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int_vector_buffer.hpp
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int_vector_buffer.hpp
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/* sdsl - succinct data structures library
Copyright (C) 2008-2013 Simon Gog
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see http://www.gnu.org/licenses/ .
*/
/*! \file int_vector_buffer.hpp
\brief int_vector_buffer.hpp contains the sdsl::int_vector_buffer class.
\author Maike Zwerger, Timo Beller and Simon Gog
*/
#ifndef INCLUDED_INT_VECTOR_BUFFER
#define INCLUDED_INT_VECTOR_BUFFER
#include "int_vector.hpp"
#include "iterators.hpp"
#include <cassert>
#include <fstream>
#include <iostream>
#include <stdio.h>
#include <string>
namespace sdsl
{
template<uint8_t t_width=0>
class int_vector_buffer
{
public:
class iterator;
private:
static_assert(t_width <= 64 , "int_vector_buffer: width must be at most 64 bits.");
sdsl::isfstream m_ifile;
sdsl::osfstream m_ofile;
std::string m_filename;
int_vector<t_width> m_buffer;
bool m_need_to_write = false;
// length of int_vector header in bytes: 0 for plain, 8 for int_vector<t_width> (0 < t_width), 9 for int_vector<0>
uint64_t m_offset = 0;
uint64_t m_buffersize = 0; // in elements! m_buffersize*width() must be a multiple of 8!
uint64_t m_size = 0; // size of int_vector_buffer
uint64_t m_begin = 0; // number in elements
//! Read block containing element at index idx.
void read_block(const uint64_t idx) {
m_begin = (idx/m_buffersize)*m_buffersize;
if (m_begin >= m_size) {
util::set_to_value(m_buffer, 0);
} else {
m_ifile.seekg(m_offset+(m_begin*width())/8);
assert(m_ifile.good());
m_ifile.read((char*) m_buffer.data(), (m_buffersize*width())/8);
if ((uint64_t)m_ifile.gcount() < (m_buffersize*width())/8) {
m_ifile.clear();
}
assert(m_ifile.good());
for (uint64_t i=m_size-m_begin; i<m_buffersize; ++i) {
m_buffer[i] = 0;
}
}
}
//! Write current block to file.
void write_block() {
if (m_need_to_write) {
m_ofile.seekp(m_offset+(m_begin*width())/8);
assert(m_ofile.good());
if (m_begin+m_buffersize >= m_size) {
//last block in file
uint64_t wb = ((m_size-m_begin)*width()+7)/8;
m_ofile.write((char*) m_buffer.data(), wb);
} else {
m_ofile.write((char*) m_buffer.data(), (m_buffersize*width())/8);
}
m_ofile.flush();
assert(m_ofile.good());
m_need_to_write = false;
}
}
//! Read value from idx.
uint64_t read(const uint64_t idx) {
assert(is_open());
assert(idx < m_size);
if (idx < m_begin or m_begin+m_buffersize <= idx) {
write_block();
read_block(idx);
}
return m_buffer[idx-m_begin];
}
//! Write value to idx.
void write(const uint64_t idx, const uint64_t value) {
assert(is_open());
// If idx is not in current block, write current block and load needed block
if (idx < m_begin or m_begin+m_buffersize <= idx) {
write_block();
read_block(idx);
}
if (m_size <= idx) {
m_size = idx+1;
}
m_need_to_write = true;
m_buffer[idx-m_begin] = value;
}
public:
//! Constructor.
int_vector_buffer() {
m_buffer = int_vector<t_width>();
}
//! Constructor for int_vector_buffer.
/*! \param filename File that contains the data read from / written to.
* \param mode Openmode:
* std::ios::in opens an existing file (that must exist already),
* std::ios::out creates a new file (that may exist already).
* \param buffersize Buffersize in bytes. This has to be a multiple of 8, if not the next multiple of 8 will be taken
* \param int_width The width of each integer.
* \param is_plain If false (default) the file will be interpreted as int_vector.
* If true the file will be interpreted as plain array with t_width bits per integer.
* In second case (is_plain==true), t_width must be 8, 16, 32 or 64.
*/
int_vector_buffer(const std::string filename, std::ios::openmode mode=std::ios::in, const uint64_t buffersize=1024*1024, const uint8_t int_width=t_width, const bool is_plain=false) {
m_filename = filename;
assert(!(mode&std::ios::app));
mode &= ~std::ios::app;
m_buffer.width(int_width);
if (is_plain) {
// is_plain is only allowed with width() in {8, 16, 32, 64}
assert(8==width() or 16==width() or 32==width() or 64==width());
} else {
m_offset = t_width ? 8 : 9;
}
// Open file for IO
m_ofile.open(m_filename, mode|std::ios::out|std::ios::binary);
assert(m_ofile.good());
m_ifile.open(m_filename, std::ios::in|std::ios::binary);
assert(m_ifile.good());
if (mode & std::ios::in) {
uint64_t size = 0;
if (is_plain) {
m_ifile.seekg(0, std::ios_base::end);
size = m_ifile.tellg()*8;
} else {
uint8_t width = 0;
int_vector<t_width>::read_header(size, width, m_ifile);
m_buffer.width(width);
}
assert(m_ifile.good());
m_size = size/width();
}
if (0==(buffersize*8)%width()) {
m_buffersize = buffersize*8/width(); // m_buffersize might not be multiple of 8, but m_buffersize*width is.
} else {
uint64_t element_buffersize = (buffersize*8)/width()+1; // one more element than fits into given buffersize in byte
m_buffersize = element_buffersize+7 - (element_buffersize+7)%8; // take next multiple of 8
}
m_buffer = int_vector<t_width>(m_buffersize, 0, width());
if (0!=m_buffersize) read_block(0);
m_need_to_write = false;
}
//! Move constructor.
int_vector_buffer(int_vector_buffer&& ivb) :
m_filename(std::move(ivb.m_filename)),
m_buffer(std::move(ivb.m_buffer)),
m_need_to_write(ivb.m_need_to_write),
m_offset(ivb.m_offset),
m_buffersize(ivb.m_buffersize),
m_size(ivb.m_size),
m_begin(ivb.m_begin) {
ivb.m_ifile.close();
ivb.m_ofile.close();
m_ifile.open(m_filename, std::ios::in|std::ios::binary);
m_ofile.open(m_filename, std::ios::in|std::ios::out|std::ios::binary);
assert(m_ifile.good());
assert(m_ofile.good());
// set ivb to default-constructor state
ivb.m_filename = "";
ivb.m_buffer = int_vector<t_width>();
ivb.m_need_to_write = false;
ivb.m_offset = 0;
ivb.m_buffersize = 0;
ivb.m_size = 0;
ivb.m_begin = 0;
}
//! Destructor.
~int_vector_buffer() {
close();
}
//! Move assignment operator.
int_vector_buffer<t_width>& operator=(int_vector_buffer&& ivb) {
close();
ivb.m_ifile.close();
ivb.m_ofile.close();
m_filename = ivb.m_filename;
m_ifile.open(m_filename, std::ios::in|std::ios::binary);
m_ofile.open(m_filename, std::ios::in|std::ios::out|std::ios::binary);
assert(m_ifile.good());
assert(m_ofile.good());
// assign the values of ivb to this
m_buffer = (int_vector<t_width>&&)ivb.m_buffer;
m_need_to_write = ivb.m_need_to_write;
m_offset = ivb.m_offset;
m_buffersize = ivb.m_buffersize;
m_size = ivb.m_size;
m_begin = ivb.m_begin;
// set ivb to default-constructor state
ivb.m_filename = "";
ivb.m_buffer = int_vector<t_width>();
ivb.m_need_to_write = false;
ivb.m_offset = 0;
ivb.m_buffersize = 0;
ivb.m_size = 0;
ivb.m_begin = 0;
return *this;
}
//! Returns the width of the integers which are accessed via the [] operator.
uint8_t width() const {
return m_buffer.width();
}
//! Returns the number of elements currently stored.
uint64_t size() const {
return m_size;
}
//! Returns the filename.
std::string filename() const {
return m_filename;
}
//! Returns the buffersize in bytes
uint64_t buffersize() const {
assert(m_buffersize*width()%8==0);
return (m_buffersize*width())/8;
}
//! Set the buffersize in bytes
void buffersize(uint64_t buffersize) {
write_block();
if (0==(buffersize*8)%width()) {
m_buffersize = buffersize*8/width(); // m_buffersize might not be multiple of 8, but m_buffersize*width() is.
} else {
uint64_t element_buffersize = (buffersize*8)/width()+1; // one more element than fits into given buffersize in byte
m_buffersize = element_buffersize+7 - (element_buffersize+7)%8; // take next multiple of 8
}
m_buffer.resize(m_buffersize);
if (0!=m_buffersize) read_block(0);
}
//! Returns whether state of underlying streams are good
bool good() {
return m_ifile.good() and m_ofile.good();
}
//! Returns whether underlying streams are currently associated to a file
bool is_open() {
return m_ifile.is_open() and m_ofile.is_open();;
}
//! Delete all content and set size to 0
void reset() {
// reset file
assert(m_ifile.good());
assert(m_ofile.good());
m_ifile.close();
m_ofile.close();
m_ofile.open(m_filename, std::ios::out|std::ios::binary);
assert(m_ofile.good());
m_ifile.open(m_filename, std::ios::in|std::ios::binary);
assert(m_ifile.good());
assert(m_ofile.good());
// reset member variables
m_need_to_write = false;
m_size = 0;
// reset buffer
read_block(0);
}
// Forward declaration
class reference;
//! [] operator
/*! \param i Index the i-th integer of length width().
* \return A reference to the i-th integer of length width().
*/
reference operator[](uint64_t idx) {
return reference(this, idx);
}
//! Appends the given element value to the end of the int_vector_buffer
void push_back(const uint64_t value) {
write(m_size, value);
}
//! Close the int_vector_buffer.
/*! It is not possible to read from / write into the int_vector_buffer after calling this method
* \param remove_file If true, the underlying file will be removed on closing.
*/
void close(bool remove_file=false) {
if (is_open()) {
if (!remove_file) {
write_block();
if (0 < m_offset) { // in case of int_vector, write header and trailing zeros
uint64_t size = m_size*width();
m_ofile.seekp(0, std::ios::beg);
int_vector<t_width>::write_header(size, width(), m_ofile);
assert(m_ofile.good());
uint64_t wb = (size+7)/8;
if (wb%8) {
m_ofile.seekp(m_offset+wb);
assert(m_ofile.good());
m_ofile.write("\0\0\0\0\0\0\0\0", 8-wb%8);
assert(m_ofile.good());
}
}
}
m_ifile.close();
assert(m_ifile.good());
m_ofile.close();
assert(m_ofile.good());
if (remove_file) {
sdsl::remove(m_filename);
}
}
}
iterator begin() {
return iterator(*this, 0);
}
iterator end() {
return iterator(*this, size());
}
//! Swap method for int_vector_buffer.
void swap(int_vector_buffer<t_width>& ivb) {
if (this != &ivb) {
m_ifile.close();
ivb.m_ifile.close();
m_ofile.close();
ivb.m_ofile.close();
std::swap(m_filename, ivb.m_filename);
m_ifile.open(m_filename, std::ios::in|std::ios::binary);
assert(m_ifile.good());
m_ofile.open(m_filename, std::ios::in|std::ios::out|std::ios::binary);
assert(m_ofile.good());
ivb.m_ifile.open(ivb.m_filename, std::ios::in|std::ios::binary);
assert(ivb.m_ifile.good());
ivb.m_ofile.open(ivb.m_filename, std::ios::in|std::ios::out|std::ios::binary);
assert(ivb.m_ofile.good());
std::swap(m_buffer, ivb.m_buffer);
std::swap(m_need_to_write, ivb.m_need_to_write);
std::swap(m_offset, ivb.m_offset);
std::swap(m_buffersize, ivb.m_buffersize);
std::swap(m_size, ivb.m_size);
std::swap(m_begin, ivb.m_begin);
}
}
class reference
{
friend class int_vector_buffer<t_width>;
private:
int_vector_buffer<t_width>* const m_int_vector_buffer = nullptr;
uint64_t m_idx = 0;
reference() {}
reference(int_vector_buffer<t_width>* _int_vector_buffer, uint64_t _idx) :
m_int_vector_buffer(_int_vector_buffer), m_idx(_idx) {}
public:
//! Conversion to int for read operations
operator uint64_t ()const {
return m_int_vector_buffer->read(m_idx);
}
//! Assignment operator for write operations
reference& operator=(const uint64_t& val) {
m_int_vector_buffer->write(m_idx, val);
return *this;
}
//! Assignment operator
reference& operator=(reference& x) {
return *this = (uint64_t)(x);
};
//! Prefix increment of the proxy object
reference& operator++() {
uint64_t x = m_int_vector_buffer->read(m_idx);
m_int_vector_buffer->write(m_idx, x+1);
return *this;
}
//! Postfix increment of the proxy object
uint64_t operator++(int) {
uint64_t val = (uint64_t)*this;
++(*this);
return val;
}
//! Prefix decrement of the proxy object
reference& operator--() {
uint64_t x = m_int_vector_buffer->read(m_idx);
m_int_vector_buffer->write(m_idx, x-1);
return *this;
}
//! Postfix decrement of the proxy object
uint64_t operator--(int) {
uint64_t val = (uint64_t)*this;
--(*this);
return val;
}
//! Add assign from the proxy object
reference& operator+=(const uint64_t x) {
uint64_t w = m_int_vector_buffer->read(m_idx);
m_int_vector_buffer->write(m_idx, w+x);
return *this;
}
//! Subtract assign from the proxy object
reference& operator-=(const uint64_t x) {
uint64_t w = m_int_vector_buffer->read(m_idx);
m_int_vector_buffer->write(m_idx, w-x);
return *this;
}
bool operator==(const reference& x)const {
return (uint64_t)*this == (uint64_t)x;
}
bool operator<(const reference& x)const {
return (uint64_t)*this < (uint64_t)x;
}
};
class iterator
{
private:
int_vector_buffer<t_width>& m_ivb;
uint64_t m_idx = 0;
public:
iterator() = delete;
iterator(int_vector_buffer<t_width>& ivb, uint64_t idx=0) : m_ivb(ivb), m_idx(idx) {}
iterator& operator++() {
++m_idx;
return *this;
}
reference operator*()const {
return m_ivb[m_idx];
}
bool operator==(const iterator& it) const {
return &m_ivb == &(it.m_ivb) and m_idx == it.m_idx;
}
bool operator!=(const iterator& it) const {
return !(*this == it);
}
};
};
} // end of namespace
#endif // include guard