
		file.close()
		-- if the function was loaded correctly
		if func then
			-- make a protected call in case of error
			return pcall(func)
		else
			-- return false to indicate the error and the error message
			return false, err
		end
	end
	-- error opening the file
	return false, "Error opening file "..sPath
end

-- getBootFiles function:
-- searches a directory for boot files
local function getBootFiles(sPath, tList)
	-- for each entry in the directory
	for _,name in ipairs(fs.list(sPath)) do
		-- get the full path to the file/directory
		local path = fs.combine(sPath, name)
		-- check if it's a file
		if not fs.isDir(path) then
			-- check if it's a boot file
			local s = string.match(v, "^(.*)%."..sBootExt.."$")
			if s then
				-- add it to the list
				table.insert(tList, path)
			end
		end
	end
end

-- The list of boot files
local tList = {}

-- Get every boot file on the specified paths
for _,path in ipairs(tBootPaths) do
	if fs.exists(path) and fs.isDir(path) then
		getBootFiles(path, tList)
	end
end
-- Get boot files from disks
if bBootFromDisk then
	for _,side in ipairs(rs.getSides()) do
		if peripheral.isPresent(side) and peripheral.getType(side) == "drive" then
			local drive = peripheral.wrap(side)
			if drive.hasData() then
				local sDiskPath = fs.combine(drive.getMountPath, "boot")
				if fs.exists(sDiskPath) and fs.isDir(sDiskPath) then
					getBootFiles(sDiskPath, tList)
				end
			end
		end
	end
end

if #tList == 0 then
	-- No boot file found, let the user know
	print("No boot file found.")
elseif #tList == 1 then
	-- Only one boot file, load it
	boot(tList[1])
else
	-- More than one boot file, let the user choose one
	local nSelected = 1 -- currently selected option
	-- redraw function: redraws the menu
	local function redraw()
		-- clear the screen
		clear()
		-- print the options
		print(sVersion)
		for i, s in ipairs(tList) do
			if i == nSelected then
				print(">"..s)
			else
				print(" "..s)
			end
		end
	end
	while true do
		-- redraw the menu
		redraw()
		-- get a key press
		local evt, k = coroutine.yield("key")
		if k == 28 then -- Enter
			-- clear the screen
			clear()
			-- load the boot file
			local ok, err = boot(tList[nSelected])
			-- check if there was an error
			if not ok then
				-- throw the error
				error(err)
			end
			-- stop the loop
			break
		elseif k == 200 then -- Up
			-- Move the cursor up
			if nSelected > 1 then
				nSelected = nSelected - 1
			else
				nSelected = #tList
			end
		elseif k == 208 then -- Down
			-- Move the cursor down
			if nSelected < #tList then
				nSelected = nSelected + 1
			else
				nSelected = 1
			end
		end
	end
end

os.shutdown() -- just in case

-- Version string
local sVersion = "CC Boot Loader 0.2"

-- Paths to search for boot files
local tBootPaths = {
"/rom/boot",
"/boot"
}
-- Wheter to load boot files from disks or not
local bBootFromDisk = true

-- clear function:
-- clears the screen and sets the cursor to the top-left corner
local function clear()
    term.clear()
    term.setCursorPos(1, 1)
end

-- write function:
-- writes the given text to the screen on the specified line
local function write(s, y)
    -- set the cursor position
    term.setCursorPos(1, y)
    -- write the text
    term.write(s)
end

-- boot function:
-- loads a boot file as a function and then calls it
local function boot(sPath)
    -- open the file
    local file = fs.open(sPath, "r")
    -- if the file is open
    if file then
        -- read the file contents and load the function
        local func, err = loadstring(file.readAll(), fs.getName(sPath))
        -- close the file handle
        file.close()
        -- if the function was loaded correctly
        if func then
            -- make a protected call in case of error
            return pcall(func)
        else
            -- return false to indicate the error and the error message
            return false, err
        end
    end
    -- error opening the file
    return false, "Error opening file "..sPath
end

-- getBootFiles function:
-- searches a directory for boot files
local function getBootFiles(sPath, tList)
    -- for each entry in the directory
    for _,name in ipairs(fs.list(sPath)) do
        -- get the full path to the file/directory
        local path = fs.combine(sPath, name)
        -- check if it's a file
        if not fs.isDir(path) then
            -- add the path to the list
            table.insert(tList, path)
        end
    end
end

-- The list of boot files
local tList = {}

-- Get every boot file on the specified paths
for _,path in ipairs(tBootPaths) do
    -- check if it's a directroy
    if fs.exists(path) and fs.isDir(path) then
        -- check for boot files
        getBootFiles(path, tList)
    end
end
-- Get boot files from disks
if bBootFromDisk then
    -- for each side
    for _,side in ipairs(rs.getSides()) do
        -- check if there's a disk drive
        if peripheral.isPresent(side) and peripheral.getType(side) == "drive" then
            -- get the drive on the current side
            local drive = peripheral.wrap(side)
            -- check if it has a floppy disk
            if drive.hasData() then
                -- get the disk boot path
                local sDiskPath = fs.combine(drive.getMountPath, "boot")
                -- check if it's a directory
                if fs.exists(sDiskPath) and fs.isDir(sDiskPath) then
                    -- check for boot files
                    getBootFiles(sDiskPath, tList)
                end
            end
        end
    end
end

if #tList == 0 then
    -- No boot file found, let the user know
    write("No boot file found.", 1)
    write("Press any key to shutdown", 2)
    coroutine.yield("key")
elseif #tList == 1 then
    -- Only one boot file, load it
    boot(tList[1])
else
    -- More than one boot file, let the user choose one
    -- currently selected option
    local nSelected = 1
    -- scroll amount
    local nScroll = 0
    -- get the terminal size
    local w, h = term.getSize()
    -- redraw function: redraws the menu
    local function redraw()
        -- clear the screen
        clear()
        -- print the boot loader version
        write(sVersion, 1)
        -- print the options
        for i = 1, math.min(#tList, h - 1) do
            if i + nScroll == nSelected then
                write(">"..tList[i + nScroll], i + 1)
            else
                write(" "..tList[i + nScroll], i + 1)
            end
        end
    end
    while true do
        -- redraw the menu
        redraw()
        -- get a key press
        local evt, k = coroutine.yield("key")
        if k == 28 then -- Enter
            -- clear the screen
            clear()
            -- load the boot file
            local ok, err = boot(tList[nSelected])
            -- check if there was an error
            if not ok then
                -- show the error
                write(err, 1)
                write("Press any key to continue", 2)
                coroutine.yield("key")
            end
            -- stop the loop
            break
        elseif k == 200 then -- Up
            -- Move the cursor up
            if nSelected > 1 then
                nSelected = nSelected - 1
                if nSelected == nScroll then
                    nScroll = nScroll - 1
                end
            else
                nSelected = #tList
                if #tList >= h then
                    nScroll = #tList - (h - 1)
                end
            end
        elseif k == 208 then -- Down
            -- Move the cursor down
            if nSelected < #tList then
                nSelected = nSelected + 1
                if nSelected - nScroll >= h then
                    nScroll = nScroll + 1
                end
            else
                nSelected = 1
                nScroll = 0
            end
        end
    end
end

os.shutdown() -- just in case

-- The boot file name
local sBootName = ".boot"
-- Paths to search for boot files
local tBootPaths = {
"/rom",
"/"
}
-- Wheter to load boot files from disks or not
local bBootFromDisk = true

-- clear function:
-- clears the screen and sets the cursor to the top-left corner
local function clear()
	term.clear()
	term.setCursorPos(1, 1)
end

-- print function:
-- writes the given text to the screen
local function print(s)
	-- get the current cursor position
	local x, y = term.getCursorPos()
	-- get the terminal size
	local w, h = term.getSize()
	-- write the text
	term.write(s)
	-- check if the cursor is at the last line
	if y >= h then
		-- scroll the screen
		scroll((y - h) + 1)
	else
		-- move the cursor down
		term.setCursorPos(1, y + 1)
	end
end

-- getBoot function:
-- loads a boot file as a function
local function getBoot(sPath)
	-- open the file
	local file = fs.open(sPath, "r")
	-- if the file is open
	if file then
		-- read the file contents and load the function
		local func, err = loadstring(file.readAll(), fs.getName(sPath))
		-- close the file handle
		file.close()
		-- if the function was loaded correctly
		if not func then
			-- return nil to indicate the error and the error message
			return nil, err
		end
		-- return the boot function
		return func
	end
	-- error opening the file
	return nil, "Error opening file "..sPath
end

local bootFunc

-- Try to load boot files from the specified paths
for _,path in ipairs(tBootPaths) do
	-- get the full path to the file
	local sPath = fs.combine(path, sBootName)
	-- check if it exists and is a file
	if fs.exists(sPath) and not fs.isDir(sPath) then
		-- try to load the boot
		bootFunc = getBoot(sPath)
		-- if the boot loaded
		if bootFunc ~= nil then
			-- stop searching
			break
		end
	end
end
-- try to load boot files from disks
if bootFunc == nil and bBootFromDisk then
	-- for each side
	for _,side in ipairs(rs.getSides()) do
		-- check if there's a disk drive
		if peripheral.isPresent(side) and peripheral.getType(side) == "drive" then
			-- get the drive on the current side
			local drive = peripheral.wrap(side)
			-- check if it has a floppy disk
			if drive.hasData() then
				-- get the disk boot path
				local sDiskPath = fs.combine(drive.getMountPath, sBootName)
				-- check if it exists and is a file
				if fs.exists(sDiskPath) and not fs.isDir(sDiskPath) then
					-- try to load the boot
					bootFunc = getBoot(sPath)
					-- if the boot loaded
					if bootFunc ~= nil then
						-- stop searching
						break
					end
				end
			end
		end
	end
end

if bootFunc == nil then
	-- No boot loaded, let the user know
	print("No boot files could be loaded")
	print("Press any key to shutdown")
	coroutine.yield("key")
else
	-- try to boot
	local ok, err = pcall(bootFunc)
	-- check if there was an error
	if not ok then
		-- show the error
		clear()
		print(err)
		print("Press any key to continue")
		coroutine.yield("key")
	end
end

os.shutdown() -- just in case

-- Version string
local sVersion = "CC Boot Loader 0.3"

-- Paths to search for boot files
local tBootPaths = {
"/rom/boot",
"/boot"
}
-- Wheter to load boot files from disks or not
local bBootFromDisk = true

-- clear function:
-- clears the screen and sets the cursor to the top-left corner
local function clear()
    term.clear()
    term.setCursorPos(1, 1)
end

-- write function:
-- writes the given text to the screen on the specified line
local function write(s, y)
    -- set the cursor position
    term.setCursorPos(1, y)
    -- write the text
    term.write(s)
end

-- boot function:
-- loads a boot file as a function and then calls it
local function boot(sPath)
    -- open the file
    local file = fs.open(sPath, "r")
    -- if the file is open
    if file then
        -- read the file contents and load the function
        local func, err = loadstring(file.readAll(), fs.getName(sPath))
        -- close the file handle
        file.close()
        -- if the function was loaded correctly
        if func then
            -- make a protected call in case of error
            return pcall(func)
        else
            -- return false to indicate the error and the error message
            return false, err
        end
    end
    -- error opening the file
    return false, "Error opening file "..sPath
end

-- getBootFiles function:
-- searches a directory for boot files
local function getBootFiles(sPath, tList)
    -- for each entry in the directory
    for _,name in ipairs(fs.list(sPath)) do
        -- get the full path to the file/directory
        local path = fs.combine(sPath, name)
        -- check if it's a file
        if not fs.isDir(path) then
            -- add the path to the list
            table.insert(tList, path)
        end
    end
end

-- The list of boot files
local tList = {}

-- Get every boot file on the specified paths
for _,path in ipairs(tBootPaths) do
    -- check if it's a directroy
    if fs.exists(path) and fs.isDir(path) then
        -- check for boot files
        getBootFiles(path, tList)
    end
end
-- Get boot files from disks
if bBootFromDisk then
    -- for each side
    for _,side in ipairs(rs.getSides()) do
        -- check if there's a disk drive
        if peripheral.isPresent(side) and peripheral.getType(side) == "drive" then
            -- check if it has a floppy disk
            if peripheral.call(side, "hasData") then
                -- get the disk boot path
                local sDiskPath = fs.combine(peripheral.call(side, "getMountPath"), "boot")
                -- check if it's a directory
                if fs.exists(sDiskPath) and fs.isDir(sDiskPath) then
                    -- check for boot files
                    getBootFiles(sDiskPath, tList)
                end
            end
        end
    end
end

if #tList == 0 then
    -- No boot file found, let the user know
    write("No boot file found.", 1)
    write("Press any key to shutdown", 2)
    coroutine.yield("key")
elseif #tList == 1 then
    -- Only one boot file, load it
    boot(tList[1])
else
    -- More than one boot file, let the user choose one
    -- currently selected option
    local nSelected = 1
    -- scroll amount
    local nScroll = 0
    -- get the terminal size
    local w, h = term.getSize()
    -- redraw function: redraws the menu
    local function redraw()
        -- clear the screen
        clear()
        -- print the boot loader version
        write(sVersion, 1)
        -- print the options
        for i = 1, math.min(#tList, h - 1) do
            if i + nScroll == nSelected then
                write(">"..tList[i + nScroll], i + 1)
            else
                write(" "..tList[i + nScroll], i + 1)
            end
        end
    end
    while true do
        -- redraw the menu
        redraw()
        -- get a key press
        local evt, k = coroutine.yield("key")
        if k == 28 then -- Enter
            -- clear the screen
            clear()
            -- load the boot file
            local ok, err = boot(tList[nSelected])
            -- check if there was an error
            if not ok then
                -- show the error
                write(err, 1)
                write("Press any key to continue", 2)
                coroutine.yield("key")
            end
            -- stop the loop
            break
        elseif k == 200 then -- Up
            -- Move the cursor up
            if nSelected > 1 then
                nSelected = nSelected - 1
                if nSelected == nScroll then
                    nScroll = nScroll - 1
                end
            else
                nSelected = #tList
                if #tList >= h then
                    nScroll = #tList - (h - 1)
                end
            end
        elseif k == 208 then -- Down
            -- Move the cursor down
            if nSelected < #tList then
                nSelected = nSelected + 1
                if nSelected - nScroll >= h then
                    nScroll = nScroll + 1
                end
            else
                nSelected = 1
                nScroll = 0
            end
        end
    end
end

os.shutdown() -- just in case

-- The boot file name
local sBootName = ".boot"
-- Paths to search for boot files
local tBootPaths = {
"/rom",
"/"
}
-- Wheter to load boot files from disks or not
local bBootFromDisk = true

-- clear function:
-- clears the screen and sets the cursor to the top-left corner
local function clear()
    term.clear()
    term.setCursorPos(1, 1)
end

-- print function:
-- writes the given text to the screen
local function print(s)
    -- get the current cursor position
    local x, y = term.getCursorPos()
    -- get the terminal size
    local w, h = term.getSize()
    -- write the text
    term.write(s)
    -- check if the cursor is at the last line
    if y >= h then
        -- scroll the screen
        scroll((y - h) + 1)
    else
        -- move the cursor down
        term.setCursorPos(1, y + 1)
    end
end

-- getBoot function:
-- loads a boot file as a function
local function getBoot(sPath)
    -- open the file
    local file = fs.open(sPath, "r")
    -- if the file is open
    if file then
        -- read the file contents and load the function
        local func, err = loadstring(file.readAll(), fs.getName(sPath))
        -- close the file handle
        file.close()
        -- if the function was loaded correctly
        if not func then
            -- return nil to indicate the error and the error message
            return nil, err
        end
        -- return the boot function
        return func
    end
    -- error opening the file
    return nil, "Error opening file "..sPath
end

local bootFunc

-- try to load boot files from the specified paths
for _,path in ipairs(tBootPaths) do
    -- get the full path to the file
    local sPath = fs.combine(path, sBootName)
    -- check if it exists and is a file
    if fs.exists(sPath) and not fs.isDir(sPath) then
        -- try to load the boot
        bootFunc = getBoot(sPath)
        -- if the boot loaded
        if bootFunc ~= nil then
            -- stop searching
            break
        end
    end
end
-- try to load boot files from disks
if bootFunc == nil and bBootFromDisk then
    -- for each side
    for _,side in ipairs(rs.getSides()) do
        -- check if there's a disk drive
        if peripheral.isPresent(side) and peripheral.getType(side) == "drive" then
            -- check if it has a floppy disk
            if peripheral.call(side, "hasData") then
                -- get the disk boot path
                local sDiskPath = fs.combine(peripheral.call(side, "getMountPath"), sBootName)
                -- check if it exists and is a file
                if fs.exists(sDiskPath) and not fs.isDir(sDiskPath) then
                    -- try to load the boot
                    bootFunc = getBoot(sPath)
                    -- if the boot loaded
                    if bootFunc ~= nil then
                        -- stop searching
                        break
                    end
                end
            end
        end
    end
end

if bootFunc == nil then
    -- No boot loaded, let the user know
    print("No boot files could be loaded")
    print("Press any key to shutdown")
    coroutine.yield("key")
else
    -- try to boot
    local ok, err = pcall(bootFunc)
    -- check if there was an error
    if not ok then
        -- show the error
        clear()
        print(err)
        print("Press any key to continue")
        coroutine.yield("key")
    end
end

os.shutdown() -- just in case