/usr/include/sdsl/sorted_multi_stack_support.hpp is in libsdsl-dev 2.0.3-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 | /* sdsl - succinct data structures library
Copyright (C) 2010 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 sorted_multi_stack_support.hpp
\brief sorted_multi_stack_support.hpp contains a data structure for a stack which contains
elements from [0..n] in sorted order. Duplicates are possible.
\author Simon Gog
*/
#ifndef INCLUDED_SDSL_SORTED_MULTI_STACK_SUPPORT
#define INCLUDED_SDSL_SORTED_MULTI_STACK_SUPPORT
#include "int_vector.hpp"
namespace sdsl
{
//! Stack which contains elements from [0..n] in sorted order. Duplicates are possible.
/*! \par Space complexity
* \f$2n\f$ bits
*/
class sorted_multi_stack_support
{
public:
typedef int_vector<64>::size_type size_type;
private:
size_type m_n; // Size of the supported vector.
size_type m_cnt; // Counter for the indices on the stack.
size_type m_top; // Topmost index of the stack.
int_vector<64> m_stack; // Memory for the stack.
int_vector<64> m_duplication_stack; // Memory for the duplications
inline size_type block_nr(size_type x) {
return x/63;
}; // maybe we can speed this up with bit hacks
inline size_type block_pos(size_type x) {
return x%63;
}; // maybe we can speed this up with bit hacks
public:
//! Constructor
/*! \param n Maximum that can be pushed onto the stack
*/
sorted_multi_stack_support(size_type n);
sorted_multi_stack_support(const sorted_multi_stack_support&) = default;
sorted_multi_stack_support(sorted_multi_stack_support&&) = default;
sorted_multi_stack_support& operator=(const sorted_multi_stack_support&) = default;
sorted_multi_stack_support& operator=(sorted_multi_stack_support&&) = default;
/*! Returns if the stack is empty.
*/
bool empty() const {
return 0==m_cnt;
};
/*! Returns the topmost index on the stack.
* \pre empty()==false
*/
size_type top() const;
/*! Pop the topmost index of the stack.
* \return True if there the value of the top element after the execution of pop()
* is not equal to the value of the top element before the execution of pop(). False otherwise.
*/
bool pop();
/*! Push the index x of vector vec onto the stack.
* \par x value which should be pushed onto the stack.
* \return True if the value on the top of the stack is smaller than x. False if the value is equal.
* \pre top() <= x
*/
bool push(size_type x);
/*! Returns the number of element is the stack.
*/
size_type size()const {
return m_cnt;
};
size_type serialize(std::ostream& out, structure_tree_node* v=nullptr,
std::string name="")const;
void load(std::istream& in);
};
inline sorted_multi_stack_support::sorted_multi_stack_support(size_type n):m_n(n), m_cnt(0), m_top(0), m_stack(), m_duplication_stack()
{
m_stack = int_vector<64>(block_nr(m_n+1)+1, 0);
m_stack[0] = 1;
m_duplication_stack = int_vector<64>((m_n>>6)+1, 0);
}
inline sorted_multi_stack_support::size_type sorted_multi_stack_support::top()const
{
return m_top-1;
}
inline bool sorted_multi_stack_support::push(size_type x)
{
x += 1;
size_type bn = block_nr(x);
if (0 == ((m_stack[bn] >> block_pos(x))&1)) { // check if x is not already on the stack
m_stack[bn] ^= (1ULL << block_pos(x));
if (bn > 0 and m_stack[bn-1] == 0) {
m_stack[bn-1] = 0x8000000000000000ULL | m_top;
}
m_top = x;
// write a 0 to the duplication stack
// do nothing as stack is initialized with zeros
++m_cnt; //< increment counter
return true;
} else { // if the element is already on the stack
// write a 1 to the duplication stack
m_duplication_stack[m_cnt>>6] ^= (1ULL << (m_cnt&0x3F));
++m_cnt; //< increment counter
return false;
}
}
inline bool sorted_multi_stack_support::pop()
{
if (m_cnt) {
--m_cnt; //< decrement counter
if ((m_duplication_stack[m_cnt>>6]>>(m_cnt&0x3F))&1) { // if it's a duplication
m_duplication_stack[m_cnt>>6] ^= (1ULL << (m_cnt&0x3F)); // delete 1
return false;
} else {
size_type bn = block_nr(m_top);
uint64_t w = m_stack[ bn ];
assert((w>>63) == 0); // highest bit is not set, as the block contains no pointer
w ^= (1ULL << block_pos(m_top));
m_stack[ bn ] = w;
if (w>0) {
m_top = bn*63 + bits::hi(w);
} else { // w==0 and cnt>0
assert(bn > 0);
w = m_stack[ bn-1 ];
if ((w>>63) == 0) { // highest bit is not set => the block contains no pointer
assert(w>0);
m_top = (bn-1)*63 + bits::hi(w);
} else { // block contains pointers
m_stack[bn-1] = 0;
m_top = w&0x7FFFFFFFFFFFFFFFULL;
}
}
return true;
}
}
return false;
}
inline sorted_multi_stack_support::size_type
sorted_multi_stack_support::serialize(std::ostream& out,
structure_tree_node* v, std::string name)const
{
structure_tree_node* child = structure_tree::add_child(v, name, util::class_name(*this));
size_type written_bytes = 0;
written_bytes += write_member(m_n, out);
written_bytes += write_member(m_top, out);
written_bytes += write_member(m_cnt, out);
written_bytes += m_stack.serialize(out);
written_bytes += m_duplication_stack.serialize(out);
structure_tree::add_size(child, written_bytes);
return written_bytes;
}
inline void sorted_multi_stack_support::load(std::istream& in)
{
read_member(m_n, in);
read_member(m_top, in);
read_member(m_cnt, in);
m_stack.load(in);
m_duplication_stack.load(in);
}
}// end namespace sdsl
#endif // end file
|