Repo created

3party/succinct/elias_fano_compressed_list.hpp

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+#pragma once
+
+#include "elias_fano.hpp"
+
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wconversion"
+#endif
+
+namespace succinct {
+
+    struct elias_fano_compressed_list
+    {
+        typedef uint64_t value_type;
+
+        elias_fano_compressed_list() {}
+
+        template <typename Range>
+        elias_fano_compressed_list(Range const& ints)
+        {
+            typedef typename boost::range_const_iterator<Range>::type iterator_t;
+
+            size_t s = 0;
+            size_t n = 0;
+            for (iterator_t iter = boost::begin(ints);
+                 iter != boost::end(ints);
+                 ++iter) {
+                s += broadword::msb(*iter + 1);
+                n += 1;
+            }
+
+            elias_fano::elias_fano_builder ef_builder(s + 1, n + 1);
+            bit_vector_builder bits_builder;
+
+            ef_builder.push_back(bits_builder.size());
+            for (iterator_t iter = boost::begin(ints);
+                 iter != boost::end(ints);
+                 ++iter) {
+                size_t val = *iter + 1;
+                size_t l = broadword::msb(val);
+                bits_builder.append_bits(val ^ (uint64_t(1) << l), l);
+                ef_builder.push_back(bits_builder.size());
+            }
+            elias_fano(&ef_builder, false).swap(m_ef);
+            bit_vector(&bits_builder).swap(m_bits);
+        }
+
+        value_type operator[](size_t idx) const
+        {
+            std::pair<size_t, size_t> r = m_ef.select_range(idx);
+            size_t l = r.second - r.first;
+            return ((uint64_t(1) << l) | m_bits.get_bits(r.first, l)) - 1;
+        }
+
+        size_t size() const
+        {
+            return m_ef.num_ones() - 1;
+        }
+
+        void swap(elias_fano_compressed_list& other)
+        {
+            m_ef.swap(other.m_ef);
+            m_bits.swap(other.m_bits);
+        }
+
+        template <typename Visitor>
+        void map(Visitor& visit) {
+            visit
+                (m_ef, "m_ef")
+                (m_bits, "m_bits")
+                ;
+        }
+
+    private:
+        elias_fano m_ef;
+        bit_vector m_bits;
+    };
+
+}
+
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#endif