1 files changed, 138 insertions, 0 deletions
diff --git a/searchlib/src/vespa/searchlib/predicate/document_features_store_saver.cpp b/searchlib/src/vespa/searchlib/predicate/document_features_store_saver.cpp
new file mode 100644
index 00000000000..08a3592da14
--- /dev/null
+++ b/searchlib/src/vespa/searchlib/predicate/document_features_store_saver.cpp
@@ -0,0 +1,138 @@
+// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include "document_features_store_saver.h"
+#include <vespa/searchlib/util/bufferwriter.h>
+#include <vespa/vespalib/objects/nbo.h>
+
+using vespalib::datastore::EntryRef;
+using search::BufferWriter;
+
+namespace search::predicate {
+
+DocumentFeaturesStoreSaver::DocumentFeaturesStoreSaver(const DocumentFeaturesStore& store)
+    : _refs(store._refs),
+      _features(store._features),
+      _ranges(store._ranges),
+      _word_store(store._word_store),
+      _arity(store._arity)
+{
+}
+
+DocumentFeaturesStoreSaver::~DocumentFeaturesStoreSaver() = default;
+
+namespace {
+
+template <typename T>
+void nbo_write(BufferWriter& writer, T value)
+{
+    auto value_nbo = vespalib::nbo::n2h(value);
+    writer.write(&value_nbo, sizeof(value_nbo));
+}
+
+template <typename RefsVector, typename RangesStore>
+void
+find_used_words(const RefsVector& refs, const RangesStore& ranges,
+                std::unordered_map<uint32_t, uint32_t>& word_map,
+                std::vector<EntryRef>& word_list)
+{
+    for (auto& cur_refs : refs) {
+        auto ranges_ref = cur_refs._ranges;
+        if (ranges_ref.valid()) {
+            auto range_vector = ranges.get(ranges_ref);
+            for (const auto& range : range_vector) {
+                if (!word_map.count(range.label_ref.ref())) {
+                    word_map[range.label_ref.ref()] = word_list.size();
+                    word_list.push_back(range.label_ref);
+                }
+            }
+        }
+    }
+}
+
+void
+serialize_words(BufferWriter& writer, const std::vector<EntryRef>& word_list,
+                const memoryindex::WordStore& word_store)
+{
+    nbo_write<uint32_t>(writer, word_list.size());;
+    for (const auto &word_ref : word_list) {
+        const char *word = word_store.getWord(word_ref);
+        uint32_t len = strlen(word);
+        nbo_write(writer, len);
+        writer.write(word, len);
+    }
+}
+
+template <typename RefsVector, typename RangesStore>
+void
+serialize_ranges(BufferWriter& writer, const RefsVector& refs, const RangesStore& ranges,
+                 std::unordered_map<uint32_t, uint32_t>& word_map)
+{
+    uint32_t ranges_size = 0;
+    if (!refs.empty()) {
+        assert(!refs.front()._ranges.valid());
+        for (auto& cur_refs : refs) {
+            if (cur_refs._ranges.valid()) {
+                ++ranges_size;
+            }
+        }
+    }
+    nbo_write(writer, ranges_size);
+    for (uint32_t doc_id = 0; doc_id < refs.size(); ++doc_id) {
+        auto ranges_ref = refs[doc_id]._ranges;
+        if (ranges_ref.valid()) {
+            nbo_write(writer, doc_id);
+            auto range_vector = ranges.get(ranges_ref);
+            nbo_write<uint32_t>(writer, range_vector.size());
+            for (const auto &range : range_vector) {
+                nbo_write(writer, word_map[range.label_ref.ref()]);
+                nbo_write(writer, range.from);
+                nbo_write(writer, range.to);
+            }
+        }
+    }
+}
+
+template <typename RefsVector, typename FeaturesStore>
+void
+serialize_features(BufferWriter& writer, const RefsVector& refs, const FeaturesStore& features)
+{
+    uint32_t features_size = 0;
+    if (!refs.empty()) {
+        assert(!refs.front()._features.valid());
+        for (auto& cur_refs : refs) {
+            if (cur_refs._features.valid()) {
+                ++features_size;
+            }
+        }
+    }
+    nbo_write(writer, features_size);
+    for (uint32_t doc_id = 0; doc_id < refs.size(); ++doc_id) {
+        auto features_ref = refs[doc_id]._features;
+        if (features_ref.valid()) {
+            nbo_write(writer, doc_id);
+            auto feature_vector = features.get(features_ref);
+            nbo_write<uint32_t>(writer, feature_vector.size());
+            for (const auto &feature : feature_vector) {
+                nbo_write(writer, feature);
+            }
+        }
+    }
+}
+
+}  // namespace
+
+void
+DocumentFeaturesStoreSaver::save(BufferWriter& writer) const
+{
+    std::vector<EntryRef> word_list;
+    std::unordered_map<uint32_t, uint32_t> word_map;
+
+    find_used_words(_refs, _ranges, word_map, word_list);
+
+    nbo_write<uint16_t>(writer, _arity);
+    serialize_words(writer, word_list, _word_store);
+    serialize_ranges(writer, _refs, _ranges, word_map);
+    serialize_features(writer, _refs, _features);
+}
+
+}