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/* This file is part of KDevelop
Copyright 2002-2005 Roberto Raggi <roberto@kdevelop.org>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License version 2 as published by the Free Software Foundation.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#ifndef SYMBOL_H
#define SYMBOL_H
#include <QtCore/QString>
#include <cstring>
#include <QtCore/QHash>
#include <QtCore/QPair>
/**@file symbol.h Symbol table for the parser.*/
/**
Symbol in the parser symbol table.
*/
struct NameSymbol
{
const char *data;
std::size_t count;
inline QString as_string() const
{
return QString::fromUtf8(data, count);
}
/**Required to put NameSymbol's into a QHash.*/
inline bool operator == (const NameSymbol &other) const
{
return count == other.count
&& std::strncmp(data, other.data, count) == 0;
}
protected:
inline NameSymbol() {}
inline NameSymbol(const char *d, std::size_t c)
: data(d), count(c) {}
private:
void operator = (const NameSymbol &);
friend class NameTable;
};
/**
@brief Required to put NameSymbol's into a QHash.
@see qHash(const QPair<const char*, std::size_t> &r) method for the reference.*/
inline uint qHash(const NameSymbol &r)
{
uint hash_value = 0;
for (std::size_t i=0; i<r.count; ++i)
hash_value = (hash_value << 5) - hash_value + r.data[i];
return hash_value;
}
/**
Required to put pairs of char* and std::size_t into a QHash.
Hash function is: hash = hash*31 + key[i].@n
It looks like a Bernstein's hash function with a different factor.
@n Original Bernstein's function is: hash = hash*33 + key[i].
@n Factor of 31 makes this function return reliably unique values
for english words with 6 symbols length.
@n More information can be found at @a http://burtleburtle.net/bob/hash/doobs.html.
*/
inline uint qHash(const QPair<const char*, std::size_t> &r)
{
uint hash_value = 0;
for (std::size_t i=0; i<r.second; ++i)
hash_value = (hash_value << 5) - hash_value + r.first[i];
return hash_value;
}
/**Symbol table for the parser.*/
class NameTable
{
public:
typedef QPair<const char *, std::size_t> KeyType;
typedef QHash<KeyType, NameSymbol*> ContainerType;
public:
NameTable() {}
~NameTable()
{
qDeleteAll(_M_storage);
}
inline const NameSymbol *findOrInsert(const char *str, std::size_t len)
{
KeyType key(str, len);
NameSymbol *name = _M_storage.value(key);
if (!name)
{
name = new NameSymbol(str, len);
_M_storage.insert(key, name);
}
return name;
}
inline std::size_t count() const
{
return _M_storage.size();
}
private:
ContainerType _M_storage;
private:
NameTable(const NameTable &other);
void operator = (const NameTable &other);
};
#endif // SYMBOL_H
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