Re: how to use lmem.h ?

[Mark Hamburg <mark@...>]

One other thing to note about my recycled buffer approach:

Unless you need it for something else, you could set the environment  
on the C function to be a weak table and then just access the value at  
a fixed integer index. The size should be obtained from the userdata  
to make this all multi-universe friendly. My first round of code here  
wasn't multi-universe friendly since it used a global for the size.

	lua_rawgeti( L, LUA_ENVIRONINDEX, 1 );
	
	size = lua_objlen( L, -1 );

	if( size < needSize ) {
		lua_pop( L, 1 );
		buf = lua_newuserdata( L, needSize );
		lua_pushvalue( L, -1 );
		lua_rawseti( L, LUA_ENVIRONINDEX, 1 );
	} else {
		buf = lua_touserdata( L, -1 );
	}

That could obviously be wrapped up in a utility function.

One other thing to do is to inflate need size if we actually do an  
allocation to make it less likely that we will have to come back  
around and do another allocation. For example, one might insist that  
it be at least 256 and a power of two up to 4096 at which point it  
needs to be a multiple of 4096. (Actually, one would probably want to  
do this with some knowledge of Lua's overhead on userdata size and the  
behavior of the underlying memory allocator. For example, we might  
actually want to be just a bit shy of these values.)

Mark