Issue/range query (#242)

BitSet and RangeQuery

1 files changed, 63 insertions, 1 deletions

diff --git a/src/query/scorer.rs b/src/query/scorer.rs
index 170e6aa..2cbeb00 100644
--- a/src/query/scorer.rs
+++ b/src/query/scorer.rs
@@ -2,6 +2,8 @@ use DocSet;
 use DocId;
 use Score;
 use collector::Collector;
+use postings::SkipResult;
+use common::BitSet;
 use std::ops::{Deref, DerefMut};
 
 /// Scored set of documents matching a query within a specific segment.
@@ -49,7 +51,7 @@ impl DocSet for EmptyScorer {
         DocId::max_value()
     }
 
-    fn size_hint(&self) -> usize {
+    fn size_hint(&self) -> u32 {
         0
     }
 }
@@ -59,3 +61,63 @@ impl Scorer for EmptyScorer {
         0f32
     }
 }
+
+
+/// Wraps a `DocSet` and simply returns a constant `Scorer`.
+/// The `ConstScorer` is useful if you have a `DocSet` where
+/// you needed a scorer.
+///
+/// The `ConstScorer`'s constant score can be set
+/// by calling `.set_score(...)`.
+pub struct ConstScorer<TDocSet: DocSet> {
+    docset: TDocSet,
+    score: Score,
+}
+
+impl<TDocSet: DocSet> ConstScorer<TDocSet> {
+
+    /// Creates a new `ConstScorer`.
+    pub fn new(docset: TDocSet) -> ConstScorer<TDocSet> {
+        ConstScorer {
+            docset,
+            score: 1f32,
+        }
+    }
+
+    /// Sets the constant score to a different value.
+    pub fn set_score(&mut self, score: Score) {
+        self.score = score;
+    }
+}
+
+impl<TDocSet: DocSet> DocSet for ConstScorer<TDocSet> {
+    fn advance(&mut self) -> bool {
+        self.docset.advance()
+    }
+
+    fn skip_next(&mut self, target: DocId) -> SkipResult {
+        self.docset.skip_next(target)
+    }
+
+    fn fill_buffer(&mut self, buffer: &mut [DocId]) -> usize {
+        self.docset.fill_buffer(buffer)
+    }
+
+    fn doc(&self) -> DocId {
+        self.docset.doc()
+    }
+
+    fn size_hint(&self) -> u32 {
+        self.docset.size_hint()
+    }
+
+    fn append_to_bitset(&mut self, bitset: &mut BitSet) {
+        self.docset.append_to_bitset(bitset);
+    }
+}
+
+impl<TDocSet: DocSet> Scorer for ConstScorer<TDocSet> {
+    fn score(&self) -> Score {
+        1f32
+    }
+}