From 3740bd8ebfddd50f12dfab44a19269a86dba08a5 2020-02-14 11:46:13
From: Christopher Esterhuyse <christopher.esterhuyse@gmail.com>
Date: 2020-02-14 11:46:13
Subject: [PATCH] trying out a matrix representation for components

---

diff --git a/src/runtime/ecs.rs b/src/runtime/ecs.rs
index 184e8eadaeb5e0ba67bd8628ac3568fe4bb311bf..b9f6ce444bceb163f8a742ef50ddc769d42f8c0e 100644
--- a/src/runtime/ecs.rs
+++ b/src/runtime/ecs.rs
@@ -75,9 +75,6 @@ impl BitSet {
     }
 }
 
-#[derive(Debug, Default)]
-struct BitMasks(HashMap<(ChannelId, bool), BitSet>);
-
 struct BitChunkIter<I: Iterator<Item = u32>> {
     chunk_iter: I,
     next_bit_index: usize,
@@ -158,44 +155,6 @@ impl Iterator for AndChunkIter<'_> {
     }
 }
 
-/// Returns an iterator over chunks for bits in range 0..bits_to_go but skipping
-/// indices for which ANY of the given bitsets has a 1
-struct NoneChunkIter<'a> {
-    // this value is not overwritten during iteration
-    // invariant: !sets.is_empty()
-    sets: &'a [&'a [u32]],
-    next_chunk_index: usize,
-    bits_to_go: usize,
-}
-impl<'a> NoneChunkIter<'a> {
-    /// a set of bitsets. the u32s of each are in ascending order of significant digits
-    /// i.e., &[0,1] means {1<<32, 0} while &[0,1] is identical to &[1] and means {1}.
-    fn new(sets: &'a [&'a [u32]], max_bit: usize) -> Self {
-        let sets = if sets.is_empty() { &[&[] as &[_]] } else { sets };
-        Self { sets, next_chunk_index: 0, bits_to_go: max_bit }
-    }
-}
-impl Iterator for NoneChunkIter<'_> {
-    type Item = u32;
-    fn next(&mut self) -> Option<u32> {
-        let neutral = match self.bits_to_go {
-            0 => None,
-            x @ 1..=31 => Some(!0u32 >> (32 - x)),
-            _ => Some(!0u32),
-        };
-        self.bits_to_go = self.bits_to_go.saturating_sub(32);
-
-        let old_chunk_index = self.next_chunk_index;
-        self.next_chunk_index += 1;
-
-        self.sets.iter().fold(neutral, move |a, b| {
-            let a = a?;
-            let b = *b.get(old_chunk_index)?;
-            Some(a & !b)
-        })
-    }
-}
-
 #[test]
 fn test_bit_iter() {
     static SETS: &[&[u32]] = &[
@@ -203,8 +162,7 @@ fn test_bit_iter() {
         &[0b101001, 0b101001],
         &[0b100001, 0b101001],
     ];
-    let _ = BitChunkIter::new(AndChunkIter::new(SETS));
-    let iter = BitChunkIter::new(NoneChunkIter::new(SETS, 9));
+    let iter = BitChunkIter::new(AndChunkIter::new(SETS));
     let indices = iter.collect::<Vec<_>>();
     println!("indices {:?}", indices);
 }