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// Copyright (C) 2010-2011, Gabriel Dos Reis.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// - Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// - Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in
// the documentation and/or other materials provided with the
// distribution.
//
// - Neither the name of The Numerical Algorithms Group Ltd. nor the
// names of its contributors may be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
// PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef OPENAXIOM_STRING_POOL_INCLUDED
#define OPENAXIOM_STRING_POOL_INCLUDED
#include <open-axiom/hash-table>
// --% Author: Gabriel Dos Reis.
// --% Description:
// --% Basic persistent string facility.
// --% A stringpool for allocating long-living string objects.
namespace OpenAxiom {
struct StringPool;
// ----------------
// -- StringItem --
// ----------------
// String data allocated from a stringpool.
struct StringItem {
const char* begin() const { return text; }
const char* end() const { return text + length; }
size_t size() const { return length; }
bool equal(const char*, size_t) const;
protected:
const char* text; // pointer to the byte sequence
size_t length; // number of bytes in this string
friend class StringPool;
StringItem() : text(), length() { }
};
// ----------------
// -- StringPool --
// ----------------
// A string-pool object is a repository of long-living string objects.
// It contains no duplicates, therefore allows fast equality
// comparison of string objects.
struct StringPool : private BasicHashTable<StringItem> {
using BasicHashTable<StringItem>::EntryType;
StringPool();
// Intern a NUL-terminated sequence of characters.
EntryType* intern(const char*);
// Intern a sequence of characters given by its start and length.
EntryType* intern(const char*, size_t);
private:
Memory::Arena<char> strings; // character blub
// Allocate a string from the internal arena.
const char* make_copy(const char*, size_t);
};
typedef const StringPool::EntryType* BasicString;
}
#endif // OPENAXIOM_STRING_POOL_INCLUDED
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