Sparse.h
/* GRAPHITE2 LICENSING
Copyright 2010, SIL International
All rights reserved.
This library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 2.1 of License, or
(at your option) any later version.
This program 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
Lesser General Public License for more details.
You should also have received a copy of the GNU Lesser General Public
License along with this library in the file named "LICENSE".
If not, write to the Free Software Foundation, 51 Franklin Street,
Suite 500, Boston, MA 02110-1335, USA or visit their web page on the
internet at http://www.fsf.org/licenses/lgpl.html.
Alternatively, the contents of this file may be used under the terms of the
Mozilla Public License (http://mozilla.org/MPL) or the GNU General Public
License, as published by the Free Software Foundation, either version 2
of the License or (at your option) any later version.
*/
#pragma once
#include "inc/Main.h"
namespace graphite2 {
class sparse
{
typedef unsigned long mask_t;
static const unsigned char SIZEOF_CHUNK = (sizeof(mask_t) - sizeof(uint16))*8;
struct chunk
{
mask_t mask:SIZEOF_CHUNK;
uint16 offset;
};
public:
typedef uint16 key;
typedef uint16 value;
template<typename I>
sparse(I first, const I last);
sparse() throw();
~sparse() throw();
value operator [] (int k) const throw();
operator bool () const throw();
size_t capacity() const throw();
size_t size() const throw();
size_t _sizeof() const throw();
CLASS_NEW_DELETE;
private:
union {
chunk * map;
value * values;
} m_array;
key m_nchunks;
};
inline
sparse::sparse() throw() : m_nchunks(0)
{
m_array.map = 0;
}
template <typename I>
sparse::sparse(I attr, const I last)
: m_nchunks(0)
{
// Find the maximum extent of the key space.
size_t n_values=0;
for (I i = attr; i != last; ++i, ++n_values)
{
const key k = i->id / SIZEOF_CHUNK;
if (k >= m_nchunks) m_nchunks = k+1;
}
m_array.values = grzeroalloc<value>((m_nchunks*sizeof(chunk) + sizeof(value)/2)/sizeof(value) + n_values*sizeof(value));
if (m_array.values == 0 || m_nchunks == 0)
{
free(m_array.values); m_array.map=0;
return;
}
chunk * ci = m_array.map;
ci->offset = (m_nchunks*sizeof(chunk) + sizeof(value)-1)/sizeof(value);
value * vi = m_array.values + ci->offset;
for (; attr != last; ++attr, ++vi)
{
const typename I::value_type v = *attr;
chunk * const ci_ = m_array.map + v.id/SIZEOF_CHUNK;
if (ci != ci_)
{
ci = ci_;
ci->offset = vi - m_array.values;
}
ci->mask |= 1UL << (SIZEOF_CHUNK - 1 - (v.id % SIZEOF_CHUNK));
*vi = v.value;
}
}
inline
sparse::operator bool () const throw()
{
return m_array.map != 0;
}
inline
size_t sparse::capacity() const throw()
{
return m_nchunks;
}
inline
size_t sparse::_sizeof() const throw()
{
return sizeof(sparse) + size()*sizeof(value) + m_nchunks*sizeof(chunk);
}
} // namespace graphite2