1 files changed, 99 insertions, 0 deletions
diff --git a/include/orcus/string_pool.hpp b/include/orcus/string_pool.hpp
new file mode 100644
index 0000000..12419bc
--- /dev/null
+++ b/include/orcus/string_pool.hpp
@@ -0,0 +1,99 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef INCLUDED_ORCUS_STRING_POOL_HPP
+#define INCLUDED_ORCUS_STRING_POOL_HPP
+
+#include "env.hpp"
+
+#include <string>
+#include <memory>
+#include <vector>
+
+namespace orcus {
+
+/**
+ * This class implements a shared string pool with the ability to merge with
+ * other pools.
+ *
+ * @note This class is not copy-constructible, but is move-constructible.
+ */
+class ORCUS_PSR_DLLPUBLIC string_pool
+{
+public:
+    string_pool(const string_pool&) = delete;
+    string_pool& operator=(const string_pool&) = delete;
+
+    string_pool();
+    string_pool(string_pool&& other);
+    ~string_pool();
+
+    /**
+     * Intern a string.
+     *
+     * @param str string to intern.
+     *
+     * @return pair whose first value is the interned string, and the second
+     *         value specifies whether it is a newly created instance (true)
+     *         or a reuse of an existing instance (false).
+     */
+    std::pair<std::string_view, bool> intern(std::string_view str);
+
+    /**
+     * Return all interned strings.
+     *
+     * @return sequence of all interned strings.  The sequence will be sorted.
+     */
+    std::vector<std::string_view> get_interned_strings() const;
+
+    /**
+     * Dump pool's content to stdout.
+     *
+     * @todo This needs to be reworked to make it more generally usable.
+     */
+    void dump() const;
+
+    /**
+     * Clear pool's content.
+     */
+    void clear();
+
+    /**
+     * Query the total number of strings stored in the pool.
+     *
+     * @return size_t total number of strings in the pool.
+     */
+    size_t size() const;
+
+    /**
+     * Swap the content with another string-pool instance.
+     *
+     *
+     * @param other string-pool instance to swap contents with.
+     */
+    void swap(string_pool& other);
+
+    /**
+     * Merge another string pool instance in.  This will not invalidate any
+     * string references to the other pool.
+     *
+     * The other string pool instance will become empty when this call
+     * returns.
+     *
+     * @param other string pool instance to merge in.
+     */
+    void merge(string_pool& other);
+
+private:
+    struct impl;
+    std::unique_ptr<impl> mp_impl;
+};
+
+}
+
+#endif
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */