/*

	Title: Tar Library
	License: v0.73 by Oberon under terms of GNU GPLv3 <http://www.gnu.org/licenses/gpl-3.0.txt>
	
	Function: tar_extract
		Get the content of a file from a tar archive.
	
	Function: tar_save
		Save a resource within a tar archive to a local file.
	
	Function: tar_delete
		Remove a file and its contents from a tar archive.
	
	Function: tar_add
		Create or update a file in a tar archive.
	
	Function: tar_list
		Get a list of files and their details from a tar archive.

*/
tar_extract(source, file, ByRef var) {
	Return, _tar(source, var, 1, file)
}
tar_save(source, file, saveas) {
	Return, _tar(null, source, 2, file, saveas)
}
tar_delete(source, file) {
	Return, _tar(source, void, 3, file)
}
tar_add(source, file, ByRef content) {
	Return, _tar(source, content, 4, file)
}
tar_list(source, ByRef var) {
	Return, _tar(source, var, 5)
}

_tar(t, ByRef d, m = 1, p1 = "", p2 = "") {
	; enum m { extract = 1, save = 2, delete = 3, add = 4, list = 5 }
	If t is xdigit
		y := t & 0xffff, t >>= 16
	Else {
		FileRead, t, *c %t%
		s := &t, y := VarSetCapacity(t), f := 1
	}
	k = 1
	c = 0
	Loop, % y // 512 {
		If (--k > 0)
			Continue
		_tar_v(n, s, 100), _tar_v(xr1, s + 124, 12), _tar_v(xr2, s + 136, 12), _tar_v(e, s + 257, 5)
		Loop, 2 {
			i := A_Index, x%i% := 0
			Loop, Parse, xr%A_Index%
				x%i% += A_LoopField * 8 ** (11 - A_Index)
		}
		If (m == 1 and n == p1)
			Return, _tar_v(d, s + 512, x1) . x1
		Else If (m == 2 and n == p1)
			Return, _tar_v(x0, s + 512, x1) . _tar_f(x0, p2, x1)
		Else If (m == 3 and n == p1)
			Return, DllCall("RtlMoveMemory", "UInt", s, "UInt", s + x0 := 512 * (1 + Ceil(x1 / 512)), "UInt", y -= x0)
				. (f ? _tar_f(t, r, y) : VarSetCapacity(d, y) . _tar_v(t, &d, y) . d := "")
		Else If m = 5
		{
			x0 = 19700101
			x0 += x2, s
			d = %d%%n%,%x1%,%x0%`n
			c++
		}
		k := 1 + Ceil(x1 / 512), s += k * 512
	}
	Return, c
}
_tar_v(ByRef v, s, l) {
	VarSetCapacity(v, l), DllCall("RtlMoveMemory", "UInt", &v, "UInt", s, "UInt", l), VarSetCapacity(v, -1)
}
_tar_f(ByRef c, f, s) {
	h := DllCall("CreateFile", "Str", f, "UInt", 0x40000000, "UInt", 1, "UInt", 0, "UInt", 2, "UInt", 0, "UInt", 0)
		, DllCall("WriteFile", "UInt", h, "UInt", &c, "UInt", s, "UIntP", c, "UInt", 0)
	Return, DllCall("CloseHandle", "UInt", h) ? c : 0
}