1 files changed, 91 insertions, 0 deletions
diff --git a/searchlib/src/vespa/searchlib/diskindex/docidmapper.h b/searchlib/src/vespa/searchlib/diskindex/docidmapper.h
new file mode 100644
index 00000000000..43e1ea44b89
--- /dev/null
+++ b/searchlib/src/vespa/searchlib/diskindex/docidmapper.h
@@ -0,0 +1,91 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+#pragma once
+
+#include <vespa/vespalib/util/array.h>
+#include <vespa/vespalib/stllike/string.h>
+
+namespace search
+{
+
+class BitVector;
+
+namespace diskindex
+{
+
+typedef vespalib::Array<uint8_t, vespalib::DefaultAlloc> SelectorArray;
+
+class DocIdMapping
+{
+public:
+    uint32_t _docIdLimit;
+    const SelectorArray *_selector;	// External ownership
+    uint8_t _selectorId;
+
+    DocIdMapping(void);
+
+    void
+    clear(void);
+
+    void
+    setup(uint32_t docIdLimit);
+
+    void
+    setup(uint32_t docIdLimit,
+          const SelectorArray *selector,
+          uint8_t selectorId);
+
+    bool
+    readDocIdLimit(const vespalib::string &dir);
+};
+
+
+class DocIdMapper
+{
+public:
+    const uint8_t *_selector;
+    uint32_t _docIdLimit; // Limit on legal input values
+    uint32_t _selectorLimit; // Limit on output
+    uint8_t _selectorId;
+
+    DocIdMapper(void)
+        : _selector(NULL),
+          _docIdLimit(0u),
+          _selectorLimit(0),
+          _selectorId(0u)
+    {
+    }
+
+    void
+    setup(const DocIdMapping &mapping)
+    {
+        _selector = (mapping._selector != NULL) ?
+                    &((*mapping._selector)[0]) : NULL;
+        _docIdLimit = mapping._docIdLimit;
+        _selectorLimit = (mapping._selector != NULL) ?
+                         (*mapping._selector).size() :
+                         0u;
+        _selectorId = mapping._selectorId;
+    }
+
+    static uint32_t
+    noDocId(void)
+    {
+        return static_cast<uint32_t>(-1);
+    }
+
+    uint32_t
+    mapDocId(uint32_t docId) const
+    {
+        assert(docId < _docIdLimit);
+        if (_selector != NULL &&
+            (docId >= _selectorLimit || _selector[docId] != _selectorId)) {
+            docId = noDocId();
+        }
+        return docId;
+    }
+};
+
+} // namespace diskindex
+
+} // namespace search
+