# HG changeset patch
# User Matthew Wild <mwild1@gmail.com>
# Date 1334791775 -3600
# Node ID cefa0be5f567f01f8835054f93241020293ee22f
# Parent  b7590015016714c17449da26eb2371a9013d3c3f
Add examples/luastate.lua from http://article.gmane.org/gmane.comp.lang.lua.general/90539

diff -r b75900150167 -r cefa0be5f567 examples/luastate.lua
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/luastate.lua	Thu Apr 19 00:29:35 2012 +0100
@@ -0,0 +1,131 @@
+-- Copyright (c) 2011-2012 by Robert G. Jakabosky <bobby@neoawareness.com>
+--
+-- Permission is hereby granted, free of charge, to any person obtaining a copy
+-- of this software and associated documentation files (the "Software"), to deal
+-- in the Software without restriction, including without limitation the rights
+-- to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+-- copies of the Software, and to permit persons to whom the Software is
+-- furnished to do so, subject to the following conditions:
+--
+-- The above copyright notice and this permission notice shall be included in
+-- all copies or substantial portions of the Software.
+--
+-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+-- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+-- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+-- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+-- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+-- THE SOFTWARE.
+
+local ltraverse = require"traverse"
+local sformat = string.format
+local have_getsize = false
+local getsize = function()
+	return 0
+end
+if not jit then
+	getsize = require"getsize"
+	have_getsize = true
+end
+
+local _M = {}
+
+function _M.dump_stats(file)
+	local type_cnts = {}
+	local function type_inc(t)
+		type_cnts[t] = (type_cnts[t] or 0) + 1
+	end
+	local type_mem = {}
+	local function type_mem_inc(v)
+		if not have_getsize then return end
+		local t = type(v)
+		local s = getsize(v)
+		type_mem[t] = (type_mem[t] or 0) + s
+	end
+	-- build metatable->type map for userdata type detection.
+	local ud_types = {}
+	local reg = debug.getregistry()
+	for k,v in pairs(reg) do
+		if type(k) == 'string' and type(v) == 'table' then
+			ud_types[v] = k
+		end
+	end
+	local function ud_type(ud)
+		return ud_types[debug.getmetatable(ud)] or "<unknown>"
+	end
+	local str_data = 0
+	local funcs = {
+	["edge"] = function(from, to, how, name)
+		type_inc"edges"
+	end,
+	["table"] = function(v)
+		type_inc"table"
+		type_mem_inc(v)
+	end,
+	["string"] = function(v)
+		type_inc"string"
+		str_data = str_data + #v
+		type_mem_inc(v)
+	end,
+	["userdata"] = function(v)
+		type_inc"userdata"
+		type_inc(ud_type(v))
+		type_mem_inc(v)
+	end,
+	["cdata"] = function(v)
+		type_inc"cdata"
+	end,
+	["func"] = function(v)
+		type_inc"function"
+		type_mem_inc(v)
+	end,
+	["thread"] = function(v)
+		type_inc"thread"
+		type_mem_inc(v)
+	end,
+	}
+	local ignores = {}
+	for k,v in pairs(funcs) do
+		ignores[#ignores + 1] = k
+		ignores[#ignores + 1] = v
+	end
+	ignores[#ignores + 1] = type_cnts
+	ignores[#ignores + 1] = funcs
+	ignores[#ignores + 1] = ignores
+
+	ltraverse.traverse(funcs, ignores)
+
+	local fd = file
+	if type(file) == 'string' then
+		fd = io.open(filename, "w")
+	end
+	fd:write(sformat("memory = %i bytes\n", collectgarbage"count" * 1024))
+	fd:write(sformat("str_data = %i\n", str_data))
+	fd:write(sformat("object type counts:\n"))
+	for t,cnt in pairs(type_cnts) do
+		fd:write(sformat("  %9s = %9i\n", t, cnt))
+	end
+	fd:write("\n")
+	if have_getsize then
+		fd:write(sformat("per type memory usage:\n"))
+		local total = 0
+		for t,mem in pairs(type_mem) do
+			total = total + mem
+			fd:write(sformat("  %9s = %9i bytes\n", t, mem))
+		end
+		fd:write(sformat("total: %9i bytes\n", total))
+		fd:write("\n")
+	end
+	--[[
+	fd:write("LUA_REGISTRY dump:\n")
+	for k,v in pairs(reg) do
+		fd:write(tostring(k),'=', tostring(v),'\n')
+	end
+	--]]
+	if type(file) == 'string' then
+		fd:close()
+	end
+end
+
+return _M