From 4ca4a3f954b2a2df17a6aaf0ccf77fafccd65d7e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Renault?= <clement@meilisearch.com>
Date: Wed, 5 Jun 2024 15:06:57 -0400
Subject: [PATCH] Make the CboRoaringBitmapCodec support intersection on
 deserialization

---
 .../cbo_roaring_bitmap_codec.rs               | 20 ++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/milli/src/heed_codec/roaring_bitmap/cbo_roaring_bitmap_codec.rs b/milli/src/heed_codec/roaring_bitmap/cbo_roaring_bitmap_codec.rs
index 1db518c7d..a04698019 100644
--- a/milli/src/heed_codec/roaring_bitmap/cbo_roaring_bitmap_codec.rs
+++ b/milli/src/heed_codec/roaring_bitmap/cbo_roaring_bitmap_codec.rs
@@ -1,5 +1,5 @@
 use std::borrow::Cow;
-use std::io;
+use std::io::{self, Cursor};
 use std::mem::size_of;
 
 use byteorder::{NativeEndian, ReadBytesExt, WriteBytesExt};
@@ -57,6 +57,24 @@ impl CboRoaringBitmapCodec {
         }
     }
 
+    pub fn intersection_with_serialized(
+        mut bytes: &[u8],
+        other: &RoaringBitmap,
+    ) -> io::Result<RoaringBitmap> {
+        // See above `deserialize_from` method for implementation details.
+        if bytes.len() <= THRESHOLD * size_of::<u32>() {
+            let mut bitmap = RoaringBitmap::new();
+            while let Ok(integer) = bytes.read_u32::<NativeEndian>() {
+                if other.contains(integer) {
+                    bitmap.insert(integer);
+                }
+            }
+            Ok(bitmap)
+        } else {
+            other.intersection_with_serialized_unchecked(Cursor::new(bytes))
+        }
+    }
+
     /// Merge serialized CboRoaringBitmaps in a buffer.
     ///
     /// if the merged values length is under the threshold, values are directly