Remove forgotten code.

- Added proptest
- Added comment to Lemire blog post.

CHANGELOG.md

@@ -9,6 +9,10 @@ Tantivy 0.14.0
 - Bugfix in `Query::explain`
 - Removed dependency on `notify` #924. Replaced with `FileWatcher` struct that polls meta file every 500ms in background thread. (@halvorboe @guilload)
 - Added `FilterCollector`, which wraps another collector and filters docs using a predicate over a fast field (@barrotsteindev)
+- Simplified the encoding of the skip reader struct. BlockWAND max tf is now encoded over a single byte. (@pmasurel)
+- `FilterCollector` now supports all Fast Field value types (@barrotsteindev)
+
+This version breaks compatibility and requires users to reindex everything.
 
 Tantivy 0.13.2
 ===================

Cargo.toml

@@ -26,7 +26,6 @@ snap = "1"
 tempfile = {version="3", optional=true}
 log = "0.4"
 serde = {version="1", features=["derive"]}
-serde_cbor = "0.11"
 serde_json = "1"
 num_cpus = "1"
 fs2={version="0.4", optional=true}

src/collector/filter_collector_wrapper.rs

@@ -9,8 +9,10 @@
 
 // ---
 // Importing tantivy...
+use std::marker::PhantomData;
+
 use crate::collector::{Collector, SegmentCollector};
-use crate::fastfield::FastFieldReader;
+use crate::fastfield::{FastFieldReader, FastValue};
 use crate::schema::Field;
 use crate::{Score, SegmentReader, TantivyError};
 
@@ -41,78 +43,104 @@ use crate::{Score, SegmentReader, TantivyError};
 ///
 /// let query_parser = QueryParser::for_index(&index, vec![title]);
 /// let query = query_parser.parse_query("diary").unwrap();
-/// let no_filter_collector = FilterCollector::new(price, &|value| value > 20_120u64, TopDocs::with_limit(2));
+/// let no_filter_collector = FilterCollector::new(price, &|value: u64| value > 20_120u64, TopDocs::with_limit(2));
 /// let top_docs = searcher.search(&query, &no_filter_collector).unwrap();
 ///
 /// assert_eq!(top_docs.len(), 1);
 /// assert_eq!(top_docs[0].1, DocAddress(0, 1));
 ///
-/// let filter_all_collector = FilterCollector::new(price, &|value| value < 5u64, TopDocs::with_limit(2));
+/// let filter_all_collector: FilterCollector<_, _, u64> = FilterCollector::new(price, &|value| value < 5u64, TopDocs::with_limit(2));
 /// let filtered_top_docs = searcher.search(&query, &filter_all_collector).unwrap();
 ///
 /// assert_eq!(filtered_top_docs.len(), 0);
 /// ```
-pub struct FilterCollector<TCollector, TPredicate>
+pub struct FilterCollector<TCollector, TPredicate, TPredicateValue: FastValue>
 where
     TPredicate: 'static,
 {
     field: Field,
     collector: TCollector,
     predicate: &'static TPredicate,
+    t_predicate_value: PhantomData<TPredicateValue>,
 }
 
-impl<TCollector, TPredicate> FilterCollector<TCollector, TPredicate>
+impl<TCollector, TPredicate, TPredicateValue: FastValue>
+    FilterCollector<TCollector, TPredicate, TPredicateValue>
 where
     TCollector: Collector + Send + Sync,
-    TPredicate: Fn(u64) -> bool + Send + Sync,
+    TPredicate: Fn(TPredicateValue) -> bool + Send + Sync,
 {
     /// Create a new FilterCollector.
     pub fn new(
         field: Field,
         predicate: &'static TPredicate,
         collector: TCollector,
-    ) -> FilterCollector<TCollector, TPredicate> {
+    ) -> FilterCollector<TCollector, TPredicate, TPredicateValue> {
         FilterCollector {
             field,
             predicate,
             collector,
+            t_predicate_value: PhantomData,
         }
     }
 }
 
-impl<TCollector, TPredicate> Collector for FilterCollector<TCollector, TPredicate>
+impl<TCollector, TPredicate, TPredicateValue: FastValue> Collector
+    for FilterCollector<TCollector, TPredicate, TPredicateValue>
 where
     TCollector: Collector + Send + Sync,
-    TPredicate: 'static + Fn(u64) -> bool + Send + Sync,
+    TPredicate: 'static + Fn(TPredicateValue) -> bool + Send + Sync,
+    TPredicateValue: 'static + FastValue,
 {
     // That's the type of our result.
     // Our standard deviation will be a float.
     type Fruit = TCollector::Fruit;
 
-    type Child = FilterSegmentCollector<TCollector::Child, TPredicate>;
+    type Child = FilterSegmentCollector<TCollector::Child, TPredicate, TPredicateValue>;
 
     fn for_segment(
         &self,
         segment_local_id: u32,
         segment_reader: &SegmentReader,
-    ) -> crate::Result<FilterSegmentCollector<TCollector::Child, TPredicate>> {
+    ) -> crate::Result<FilterSegmentCollector<TCollector::Child, TPredicate, TPredicateValue>> {
+        let schema = segment_reader.schema();
+        let field_entry = schema.get_field_entry(self.field);
+        if !field_entry.is_fast() {
+            return Err(TantivyError::SchemaError(format!(
+                "Field {:?} is not a fast field.",
+                field_entry.name()
+            )));
+        }
+        let requested_type = TPredicateValue::to_type();
+        let field_schema_type = field_entry.field_type().value_type();
+        if requested_type != field_schema_type {
+            return Err(TantivyError::SchemaError(format!(
+                "Field {:?} is of type {:?}!={:?}",
+                field_entry.name(),
+                requested_type,
+                field_schema_type
+            )));
+        }
+
         let fast_field_reader = segment_reader
             .fast_fields()
-            .u64(self.field)
+            .typed_fast_field_reader(self.field)
             .ok_or_else(|| {
-                let field_name = segment_reader.schema().get_field_name(self.field);
                 TantivyError::SchemaError(format!(
-                    "Field {:?} is not a u64 fast field.",
-                    field_name
+                    "{:?} is not declared as a fast field in the schema.",
+                    self.field
                 ))
             })?;
+
         let segment_collector = self
             .collector
             .for_segment(segment_local_id, segment_reader)?;
+
         Ok(FilterSegmentCollector {
             fast_field_reader,
             segment_collector,
             predicate: self.predicate,
+            t_predicate_value: PhantomData,
         })
     }
 
@@ -128,20 +156,23 @@ where
     }
 }
 
-pub struct FilterSegmentCollector<TSegmentCollector, TPredicate>
+pub struct FilterSegmentCollector<TSegmentCollector, TPredicate, TPredicateValue>
 where
     TPredicate: 'static,
+    TPredicateValue: 'static + FastValue,
 {
-    fast_field_reader: FastFieldReader<u64>,
+    fast_field_reader: FastFieldReader<TPredicateValue>,
     segment_collector: TSegmentCollector,
     predicate: &'static TPredicate,
+    t_predicate_value: PhantomData<TPredicateValue>,
 }
 
-impl<TSegmentCollector, TPredicate> SegmentCollector
-    for FilterSegmentCollector<TSegmentCollector, TPredicate>
+impl<TSegmentCollector, TPredicate, TPredicateValue> SegmentCollector
+    for FilterSegmentCollector<TSegmentCollector, TPredicate, TPredicateValue>
 where
     TSegmentCollector: SegmentCollector,
-    TPredicate: 'static + Fn(u64) -> bool + Send + Sync,
+    TPredicate: 'static + Fn(TPredicateValue) -> bool + Send + Sync,
+    TPredicateValue: 'static + FastValue,
 {
     type Fruit = TSegmentCollector::Fruit;
 

src/collector/tests.rs

@@ -8,6 +8,13 @@ use crate::DocId;
 use crate::Score;
 use crate::SegmentLocalId;
 
+use crate::collector::{FilterCollector, TopDocs};
+use crate::query::QueryParser;
+use crate::schema::{Schema, FAST, TEXT};
+use crate::DateTime;
+use crate::{doc, Index};
+use std::str::FromStr;
+
 pub const TEST_COLLECTOR_WITH_SCORE: TestCollector = TestCollector {
     compute_score: true,
 };
@@ -16,6 +23,54 @@ pub const TEST_COLLECTOR_WITHOUT_SCORE: TestCollector = TestCollector {
     compute_score: true,
 };
 
+#[test]
+pub fn test_filter_collector() {
+    let mut schema_builder = Schema::builder();
+    let title = schema_builder.add_text_field("title", TEXT);
+    let price = schema_builder.add_u64_field("price", FAST);
+    let date = schema_builder.add_date_field("date", FAST);
+    let schema = schema_builder.build();
+    let index = Index::create_in_ram(schema);
+
+    let mut index_writer = index.writer_with_num_threads(1, 10_000_000).unwrap();
+    index_writer.add_document(doc!(title => "The Name of the Wind", price => 30_200u64, date => DateTime::from_str("1898-04-09T00:00:00+00:00").unwrap()));
+    index_writer.add_document(doc!(title => "The Diary of Muadib", price => 29_240u64, date => DateTime::from_str("2020-04-09T00:00:00+00:00").unwrap()));
+    index_writer.add_document(doc!(title => "The Diary of Anne Frank", price => 18_240u64, date => DateTime::from_str("2019-04-20T00:00:00+00:00").unwrap()));
+    index_writer.add_document(doc!(title => "A Dairy Cow", price => 21_240u64, date => DateTime::from_str("2019-04-09T00:00:00+00:00").unwrap()));
+    index_writer.add_document(doc!(title => "The Diary of a Young Girl", price => 20_120u64, date => DateTime::from_str("2018-04-09T00:00:00+00:00").unwrap()));
+    assert!(index_writer.commit().is_ok());
+
+    let reader = index.reader().unwrap();
+    let searcher = reader.searcher();
+
+    let query_parser = QueryParser::for_index(&index, vec![title]);
+    let query = query_parser.parse_query("diary").unwrap();
+    let filter_some_collector = FilterCollector::new(
+        price,
+        &|value: u64| value > 20_120u64,
+        TopDocs::with_limit(2),
+    );
+    let top_docs = searcher.search(&query, &filter_some_collector).unwrap();
+
+    assert_eq!(top_docs.len(), 1);
+    assert_eq!(top_docs[0].1, DocAddress(0, 1));
+
+    let filter_all_collector: FilterCollector<_, _, u64> =
+        FilterCollector::new(price, &|value| value < 5u64, TopDocs::with_limit(2));
+    let filtered_top_docs = searcher.search(&query, &filter_all_collector).unwrap();
+
+    assert_eq!(filtered_top_docs.len(), 0);
+
+    fn date_filter(value: DateTime) -> bool {
+        (value - DateTime::from_str("2019-04-09T00:00:00+00:00").unwrap()).num_weeks() > 0
+    }
+
+    let filter_dates_collector = FilterCollector::new(date, &date_filter, TopDocs::with_limit(5));
+    let filtered_date_docs = searcher.search(&query, &filter_dates_collector).unwrap();
+
+    assert_eq!(filtered_date_docs.len(), 2);
+}
+
 /// Stores all of the doc ids.
 /// This collector is only used for tests.
 /// It is unusable in pr

src/common/mod.rs

@@ -115,11 +115,16 @@ pub fn u64_to_i64(val: u64) -> i64 {
 /// For simplicity, tantivy internally handles `f64` as `u64`.
 /// The mapping is defined by this function.
 ///
-/// Maps `f64` to `u64` so that lexical order is preserved.
+/// Maps `f64` to `u64` in a monotonic manner, so that bytes lexical order is preserved.
 ///
 /// This is more suited than simply casting (`val as u64`)
 /// which would truncate the result
 ///
+/// # Reference
+///
+/// Daniel Lemire's [blog post](https://lemire.me/blog/2020/12/14/converting-floating-point-numbers-to-integers-while-preserving-order/)
+/// explains the mapping in a clear manner.
+///
 /// # See also
 /// The [reverse mapping is `u64_to_f64`](./fn.u64_to_f64.html).
 #[inline(always)]
@@ -148,6 +153,7 @@ pub(crate) mod test {
     pub use super::minmax;
     pub use super::serialize::test::fixed_size_test;
     use super::{compute_num_bits, f64_to_u64, i64_to_u64, u64_to_f64, u64_to_i64};
+    use proptest::prelude::*;
     use std::f64;
 
     fn test_i64_converter_helper(val: i64) {
@@ -158,6 +164,15 @@ pub(crate) mod test {
         assert_eq!(u64_to_f64(f64_to_u64(val)), val);
     }
 
+    proptest! {
+        #[test]
+        fn test_f64_converter_monotonicity_proptest((left, right) in (proptest::num::f64::NORMAL, proptest::num::f64::NORMAL)) {
+            let left_u64 = f64_to_u64(left);
+            let right_u64 = f64_to_u64(right);
+            assert_eq!(left_u64 < right_u64,  left < right);
+        }
+    }
+
     #[test]
     fn test_i64_converter() {
         assert_eq!(i64_to_u64(i64::min_value()), u64::min_value());

src/core/segment_reader.rs

@@ -310,7 +310,7 @@ impl SegmentReader {
     }
 
     /// Returns an iterator that will iterate over the alive document ids
-    pub fn doc_ids_alive<'a>(&'a self) -> impl Iterator<Item = DocId> + 'a {
+    pub fn doc_ids_alive(&self) -> impl Iterator<Item = DocId> + '_ {
         (0u32..self.max_doc).filter(move |doc| !self.is_deleted(*doc))
     }
 

src/directory/error.rs

@@ -58,7 +58,8 @@ pub enum OpenWriteError {
 }
 
 impl OpenWriteError {
-    pub(crate) fn wrap_io_error(io_error: io::Error, filepath: PathBuf) -> Self {
+    /// Wraps an io error.
+    pub fn wrap_io_error(io_error: io::Error, filepath: PathBuf) -> Self {
         Self::IOError { io_error, filepath }
     }
 }
@@ -143,7 +144,8 @@ pub enum OpenReadError {
 }
 
 impl OpenReadError {
-    pub(crate) fn wrap_io_error(io_error: io::Error, filepath: PathBuf) -> Self {
+    /// Wraps an io error.
+    pub fn wrap_io_error(io_error: io::Error, filepath: PathBuf) -> Self {
         Self::IOError { io_error, filepath }
     }
 }

src/directory/file_watcher.rs

@@ -3,7 +3,7 @@ use crc32fast::Hasher;
 use std::fs;
 use std::io;
 use std::io::BufRead;
-use std::path::PathBuf;
+use std::path::Path;
 use std::sync::atomic::{AtomicUsize, Ordering};
 use std::sync::Arc;
 use std::thread;
@@ -13,15 +13,15 @@ pub const POLLING_INTERVAL: Duration = Duration::from_millis(if cfg!(test) { 1 }
 
 // Watches a file and executes registered callbacks when the file is modified.
 pub struct FileWatcher {
-    path: Arc<PathBuf>,
+    path: Arc<Path>,
     callbacks: Arc<WatchCallbackList>,
     state: Arc<AtomicUsize>, // 0: new, 1: runnable, 2: terminated
 }
 
 impl FileWatcher {
-    pub fn new(path: &PathBuf) -> FileWatcher {
+    pub fn new(path: &Path) -> FileWatcher {
         FileWatcher {
-            path: Arc::new(path.clone()),
+            path: Arc::from(path),
             callbacks: Default::default(),
             state: Default::default(),
         }
@@ -63,7 +63,7 @@ impl FileWatcher {
         handle
     }
 
-    fn compute_checksum(path: &PathBuf) -> Result<u32, io::Error> {
+    fn compute_checksum(path: &Path) -> Result<u32, io::Error> {
         let reader = match fs::File::open(path) {
             Ok(f) => io::BufReader::new(f),
             Err(e) => {

src/directory/footer.rs

@@ -115,6 +115,18 @@ impl Footer {
                 }
                 Ok(())
             }
+            VersionedFooter::V3 {
+                crc32: _crc,
+                store_compression,
+            } => {
+                if &library_version.store_compression != store_compression {
+                    return Err(Incompatibility::CompressionMismatch {
+                        library_compression_format: library_version.store_compression.to_string(),
+                        index_compression_format: store_compression.to_string(),
+                    });
+                }
+                Ok(())
+            }
             VersionedFooter::UnknownVersion => Err(Incompatibility::IndexMismatch {
                 library_version: library_version.clone(),
                 index_version: self.version.clone(),
@@ -136,24 +148,31 @@ pub enum VersionedFooter {
         crc32: CrcHashU32,
         store_compression: String,
     },
+    // Block wand max termfred on 1 byte
+    V3 {
+        crc32: CrcHashU32,
+        store_compression: String,
+    },
 }
 
 impl BinarySerializable for VersionedFooter {
     fn serialize<W: io::Write>(&self, writer: &mut W) -> io::Result<()> {
         let mut buf = Vec::new();
         match self {
-            VersionedFooter::V2 {
+            VersionedFooter::V3 {
                 crc32,
                 store_compression: compression,
             } => {
                 // Serializes a valid `VersionedFooter` or panics if the version is unknown
                 // [   version    |   crc_hash  | compression_mode ]
                 // [    0..4      |     4..8    |     variable     ]
-                BinarySerializable::serialize(&2u32, &mut buf)?;
+                BinarySerializable::serialize(&3u32, &mut buf)?;
                 BinarySerializable::serialize(crc32, &mut buf)?;
                 BinarySerializable::serialize(compression, &mut buf)?;
             }
-            VersionedFooter::V1 { .. } | VersionedFooter::UnknownVersion => {
+            VersionedFooter::V2 { .. }
+            | VersionedFooter::V1 { .. }
+            | VersionedFooter::UnknownVersion => {
                 return Err(io::Error::new(
                     io::ErrorKind::InvalidInput,
                     "Cannot serialize an unknown versioned footer ",
@@ -182,7 +201,7 @@ impl BinarySerializable for VersionedFooter {
         reader.read_exact(&mut buf[..])?;
         let mut cursor = &buf[..];
         let version = u32::deserialize(&mut cursor)?;
-        if version != 1 && version != 2 {
+        if version > 3 {
             return Ok(VersionedFooter::UnknownVersion);
         }
         let crc32 = u32::deserialize(&mut cursor)?;
@@ -192,12 +211,17 @@ impl BinarySerializable for VersionedFooter {
                 crc32,
                 store_compression,
             }
-        } else {
-            assert_eq!(version, 2);
+        } else if version == 2 {
             VersionedFooter::V2 {
                 crc32,
                 store_compression,
             }
+        } else {
+            assert_eq!(version, 3);
+            VersionedFooter::V3 {
+                crc32,
+                store_compression,
+            }
         })
     }
 }
@@ -205,6 +229,7 @@ impl BinarySerializable for VersionedFooter {
 impl VersionedFooter {
     pub fn crc(&self) -> Option<CrcHashU32> {
         match self {
+            VersionedFooter::V3 { crc32, .. } => Some(*crc32),
             VersionedFooter::V2 { crc32, .. } => Some(*crc32),
             VersionedFooter::V1 { crc32, .. } => Some(*crc32),
             VersionedFooter::UnknownVersion { .. } => None,
@@ -243,7 +268,7 @@ impl<W: TerminatingWrite> Write for FooterProxy<W> {
 impl<W: TerminatingWrite> TerminatingWrite for FooterProxy<W> {
     fn terminate_ref(&mut self, _: AntiCallToken) -> io::Result<()> {
         let crc32 = self.hasher.take().unwrap().finalize();
-        let footer = Footer::new(VersionedFooter::V2 {
+        let footer = Footer::new(VersionedFooter::V3 {
             crc32,
             store_compression: crate::store::COMPRESSION.to_string(),
         });
@@ -278,7 +303,7 @@ mod tests {
         let footer = Footer::deserialize(&mut &vec[..]).unwrap();
         assert!(matches!(
            footer.versioned_footer,
-           VersionedFooter::V2 { store_compression, .. }
+           VersionedFooter::V3 { store_compression, .. }
            if store_compression == crate::store::COMPRESSION
         ));
         assert_eq!(&footer.version, crate::version());
@@ -288,7 +313,7 @@ mod tests {
     fn test_serialize_deserialize_footer() {
         let mut buffer = Vec::new();
         let crc32 = 123456u32;
-        let footer: Footer = Footer::new(VersionedFooter::V2 {
+        let footer: Footer = Footer::new(VersionedFooter::V3 {
             crc32,
             store_compression: "lz4".to_string(),
         });
@@ -300,7 +325,7 @@ mod tests {
     #[test]
     fn footer_length() {
         let crc32 = 1111111u32;
-        let versioned_footer = VersionedFooter::V2 {
+        let versioned_footer = VersionedFooter::V3 {
             crc32,
             store_compression: "lz4".to_string(),
         };
@@ -321,7 +346,7 @@ mod tests {
             // versionned footer length
             12 | 128,
             // index format version
-            2,
+            3,
             0,
             0,
             0,
@@ -340,7 +365,7 @@ mod tests {
         let versioned_footer = VersionedFooter::deserialize(&mut cursor).unwrap();
         assert!(cursor.is_empty());
         let expected_crc: u32 = LittleEndian::read_u32(&v_footer_bytes[5..9]) as CrcHashU32;
-        let expected_versioned_footer: VersionedFooter = VersionedFooter::V2 {
+        let expected_versioned_footer: VersionedFooter = VersionedFooter::V3 {
             crc32: expected_crc,
             store_compression: "lz4".to_string(),
         };

src/fastfield/reader.rs

@@ -51,6 +51,15 @@ impl<Item: FastValue> FastFieldReader<Item> {
         }
     }
 
+    pub(crate) fn cast<TFastValue: FastValue>(self) -> FastFieldReader<TFastValue> {
+        FastFieldReader {
+            bit_unpacker: self.bit_unpacker,
+            min_value_u64: self.min_value_u64,
+            max_value_u64: self.max_value_u64,
+            _phantom: PhantomData,
+        }
+    }
+
     /// Return the value associated to the given document.
     ///
     /// This accessor should return as fast as possible.

src/fastfield/readers.rs

@@ -1,6 +1,6 @@
 use crate::common::CompositeFile;
-use crate::fastfield::BytesFastFieldReader;
 use crate::fastfield::MultiValueIntFastFieldReader;
+use crate::fastfield::{BytesFastFieldReader, FastValue};
 use crate::fastfield::{FastFieldNotAvailableError, FastFieldReader};
 use crate::schema::{Cardinality, Field, FieldType, Schema};
 use crate::space_usage::PerFieldSpaceUsage;
@@ -201,6 +201,14 @@ impl FastFieldReaders {
         None
     }
 
+    pub(crate) fn typed_fast_field_reader<TFastValue: FastValue>(
+        &self,
+        field: Field,
+    ) -> Option<FastFieldReader<TFastValue>> {
+        self.u64_lenient(field)
+            .map(|fast_field_reader| fast_field_reader.cast())
+    }
+
     /// Returns the `i64` fast field reader reader associated to `field`.
     ///
     /// If `field` is not a i64 fast field, this method returns `None`.

src/indexer/merger.rs

@@ -512,12 +512,10 @@ impl IndexMerger {
             .collect::<crate::Result<Vec<_>>>()?;
 
         let mut field_term_streams = Vec::new();
-
         for field_reader in &field_readers {
             let terms = field_reader.terms();
+            field_term_streams.push(terms.stream()?);
             max_term_ords.push(terms.num_terms() as u64);
-            let term_stream = terms.stream()?;
-            field_term_streams.push(term_stream);
         }
 
         let mut term_ord_mapping_opt = if *field_type == FieldType::HierarchicalFacet {

src/indexer/segment_writer.rs

@@ -11,7 +11,8 @@ use crate::schema::Schema;
 use crate::schema::Term;
 use crate::schema::Value;
 use crate::schema::{Field, FieldEntry};
-use crate::tokenizer::{BoxTokenStream, PreTokenizedStream};
+use crate::tokenizer::PreTokenizedStream;
+use crate::tokenizer::TokenStream;
 use crate::tokenizer::{FacetTokenizer, TextAnalyzer};
 use crate::tokenizer::{TokenStreamChain, Tokenizer};
 use crate::Opstamp;
@@ -141,13 +142,13 @@ impl SegmentWriter {
             }
             let (term_buffer, multifield_postings) =
                 (&mut self.term_buffer, &mut self.multifield_postings);
-            match *field_entry.field_type() {
+            match field_entry.field_type() {
                 FieldType::HierarchicalFacet => {
                     term_buffer.set_field(field);
                     let facets =
                         field_values
                             .iter()
-                            .flat_map(|field_value| match *field_value.value() {
+                            .flat_map(|field_value| match field_value.value() {
                                 Value::Facet(ref facet) => Some(facet.encoded_str()),
                                 _ => {
                                     panic!("Expected hierarchical facet");
@@ -172,37 +173,38 @@ impl SegmentWriter {
                     }
                 }
                 FieldType::Str(_) => {
-                    let mut token_streams: Vec<BoxTokenStream> = vec![];
-                    let mut offsets = vec![];
+                    let mut streams_with_offsets = vec![];
                     let mut total_offset = 0;
 
                     for field_value in field_values {
                         match field_value.value() {
                             Value::PreTokStr(tok_str) => {
-                                offsets.push(total_offset);
+                                streams_with_offsets.push((
+                                    Box::new(PreTokenizedStream::from(tok_str.clone()))
+                                        as Box<dyn TokenStream>,
+                                    total_offset,
+                                ));
                                 if let Some(last_token) = tok_str.tokens.last() {
                                     total_offset += last_token.offset_to;
                                 }
-                                token_streams
-                                    .push(PreTokenizedStream::from(tok_str.clone()).into());
                             }
                             Value::Str(ref text) => {
                                 if let Some(ref mut tokenizer) =
                                     self.tokenizers[field.field_id() as usize]
                                 {
-                                    offsets.push(total_offset);
+                                    streams_with_offsets
+                                        .push((tokenizer.token_stream(text), total_offset));
                                     total_offset += text.len();
-                                    token_streams.push(tokenizer.token_stream(text));
                                 }
                             }
                             _ => (),
                         }
                     }
 
-                    let num_tokens = if token_streams.is_empty() {
+                    let num_tokens = if streams_with_offsets.is_empty() {
                         0
                     } else {
-                        let mut token_stream = TokenStreamChain::new(offsets, token_streams);
+                        let mut token_stream = TokenStreamChain::new(streams_with_offsets);
                         multifield_postings.index_text(
                             doc_id,
                             field,

src/lib.rs

@@ -174,7 +174,7 @@ use once_cell::sync::Lazy;
 use serde::{Deserialize, Serialize};
 
 /// Index format version.
-const INDEX_FORMAT_VERSION: u32 = 2;
+const INDEX_FORMAT_VERSION: u32 = 3;
 
 /// Structure version for the index.
 #[derive(Clone, PartialEq, Eq, Serialize, Deserialize)]

src/positions/reader.rs

@@ -132,7 +132,7 @@ impl PositionReader {
             "offset arguments should be increasing."
         );
         let delta_to_block_offset = offset as i64 - self.block_offset as i64;
-        if delta_to_block_offset < 0 || delta_to_block_offset >= 128 {
+        if !(0..128).contains(&delta_to_block_offset) {
             // The first position is not within the first block.
             // We need to decompress the first block.
             let delta_to_anchor_offset = offset - self.anchor_offset;

src/postings/block_search.rs

@@ -109,9 +109,9 @@ impl BlockSearcher {
     /// The results should be equivalent to
     /// ```compile_fail
     /// block[..]
-    //       .iter()
-    //       .take_while(|&&val| val < target)
-    //       .count()
+    ///       .iter()
+    ///       .take_while(|&&val| val < target)
+    ///       .count()
     /// ```
     ///
     /// The `start` argument is just used to hint that the response is

src/postings/skip.rs

@@ -1,32 +1,46 @@
-use crate::common::{read_u32_vint_no_advance, serialize_vint_u32, BinarySerializable};
+use std::convert::TryInto;
+
 use crate::directory::OwnedBytes;
 use crate::postings::compression::{compressed_block_size, COMPRESSION_BLOCK_SIZE};
 use crate::query::BM25Weight;
 use crate::schema::IndexRecordOption;
 use crate::{DocId, Score, TERMINATED};
 
+#[inline(always)]
+fn encode_block_wand_max_tf(max_tf: u32) -> u8 {
+    max_tf.min(u8::MAX as u32) as u8
+}
+
+#[inline(always)]
+fn decode_block_wand_max_tf(max_tf_code: u8) -> u32 {
+    if max_tf_code == u8::MAX {
+        u32::MAX
+    } else {
+        max_tf_code as u32
+    }
+}
+
+#[inline(always)]
+fn read_u32(data: &[u8]) -> u32 {
+    u32::from_le_bytes(data[..4].try_into().unwrap())
+}
+
+#[inline(always)]
+fn write_u32(val: u32, buf: &mut Vec<u8>) {
+    buf.extend_from_slice(&val.to_le_bytes());
+}
+
 pub struct SkipSerializer {
     buffer: Vec<u8>,
-    prev_doc: DocId,
 }
 
 impl SkipSerializer {
     pub fn new() -> SkipSerializer {
-        SkipSerializer {
-            buffer: Vec::new(),
-            prev_doc: 0u32,
-        }
+        SkipSerializer { buffer: Vec::new() }
     }
 
     pub fn write_doc(&mut self, last_doc: DocId, doc_num_bits: u8) {
-        assert!(
-            last_doc > self.prev_doc,
-            "write_doc(...) called with non-increasing doc ids. \
-             Did you forget to call clear maybe?"
-        );
-        let delta_doc = last_doc - self.prev_doc;
-        self.prev_doc = last_doc;
-        delta_doc.serialize(&mut self.buffer).unwrap();
+        write_u32(last_doc, &mut self.buffer);
         self.buffer.push(doc_num_bits);
     }
 
@@ -35,16 +49,13 @@ impl SkipSerializer {
     }
 
     pub fn write_total_term_freq(&mut self, tf_sum: u32) {
-        tf_sum
-            .serialize(&mut self.buffer)
-            .expect("Should never fail");
+        write_u32(tf_sum, &mut self.buffer);
     }
 
     pub fn write_blockwand_max(&mut self, fieldnorm_id: u8, term_freq: u32) {
-        self.buffer.push(fieldnorm_id);
-        let mut buf = [0u8; 8];
-        let bytes = serialize_vint_u32(term_freq, &mut buf);
-        self.buffer.extend_from_slice(bytes);
+        let block_wand_tf = encode_block_wand_max_tf(term_freq);
+        self.buffer
+            .extend_from_slice(&[fieldnorm_id, block_wand_tf]);
     }
 
     pub fn data(&self) -> &[u8] {
@@ -52,7 +63,6 @@ impl SkipSerializer {
     }
 
     pub fn clear(&mut self) {
-        self.prev_doc = 0u32;
         self.buffer.clear();
     }
 }
@@ -159,18 +169,13 @@ impl SkipReader {
     }
 
     fn read_block_info(&mut self) {
-        let doc_delta = {
-            let bytes = self.owned_read.as_slice();
-            let mut buf = [0; 4];
-            buf.copy_from_slice(&bytes[..4]);
-            u32::from_le_bytes(buf)
-        };
-        self.last_doc_in_block += doc_delta as DocId;
-        let doc_num_bits = self.owned_read.as_slice()[4];
-
+        let bytes = self.owned_read.as_slice();
+        let advance_len: usize;
+        self.last_doc_in_block = read_u32(bytes);
+        let doc_num_bits = bytes[4];
         match self.skip_info {
             IndexRecordOption::Basic => {
-                self.owned_read.advance(5);
+                advance_len = 5;
                 self.block_info = BlockInfo::BitPacked {
                     doc_num_bits,
                     tf_num_bits: 0,
@@ -180,11 +185,10 @@ impl SkipReader {
                 };
             }
             IndexRecordOption::WithFreqs => {
-                let bytes = self.owned_read.as_slice();
                 let tf_num_bits = bytes[5];
                 let block_wand_fieldnorm_id = bytes[6];
-                let (block_wand_term_freq, num_bytes) = read_u32_vint_no_advance(&bytes[7..]);
-                self.owned_read.advance(7 + num_bytes);
+                let block_wand_term_freq = decode_block_wand_max_tf(bytes[7]);
+                advance_len = 8;
                 self.block_info = BlockInfo::BitPacked {
                     doc_num_bits,
                     tf_num_bits,
@@ -194,16 +198,11 @@ impl SkipReader {
                 };
             }
             IndexRecordOption::WithFreqsAndPositions => {
-                let bytes = self.owned_read.as_slice();
                 let tf_num_bits = bytes[5];
-                let tf_sum = {
-                    let mut buf = [0; 4];
-                    buf.copy_from_slice(&bytes[6..10]);
-                    u32::from_le_bytes(buf)
-                };
+                let tf_sum = read_u32(&bytes[6..10]);
                 let block_wand_fieldnorm_id = bytes[10];
-                let (block_wand_term_freq, num_bytes) = read_u32_vint_no_advance(&bytes[11..]);
-                self.owned_read.advance(11 + num_bytes);
+                let block_wand_term_freq = decode_block_wand_max_tf(bytes[11]);
+                advance_len = 12;
                 self.block_info = BlockInfo::BitPacked {
                     doc_num_bits,
                     tf_num_bits,
@@ -213,6 +212,7 @@ impl SkipReader {
                 };
             }
         }
+        self.owned_read.advance(advance_len);
     }
 
     pub fn block_info(&self) -> BlockInfo {
@@ -274,6 +274,24 @@ mod tests {
     use crate::directory::OwnedBytes;
     use crate::postings::compression::COMPRESSION_BLOCK_SIZE;
 
+    #[test]
+    fn test_encode_block_wand_max_tf() {
+        for tf in 0..255 {
+            assert_eq!(super::encode_block_wand_max_tf(tf), tf as u8);
+        }
+        for &tf in &[255, 256, 1_000_000, u32::MAX] {
+            assert_eq!(super::encode_block_wand_max_tf(tf), 255);
+        }
+    }
+
+    #[test]
+    fn test_decode_block_wand_max_tf() {
+        for tf in 0..255 {
+            assert_eq!(super::decode_block_wand_max_tf(tf), tf as u32);
+        }
+        assert_eq!(super::decode_block_wand_max_tf(255), u32::MAX);
+    }
+
     #[test]
     fn test_skip_with_freq() {
         let buf = {

src/query/boolean_query/boolean_weight.rs

@@ -1,5 +1,3 @@
-use rayon::iter::IntoParallelRefIterator;
-
 use crate::core::SegmentReader;
 use crate::postings::FreqReadingOption;
 use crate::query::explanation::does_not_match;
@@ -24,7 +22,7 @@ enum SpecializedScorer {
 
 fn scorer_union<TScoreCombiner>(scorers: Vec<Box<dyn Scorer>>) -> SpecializedScorer
 where
-    TScoreCombiner: ScoreCombiner + Send,
+    TScoreCombiner: ScoreCombiner,
 {
     assert!(!scorers.is_empty());
     if scorers.len() == 1 {
@@ -54,7 +52,7 @@ where
     SpecializedScorer::Other(Box::new(Union::<_, TScoreCombiner>::from(scorers)))
 }
 
-fn into_box_scorer<TScoreCombiner: ScoreCombiner + Send>(scorer: SpecializedScorer) -> Box<dyn Scorer> {
+fn into_box_scorer<TScoreCombiner: ScoreCombiner>(scorer: SpecializedScorer) -> Box<dyn Scorer> {
     match scorer {
         SpecializedScorer::TermUnion(term_scorers) => {
             let union_scorer = Union::<TermScorer, TScoreCombiner>::from(term_scorers);
@@ -82,32 +80,18 @@ impl BooleanWeight {
         reader: &SegmentReader,
         boost: Score,
     ) -> crate::Result<HashMap<Occur, Vec<Box<dyn Scorer>>>> {
-        use rayon::iter::ParallelIterator;
-        use rayon::iter::IndexedParallelIterator;
         let mut per_occur_scorers: HashMap<Occur, Vec<Box<dyn Scorer>>> = HashMap::new();
-        let mut items_res: Vec<crate::Result<(Occur, Box<dyn Scorer>)>> = Vec::new();
-        let pool = rayon::ThreadPoolBuilder::new().num_threads(self.weights.len()).build().unwrap();
-        pool.install(|| {
-        self.weights.iter()
-            .collect::<Vec<_>>()
-            .par_iter()
-            .map(|(occur, subweight)| {
-                let sub_scorer: Box<dyn Scorer> = subweight.scorer(reader, boost)?;
-                Ok((*occur, sub_scorer))
-            })
-            .collect_into_vec(&mut items_res);
-        });
-        for item_res in items_res {
-            let (occur, sub_scorer) = item_res?;
+        for &(ref occur, ref subweight) in &self.weights {
+            let sub_scorer: Box<dyn Scorer> = subweight.scorer(reader, boost)?;
             per_occur_scorers
-                .entry(occur)
+                .entry(*occur)
                 .or_insert_with(Vec::new)
                 .push(sub_scorer);
         }
         Ok(per_occur_scorers)
     }
 
-    fn complex_scorer<TScoreCombiner: ScoreCombiner >(
+    fn complex_scorer<TScoreCombiner: ScoreCombiner>(
         &self,
         reader: &SegmentReader,
         boost: Score,

src/store/compression_lz4.rs

@@ -3,7 +3,7 @@ use std::io::{self, Read, Write};
 /// Name of the compression scheme used in the doc store.
 ///
 /// This name is appended to the version string of tantivy.
-pub const COMPRESSION: &'static str = "lz4";
+pub const COMPRESSION: &str = "lz4";
 
 pub fn compress(uncompressed: &[u8], compressed: &mut Vec<u8>) -> io::Result<()> {
     compressed.clear();

src/store/index/skip_index.rs

@@ -35,11 +35,11 @@ struct Layer {
 }
 
 impl Layer {
-    fn cursor<'a>(&'a self) -> impl Iterator<Item = Checkpoint> + 'a {
+    fn cursor(&self) -> impl Iterator<Item = Checkpoint> + '_ {
         self.cursor_at_offset(0u64)
     }
 
-    fn cursor_at_offset<'a>(&'a self, start_offset: u64) -> impl Iterator<Item = Checkpoint> + 'a {
+    fn cursor_at_offset(&self, start_offset: u64) -> impl Iterator<Item = Checkpoint> + '_ {
         let data = &self.data.as_slice();
         LayerCursor {
             remaining: &data[start_offset as usize..],
@@ -59,7 +59,7 @@ pub struct SkipIndex {
 }
 
 impl SkipIndex {
-    pub(crate) fn checkpoints<'a>(&'a self) -> impl Iterator<Item = Checkpoint> + 'a {
+    pub(crate) fn checkpoints(&self) -> impl Iterator<Item = Checkpoint> + '_ {
         self.layers
             .last()
             .into_iter()

src/store/reader.rs

@@ -46,7 +46,7 @@ impl StoreReader {
         })
     }
 
-    pub(crate) fn block_checkpoints<'a>(&'a self) -> impl Iterator<Item = Checkpoint> + 'a {
+    pub(crate) fn block_checkpoints(&self) -> impl Iterator<Item = Checkpoint> + '_ {
         self.skip_index.checkpoints()
     }
 

src/termdict/mod.rs

@@ -22,10 +22,8 @@ A second datastructure makes it possible to access a [`TermInfo`](../postings/st
 
 use tantivy_fst::automaton::AlwaysMatch;
 
-// mod fst_termdict;
-// use fst_termdict as termdict;
-mod sstable_termdict;
-use sstable_termdict as termdict;
+mod fst_termdict;
+use fst_termdict as termdict;
 
 mod merger;
 

src/termdict/sstable_termdict/mod.rs

@@ -1,148 +0,0 @@
-use std::io;
-
-mod sstable;
-mod streamer;
-mod termdict;
-
-use self::sstable::value::{ValueReader, ValueWriter};
-use self::sstable::{BlockReader, SSTable};
-
-use crate::common::VInt;
-use crate::postings::TermInfo;
-
-pub use self::streamer::{TermStreamer, TermStreamerBuilder};
-pub use self::termdict::{TermDictionary, TermDictionaryBuilder};
-
-pub struct TermSSTable;
-
-impl SSTable for TermSSTable {
-    type Value = TermInfo;
-    type Reader = TermInfoReader;
-    type Writer = TermInfoWriter;
-}
-
-#[derive(Default)]
-pub struct TermInfoReader {
-    term_infos: Vec<TermInfo>,
-}
-
-impl ValueReader for TermInfoReader {
-    type Value = TermInfo;
-
-    fn value(&self, idx: usize) -> &TermInfo {
-        &self.term_infos[idx]
-    }
-
-    fn read(&mut self, reader: &mut BlockReader) -> io::Result<()> {
-        self.term_infos.clear();
-        let num_els = VInt::deserialize_u64(reader)?;
-        let mut start_offset = VInt::deserialize_u64(reader)?;
-        let mut positions_idx = 0;
-        for _ in 0..num_els {
-            let doc_freq = VInt::deserialize_u64(reader)? as u32;
-            let posting_num_bytes = VInt::deserialize_u64(reader)?;
-            let stop_offset = start_offset + posting_num_bytes;
-            let delta_positions_idx = VInt::deserialize_u64(reader)?;
-            positions_idx += delta_positions_idx;
-            let term_info = TermInfo {
-                doc_freq,
-                postings_start_offset: start_offset,
-                postings_stop_offset: stop_offset,
-                positions_idx,
-            };
-            self.term_infos.push(term_info);
-            start_offset = stop_offset;
-        }
-        Ok(())
-    }
-}
-
-#[derive(Default)]
-pub struct TermInfoWriter {
-    term_infos: Vec<TermInfo>,
-}
-
-impl ValueWriter for TermInfoWriter {
-    type Value = TermInfo;
-
-    fn write(&mut self, term_info: &TermInfo) {
-        self.term_infos.push(term_info.clone());
-    }
-
-    fn write_block(&mut self, buffer: &mut Vec<u8>) {
-        VInt(self.term_infos.len() as u64).serialize_into_vec(buffer);
-        if self.term_infos.is_empty() {
-            return;
-        }
-        let mut prev_position_idx = 0u64;
-        VInt(self.term_infos[0].postings_start_offset).serialize_into_vec(buffer);
-        for term_info in &self.term_infos {
-            VInt(term_info.doc_freq as u64).serialize_into_vec(buffer);
-            VInt(term_info.postings_stop_offset - term_info.postings_start_offset)
-                .serialize_into_vec(buffer);
-            VInt(term_info.positions_idx - prev_position_idx).serialize_into_vec(buffer);
-            prev_position_idx = term_info.positions_idx;
-        }
-        self.term_infos.clear();
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use std::io;
-
-    use super::BlockReader;
-
-    use crate::directory::OwnedBytes;
-    use crate::postings::TermInfo;
-    use crate::termdict::sstable_termdict::sstable::value::{ValueReader, ValueWriter};
-    use crate::termdict::sstable_termdict::TermInfoReader;
-
-    #[test]
-    fn test_block_terminfos() -> io::Result<()> {
-        let mut term_info_writer = super::TermInfoWriter::default();
-        term_info_writer.write(&TermInfo {
-            doc_freq: 120u32,
-            postings_start_offset: 17u64,
-            postings_stop_offset: 45u64,
-            positions_idx: 10u64,
-        });
-        term_info_writer.write(&TermInfo {
-            doc_freq: 10u32,
-            postings_start_offset: 45u64,
-            postings_stop_offset: 450u64,
-            positions_idx: 104u64,
-        });
-        term_info_writer.write(&TermInfo {
-            doc_freq: 17u32,
-            postings_start_offset: 450u64,
-            postings_stop_offset: 462u64,
-            positions_idx: 210u64,
-        });
-        let mut buffer = Vec::new();
-        term_info_writer.write_block(&mut buffer);
-        let mut block_reader = make_block_reader(&buffer[..]);
-        let mut term_info_reader = TermInfoReader::default();
-        term_info_reader.read(&mut block_reader)?;
-        assert_eq!(
-            term_info_reader.value(0),
-            &TermInfo {
-                doc_freq: 120u32,
-                postings_start_offset: 17u64,
-                postings_stop_offset: 45u64,
-                positions_idx: 10u64
-            }
-        );
-        assert!(block_reader.buffer().is_empty());
-        Ok(())
-    }
-
-    fn make_block_reader(data: &[u8]) -> BlockReader {
-        let mut buffer = (data.len() as u32).to_le_bytes().to_vec();
-        buffer.extend_from_slice(data);
-        let owned_bytes = OwnedBytes::new(buffer);
-        let mut block_reader = BlockReader::new(Box::new(owned_bytes));
-        block_reader.read_block().unwrap();
-        block_reader
-    }
-}

src/termdict/sstable_termdict/sstable/block_reader.rs

@@ -1,84 +0,0 @@
-use byteorder::{LittleEndian, ReadBytesExt};
-use std::io::{self, Read};
-
-pub struct BlockReader<'a> {
-    buffer: Vec<u8>,
-    reader: Box<dyn io::Read + 'a>,
-    offset: usize,
-}
-
-impl<'a> BlockReader<'a> {
-    pub fn new(reader: Box<dyn io::Read + 'a>) -> BlockReader<'a> {
-        BlockReader {
-            buffer: Vec::new(),
-            reader,
-            offset: 0,
-        }
-    }
-
-    pub fn deserialize_u64(&mut self) -> u64 {
-        let (num_bytes, val) = super::vint::deserialize_read(self.buffer());
-        self.advance(num_bytes);
-        val
-    }
-
-    #[inline(always)]
-    pub fn buffer_from_to(&self, start: usize, end: usize) -> &[u8] {
-        &self.buffer[start..end]
-    }
-
-    pub fn buffer_from(&self, start: usize) -> &[u8] {
-        &self.buffer[start..]
-    }
-
-    pub fn read_block(&mut self) -> io::Result<bool> {
-        self.offset = 0;
-        let block_len_res = self.reader.read_u32::<LittleEndian>();
-        if let Err(err) = &block_len_res {
-            if err.kind() == io::ErrorKind::UnexpectedEof {
-                return Ok(false);
-            }
-        }
-        let block_len = block_len_res?;
-        if block_len == 0u32 {
-            self.buffer.clear();
-            return Ok(false);
-        }
-        self.buffer.resize(block_len as usize, 0u8);
-        self.reader.read_exact(&mut self.buffer[..])?;
-        Ok(true)
-    }
-
-    pub fn offset(&self) -> usize {
-        self.offset
-    }
-
-    pub fn advance(&mut self, num_bytes: usize) {
-        self.offset += num_bytes;
-    }
-
-    pub fn buffer(&self) -> &[u8] {
-        &self.buffer[self.offset..]
-    }
-}
-
-impl<'a> io::Read for BlockReader<'a> {
-    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        let len = self.buffer().read(buf)?;
-        self.advance(len);
-        Ok(len)
-    }
-
-    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
-        let len = self.buffer.len();
-        buf.extend_from_slice(self.buffer());
-        self.advance(len);
-        Ok(len)
-    }
-
-    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
-        self.buffer().read_exact(buf)?;
-        self.advance(buf.len());
-        Ok(())
-    }
-}

src/termdict/sstable_termdict/sstable/delta.rs

@@ -1,203 +0,0 @@
-use std::io::{self, BufWriter, Write};
-
-use crate::common::CountingWriter;
-
-use super::value::ValueWriter;
-use super::{value, vint, BlockReader};
-
-const FOUR_BIT_LIMITS: usize = 1 << 4;
-const VINT_MODE: u8 = 1u8;
-const BLOCK_LEN: usize = 256_000;
-
-pub struct DeltaWriter<W, TValueWriter>
-where
-    W: io::Write,
-{
-    block: Vec<u8>,
-    write: CountingWriter<BufWriter<W>>,
-    value_writer: TValueWriter,
-}
-
-impl<W, TValueWriter> DeltaWriter<W, TValueWriter>
-where
-    W: io::Write,
-    TValueWriter: ValueWriter,
-{
-    pub fn new(wrt: W) -> Self {
-        DeltaWriter {
-            block: Vec::with_capacity(BLOCK_LEN * 2),
-            write: CountingWriter::wrap(BufWriter::new(wrt)),
-            value_writer: TValueWriter::default(),
-        }
-    }
-}
-
-impl<W, TValueWriter> DeltaWriter<W, TValueWriter>
-where
-    W: io::Write,
-    TValueWriter: value::ValueWriter,
-{
-    pub fn flush_block(&mut self) -> io::Result<Option<(u64, u64)>> {
-        if self.block.is_empty() {
-            return Ok(None);
-        }
-        let start_offset = self.write.written_bytes();
-        // TODO avoid buffer allocation
-        let mut buffer = Vec::new();
-        self.value_writer.write_block(&mut buffer);
-        let block_len = buffer.len() + self.block.len();
-        self.write.write_all(&(block_len as u32).to_le_bytes())?;
-        self.write.write_all(&buffer[..])?;
-        self.write.write_all(&mut self.block[..])?;
-        let end_offset = self.write.written_bytes();
-        self.block.clear();
-        Ok(Some((start_offset, end_offset)))
-    }
-
-    fn encode_keep_add(&mut self, keep_len: usize, add_len: usize) {
-        if keep_len < FOUR_BIT_LIMITS && add_len < FOUR_BIT_LIMITS {
-            let b = (keep_len | add_len << 4) as u8;
-            self.block.extend_from_slice(&[b])
-        } else {
-            let mut buf = [VINT_MODE; 20];
-            let mut len = 1 + vint::serialize(keep_len as u64, &mut buf[1..]);
-            len += vint::serialize(add_len as u64, &mut buf[len..]);
-            self.block.extend_from_slice(&mut buf[..len])
-        }
-    }
-
-    pub(crate) fn write_suffix(&mut self, common_prefix_len: usize, suffix: &[u8]) {
-        let keep_len = common_prefix_len;
-        let add_len = suffix.len();
-        self.encode_keep_add(keep_len, add_len);
-        self.block.extend_from_slice(suffix);
-    }
-
-    pub(crate) fn write_value(&mut self, value: &TValueWriter::Value) {
-        self.value_writer.write(value);
-    }
-
-    pub fn write_delta(
-        &mut self,
-        common_prefix_len: usize,
-        suffix: &[u8],
-        value: &TValueWriter::Value,
-    ) {
-        self.write_suffix(common_prefix_len, suffix);
-        self.write_value(value);
-    }
-
-    pub fn flush_block_if_required(&mut self) -> io::Result<Option<(u64, u64)>> {
-        if self.block.len() > BLOCK_LEN {
-            return self.flush_block();
-        }
-        Ok(None)
-    }
-
-    pub fn finalize(mut self) -> CountingWriter<BufWriter<W>> {
-        self.write
-    }
-}
-
-pub struct DeltaReader<'a, TValueReader> {
-    common_prefix_len: usize,
-    suffix_start: usize,
-    suffix_end: usize,
-    value_reader: TValueReader,
-    block_reader: BlockReader<'a>,
-    idx: usize,
-}
-
-impl<'a, TValueReader> DeltaReader<'a, TValueReader>
-where
-    TValueReader: value::ValueReader,
-{
-    pub fn new<R: io::Read + 'a>(reader: R) -> Self {
-        DeltaReader {
-            idx: 0,
-            common_prefix_len: 0,
-            suffix_start: 0,
-            suffix_end: 0,
-            value_reader: TValueReader::default(),
-            block_reader: BlockReader::new(Box::new(reader)),
-        }
-    }
-
-    fn deserialize_vint(&mut self) -> u64 {
-        self.block_reader.deserialize_u64()
-    }
-
-    fn read_keep_add(&mut self) -> Option<(usize, usize)> {
-        let b = {
-            let buf = &self.block_reader.buffer();
-            if buf.is_empty() {
-                return None;
-            }
-            buf[0]
-        };
-        self.block_reader.advance(1);
-        match b {
-            VINT_MODE => {
-                let keep = self.deserialize_vint() as usize;
-                let add = self.deserialize_vint() as usize;
-                Some((keep, add))
-            }
-            b => {
-                let keep = (b & 0b1111) as usize;
-                let add = (b >> 4) as usize;
-                Some((keep, add))
-            }
-        }
-    }
-
-    fn read_delta_key(&mut self) -> bool {
-        if let Some((keep, add)) = self.read_keep_add() {
-            self.common_prefix_len = keep;
-            self.suffix_start = self.block_reader.offset();
-            self.suffix_end = self.suffix_start + add;
-            self.block_reader.advance(add);
-            true
-        } else {
-            false
-        }
-    }
-
-    pub fn advance(&mut self) -> io::Result<bool> {
-        if self.block_reader.buffer().is_empty() {
-            if !self.block_reader.read_block()? {
-                return Ok(false);
-            }
-            self.value_reader.read(&mut self.block_reader)?;
-            self.idx = 0;
-        } else {
-            self.idx += 1;
-        }
-        if !self.read_delta_key() {
-            return Ok(false);
-        }
-        Ok(true)
-    }
-
-    pub fn common_prefix_len(&self) -> usize {
-        self.common_prefix_len
-    }
-
-    pub fn suffix(&self) -> &[u8] {
-        &self
-            .block_reader
-            .buffer_from_to(self.suffix_start, self.suffix_end)
-    }
-
-    pub fn suffix_from(&self, offset: usize) -> &[u8] {
-        &self.block_reader.buffer_from_to(
-            self.suffix_start
-                .wrapping_add(offset)
-                .wrapping_sub(self.common_prefix_len),
-            self.suffix_end,
-        )
-    }
-
-    pub fn value(&self) -> &TValueReader::Value {
-        self.value_reader.value(self.idx)
-    }
-}

src/termdict/sstable_termdict/sstable/merge/heap_merge.rs

@@ -1,72 +0,0 @@
-use crate::termdict::sstable_termdict::sstable::{Reader, SSTable, Writer};
-
-use super::SingleValueMerger;
-use super::ValueMerger;
-use std::cmp::Ordering;
-use std::collections::binary_heap::PeekMut;
-use std::collections::BinaryHeap;
-use std::io;
-
-struct HeapItem<B: AsRef<[u8]>>(B);
-
-impl<B: AsRef<[u8]>> Ord for HeapItem<B> {
-    fn cmp(&self, other: &Self) -> Ordering {
-        other.0.as_ref().cmp(self.0.as_ref())
-    }
-}
-impl<B: AsRef<[u8]>> PartialOrd for HeapItem<B> {
-    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        Some(other.0.as_ref().cmp(self.0.as_ref()))
-    }
-}
-
-impl<B: AsRef<[u8]>> Eq for HeapItem<B> {}
-impl<B: AsRef<[u8]>> PartialEq for HeapItem<B> {
-    fn eq(&self, other: &Self) -> bool {
-        self.0.as_ref() == other.0.as_ref()
-    }
-}
-
-pub fn merge_sstable<SST: SSTable, W: io::Write, M: ValueMerger<SST::Value>>(
-    readers: Vec<Reader<SST::Reader>>,
-    mut writer: Writer<W, SST::Writer>,
-    mut merger: M,
-) -> io::Result<()> {
-    let mut heap: BinaryHeap<HeapItem<Reader<SST::Reader>>> =
-        BinaryHeap::with_capacity(readers.len());
-    for mut reader in readers {
-        if reader.advance()? {
-            heap.push(HeapItem(reader));
-        }
-    }
-    loop {
-        let len = heap.len();
-        let mut value_merger;
-        if let Some(mut head) = heap.peek_mut() {
-            writer.write_key(head.0.key());
-            value_merger = merger.new_value(head.0.value());
-            if !head.0.advance()? {
-                PeekMut::pop(head);
-            }
-        } else {
-            break;
-        }
-        for _ in 0..len - 1 {
-            if let Some(mut head) = heap.peek_mut() {
-                if head.0.key() == writer.current_key() {
-                    value_merger.add(head.0.value());
-                    if !head.0.advance()? {
-                        PeekMut::pop(head);
-                    }
-                    continue;
-                }
-            }
-            break;
-        }
-        let value = value_merger.finish();
-        writer.write_value(&value);
-        writer.flush_block_if_required()?;
-    }
-    writer.finalize()?;
-    Ok(())
-}

src/termdict/sstable_termdict/sstable/merge/mod.rs

@@ -1,184 +0,0 @@
-mod heap_merge;
-
-pub use self::heap_merge::merge_sstable;
-
-pub trait SingleValueMerger<V> {
-    fn add(&mut self, v: &V);
-    fn finish(self) -> V;
-}
-
-pub trait ValueMerger<V> {
-    type TSingleValueMerger: SingleValueMerger<V>;
-    fn new_value(&mut self, v: &V) -> Self::TSingleValueMerger;
-}
-
-#[derive(Default)]
-pub struct KeepFirst;
-
-pub struct FirstVal<V>(V);
-
-impl<V: Clone> ValueMerger<V> for KeepFirst {
-    type TSingleValueMerger = FirstVal<V>;
-
-    fn new_value(&mut self, v: &V) -> FirstVal<V> {
-        FirstVal(v.clone())
-    }
-}
-
-impl<V> SingleValueMerger<V> for FirstVal<V> {
-    fn add(&mut self, _: &V) {}
-
-    fn finish(self) -> V {
-        self.0
-    }
-}
-
-pub struct VoidMerge;
-impl ValueMerger<()> for VoidMerge {
-    type TSingleValueMerger = ();
-
-    fn new_value(&mut self, _: &()) -> () {
-        ()
-    }
-}
-
-pub struct U64Merge;
-impl ValueMerger<u64> for U64Merge {
-    type TSingleValueMerger = u64;
-
-    fn new_value(&mut self, val: &u64) -> u64 {
-        *val
-    }
-}
-
-impl SingleValueMerger<u64> for u64 {
-    fn add(&mut self, val: &u64) {
-        *self += *val;
-    }
-
-    fn finish(self) -> u64 {
-        self
-    }
-}
-
-impl SingleValueMerger<()> for () {
-    fn add(&mut self, _: &()) {}
-
-    fn finish(self) -> () {
-        ()
-    }
-}
-
-#[cfg(test)]
-mod tests {
-
-    use super::super::SSTable;
-    use super::super::{SSTableMonotonicU64, VoidSSTable};
-    use super::U64Merge;
-    use super::VoidMerge;
-    use std::collections::{BTreeMap, BTreeSet};
-    use std::str;
-
-    fn write_sstable(keys: &[&'static str]) -> Vec<u8> {
-        let mut buffer: Vec<u8> = vec![];
-        {
-            let mut sstable_writer = VoidSSTable::writer(&mut buffer);
-            for &key in keys {
-                assert!(sstable_writer.write(key.as_bytes(), &()).is_ok());
-            }
-            assert!(sstable_writer.finalize().is_ok());
-        }
-        dbg!(&buffer);
-        buffer
-    }
-
-    fn write_sstable_u64(keys: &[(&'static str, u64)]) -> Vec<u8> {
-        let mut buffer: Vec<u8> = vec![];
-        {
-            let mut sstable_writer = SSTableMonotonicU64::writer(&mut buffer);
-            for (key, val) in keys {
-                assert!(sstable_writer.write(key.as_bytes(), val).is_ok());
-            }
-            assert!(sstable_writer.finalize().is_ok());
-        }
-        buffer
-    }
-
-    fn merge_test_aux(arrs: &[&[&'static str]]) {
-        let sstables = arrs.iter().cloned().map(write_sstable).collect::<Vec<_>>();
-        let sstables_ref: Vec<&[u8]> = sstables.iter().map(|s| s.as_ref()).collect();
-        let mut merged = BTreeSet::new();
-        for &arr in arrs.iter() {
-            for &s in arr {
-                merged.insert(s.to_string());
-            }
-        }
-        let mut w = Vec::new();
-        assert!(VoidSSTable::merge(sstables_ref, &mut w, VoidMerge).is_ok());
-        let mut reader = VoidSSTable::reader(&w[..]);
-        for k in merged {
-            assert!(reader.advance().unwrap());
-            assert_eq!(reader.key(), k.as_bytes());
-        }
-        assert!(!reader.advance().unwrap());
-    }
-
-    fn merge_test_u64_monotonic_aux(arrs: &[&[(&'static str, u64)]]) {
-        let sstables = arrs
-            .iter()
-            .cloned()
-            .map(write_sstable_u64)
-            .collect::<Vec<_>>();
-        let sstables_ref: Vec<&[u8]> = sstables.iter().map(|s| s.as_ref()).collect();
-        let mut merged = BTreeMap::new();
-        for &arr in arrs.iter() {
-            for (key, val) in arr {
-                let entry = merged.entry(key.to_string()).or_insert(0u64);
-                *entry += val;
-            }
-        }
-        let mut w = Vec::new();
-        assert!(SSTableMonotonicU64::merge(sstables_ref, &mut w, U64Merge).is_ok());
-        let mut reader = SSTableMonotonicU64::reader(&w[..]);
-        for (k, v) in merged {
-            assert!(reader.advance().unwrap());
-            assert_eq!(reader.key(), k.as_bytes());
-            assert_eq!(reader.value(), &v);
-        }
-        assert!(!reader.advance().unwrap());
-    }
-
-    #[test]
-    fn test_merge_simple_reproduce() {
-        let sstable_data = write_sstable(&["a"]);
-        let mut reader = VoidSSTable::reader(&sstable_data[..]);
-        assert!(reader.advance().unwrap());
-        assert_eq!(reader.key(), b"a");
-        assert!(!reader.advance().unwrap());
-    }
-
-    #[test]
-    fn test_merge() {
-        merge_test_aux(&[]);
-        merge_test_aux(&[&["a"]]);
-        merge_test_aux(&[&["a", "b"], &["ab"]]); // a, ab, b
-        merge_test_aux(&[&["a", "b"], &["a", "b"]]);
-        merge_test_aux(&[
-            &["happy", "hello", "payer", "tax"],
-            &["habitat", "hello", "zoo"],
-            &[],
-            &["a"],
-        ]);
-        merge_test_aux(&[&["a"]]);
-        merge_test_aux(&[&["a", "b"], &["ab"]]);
-        merge_test_aux(&[&["a", "b"], &["a", "b"]]);
-    }
-
-    #[test]
-    fn test_merge_u64() {
-        merge_test_u64_monotonic_aux(&[]);
-        merge_test_u64_monotonic_aux(&[&[("a", 1u64)]]);
-        merge_test_u64_monotonic_aux(&[&[("a", 1u64), ("b", 3u64)], &[("ab", 2u64)]]); // a, ab, b
-        merge_test_u64_monotonic_aux(&[&[("a", 1u64), ("b", 2u64)], &[("a", 16u64), ("b", 23u64)]]);
-    }
-}

src/termdict/sstable_termdict/sstable/mod.rs

@@ -1,365 +0,0 @@
-use merge::ValueMerger;
-use std::io::{self, Write};
-use std::usize;
-
-mod delta;
-pub mod merge;
-pub mod value;
-
-pub(crate) mod sstable_index;
-
-pub(crate) use self::sstable_index::{SSTableIndex, SSTableIndexBuilder};
-pub(crate) mod vint;
-
-mod block_reader;
-pub use self::delta::DeltaReader;
-use self::delta::DeltaWriter;
-use self::value::{U64MonotonicReader, U64MonotonicWriter, ValueReader, ValueWriter};
-
-pub use self::block_reader::BlockReader;
-pub use self::merge::VoidMerge;
-
-const DEFAULT_KEY_CAPACITY: usize = 50;
-
-pub(crate) fn common_prefix_len(left: &[u8], right: &[u8]) -> usize {
-    left.iter()
-        .cloned()
-        .zip(right.iter().cloned())
-        .take_while(|(left, right)| left == right)
-        .count()
-}
-
-pub trait SSTable: Sized {
-    type Value;
-    type Reader: ValueReader<Value = Self::Value>;
-    type Writer: ValueWriter<Value = Self::Value>;
-
-    fn delta_writer<W: io::Write>(write: W) -> DeltaWriter<W, Self::Writer> {
-        DeltaWriter::new(write)
-    }
-
-    fn writer<W: io::Write>(write: W) -> Writer<W, Self::Writer> {
-        Writer {
-            previous_key: Vec::with_capacity(DEFAULT_KEY_CAPACITY),
-            num_terms: 0u64,
-            index_builder: SSTableIndexBuilder::default(),
-            delta_writer: Self::delta_writer(write),
-            first_ordinal_of_the_block: 0u64,
-        }
-    }
-
-    fn delta_reader<'a, R: io::Read + 'a>(reader: R) -> DeltaReader<'a, Self::Reader> {
-        DeltaReader::new(reader)
-    }
-
-    fn reader<'a, R: io::Read + 'a>(reader: R) -> Reader<'a, Self::Reader> {
-        Reader {
-            key: Vec::with_capacity(DEFAULT_KEY_CAPACITY),
-            delta_reader: Self::delta_reader(reader),
-        }
-    }
-
-    fn merge<R: io::Read, W: io::Write, M: ValueMerger<Self::Value>>(
-        io_readers: Vec<R>,
-        w: W,
-        merger: M,
-    ) -> io::Result<()> {
-        let readers: Vec<_> = io_readers.into_iter().map(Self::reader).collect();
-        let writer = Self::writer(w);
-        merge::merge_sstable::<Self, _, _>(readers, writer, merger)
-    }
-}
-
-pub struct VoidSSTable;
-
-impl SSTable for VoidSSTable {
-    type Value = ();
-    type Reader = value::VoidReader;
-    type Writer = value::VoidWriter;
-}
-
-pub struct SSTableMonotonicU64;
-
-impl SSTable for SSTableMonotonicU64 {
-    type Value = u64;
-
-    type Reader = U64MonotonicReader;
-
-    type Writer = U64MonotonicWriter;
-}
-
-pub struct Reader<'a, TValueReader> {
-    key: Vec<u8>,
-    delta_reader: DeltaReader<'a, TValueReader>,
-}
-
-impl<'a, TValueReader> Reader<'a, TValueReader>
-where
-    TValueReader: ValueReader,
-{
-    pub fn advance(&mut self) -> io::Result<bool> {
-        if !self.delta_reader.advance()? {
-            return Ok(false);
-        }
-        let common_prefix_len = self.delta_reader.common_prefix_len();
-        let suffix = self.delta_reader.suffix();
-        let new_len = self.delta_reader.common_prefix_len() + suffix.len();
-        self.key.resize(new_len, 0u8);
-        self.key[common_prefix_len..].copy_from_slice(suffix);
-        Ok(true)
-    }
-
-    pub fn key(&self) -> &[u8] {
-        &self.key
-    }
-
-    pub fn value(&self) -> &TValueReader::Value {
-        self.delta_reader.value()
-    }
-
-    pub(crate) fn into_delta_reader(self) -> DeltaReader<'a, TValueReader> {
-        assert!(self.key.is_empty());
-        self.delta_reader
-    }
-}
-
-impl<'a, TValueReader> AsRef<[u8]> for Reader<'a, TValueReader> {
-    fn as_ref(&self) -> &[u8] {
-        &self.key
-    }
-}
-
-pub struct Writer<W, TValueWriter>
-where
-    W: io::Write,
-{
-    previous_key: Vec<u8>,
-    index_builder: SSTableIndexBuilder,
-    delta_writer: DeltaWriter<W, TValueWriter>,
-    num_terms: u64,
-    first_ordinal_of_the_block: u64,
-}
-
-impl<W, TValueWriter> Writer<W, TValueWriter>
-where
-    W: io::Write,
-    TValueWriter: value::ValueWriter,
-{
-    pub(crate) fn current_key(&self) -> &[u8] {
-        &self.previous_key[..]
-    }
-
-    pub fn write_key(&mut self, key: &[u8]) {
-        let keep_len = common_prefix_len(&self.previous_key, key);
-        let add_len = key.len() - keep_len;
-        let increasing_keys = add_len > 0 && (self.previous_key.len() == keep_len)
-            || self.previous_key.is_empty()
-            || self.previous_key[keep_len] < key[keep_len];
-        assert!(
-            increasing_keys,
-            "Keys should be increasing. ({:?} > {:?})",
-            self.previous_key, key
-        );
-        self.previous_key.resize(key.len(), 0u8);
-        self.previous_key[keep_len..].copy_from_slice(&key[keep_len..]);
-        self.delta_writer.write_suffix(keep_len, &key[keep_len..]);
-    }
-
-    pub(crate) fn into_delta_writer(self) -> DeltaWriter<W, TValueWriter> {
-        self.delta_writer
-    }
-
-    pub fn write(&mut self, key: &[u8], value: &TValueWriter::Value) -> io::Result<()> {
-        self.write_key(key);
-        self.write_value(value)?;
-        Ok(())
-    }
-
-    pub fn write_value(&mut self, value: &TValueWriter::Value) -> io::Result<()> {
-        self.delta_writer.write_value(value);
-        self.num_terms += 1u64;
-        self.flush_block_if_required()
-    }
-
-    pub fn flush_block_if_required(&mut self) -> io::Result<()> {
-        if let Some((start_offset, end_offset)) = self.delta_writer.flush_block_if_required()? {
-            self.index_builder.add_block(
-                &self.previous_key[..],
-                start_offset,
-                end_offset,
-                self.first_ordinal_of_the_block,
-            );
-            self.first_ordinal_of_the_block = self.num_terms;
-            self.previous_key.clear();
-        }
-        Ok(())
-    }
-
-    pub fn finalize(mut self) -> io::Result<W> {
-        if let Some((start_offset, end_offset)) = self.delta_writer.flush_block()? {
-            self.index_builder.add_block(
-                &self.previous_key[..],
-                start_offset,
-                end_offset,
-                self.first_ordinal_of_the_block,
-            );
-            self.first_ordinal_of_the_block = self.num_terms;
-        }
-        let mut wrt = self.delta_writer.finalize();
-        wrt.write_all(&0u32.to_le_bytes())?;
-
-        let offset = wrt.written_bytes();
-
-        self.index_builder.serialize(&mut wrt)?;
-        wrt.write_all(&offset.to_le_bytes())?;
-        wrt.write_all(&self.num_terms.to_le_bytes())?;
-        let wrt = wrt.finish();
-        Ok(wrt.into_inner()?)
-    }
-}
-#[cfg(test)]
-mod test {
-    use std::io;
-
-    use super::SSTable;
-    use super::VoidMerge;
-    use super::VoidSSTable;
-    use super::{common_prefix_len, SSTableMonotonicU64};
-
-    fn aux_test_common_prefix_len(left: &str, right: &str, expect_len: usize) {
-        assert_eq!(
-            common_prefix_len(left.as_bytes(), right.as_bytes()),
-            expect_len
-        );
-        assert_eq!(
-            common_prefix_len(right.as_bytes(), left.as_bytes()),
-            expect_len
-        );
-    }
-
-    #[test]
-    fn test_common_prefix_len() {
-        aux_test_common_prefix_len("a", "ab", 1);
-        aux_test_common_prefix_len("", "ab", 0);
-        aux_test_common_prefix_len("ab", "abc", 2);
-        aux_test_common_prefix_len("abde", "abce", 2);
-    }
-
-    #[test]
-    fn test_long_key_diff() {
-        let long_key = (0..1_024).map(|x| (x % 255) as u8).collect::<Vec<_>>();
-        let long_key2 = (1..300).map(|x| (x % 255) as u8).collect::<Vec<_>>();
-        let mut buffer = vec![];
-        {
-            let mut sstable_writer = VoidSSTable::writer(&mut buffer);
-            assert!(sstable_writer.write(&long_key[..], &()).is_ok());
-            assert!(sstable_writer.write(&[0, 3, 4], &()).is_ok());
-            assert!(sstable_writer.write(&long_key2[..], &()).is_ok());
-            assert!(sstable_writer.finalize().is_ok());
-        }
-        let mut sstable_reader = VoidSSTable::reader(&buffer[..]);
-        assert!(sstable_reader.advance().unwrap());
-        assert_eq!(sstable_reader.key(), &long_key[..]);
-        assert!(sstable_reader.advance().unwrap());
-        assert_eq!(sstable_reader.key(), &[0, 3, 4]);
-        assert!(sstable_reader.advance().unwrap());
-        assert_eq!(sstable_reader.key(), &long_key2[..]);
-        assert!(!sstable_reader.advance().unwrap());
-    }
-
-    #[test]
-    fn test_simple_sstable() {
-        let mut buffer = vec![];
-        {
-            let mut sstable_writer = VoidSSTable::writer(&mut buffer);
-            assert!(sstable_writer.write(&[17u8], &()).is_ok());
-            assert!(sstable_writer.write(&[17u8, 18u8, 19u8], &()).is_ok());
-            assert!(sstable_writer.write(&[17u8, 20u8], &()).is_ok());
-            assert!(sstable_writer.finalize().is_ok());
-        }
-        assert_eq!(
-            &buffer,
-            &[
-                // block len
-                7u8, 0u8, 0u8, 0u8, // keep 0 push 1 |  ""
-                16u8, 17u8, // keep 1 push 2 | 18 19
-                33u8, 18u8, 19u8, // keep 1 push 1 | 20
-                17u8, 20u8, 0u8, 0u8, 0u8, 0u8, // no more blocks
-                // index
-                161, 102, 98, 108, 111, 99, 107, 115, 129, 162, 104, 108, 97, 115, 116, 95, 107,
-                101, 121, 130, 17, 20, 106, 98, 108, 111, 99, 107, 95, 97, 100, 100, 114, 163, 108,
-                115, 116, 97, 114, 116, 95, 111, 102, 102, 115, 101, 116, 0, 106, 101, 110, 100,
-                95, 111, 102, 102, 115, 101, 116, 11, 109, 102, 105, 114, 115, 116, 95, 111, 114,
-                100, 105, 110, 97, 108, 0, 15, 0, 0, 0, 0, 0, 0, 0, // offset for the index
-                3u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8 // num terms
-            ]
-        );
-        let mut sstable_reader = VoidSSTable::reader(&buffer[..]);
-        assert!(sstable_reader.advance().unwrap());
-        assert_eq!(sstable_reader.key(), &[17u8]);
-        assert!(sstable_reader.advance().unwrap());
-        assert_eq!(sstable_reader.key(), &[17u8, 18u8, 19u8]);
-        assert!(sstable_reader.advance().unwrap());
-        assert_eq!(sstable_reader.key(), &[17u8, 20u8]);
-        assert!(!sstable_reader.advance().unwrap());
-    }
-
-    #[test]
-    #[should_panic]
-    fn test_simple_sstable_non_increasing_key() {
-        let mut buffer = vec![];
-        let mut sstable_writer = VoidSSTable::writer(&mut buffer);
-        assert!(sstable_writer.write(&[17u8], &()).is_ok());
-        assert!(sstable_writer.write(&[16u8], &()).is_ok());
-    }
-
-    #[test]
-    fn test_merge_abcd_abe() {
-        let mut buffer = Vec::new();
-        {
-            let mut writer = VoidSSTable::writer(&mut buffer);
-            writer.write(b"abcd", &()).unwrap();
-            writer.write(b"abe", &()).unwrap();
-            writer.finalize().unwrap();
-        }
-        let mut output = Vec::new();
-        assert!(VoidSSTable::merge(vec![&buffer[..], &buffer[..]], &mut output, VoidMerge).is_ok());
-        assert_eq!(&output[..], &buffer[..]);
-    }
-
-    #[test]
-    fn test_sstable() {
-        let mut buffer = Vec::new();
-        {
-            let mut writer = VoidSSTable::writer(&mut buffer);
-            writer.write(b"abcd", &()).unwrap();
-            writer.write(b"abe", &()).unwrap();
-            writer.finalize().unwrap();
-        }
-        let mut output = Vec::new();
-        assert!(VoidSSTable::merge(vec![&buffer[..], &buffer[..]], &mut output, VoidMerge).is_ok());
-        assert_eq!(&output[..], &buffer[..]);
-    }
-
-    #[test]
-    fn test_sstable_u64() -> io::Result<()> {
-        let mut buffer = Vec::new();
-        let mut writer = SSTableMonotonicU64::writer(&mut buffer);
-        writer.write(b"abcd", &1u64)?;
-        writer.write(b"abe", &4u64)?;
-        writer.write(b"gogo", &4324234234234234u64)?;
-        writer.finalize()?;
-        let mut reader = SSTableMonotonicU64::reader(&buffer[..]);
-        assert!(reader.advance()?);
-        assert_eq!(reader.key(), b"abcd");
-        assert_eq!(reader.value(), &1u64);
-        assert!(reader.advance()?);
-        assert_eq!(reader.key(), b"abe");
-        assert_eq!(reader.value(), &4u64);
-        assert!(reader.advance()?);
-        assert_eq!(reader.key(), b"gogo");
-        assert_eq!(reader.value(), &4324234234234234u64);
-        assert!(!reader.advance()?);
-        Ok(())
-    }
-}

src/termdict/sstable_termdict/sstable/sstable_index.rs

@@ -1,90 +0,0 @@
-use std::io;
-
-use serde;
-use serde::{Deserialize, Serialize};
-
-#[derive(Default, Debug, Serialize, Deserialize)]
-pub struct SSTableIndex {
-    blocks: Vec<BlockMeta>,
-}
-
-impl SSTableIndex {
-    pub fn load(data: &[u8]) -> SSTableIndex {
-        // TODO
-        serde_cbor::de::from_slice(data).unwrap()
-    }
-
-    pub fn search(&self, key: &[u8]) -> Option<BlockAddr> {
-        self.blocks
-            .iter()
-            .find(|block| &block.last_key[..] >= &key)
-            .map(|block| block.block_addr)
-    }
-}
-
-#[derive(Clone, Eq, PartialEq, Debug, Copy, Serialize, Deserialize)]
-pub struct BlockAddr {
-    pub start_offset: u64,
-    pub end_offset: u64,
-    pub first_ordinal: u64,
-}
-
-#[derive(Debug, Serialize, Deserialize)]
-struct BlockMeta {
-    pub last_key: Vec<u8>,
-    pub block_addr: BlockAddr,
-}
-
-#[derive(Default)]
-pub struct SSTableIndexBuilder {
-    index: SSTableIndex,
-}
-
-impl SSTableIndexBuilder {
-    pub fn add_block(
-        &mut self,
-        last_key: &[u8],
-        start_offset: u64,
-        stop_offset: u64,
-        first_ordinal: u64,
-    ) {
-        self.index.blocks.push(BlockMeta {
-            last_key: last_key.to_vec(),
-            block_addr: BlockAddr {
-                start_offset,
-                end_offset: stop_offset,
-                first_ordinal,
-            },
-        })
-    }
-
-    pub fn serialize(&self, wrt: &mut dyn io::Write) -> io::Result<()> {
-        serde_cbor::ser::to_writer(wrt, &self.index).unwrap();
-        Ok(())
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::{BlockAddr, SSTableIndex, SSTableIndexBuilder};
-
-    #[test]
-    fn test_sstable_index() {
-        let mut sstable_builder = SSTableIndexBuilder::default();
-        sstable_builder.add_block(b"aaa", 10u64, 20u64, 0u64);
-        sstable_builder.add_block(b"bbbbbbb", 20u64, 30u64, 564);
-        sstable_builder.add_block(b"ccc", 30u64, 40u64, 10u64);
-        sstable_builder.add_block(b"dddd", 40u64, 50u64, 15u64);
-        let mut buffer: Vec<u8> = Vec::new();
-        sstable_builder.serialize(&mut buffer).unwrap();
-        let sstable = SSTableIndex::load(&buffer[..]);
-        assert_eq!(
-            sstable.search(b"bbbde"),
-            Some(BlockAddr {
-                first_ordinal: 10u64,
-                start_offset: 30u64,
-                end_offset: 40u64
-            })
-        );
-    }
-}

src/termdict/sstable_termdict/sstable/value.rs

@@ -1,94 +0,0 @@
-use super::{vint, BlockReader};
-use std::io;
-
-pub trait ValueReader: Default {
-    type Value;
-
-    fn value(&self, idx: usize) -> &Self::Value;
-
-    fn read(&mut self, reader: &mut BlockReader) -> io::Result<()>;
-}
-
-pub trait ValueWriter: Default {
-    type Value;
-
-    fn write(&mut self, val: &Self::Value);
-
-    fn write_block(&mut self, writer: &mut Vec<u8>);
-}
-
-#[derive(Default)]
-pub struct VoidReader;
-
-impl ValueReader for VoidReader {
-    type Value = ();
-
-    fn value(&self, _idx: usize) -> &() {
-        &()
-    }
-
-    fn read(&mut self, _reader: &mut BlockReader) -> io::Result<()> {
-        Ok(())
-    }
-}
-
-#[derive(Default)]
-pub struct VoidWriter;
-
-impl ValueWriter for VoidWriter {
-    type Value = ();
-
-    fn write(&mut self, _val: &()) {}
-
-    fn write_block(&mut self, _writer: &mut Vec<u8>) {}
-}
-
-#[derive(Default)]
-pub struct U64MonotonicWriter {
-    vals: Vec<u64>,
-}
-
-impl ValueWriter for U64MonotonicWriter {
-    type Value = u64;
-
-    fn write(&mut self, val: &Self::Value) {
-        self.vals.push(*val);
-    }
-
-    fn write_block(&mut self, writer: &mut Vec<u8>) {
-        let mut prev_val = 0u64;
-        vint::serialize_into_vec(self.vals.len() as u64, writer);
-        for &val in &self.vals {
-            let delta = val - prev_val;
-            vint::serialize_into_vec(delta, writer);
-            prev_val = val;
-        }
-        self.vals.clear();
-    }
-}
-
-#[derive(Default)]
-pub struct U64MonotonicReader {
-    vals: Vec<u64>,
-}
-
-impl ValueReader for U64MonotonicReader {
-    type Value = u64;
-
-    fn value(&self, idx: usize) -> &Self::Value {
-        &self.vals[idx]
-    }
-
-    fn read(&mut self, reader: &mut BlockReader) -> io::Result<()> {
-        let len = reader.deserialize_u64() as usize;
-        self.vals.clear();
-        let mut prev_val = 0u64;
-        for _ in 0..len {
-            let delta = reader.deserialize_u64() as u64;
-            let val = prev_val + delta;
-            self.vals.push(val);
-            prev_val = val;
-        }
-        Ok(())
-    }
-}

src/termdict/sstable_termdict/sstable/vint.rs

@@ -1,74 +0,0 @@
-use super::BlockReader;
-
-const CONTINUE_BIT: u8 = 128u8;
-
-pub fn serialize(mut val: u64, buffer: &mut [u8]) -> usize {
-    for (i, b) in buffer.iter_mut().enumerate() {
-        let next_byte: u8 = (val & 127u64) as u8;
-        val = val >> 7;
-        if val == 0u64 {
-            *b = next_byte;
-            return i + 1;
-        } else {
-            *b = next_byte | CONTINUE_BIT;
-        }
-    }
-    10 //< actually unreachable
-}
-
-pub fn serialize_into_vec(val: u64, buffer: &mut Vec<u8>) {
-    let mut buf = [0u8; 10];
-    let num_bytes = serialize(val, &mut buf[..]);
-    buffer.extend_from_slice(&buf[..num_bytes]);
-}
-
-// super slow but we don't care
-pub fn deserialize_read(buf: &[u8]) -> (usize, u64) {
-    let mut result = 0u64;
-    let mut shift = 0u64;
-    let mut consumed = 0;
-
-    for &b in buf {
-        consumed += 1;
-        result |= u64::from(b % 128u8) << shift;
-        if b < CONTINUE_BIT {
-            break;
-        }
-        shift += 7;
-    }
-    (consumed, result)
-}
-
-pub fn deserialize_from_block(block: &mut BlockReader) -> u64 {
-    let (num_bytes, val) = deserialize_read(block.buffer());
-    block.advance(num_bytes);
-    val
-}
-
-#[cfg(test)]
-mod tests {
-    use super::{deserialize_read, serialize};
-    use std::u64;
-
-    fn aux_test_int(val: u64, expect_len: usize) {
-        let mut buffer = [0u8; 14];
-        assert_eq!(serialize(val, &mut buffer[..]), expect_len);
-        assert_eq!(deserialize_read(&buffer), (expect_len, val));
-    }
-
-    #[test]
-    fn test_vint() {
-        aux_test_int(0u64, 1);
-        aux_test_int(17u64, 1);
-        aux_test_int(127u64, 1);
-        aux_test_int(128u64, 2);
-        aux_test_int(123423418u64, 4);
-        for i in 1..63 {
-            let power_of_two = 1u64 << i;
-            aux_test_int(power_of_two + 1, (i / 7) + 1);
-            aux_test_int(power_of_two, (i / 7) + 1);
-            aux_test_int(power_of_two - 1, ((i - 1) / 7) + 1);
-        }
-        aux_test_int(u64::MAX, 10);
-    }
-}

src/termdict/sstable_termdict/streamer.rs

@@ -1,227 +0,0 @@
-use super::TermDictionary;
-use crate::postings::TermInfo;
-use crate::termdict::sstable_termdict::TermInfoReader;
-use crate::termdict::TermOrdinal;
-use std::io;
-use std::ops::Bound;
-use tantivy_fst::automaton::AlwaysMatch;
-use tantivy_fst::Automaton;
-
-/// `TermStreamerBuilder` is a helper object used to define
-/// a range of terms that should be streamed.
-pub struct TermStreamerBuilder<'a, A = AlwaysMatch>
-where
-    A: Automaton,
-    A::State: Clone,
-{
-    term_dict: &'a TermDictionary,
-    automaton: A,
-    lower: Bound<Vec<u8>>,
-    upper: Bound<Vec<u8>>,
-}
-
-impl<'a, A> TermStreamerBuilder<'a, A>
-where
-    A: Automaton,
-    A::State: Clone,
-{
-    pub(crate) fn new(term_dict: &'a TermDictionary, automaton: A) -> Self {
-        TermStreamerBuilder {
-            term_dict,
-            automaton,
-            lower: Bound::Unbounded,
-            upper: Bound::Unbounded,
-        }
-    }
-
-    /// Limit the range to terms greater or equal to the bound
-    pub fn ge<T: AsRef<[u8]>>(mut self, bound: T) -> Self {
-        self.lower = Bound::Included(bound.as_ref().to_owned());
-        self
-    }
-
-    /// Limit the range to terms strictly greater than the bound
-    pub fn gt<T: AsRef<[u8]>>(mut self, bound: T) -> Self {
-        self.lower = Bound::Excluded(bound.as_ref().to_owned());
-        self
-    }
-
-    /// Limit the range to terms lesser or equal to the bound
-    pub fn le<T: AsRef<[u8]>>(mut self, bound: T) -> Self {
-        self.upper = Bound::Included(bound.as_ref().to_owned());
-        self
-    }
-
-    /// Limit the range to terms lesser or equal to the bound
-    pub fn lt<T: AsRef<[u8]>>(mut self, bound: T) -> Self {
-        self.lower = Bound::Excluded(bound.as_ref().to_owned());
-        self
-    }
-
-    pub fn backward(mut self) -> Self {
-        unimplemented!()
-    }
-
-    /// Creates the stream corresponding to the range
-    /// of terms defined using the `TermStreamerBuilder`.
-    pub fn into_stream(self) -> io::Result<TermStreamer<'a, A>> {
-        let start_state = self.automaton.start();
-        let delta_reader = self.term_dict.sstable_delta_reader()?;
-        Ok(TermStreamer {
-            automaton: self.automaton,
-            states: vec![start_state],
-            delta_reader,
-            key: Vec::new(),
-            term_ord: 0u64,
-        })
-    }
-}
-
-/// `TermStreamer` acts as a cursor over a range of terms of a segment.
-/// Terms are guaranteed to be sorted.
-pub struct TermStreamer<'a, A = AlwaysMatch>
-where
-    A: Automaton,
-    A::State: Clone,
-{
-    automaton: A,
-    states: Vec<A::State>,
-    delta_reader: super::sstable::DeltaReader<'a, TermInfoReader>,
-    key: Vec<u8>,
-    term_ord: TermOrdinal,
-}
-
-impl<'a, A> TermStreamer<'a, A>
-where
-    A: Automaton,
-    A::State: Clone,
-{
-    /// Advance position the stream on the next item.
-    /// Before the first call to `.advance()`, the stream
-    /// is an unitialized state.
-    pub fn advance(&mut self) -> bool {
-        while self.delta_reader.advance().unwrap() {
-            self.term_ord += 1u64;
-            let common_prefix_len = self.delta_reader.common_prefix_len();
-            self.states.truncate(common_prefix_len + 1);
-            self.key.truncate(common_prefix_len);
-            let mut state: A::State = self.states.last().unwrap().clone();
-            for &b in self.delta_reader.suffix() {
-                state = self.automaton.accept(&state, b);
-                self.states.push(state.clone());
-            }
-            self.key.extend_from_slice(self.delta_reader.suffix());
-            if self.automaton.is_match(&state) {
-                return true;
-            }
-        }
-        false
-    }
-
-    /// Returns the `TermOrdinal` of the given term.
-    ///
-    /// May panic if the called as `.advance()` as never
-    /// been called before.
-    pub fn term_ord(&self) -> TermOrdinal {
-        self.term_ord
-    }
-
-    /// Accesses the current key.
-    ///
-    /// `.key()` should return the key that was returned
-    /// by the `.next()` method.
-    ///
-    /// If the end of the stream as been reached, and `.next()`
-    /// has been called and returned `None`, `.key()` remains
-    /// the value of the last key encountered.
-    ///
-    /// Before any call to `.next()`, `.key()` returns an empty array.
-    pub fn key(&self) -> &[u8] {
-        &self.key
-    }
-
-    /// Accesses the current value.
-    ///
-    /// Calling `.value()` after the end of the stream will return the
-    /// last `.value()` encountered.
-    ///
-    /// # Panics
-    ///
-    /// Calling `.value()` before the first call to `.advance()` returns
-    /// `V::default()`.
-    pub fn value(&self) -> &TermInfo {
-        self.delta_reader.value()
-    }
-
-    /// Return the next `(key, value)` pair.
-    #[cfg_attr(feature = "cargo-clippy", allow(clippy::should_implement_trait))]
-    pub fn next(&mut self) -> Option<(&[u8], &TermInfo)> {
-        if self.advance() {
-            Some((self.key(), self.value()))
-        } else {
-            None
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::super::TermDictionary;
-    use crate::directory::OwnedBytes;
-    use crate::postings::TermInfo;
-
-    fn make_term_info(i: u64) -> TermInfo {
-        TermInfo {
-            doc_freq: 1000u32 + i as u32,
-            positions_idx: i * 500,
-            postings_start_offset: (i + 10) * (i * 10),
-            postings_stop_offset: ((i + 1) + 10) * ((i + 1) * 10),
-        }
-    }
-
-    fn create_test_term_dictionary() -> crate::Result<TermDictionary> {
-        let mut term_dict_builder = super::super::TermDictionaryBuilder::create(Vec::new())?;
-        term_dict_builder.insert(b"abaisance", &make_term_info(0u64))?;
-        term_dict_builder.insert(b"abalation", &make_term_info(1u64))?;
-        term_dict_builder.insert(b"abalienate", &make_term_info(2u64))?;
-        term_dict_builder.insert(b"abandon", &make_term_info(3u64))?;
-        let buffer = term_dict_builder.finish()?;
-        let owned_bytes = OwnedBytes::new(buffer);
-        TermDictionary::from_bytes(owned_bytes)
-    }
-
-    #[test]
-    fn test_sstable_stream() -> crate::Result<()> {
-        let term_dict = create_test_term_dictionary()?;
-        let mut term_streamer = term_dict.stream()?;
-        assert!(term_streamer.advance());
-        assert_eq!(term_streamer.key(), b"abaisance");
-        assert_eq!(term_streamer.value().doc_freq, 1000u32);
-        assert!(term_streamer.advance());
-        assert_eq!(term_streamer.key(), b"abalation");
-        assert_eq!(term_streamer.value().doc_freq, 1001u32);
-        assert!(term_streamer.advance());
-        assert_eq!(term_streamer.key(), b"abalienate");
-        assert_eq!(term_streamer.value().doc_freq, 1002u32);
-        assert!(term_streamer.advance());
-        assert_eq!(term_streamer.key(), b"abandon");
-        assert_eq!(term_streamer.value().doc_freq, 1003u32);
-        assert!(!term_streamer.advance());
-        Ok(())
-    }
-
-    #[test]
-    fn test_sstable_search() -> crate::Result<()> {
-        let term_dict = create_test_term_dictionary()?;
-        let ptn = tantivy_fst::Regex::new("ab.*t.*").unwrap();
-        let mut term_streamer = term_dict.search(ptn).into_stream()?;
-        assert!(term_streamer.advance());
-        assert_eq!(term_streamer.key(), b"abalation");
-        assert_eq!(term_streamer.value().doc_freq, 1001u32);
-        assert!(term_streamer.advance());
-        assert_eq!(term_streamer.key(), b"abalienate");
-        assert_eq!(term_streamer.value().doc_freq, 1002u32);
-        assert!(!term_streamer.advance());
-        Ok(())
-    }
-}

src/termdict/sstable_termdict/termdict.rs

@@ -1,228 +0,0 @@
-use std::io;
-
-use crate::common::BinarySerializable;
-use crate::directory::{FileSlice, OwnedBytes};
-use crate::postings::TermInfo;
-use crate::termdict::sstable_termdict::sstable::sstable_index::BlockAddr;
-use crate::termdict::sstable_termdict::sstable::Writer;
-use crate::termdict::sstable_termdict::sstable::{DeltaReader, SSTable};
-use crate::termdict::sstable_termdict::sstable::{Reader, SSTableIndex};
-use crate::termdict::sstable_termdict::{
-    TermInfoReader, TermInfoWriter, TermSSTable, TermStreamer, TermStreamerBuilder,
-};
-use crate::termdict::TermOrdinal;
-use crate::HasLen;
-use once_cell::sync::Lazy;
-use tantivy_fst::automaton::AlwaysMatch;
-use tantivy_fst::Automaton;
-
-pub struct TermInfoSSTable;
-impl SSTable for TermInfoSSTable {
-    type Value = TermInfo;
-    type Reader = TermInfoReader;
-    type Writer = TermInfoWriter;
-}
-pub struct TermDictionaryBuilder<W: io::Write> {
-    sstable_writer: Writer<W, TermInfoWriter>,
-}
-
-impl<W: io::Write> TermDictionaryBuilder<W> {
-    /// Creates a new `TermDictionaryBuilder`
-    pub fn create(w: W) -> io::Result<Self> {
-        let sstable_writer = TermSSTable::writer(w);
-        Ok(TermDictionaryBuilder { sstable_writer })
-    }
-
-    /// Inserts a `(key, value)` pair in the term dictionary.
-    ///
-    /// *Keys have to be inserted in order.*
-    pub fn insert<K: AsRef<[u8]>>(&mut self, key_ref: K, value: &TermInfo) -> io::Result<()> {
-        let key = key_ref.as_ref();
-        self.insert_key(key)?;
-        self.insert_value(value)?;
-        Ok(())
-    }
-
-    /// # Warning
-    /// Horribly dangerous internal API
-    ///
-    /// If used, it must be used by systematically alternating calls
-    /// to insert_key and insert_value.
-    ///
-    /// Prefer using `.insert(key, value)`
-    pub(crate) fn insert_key(&mut self, key: &[u8]) -> io::Result<()> {
-        self.sstable_writer.write_key(key);
-        Ok(())
-    }
-
-    /// # Warning
-    ///
-    /// Horribly dangerous internal API. See `.insert_key(...)`.
-    pub(crate) fn insert_value(&mut self, term_info: &TermInfo) -> io::Result<()> {
-        self.sstable_writer.write_value(term_info);
-        Ok(())
-    }
-
-    /// Finalize writing the builder, and returns the underlying
-    /// `Write` object.
-    pub fn finish(self) -> io::Result<W> {
-        self.sstable_writer.finalize()
-    }
-}
-
-static EMPTY_TERM_DICT_FILE: Lazy<FileSlice> = Lazy::new(|| {
-    let term_dictionary_data: Vec<u8> = TermDictionaryBuilder::create(Vec::<u8>::new())
-        .expect("Creating a TermDictionaryBuilder in a Vec<u8> should never fail")
-        .finish()
-        .expect("Writing in a Vec<u8> should never fail");
-    FileSlice::from(term_dictionary_data)
-});
-
-/// The term dictionary contains all of the terms in
-/// `tantivy index` in a sorted manner.
-///
-/// The `Fst` crate is used to associate terms to their
-/// respective `TermOrdinal`. The `TermInfoStore` then makes it
-/// possible to fetch the associated `TermInfo`.
-pub struct TermDictionary {
-    sstable_slice: FileSlice,
-    sstable_index: SSTableIndex,
-    num_terms: u64,
-}
-
-impl TermDictionary {
-    pub(crate) fn sstable_reader(&self) -> io::Result<Reader<'static, TermInfoReader>> {
-        let data = self.sstable_slice.read_bytes()?;
-        Ok(TermInfoSSTable::reader(data))
-    }
-
-    pub(crate) fn sstable_reader_block(
-        &self,
-        block_addr: BlockAddr,
-    ) -> io::Result<Reader<'static, TermInfoReader>> {
-        let data = self.sstable_slice.read_bytes_slice(
-            block_addr.start_offset as usize,
-            block_addr.end_offset as usize,
-        )?;
-        Ok(TermInfoSSTable::reader(data))
-    }
-
-    pub(crate) fn sstable_delta_reader(&self) -> io::Result<DeltaReader<'static, TermInfoReader>> {
-        let data = self.sstable_slice.read_bytes()?;
-        Ok(TermInfoSSTable::delta_reader(data))
-    }
-
-    /// Opens a `TermDictionary`.
-    pub fn open(term_dictionary_file: FileSlice) -> crate::Result<Self> {
-        let (main_slice, footer_len_slice) = term_dictionary_file.split_from_end(16);
-        let mut footer_len_bytes: OwnedBytes = footer_len_slice.read_bytes()?;
-        let index_offset = u64::deserialize(&mut footer_len_bytes)?;
-        let num_terms = u64::deserialize(&mut footer_len_bytes)?;
-        let (sstable_slice, index_slice) = main_slice.split(index_offset as usize);
-        // dbg!(index_slice.len());
-        let sstable_index_bytes = index_slice.read_bytes()?;
-        let sstable_index = SSTableIndex::load(sstable_index_bytes.as_slice());
-        // dbg!(&sstable_index);
-        Ok(TermDictionary {
-            sstable_slice,
-            sstable_index,
-            num_terms,
-        })
-    }
-
-    pub fn from_bytes(owned_bytes: OwnedBytes) -> crate::Result<TermDictionary> {
-        TermDictionary::open(FileSlice::new(Box::new(owned_bytes)))
-    }
-
-    /// Creates an empty term dictionary which contains no terms.
-    pub fn empty() -> Self {
-        TermDictionary::open(EMPTY_TERM_DICT_FILE.clone()).unwrap()
-    }
-
-    /// Returns the number of terms in the dictionary.
-    /// Term ordinals range from 0 to `num_terms() - 1`.
-    pub fn num_terms(&self) -> usize {
-        self.num_terms as usize
-    }
-
-    /// Returns the ordinal associated to a given term.
-    pub fn term_ord<K: AsRef<[u8]>>(&self, key: K) -> io::Result<Option<TermOrdinal>> {
-        let mut term_ord = 0u64;
-        let key_bytes = key.as_ref();
-        let mut sstable_reader = self.sstable_reader()?;
-        while sstable_reader.advance().unwrap_or(false) {
-            if sstable_reader.key() == key_bytes {
-                return Ok(Some(term_ord));
-            }
-            term_ord += 1;
-        }
-        Ok(None)
-    }
-
-    /// Returns the term associated to a given term ordinal.
-    ///
-    /// Term ordinals are defined as the position of the term in
-    /// the sorted list of terms.
-    ///
-    /// Returns true iff the term has been found.
-    ///
-    /// Regardless of whether the term is found or not,
-    /// the buffer may be modified.
-    pub fn ord_to_term(&self, ord: TermOrdinal, bytes: &mut Vec<u8>) -> io::Result<bool> {
-        let mut sstable_reader = self.sstable_reader()?;
-        bytes.clear();
-        for _ in 0..(ord + 1) {
-            if !sstable_reader.advance().unwrap_or(false) {
-                return Ok(false);
-            }
-        }
-        bytes.extend_from_slice(sstable_reader.key());
-        Ok(true)
-    }
-
-    /// Returns the number of terms in the dictionary.
-    pub fn term_info_from_ord(&self, term_ord: TermOrdinal) -> io::Result<TermInfo> {
-        let mut sstable_reader = self.sstable_reader()?;
-        for _ in 0..(term_ord + 1) {
-            if !sstable_reader.advance().unwrap_or(false) {
-                return Ok(TermInfo::default());
-            }
-        }
-        Ok(sstable_reader.value().clone())
-    }
-
-    /// Lookups the value corresponding to the key.
-    pub fn get<K: AsRef<[u8]>>(&self, key: K) -> io::Result<Option<TermInfo>> {
-        if let Some(block_addr) = self.sstable_index.search(key.as_ref()) {
-            let mut sstable_reader = self.sstable_reader_block(block_addr)?;
-            let key_bytes = key.as_ref();
-            while sstable_reader.advance().unwrap_or(false) {
-                if sstable_reader.key() == key_bytes {
-                    let term_info = sstable_reader.value().clone();
-                    return Ok(Some(term_info));
-                }
-            }
-        }
-        Ok(None)
-    }
-
-    // Returns a range builder, to stream all of the terms
-    // within an interval.
-    pub fn range(&self) -> TermStreamerBuilder<'_> {
-        TermStreamerBuilder::new(self, AlwaysMatch)
-    }
-
-    // A stream of all the sorted terms. [See also `.stream_field()`](#method.stream_field)
-    pub fn stream(&self) -> io::Result<TermStreamer<'_>> {
-        self.range().into_stream()
-    }
-
-    // Returns a search builder, to stream all of the terms
-    // within the Automaton
-    pub fn search<'a, A: Automaton + 'a>(&'a self, automaton: A) -> TermStreamerBuilder<'a, A>
-    where
-        A::State: Clone,
-    {
-        TermStreamerBuilder::<A>::new(self, automaton)
-    }
-}

src/termdict/tests.rs

@@ -249,8 +249,7 @@ fn test_empty_string() -> crate::Result<()> {
     Ok(())
 }
 
-#[test]
-fn test_stream_range_boundaries() -> crate::Result<()> {
+fn stream_range_test_dict() -> crate::Result<TermDictionary> {
     let buffer: Vec<u8> = {
         let mut term_dictionary_builder = TermDictionaryBuilder::create(Vec::new())?;
         for i in 0u8..10u8 {
@@ -260,84 +259,96 @@ fn test_stream_range_boundaries() -> crate::Result<()> {
         term_dictionary_builder.finish()?
     };
     let file = FileSlice::from(buffer);
-    let term_dictionary: TermDictionary = TermDictionary::open(file)?;
+    TermDictionary::open(file)
+}
 
-    let value_list = |mut streamer: TermStreamer<'_>, backwards: bool| {
+#[test]
+fn test_stream_range_boundaries_forward() -> crate::Result<()> {
+    let term_dictionary = stream_range_test_dict()?;
+    let value_list = |mut streamer: TermStreamer<'_>| {
         let mut res: Vec<u32> = vec![];
         while let Some((_, ref v)) = streamer.next() {
             res.push(v.doc_freq);
         }
-        if backwards {
-            res.reverse();
-        }
         res
     };
-    {
-        let range = term_dictionary.range().backward().into_stream()?;
-        assert_eq!(
-            value_list(range, true),
-            vec![0u32, 1u32, 2u32, 3u32, 4u32, 5u32, 6u32, 7u32, 8u32, 9u32]
-        );
-    }
     {
         let range = term_dictionary.range().ge([2u8]).into_stream()?;
         assert_eq!(
-            value_list(range, false),
-            vec![2u32, 3u32, 4u32, 5u32, 6u32, 7u32, 8u32, 9u32]
-        );
-    }
-    {
-        let range = term_dictionary.range().ge([2u8]).backward().into_stream()?;
-        assert_eq!(
-            value_list(range, true),
+            value_list(range),
             vec![2u32, 3u32, 4u32, 5u32, 6u32, 7u32, 8u32, 9u32]
         );
     }
     {
         let range = term_dictionary.range().gt([2u8]).into_stream()?;
         assert_eq!(
-            value_list(range, false),
-            vec![3u32, 4u32, 5u32, 6u32, 7u32, 8u32, 9u32]
-        );
-    }
-    {
-        let range = term_dictionary.range().gt([2u8]).backward().into_stream()?;
-        assert_eq!(
-            value_list(range, true),
+            value_list(range),
             vec![3u32, 4u32, 5u32, 6u32, 7u32, 8u32, 9u32]
         );
     }
     {
         let range = term_dictionary.range().lt([6u8]).into_stream()?;
-        assert_eq!(
-            value_list(range, false),
-            vec![0u32, 1u32, 2u32, 3u32, 4u32, 5u32]
-        );
-    }
-    {
-        let range = term_dictionary.range().lt([6u8]).backward().into_stream()?;
-        assert_eq!(
-            value_list(range, true),
-            vec![0u32, 1u32, 2u32, 3u32, 4u32, 5u32]
-        );
+        assert_eq!(value_list(range), vec![0u32, 1u32, 2u32, 3u32, 4u32, 5u32]);
     }
     {
         let range = term_dictionary.range().le([6u8]).into_stream()?;
         assert_eq!(
-            value_list(range, false),
-            vec![0u32, 1u32, 2u32, 3u32, 4u32, 5u32, 6u32]
-        );
-    }
-    {
-        let range = term_dictionary.range().le([6u8]).backward().into_stream()?;
-        assert_eq!(
-            value_list(range, true),
+            value_list(range),
             vec![0u32, 1u32, 2u32, 3u32, 4u32, 5u32, 6u32]
         );
     }
     {
         let range = term_dictionary.range().ge([0u8]).lt([5u8]).into_stream()?;
-        assert_eq!(value_list(range, false), vec![0u32, 1u32, 2u32, 3u32, 4u32]);
+        assert_eq!(value_list(range), vec![0u32, 1u32, 2u32, 3u32, 4u32]);
+    }
+    Ok(())
+}
+
+#[test]
+fn test_stream_range_boundaries_backward() -> crate::Result<()> {
+    let term_dictionary = stream_range_test_dict()?;
+    let value_list_backward = |mut streamer: TermStreamer<'_>| {
+        let mut res: Vec<u32> = vec![];
+        while let Some((_, ref v)) = streamer.next() {
+            res.push(v.doc_freq);
+        }
+        res.reverse();
+        res
+    };
+    {
+        let range = term_dictionary.range().backward().into_stream()?;
+        assert_eq!(
+            value_list_backward(range),
+            vec![0u32, 1u32, 2u32, 3u32, 4u32, 5u32, 6u32, 7u32, 8u32, 9u32]
+        );
+    }
+    {
+        let range = term_dictionary.range().ge([2u8]).backward().into_stream()?;
+        assert_eq!(
+            value_list_backward(range),
+            vec![2u32, 3u32, 4u32, 5u32, 6u32, 7u32, 8u32, 9u32]
+        );
+    }
+    {
+        let range = term_dictionary.range().gt([2u8]).backward().into_stream()?;
+        assert_eq!(
+            value_list_backward(range),
+            vec![3u32, 4u32, 5u32, 6u32, 7u32, 8u32, 9u32]
+        );
+    }
+    {
+        let range = term_dictionary.range().lt([6u8]).backward().into_stream()?;
+        assert_eq!(
+            value_list_backward(range),
+            vec![0u32, 1u32, 2u32, 3u32, 4u32, 5u32]
+        );
+    }
+    {
+        let range = term_dictionary.range().le([6u8]).backward().into_stream()?;
+        assert_eq!(
+            value_list_backward(range),
+            vec![0u32, 1u32, 2u32, 3u32, 4u32, 5u32, 6u32]
+        );
     }
     {
         let range = term_dictionary
@@ -346,11 +357,38 @@ fn test_stream_range_boundaries() -> crate::Result<()> {
             .lt([5u8])
             .backward()
             .into_stream()?;
-        assert_eq!(value_list(range, true), vec![0u32, 1u32, 2u32, 3u32, 4u32]);
+        assert_eq!(
+            value_list_backward(range),
+            vec![0u32, 1u32, 2u32, 3u32, 4u32]
+        );
     }
     Ok(())
 }
 
+#[test]
+fn test_ord_to_term() -> crate::Result<()> {
+    let termdict = stream_range_test_dict()?;
+    let mut bytes = vec![];
+    for b in 0u8..10u8 {
+        termdict.ord_to_term(b as u64, &mut bytes)?;
+        assert_eq!(&bytes, &[b]);
+    }
+    Ok(())
+}
+
+#[test]
+fn test_stream_term_ord() -> crate::Result<()> {
+    let termdict = stream_range_test_dict()?;
+    let mut stream = termdict.stream()?;
+    for b in 0u8..10u8 {
+        assert!(stream.advance(), true);
+        assert_eq!(stream.term_ord(), b as u64);
+        assert_eq!(stream.key(), &[b]);
+    }
+    assert!(!stream.advance());
+    Ok(())
+}
+
 #[test]
 fn test_automaton_search() -> crate::Result<()> {
     use crate::query::DFAWrapper;

src/tokenizer/alphanum_only.rs

@@ -19,7 +19,7 @@
 //! // the "emoji" is dropped because its not an alphanum
 //! assert!(stream.next().is_none());
 //! ```
-use super::{BoxTokenStream, Token, TokenFilter, TokenStream};
+use super::{Token, TokenFilter, TokenStream};
 
 /// `TokenFilter` that removes all tokens that contain non
 /// ascii alphanumeric characters.
@@ -27,7 +27,7 @@ use super::{BoxTokenStream, Token, TokenFilter, TokenStream};
 pub struct AlphaNumOnlyFilter;
 
 pub struct AlphaNumOnlyFilterStream<'a> {
-    tail: BoxTokenStream<'a>,
+    tail: Box<dyn TokenStream + 'a>,
 }
 
 impl<'a> AlphaNumOnlyFilterStream<'a> {
@@ -37,8 +37,8 @@ impl<'a> AlphaNumOnlyFilterStream<'a> {
 }
 
 impl TokenFilter for AlphaNumOnlyFilter {
-    fn transform<'a>(&self, token_stream: BoxTokenStream<'a>) -> BoxTokenStream<'a> {
-        BoxTokenStream::from(AlphaNumOnlyFilterStream { tail: token_stream })
+    fn transform<'a>(&self, token_stream: Box<dyn TokenStream + 'a>) -> Box<dyn TokenStream + 'a> {
+        Box::new(AlphaNumOnlyFilterStream { tail: token_stream })
     }
 }
 

src/tokenizer/ascii_folding_filter.rs

@@ -1,4 +1,4 @@
-use super::{BoxTokenStream, Token, TokenFilter, TokenStream};
+use super::{Token, TokenFilter, TokenStream};
 use std::mem;
 
 /// This class converts alphabetic, numeric, and symbolic Unicode characters
@@ -8,8 +8,8 @@ use std::mem;
 pub struct AsciiFoldingFilter;
 
 impl TokenFilter for AsciiFoldingFilter {
-    fn transform<'a>(&self, token_stream: BoxTokenStream<'a>) -> BoxTokenStream<'a> {
-        From::from(AsciiFoldingFilterTokenStream {
+    fn transform<'a>(&self, token_stream: Box<dyn TokenStream + 'a>) -> Box<dyn TokenStream + 'a> {
+        Box::new(AsciiFoldingFilterTokenStream {
             tail: token_stream,
             buffer: String::with_capacity(100),
         })
@@ -18,7 +18,7 @@ impl TokenFilter for AsciiFoldingFilter {
 
 pub struct AsciiFoldingFilterTokenStream<'a> {
     buffer: String,
-    tail: BoxTokenStream<'a>,
+    tail: Box<dyn TokenStream + 'a>,
 }
 
 impl<'a> TokenStream for AsciiFoldingFilterTokenStream<'a> {

src/tokenizer/facet_tokenizer.rs

@@ -1,4 +1,4 @@
-use super::{BoxTokenStream, Token, TokenStream, Tokenizer};
+use super::{Token, TokenStream, Tokenizer};
 use crate::schema::FACET_SEP_BYTE;
 
 /// The `FacetTokenizer` process a `Facet` binary representation
@@ -26,13 +26,12 @@ pub struct FacetTokenStream<'a> {
 }
 
 impl Tokenizer for FacetTokenizer {
-    fn token_stream<'a>(&self, text: &'a str) -> BoxTokenStream<'a> {
-        FacetTokenStream {
+    fn token_stream<'a>(&self, text: &'a str) -> Box<dyn TokenStream + 'a> {
+        Box::new(FacetTokenStream {
             text,
             state: State::RootFacetNotEmitted, //< pos is the first char that has not been processed yet.
             token: Token::default(),
-        }
-        .into()
+        })
     }
 }
 

src/tokenizer/lower_caser.rs

@@ -1,10 +1,9 @@
 use super::{Token, TokenFilter, TokenStream};
-use crate::tokenizer::BoxTokenStream;
 use std::mem;
 
 impl TokenFilter for LowerCaser {
-    fn transform<'a>(&self, token_stream: BoxTokenStream<'a>) -> BoxTokenStream<'a> {
-        BoxTokenStream::from(LowerCaserTokenStream {
+    fn transform<'a>(&self, token_stream: Box<dyn TokenStream + 'a>) -> Box<dyn TokenStream + 'a> {
+        Box::new(LowerCaserTokenStream {
             tail: token_stream,
             buffer: String::with_capacity(100),
         })
@@ -17,7 +16,7 @@ pub struct LowerCaser;
 
 pub struct LowerCaserTokenStream<'a> {
     buffer: String,
-    tail: BoxTokenStream<'a>,
+    tail: Box<dyn TokenStream + 'a>,
 }
 
 // writes a lowercased version of text into output.

src/tokenizer/mod.rs

@@ -145,9 +145,7 @@ pub use self::stop_word_filter::StopWordFilter;
 pub(crate) use self::token_stream_chain::TokenStreamChain;
 
 pub use self::tokenized_string::{PreTokenizedStream, PreTokenizedString};
-pub use self::tokenizer::{
-    BoxTokenFilter, BoxTokenStream, TextAnalyzer, Token, TokenFilter, TokenStream, Tokenizer,
-};
+pub use self::tokenizer::{TextAnalyzer, Token, TokenFilter, TokenStream, Tokenizer};
 
 pub use self::tokenizer_manager::TokenizerManager;
 

src/tokenizer/ngram_tokenizer.rs

@@ -1,5 +1,4 @@
 use super::{Token, TokenStream, Tokenizer};
-use crate::tokenizer::BoxTokenStream;
 
 /// Tokenize the text by splitting words into n-grams of the given size(s)
 ///
@@ -131,8 +130,8 @@ pub struct NgramTokenStream<'a> {
 }
 
 impl Tokenizer for NgramTokenizer {
-    fn token_stream<'a>(&self, text: &'a str) -> BoxTokenStream<'a> {
-        From::from(NgramTokenStream {
+    fn token_stream<'a>(&self, text: &'a str) -> Box<dyn TokenStream + 'a> {
+        Box::new(NgramTokenStream {
             ngram_charidx_iterator: StutteringIterator::new(
                 CodepointFrontiers::for_str(text),
                 self.min_gram,
@@ -308,9 +307,9 @@ mod tests {
     use super::StutteringIterator;
     use crate::tokenizer::tests::assert_token;
     use crate::tokenizer::tokenizer::Tokenizer;
-    use crate::tokenizer::{BoxTokenStream, Token};
+    use crate::tokenizer::{Token, TokenStream};
 
-    fn test_helper(mut tokenizer: BoxTokenStream) -> Vec<Token> {
+    fn test_helper(mut tokenizer: Box<dyn TokenStream>) -> Vec<Token> {
         let mut tokens: Vec<Token> = vec![];
         tokenizer.process(&mut |token: &Token| tokens.push(token.clone()));
         tokens

src/tokenizer/raw_tokenizer.rs

@@ -1,5 +1,4 @@
 use super::{Token, TokenStream, Tokenizer};
-use crate::tokenizer::BoxTokenStream;
 
 /// For each value of the field, emit a single unprocessed token.
 #[derive(Clone)]
@@ -11,7 +10,7 @@ pub struct RawTokenStream {
 }
 
 impl Tokenizer for RawTokenizer {
-    fn token_stream<'a>(&self, text: &'a str) -> BoxTokenStream<'a> {
+    fn token_stream<'a>(&self, text: &'a str) -> Box<dyn TokenStream + 'a> {
         let token = Token {
             offset_from: 0,
             offset_to: text.len(),
@@ -19,11 +18,10 @@ impl Tokenizer for RawTokenizer {
             text: text.to_string(),
             position_length: 1,
         };
-        RawTokenStream {
+        Box::new(RawTokenStream {
             token,
             has_token: true,
-        }
-        .into()
+        })
     }
 }
 

src/tokenizer/remove_long.rs

@@ -13,7 +13,6 @@
 //! ```
 //!
 use super::{Token, TokenFilter, TokenStream};
-use crate::tokenizer::BoxTokenStream;
 
 /// `RemoveLongFilter` removes tokens that are longer
 /// than a given number of bytes (in UTF-8 representation).
@@ -39,8 +38,8 @@ impl<'a> RemoveLongFilterStream<'a> {
 }
 
 impl TokenFilter for RemoveLongFilter {
-    fn transform<'a>(&self, token_stream: BoxTokenStream<'a>) -> BoxTokenStream<'a> {
-        BoxTokenStream::from(RemoveLongFilterStream {
+    fn transform<'a>(&self, token_stream: Box<dyn TokenStream + 'a>) -> Box<dyn TokenStream + 'a> {
+        Box::new(RemoveLongFilterStream {
             token_length_limit: self.length_limit,
             tail: token_stream,
         })
@@ -49,7 +48,7 @@ impl TokenFilter for RemoveLongFilter {
 
 pub struct RemoveLongFilterStream<'a> {
     token_length_limit: usize,
-    tail: BoxTokenStream<'a>,
+    tail: Box<dyn TokenStream + 'a>,
 }
 
 impl<'a> TokenStream for RemoveLongFilterStream<'a> {

src/tokenizer/simple_tokenizer.rs

@@ -1,4 +1,3 @@
-use super::BoxTokenStream;
 use super::{Token, TokenStream, Tokenizer};
 use std::str::CharIndices;
 
@@ -13,8 +12,8 @@ pub struct SimpleTokenStream<'a> {
 }
 
 impl Tokenizer for SimpleTokenizer {
-    fn token_stream<'a>(&self, text: &'a str) -> BoxTokenStream<'a> {
-        BoxTokenStream::from(SimpleTokenStream {
+    fn token_stream<'a>(&self, text: &'a str) -> Box<dyn TokenStream + 'a> {
+        Box::new(SimpleTokenStream {
             text,
             chars: text.char_indices(),
             token: Token::default(),

src/tokenizer/stemmer.rs

@@ -1,5 +1,4 @@
 use super::{Token, TokenFilter, TokenStream};
-use crate::tokenizer::BoxTokenStream;
 use rust_stemmers::{self, Algorithm};
 use serde::{Deserialize, Serialize};
 
@@ -78,9 +77,9 @@ impl Default for Stemmer {
 }
 
 impl TokenFilter for Stemmer {
-    fn transform<'a>(&self, token_stream: BoxTokenStream<'a>) -> BoxTokenStream<'a> {
+    fn transform<'a>(&self, token_stream: Box<dyn TokenStream + 'a>) -> Box<dyn TokenStream + 'a> {
         let inner_stemmer = rust_stemmers::Stemmer::create(self.stemmer_algorithm);
-        BoxTokenStream::from(StemmerTokenStream {
+        Box::new(StemmerTokenStream {
             tail: token_stream,
             stemmer: inner_stemmer,
         })
@@ -88,7 +87,7 @@ impl TokenFilter for Stemmer {
 }
 
 pub struct StemmerTokenStream<'a> {
-    tail: BoxTokenStream<'a>,
+    tail: Box<dyn TokenStream + 'a>,
     stemmer: rust_stemmers::Stemmer,
 }
 

src/tokenizer/stop_word_filter.rs

@@ -11,7 +11,6 @@
 //! assert!(stream.next().is_none());
 //! ```
 use super::{Token, TokenFilter, TokenStream};
-use crate::tokenizer::BoxTokenStream;
 use fnv::FnvHasher;
 use std::collections::HashSet;
 use std::hash::BuildHasherDefault;
@@ -51,12 +50,12 @@ impl StopWordFilter {
 
 pub struct StopWordFilterStream<'a> {
     words: StopWordHashSet,
-    tail: BoxTokenStream<'a>,
+    tail: Box<dyn TokenStream + 'a>,
 }
 
 impl TokenFilter for StopWordFilter {
-    fn transform<'a>(&self, token_stream: BoxTokenStream<'a>) -> BoxTokenStream<'a> {
-        BoxTokenStream::from(StopWordFilterStream {
+    fn transform<'a>(&self, token_stream: Box<dyn TokenStream + 'a>) -> Box<dyn TokenStream + 'a> {
+        Box::new(StopWordFilterStream {
             words: self.words.clone(),
             tail: token_stream,
         })

src/tokenizer/token_stream_chain.rs

@@ -1,11 +1,9 @@
-use crate::tokenizer::{BoxTokenStream, Token, TokenStream};
-use std::ops::DerefMut;
+use crate::tokenizer::{Token, TokenStream};
 
 const POSITION_GAP: usize = 2;
 
 pub(crate) struct TokenStreamChain<'a> {
-    offsets: Vec<usize>,
-    token_streams: Vec<BoxTokenStream<'a>>,
+    streams_with_offsets: Vec<(Box<dyn TokenStream + 'a>, usize)>,
     position_shift: usize,
     stream_idx: usize,
     token: Token,
@@ -13,13 +11,11 @@ pub(crate) struct TokenStreamChain<'a> {
 
 impl<'a> TokenStreamChain<'a> {
     pub fn new(
-        offsets: Vec<usize>,
-        token_streams: Vec<BoxTokenStream<'a>>,
+        streams_with_offsets: Vec<(Box<dyn TokenStream + 'a>, usize)>,
     ) -> TokenStreamChain<'a> {
         TokenStreamChain {
-            offsets,
+            streams_with_offsets,
             stream_idx: 0,
-            token_streams,
             position_shift: 0,
             token: Token::default(),
         }
@@ -28,11 +24,10 @@ impl<'a> TokenStreamChain<'a> {
 
 impl<'a> TokenStream for TokenStreamChain<'a> {
     fn advance(&mut self) -> bool {
-        while self.stream_idx < self.token_streams.len() {
-            let token_stream = self.token_streams[self.stream_idx].deref_mut();
+        while self.stream_idx < self.streams_with_offsets.len() {
+            let (ref mut token_stream, offset_offset) = self.streams_with_offsets[self.stream_idx];
             if token_stream.advance() {
                 let token = token_stream.token();
-                let offset_offset = self.offsets[self.stream_idx];
                 self.token.offset_from = token.offset_from + offset_offset;
                 self.token.offset_to = token.offset_to + offset_offset;
                 self.token.position = token.position + self.position_shift;
@@ -49,7 +44,7 @@ impl<'a> TokenStream for TokenStreamChain<'a> {
 
     fn token(&self) -> &Token {
         assert!(
-            self.stream_idx <= self.token_streams.len(),
+            self.stream_idx <= self.streams_with_offsets.len(),
             "You called .token(), after the end of the token stream has been reached"
         );
         &self.token
@@ -57,7 +52,7 @@ impl<'a> TokenStream for TokenStreamChain<'a> {
 
     fn token_mut(&mut self) -> &mut Token {
         assert!(
-            self.stream_idx <= self.token_streams.len(),
+            self.stream_idx <= self.streams_with_offsets.len(),
             "You called .token(), after the end of the token stream has been reached"
         );
         &mut self.token
@@ -73,10 +68,10 @@ mod tests {
     #[test]
     fn test_chain_first_emits_no_tokens() {
         let token_streams = vec![
-            SimpleTokenizer.token_stream(""),
-            SimpleTokenizer.token_stream("hello world"),
+            (SimpleTokenizer.token_stream(""), 0),
+            (SimpleTokenizer.token_stream("hello world"), 0),
         ];
-        let mut token_chain = TokenStreamChain::new(vec![0, 0], token_streams);
+        let mut token_chain = TokenStreamChain::new(token_streams);
 
         assert!(token_chain.advance());
         assert_eq!(token_chain.token().text, "hello");

src/tokenizer/tokenized_string.rs

@@ -1,4 +1,4 @@
-use crate::tokenizer::{BoxTokenStream, Token, TokenStream, TokenStreamChain};
+use crate::tokenizer::{Token, TokenStream, TokenStreamChain};
 use serde::{Deserialize, Serialize};
 use std::cmp::Ordering;
 
@@ -42,24 +42,23 @@ impl PreTokenizedStream {
     /// Creates a TokenStream from PreTokenizedString array
     pub fn chain_tokenized_strings<'a>(
         tok_strings: &'a [&'a PreTokenizedString],
-    ) -> BoxTokenStream {
+    ) -> Box<dyn TokenStream> {
         if tok_strings.len() == 1 {
-            PreTokenizedStream::from((*tok_strings[0]).clone()).into()
+            Box::new(PreTokenizedStream::from(tok_strings[0].to_owned()))
         } else {
-            let mut offsets = vec![];
+            let mut streams_with_offsets = vec![];
             let mut total_offset = 0;
             for &tok_string in tok_strings {
-                offsets.push(total_offset);
+                streams_with_offsets.push((
+                    Box::new(PreTokenizedStream::from(tok_string.to_owned()))
+                        as Box<dyn TokenStream>,
+                    total_offset,
+                ));
                 if let Some(last_token) = tok_string.tokens.last() {
                     total_offset += last_token.offset_to;
                 }
             }
-            // TODO remove the string cloning.
-            let token_streams: Vec<BoxTokenStream<'static>> = tok_strings
-                .iter()
-                .map(|&tok_string| PreTokenizedStream::from((*tok_string).clone()).into())
-                .collect();
-            TokenStreamChain::new(offsets, token_streams).into()
+            Box::new(TokenStreamChain::new(streams_with_offsets))
         }
     }
 }

src/tokenizer/tokenizer.rs

@@ -2,8 +2,6 @@ use crate::tokenizer::TokenStreamChain;
 use serde::{Deserialize, Serialize};
 /// The tokenizer module contains all of the tools used to process
 /// text in `tantivy`.
-use std::borrow::{Borrow, BorrowMut};
-use std::ops::{Deref, DerefMut};
 
 /// Token
 #[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq)]
@@ -40,7 +38,7 @@ impl Default for Token {
 /// It simply wraps a `Tokenizer` and a list of `TokenFilter` that are applied sequentially.
 pub struct TextAnalyzer {
     tokenizer: Box<dyn Tokenizer>,
-    token_filters: Vec<BoxTokenFilter>,
+    token_filters: Vec<Box<dyn TokenFilter>>,
 }
 
 impl<T: Tokenizer> From<T> for TextAnalyzer {
@@ -50,11 +48,14 @@ impl<T: Tokenizer> From<T> for TextAnalyzer {
 }
 
 impl TextAnalyzer {
-    /// Creates a new `TextAnalyzer` given a tokenizer and a vector of `BoxTokenFilter`.
+    /// Creates a new `TextAnalyzer` given a tokenizer and a vector of `Box<dyn TokenFilter>`.
     ///
     /// When creating a `TextAnalyzer` from a `Tokenizer` alone, prefer using
     /// `TextAnalyzer::from(tokenizer)`.
-    pub fn new<T: Tokenizer>(tokenizer: T, token_filters: Vec<BoxTokenFilter>) -> TextAnalyzer {
+    pub fn new<T: Tokenizer>(
+        tokenizer: T,
+        token_filters: Vec<Box<dyn TokenFilter>>,
+    ) -> TextAnalyzer {
         TextAnalyzer {
             tokenizer: Box::new(tokenizer),
             token_filters,
@@ -77,8 +78,8 @@ impl TextAnalyzer {
     ///     .filter(Stemmer::default());
     /// ```
     ///
-    pub fn filter<F: Into<BoxTokenFilter>>(mut self, token_filter: F) -> Self {
-        self.token_filters.push(token_filter.into());
+    pub fn filter<F: TokenFilter>(mut self, token_filter: F) -> Self {
+        self.token_filters.push(Box::new(token_filter));
         self
     }
 
@@ -87,28 +88,19 @@ impl TextAnalyzer {
     /// The resulting `BoxTokenStream` is equivalent to what would be obtained if the &str were
     /// one concatenated `&str`, with an artificial position gap of `2` between the different fields
     /// to prevent accidental `PhraseQuery` to match accross two terms.
-    pub fn token_stream_texts<'a>(&self, texts: &'a [&'a str]) -> BoxTokenStream<'a> {
-        assert!(!texts.is_empty());
-        if texts.len() == 1 {
-            self.token_stream(texts[0])
-        } else {
-            let mut offsets = vec![];
-            let mut total_offset = 0;
-            for &text in texts {
-                offsets.push(total_offset);
-                total_offset += text.len();
-            }
-            let token_streams: Vec<BoxTokenStream<'a>> = texts
-                .iter()
-                .cloned()
-                .map(|text| self.token_stream(text))
-                .collect();
-            From::from(TokenStreamChain::new(offsets, token_streams))
+    pub fn token_stream_texts<'a>(&self, texts: &'a [&str]) -> Box<dyn TokenStream + 'a> {
+        debug_assert!(!texts.is_empty());
+        let mut streams_with_offsets = vec![];
+        let mut total_offset = 0;
+        for &text in texts {
+            streams_with_offsets.push((self.token_stream(text), total_offset));
+            total_offset += text.len();
         }
+        Box::new(TokenStreamChain::new(streams_with_offsets))
     }
 
     /// Creates a token stream for a given `str`.
-    pub fn token_stream<'a>(&self, text: &'a str) -> BoxTokenStream<'a> {
+    pub fn token_stream<'a>(&self, text: &'a str) -> Box<dyn TokenStream + 'a> {
         let mut token_stream = self.tokenizer.token_stream(text);
         for token_filter in &self.token_filters {
             token_stream = token_filter.transform(token_stream);
@@ -140,7 +132,7 @@ impl Clone for TextAnalyzer {
 /// This API may change to use associated types.
 pub trait Tokenizer: 'static + Send + Sync + TokenizerClone {
     /// Creates a token stream for a given `str`.
-    fn token_stream<'a>(&self, text: &'a str) -> BoxTokenStream<'a>;
+    fn token_stream<'a>(&self, text: &'a str) -> Box<dyn TokenStream + 'a>;
 }
 
 pub trait TokenizerClone {
@@ -153,69 +145,6 @@ impl<T: Tokenizer + Clone> TokenizerClone for T {
     }
 }
 
-impl<'a> TokenStream for Box<dyn TokenStream + 'a> {
-    fn advance(&mut self) -> bool {
-        let token_stream: &mut dyn TokenStream = self.borrow_mut();
-        token_stream.advance()
-    }
-
-    fn token<'b>(&'b self) -> &'b Token {
-        let token_stream: &'b (dyn TokenStream + 'a) = self.borrow();
-        token_stream.token()
-    }
-
-    fn token_mut<'b>(&'b mut self) -> &'b mut Token {
-        let token_stream: &'b mut (dyn TokenStream + 'a) = self.borrow_mut();
-        token_stream.token_mut()
-    }
-}
-
-/// Simple wrapper of `Box<dyn TokenStream + 'a>`.
-///
-/// See `TokenStream` for more information.
-pub struct BoxTokenStream<'a>(Box<dyn TokenStream + 'a>);
-
-impl<'a, T> From<T> for BoxTokenStream<'a>
-where
-    T: TokenStream + 'a,
-{
-    fn from(token_stream: T) -> BoxTokenStream<'a> {
-        BoxTokenStream(Box::new(token_stream))
-    }
-}
-
-impl<'a> Deref for BoxTokenStream<'a> {
-    type Target = dyn TokenStream + 'a;
-
-    fn deref(&self) -> &Self::Target {
-        &*self.0
-    }
-}
-impl<'a> DerefMut for BoxTokenStream<'a> {
-    fn deref_mut(&mut self) -> &mut Self::Target {
-        &mut *self.0
-    }
-}
-
-/// Simple wrapper of `Box<dyn TokenFilter + 'a>`.
-///
-/// See `TokenStream` for more information.
-pub struct BoxTokenFilter(Box<dyn TokenFilter>);
-
-impl Deref for BoxTokenFilter {
-    type Target = dyn TokenFilter;
-
-    fn deref(&self) -> &dyn TokenFilter {
-        &*self.0
-    }
-}
-
-impl<T: TokenFilter> From<T> for BoxTokenFilter {
-    fn from(tokenizer: T) -> BoxTokenFilter {
-        BoxTokenFilter(Box::new(tokenizer))
-    }
-}
-
 /// `TokenStream` is the result of the tokenization.
 ///
 /// It consists consumable stream of `Token`s.
@@ -295,18 +224,18 @@ pub trait TokenStream {
 }
 
 pub trait TokenFilterClone {
-    fn box_clone(&self) -> BoxTokenFilter;
+    fn box_clone(&self) -> Box<dyn TokenFilter>;
 }
 
 /// Trait for the pluggable components of `Tokenizer`s.
 pub trait TokenFilter: 'static + Send + Sync + TokenFilterClone {
     /// Wraps a token stream and returns the modified one.
-    fn transform<'a>(&self, token_stream: BoxTokenStream<'a>) -> BoxTokenStream<'a>;
+    fn transform<'a>(&self, token_stream: Box<dyn TokenStream + 'a>) -> Box<dyn TokenStream + 'a>;
 }
 
 impl<T: TokenFilter + Clone> TokenFilterClone for T {
-    fn box_clone(&self) -> BoxTokenFilter {
-        BoxTokenFilter::from(self.clone())
+    fn box_clone(&self) -> Box<dyn TokenFilter> {
+        Box::new(self.clone())
     }
 }