-- Copyright (C) 1997-2011 Sam Lantinga <slouken@libsdl.org>

--

-- This software is provided 'as-is', without any express or implied

-- warranty.  In no event will the authors be held liable for any damages

-- arising from the use of this software.

--

-- Permission is granted to anyone to use this software for any purpose,

-- including commercial applications, and to alter it and redistribute it

-- freely.

--

-- Meta-build system using premake created and maintained by

-- Benjamin Henning <b.henning@digipen.edu>

--[[

sdl_file.lua

	This function contains a wrapper for the I/O file operations, providing a few

	custom functions which simplify the file I/O process (especially useful for

	the vast amount of generation used by the meta-build system).

]]

-- Given a filename and open mode (look at io.open for more information), opens

-- the file with various contained functions for printing to the file, writing

-- to the file, reading from the file, or closing the file. If the filename is

-- nil, then this will open a file in a special text mode. In that case, the

-- mode is ignored. Returned is an instanced table with all of the

-- aforementioned functions.

--

-- The print function is associated with textprint/fileprint, the write function

-- with textwrite/filewrite, the read function with fileread, and the close

-- function with textclose/fileclose.

function fileopen(file, mode)

	if file == nil then

		return { texth = "", print = textprint, write = textwrite, read = nil, close = textclose }

	else

		return { fileh = io.open(file, mode), print = fileprint, write = filewrite, read = fileread, close = fileclose }

	end

end

-- Given a filename and file mode, reads the entire contents of the file and

-- returns the contents as a string.

function readfile(file, mode)

	local file = fileopen(file, mode)

	local content = file:read()

	file:close()

	return content

end

-- Given a file, the number of tabs to indent, and a line to print, append the

-- line tabbed n times with an appended newline to the end of the input text.

function textprint(f, tabs, line)

	for i = 0, tabs - 1, 1 do

		f.texth = f.texth .. "\t"

	end

	f.texth = f.texth .. line .. "\n"

end

-- Given a file, the number of tabs to indent, and a line to print, append the

-- line tabbed n times with an appended newline to the end of the input file.

function fileprint(f, tabs, line)

	for i = 0, tabs - 1, 1 do

		f.fileh:write("\t")

	end

	f.fileh:write(line .. "\n")

end

-- Given a file and some text, append the text to the end of the input text.

function textwrite(f, text)

	f.texth = f.texth .. text

end

-- Given a file and some text, append the text to the end of the input file.

function filewrite(f, text)

	f.fileh:write(text)

end

-- Given a file, read all the contents of the file and return them as a string.

function fileread(file)

	return file.fileh:read("*all")

end

-- Given a file opened in text mode, return the result of the current file

-- operations as a text string.

function textclose(file)

	return file.texth

end

-- Given a file opened regularly, close the file handle resource, preventing

-- any future I/O operations.

function fileclose(file)

	file.fileh:close()

end

-- Given a source path, builds a table containing all directories and recursive

-- subdirectories which contain files, and returns the table. Each entry in the

-- table will have a '/' at the end of its path, plus they will all be relative

-- to the parent source path. The table will contain a single entry with the

-- value '/' to indicate the source path itself.

function createDirTable(sourcePath)

	local dirs = os.matchdirs(sourcePath.."/**")

	for k,d in pairs(dirs) do

		dirs[k] = string.sub(d, #sourcePath + 1) .. "/"

	end

	table.insert(dirs, "/")

	return dirs

end

-- This works like os.pathsearch, but for directories. Look at the premake

-- documentation for os.pathsearch for more information.

os.dirpathsearch = function(subdir, path, path_delimiter)

	for i,p in ipairs(explode(path, path_delimiter)) do

		local needle = p .. "/" .. subdir

		if os.isdir(needle) then

			return needle

		end

	end

	return nil

end

-- Given a variable number of environmental variable names, this will join them

-- together based on the current OS path delimeter and quietly ignoring those

-- variables which do not exist on this system. The resulting path is always

-- normalized for Unix-based path separators, regardless of the system.

os.getenvpath = function(...)

	local path = ""

	local pathDelimeter = ":"

	if os.is("windows") then

		pathDelimeter = ";"

	end

	for i,a in ipairs(arg) do

		local value = os.getenv(a)

		if value then

			if #path > 0 then

				path = path .. pathDelimeter

			end

			path = path .. value

		end

	end

	-- normalize path to unix

	return path:gsub("\\", "/"):gsub("//", "/")

end