-- Copyright (C) 1997-2016 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_string.lua

	Contains a few convenient string utility functions which are not supported in

	Lua or not supported as intended.

]]

-- Performs a non-pattern based substring search of one string in another

-- string. It's of O(n^2) complexity. It returns nil if the result cannot be

-- found, otherwise it returns the starting index of the first found occurrence.

string.indexOf = function(str, substr)

	local pos = 1

	local i = 1

	for i = 1, str:len(), 1 do

		if str:sub(i, i) == substr:sub(pos, pos) then

			-- have we matched the complete string?

			if pos == substr:len() then

				return i - pos + 1-- starting pos

			end

			-- matched character...keep going

			pos = pos + 1

		else

			-- restart, no match

			pos = 0

		end

	end

	if pos == substr:len() then

		return i - pos + 1

	end

	return nil -- no match

end

-- This is a public-access version of the explode function defined below.

function explode(str, delim)

	return str:explode(delim)

end

-- Explodes a string into an array of elements, separated by a non-pattern

-- delimiter. This function is part of the string table, allowing for a

-- member-based invocation for strings.

string.explode = function(str, delim)

	local exploded = { }

	local needle = string.find(str, delim)

	while needle ~= nil do

		table.insert(exploded, string.sub(str, 0, needle - 1))

		str = string.sub(str, needle + 1)

		needle = string.find(str, delim)

	end

	table.insert(exploded, str)

	return exploded

end

-- Similar to table.concat, except it supports more advanced token pasting. This

-- function is vastly used by the main meta-build script (premake4.lua) to

-- generate all the main lines of code for various tables that need to be in the

-- generated lua file.

--  - tbl: table of values to implode into a string

--  - prefix: string to paste before entire result

--  - pre: string to always paste before each entry in table

--  - post: string to always paste after each entry in table

--  - join: string to paste between entries (inclusive)

--  - suffix: string to paste after entire result

-- Returns the imploded string.

function implode(tbl, prefix, pre, post, join, suffix)

	local result = ""

	-- not the most efficient way to do this, but...

	local itbl = { }

	for k,v in pairs(tbl) do

		itbl[#itbl + 1] = v

	end

	for i = 1, #itbl, 1 do

		if pre ~= nil then

			result = result .. pre

		end

		result = result .. itbl[i]

		if post ~= nil then

			result = result .. post

		end

		if i ~= #itbl then

			result = result .. join

		end

	end

	if prefix ~= nil then

		result = prefix .. result

	end

	if suffix ~= nil then

		result = result .. suffix

	end

	return result

end