Port to using the newer graph, which offers iterators instead of the

older `each` method, but is otherwise identical.

1 files changed, 32 insertions, 0 deletions

diff --git a/src/librustc_data_structures/bitvec.rs b/src/librustc_data_structures/bitvec.rs
new file mode 100644
index 00000000000..f5924ef5a3f
--- /dev/null
+++ b/src/librustc_data_structures/bitvec.rs
@@ -0,0 +1,32 @@
+use std::iter;
+
+/// A very simple BitVector type.
+pub struct BitVector {
+    data: Vec<u64>
+}
+
+impl BitVector {
+    pub fn new(num_bits: usize) -> BitVector {
+        let num_words = (num_bits + 63) / 64;
+        BitVector { data: iter::repeat(0).take(num_words).collect() }
+    }
+
+    fn word_mask(&self, bit: usize) -> (usize, u64) {
+        let word = bit / 64;
+        let mask = 1 << (bit % 64);
+        (word, mask)
+    }
+
+    pub fn contains(&self, bit: usize) -> bool {
+        let (word, mask) = self.word_mask(bit);
+        (self.data[word] & mask) != 0
+    }
+
+    pub fn insert(&mut self, bit: usize) -> bool {
+        let (word, mask) = self.word_mask(bit);
+        let data = &mut self.data[word];
+        let value = *data;
+        *data = value | mask;
+        (value | mask) != value
+    }
+}