undo scratch alloc change

alloc.d

@@ -10,14 +10,14 @@ import core.stdc.string : memset;
 import core.memory;
 
 static Scratch g_scratch;
+static u64     g_scratch_index;
 
 const DEFAULT_ALIGNMENT = (void *).sizeof * 2;
 
 struct Scratch
 {
-	Arena[] arenas;
-	u64     index;
-	bool    init;
+	Arena arena;
+	bool  init;
 }
 
 struct ArenaPool
@@ -189,34 +189,25 @@ Free(T)(T* ptr)
 }
 
 void
-ResetScratch(u64 size, u64 count)
+ResetScratch(u64 size)
 {
-	with(g_scratch)
+	if(!g_scratch.init)
 	{
-		if(!init)
-		{
-			arenas = AllocArray!(Arena)(count);
-			for(u64 i = 0; i < count; i += 1)
-			{
-				arenas[i] = CreateArena(size);
-			}
-
-			g_scratch.init = true;
-		}
-
-		index = index % count;
-		Reset(&arenas[index]);
+		g_scratch.arena = CreateArena(size);
+		g_scratch.init = true;
 	}
+
+	Reset(&g_scratch.arena);
 }
 
 T*
 ScratchAlloc(T)()
 {
-	return Alloc!(T)(&g_scratch.arenas[g_scratch.index]);
+	return Alloc!(T)(&g_scratch.arena);
 }
 
 T[]
 ScratchAlloc(T)(u64 count)
 {
-	return AllocArray!(T)(&g_scratch.arenas[g_scratch.index], count);
+	return AllocArray!(T)(&g_scratch.arena, count);
 }