premake/util/sdl_string.lua
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     1 -- Copyright (C) 1997-2011 Sam Lantinga <slouken@libsdl.org>
       
     2 --
       
     3 -- This software is provided 'as-is', without any express or implied
       
     4 -- warranty.  In no event will the authors be held liable for any damages
       
     5 -- arising from the use of this software.
       
     6 --
       
     7 -- Permission is granted to anyone to use this software for any purpose,
       
     8 -- including commercial applications, and to alter it and redistribute it
       
     9 -- freely.
       
    10 --
       
    11 -- Meta-build system using premake created and maintained by
       
    12 -- Benjamin Henning <b.henning@digipen.edu>
       
    13 
       
    14 --[[
       
    15 sdl_string.lua
       
    16 
       
    17 	Contains a few convenient string utility functions which are not supported in
       
    18 	Lua or not supported as intended.
       
    19 ]]
       
    20 
       
    21 -- Performs a non-pattern based substring search of one string in another
       
    22 -- string. It's of O(n^2) complexity. It returns nil if the result cannot be
       
    23 -- found, otherwise it returns the starting index of the first found occurrence.
       
    24 string.indexOf = function(str, substr)
       
    25 	local pos = 1
       
    26 	local i = 1
       
    27 	for i = 1, str:len(), 1 do
       
    28 		if str:sub(i, i) == substr:sub(pos, pos) then
       
    29 			-- have we matched the complete string?
       
    30 			if pos == substr:len() then
       
    31 				return i - pos + 1-- starting pos
       
    32 			end
       
    33 			-- matched character...keep going
       
    34 			pos = pos + 1
       
    35 		else
       
    36 			-- restart, no match
       
    37 			pos = 0
       
    38 		end
       
    39 	end
       
    40 	if pos == substr:len() then
       
    41 		return i - pos + 1
       
    42 	end
       
    43 	return nil -- no match
       
    44 end
       
    45 
       
    46 -- This is a public-access version of the explode function defined below.
       
    47 function explode(str, delim)
       
    48 	return str:explode(delim)
       
    49 end
       
    50 
       
    51 -- Explodes a string into an array of elements, separated by a non-pattern
       
    52 -- delimiter. This function is part of the string table, allowing for a
       
    53 -- member-based invocation for strings.
       
    54 string.explode = function(str, delim)
       
    55 	local exploded = { }
       
    56 	local needle = string.find(str, delim)
       
    57 	while needle ~= nil do
       
    58 		table.insert(exploded, string.sub(str, 0, needle - 1))
       
    59 		str = string.sub(str, needle + 1)
       
    60 		needle = string.find(str, delim)
       
    61 	end
       
    62 	table.insert(exploded, str)
       
    63 	return exploded
       
    64 end
       
    65 
       
    66 -- Similar to table.concat, except it supports more advanced token pasting. This
       
    67 -- function is vastly used by the main meta-build script (premake4.lua) to
       
    68 -- generate all the main lines of code for various tables that need to be in the
       
    69 -- generated lua file.
       
    70 --  - tbl: table of values to implode into a string
       
    71 --  - prefix: string to paste before entire result
       
    72 --  - pre: string to always paste before each entry in table
       
    73 --  - post: string to always paste after each entry in table
       
    74 --  - join: string to paste between entries (inclusive)
       
    75 --  - suffix: string to paste after entire result
       
    76 -- Returns the imploded string.
       
    77 function implode(tbl, prefix, pre, post, join, suffix)
       
    78 	local result = ""
       
    79 	-- not the most efficient way to do this, but...
       
    80 	local itbl = { }
       
    81 	for k,v in pairs(tbl) do
       
    82 		itbl[#itbl + 1] = v
       
    83 	end
       
    84 	for i = 1, #itbl, 1 do
       
    85 		if pre ~= nil then
       
    86 			result = result .. pre
       
    87 		end
       
    88 		result = result .. itbl[i]
       
    89 		if post ~= nil then
       
    90 			result = result .. post
       
    91 		end
       
    92 		if i ~= #itbl then
       
    93 			result = result .. join
       
    94 		end
       
    95 	end
       
    96 	if prefix ~= nil then
       
    97 		result = prefix .. result
       
    98 	end
       
    99 	if suffix ~= nil then
       
   100 		result = result .. suffix
       
   101 	end
       
   102 	return result
       
   103 end