Report statistics byte counts in bytes

fuzz/fuzz_targets/arbitrary_ops/mod.rs

@@ -190,12 +190,12 @@ impl ReadBitmapOperation {
                     v.n_values_run_containers =
                         expected.n_values_run_containers.try_into().unwrap();
                     v.n_values_bitset_containers = expected.n_values_bitset_containers.into();
-                    // The n_bytes_* fields are not directly comparable:
-                    // they are based on the number of bytes of _capacity_ of the
-                    // containers, which depends on the allocation strategy.
+                    // n_bytes_array_containers is not directly comparable:
+                    // it is based on the _capacity_ of the array containers,
+                    // which depends on the allocation strategy.
                     // v.n_bytes_array_containers = expected.n_bytes_array_containers.into();
-                    // v.n_bytes_run_containers = expected.n_bytes_run_containers.into();
-                    // v.n_bytes_bitset_containers = expected.n_bytes_bitset_containers.into();
+                    v.n_bytes_run_containers = expected.n_bytes_run_containers.into();
+                    v.n_bytes_bitset_containers = expected.n_bytes_bitset_containers.into();
                     v.max_value = x.maximum();
                     v.min_value = x.minimum();
                     v.cardinality = x.cardinality();

roaring/src/bitmap/statistics.rs

@@ -3,7 +3,7 @@ use core::mem;
 use crate::bitmap::container::Container;
 use crate::RoaringBitmap;
 
-use super::store::Store;
+use super::store::{Store, BITMAP_BYTES};
 
 /// Detailed statistics on the composition of a bitmap.
 #[derive(Clone, Copy, PartialEq, Debug)]
@@ -53,7 +53,7 @@ impl RoaringBitmap {
     /// assert_eq!(statistics.n_values_array_containers, 99);
     /// assert_eq!(statistics.n_values_run_containers, 0);
     /// assert_eq!(statistics.n_values_bitset_containers, 0);
-    /// assert_eq!(statistics.n_bytes_array_containers, 512);
+    /// assert_eq!(statistics.n_bytes_array_containers, 256);
     /// assert_eq!(statistics.n_bytes_run_containers, 0);
     /// assert_eq!(statistics.n_bytes_bitset_containers, 0);
     /// assert_eq!(statistics.max_value, Some(99));
@@ -78,13 +78,13 @@ impl RoaringBitmap {
                 Store::Array(array) => {
                     cardinality += array.len();
                     n_values_array_containers += array.len() as u32;
-                    n_bytes_array_containers += (array.capacity() * mem::size_of::<u32>()) as u64;
+                    n_bytes_array_containers += (array.capacity() * mem::size_of::<u16>()) as u64;
                     n_array_containers += 1;
                 }
                 Store::Bitmap(bitmap) => {
                     cardinality += bitmap.len();
                     n_values_bitset_containers += bitmap.len();
-                    n_bytes_bitset_containers += bitmap.capacity() as u64;
+                    n_bytes_bitset_containers += BITMAP_BYTES as u64;
                     n_bitset_containers += 1;
                 }
                 Store::Run(runs) => {

roaring/src/bitmap/store/bitmap_store.rs

@@ -28,10 +28,6 @@ impl BitmapStore {
         BitmapStore { len: 0, bits: Box::new([0; BITMAP_LENGTH]) }
     }
 
-    pub fn capacity(&self) -> usize {
-        BITMAP_LENGTH * u64::BITS as usize
-    }
-
     pub fn try_from(len: u64, bits: Box<[u64; BITMAP_LENGTH]>) -> Result<BitmapStore, Error> {
         let actual_len = bits.iter().map(|v| v.count_ones() as u64).sum();
         if len != actual_len {

roaring/tests/lib.rs

@@ -167,3 +167,11 @@ fn statistics_full_run() {
     assert_eq!(stats.cardinality, expected);
     assert_eq!(stats.n_values_run_containers, expected);
 }
+
+#[test]
+fn statistics_bitset_bytes() {
+    let bitmap = RoaringBitmap::from_iter((0..10_000).map(|v| v * 2));
+    let stats = bitmap.statistics();
+    assert_eq!(stats.n_bitset_containers, 1);
+    assert_eq!(stats.n_bytes_bitset_containers, 8192);
+}