// Copyright (c) 2005, Google Inc.
// 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 Google Inc. 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.
// ---
//
//
// A sparsetable is a random container that implements a sparse array,
// that is, an array that uses very little memory to store unassigned
// indices (in this case, between 1-2 bits per unassigned index). For
// instance, if you allocate an array of size 5 and assign a[2] = <big
// struct>, then a[2] will take up a lot of memory but a[0], a[1],
// a[3], and a[4] will not. Array elements that have a value are
// called "assigned". Array elements that have no value yet, or have
// had their value cleared using erase() or clear(), are called
// "unassigned".
//
// Unassigned values seem to have the default value of T (see below).
// Nevertheless, there is a difference between an unassigned index and
// one explicitly assigned the value of T(). The latter is considered
// assigned.
//
// Access to an array element is constant time, as is insertion and
// deletion. Insertion and deletion may be fairly slow, however:
// because of this container's memory economy, each insert and delete
// causes a memory reallocation.
//
// NOTE: You should not test(), get(), or set() any index that is
// greater than sparsetable.size(). If you need to do that, call
// resize() first.
//
// --- Template parameters
// PARAMETER DESCRIPTION DEFAULT
// T The value of the array: the type of --
// object that is stored in the array.
//
// GROUP_SIZE How large each "group" in the table 48
// is (see below). Larger values use
// a little less memory but cause most
// operations to be a little slower
//
// Alloc: Allocator to use to allocate memory. libc_allocator_with_realloc
//
// --- Model of
// Random Access Container
//
// --- Type requirements
// T must be Copy Constructible. It need not be Assignable.
//
// --- Public base classes
// None.
//
// --- Members
// Type members
//
// MEMBER WHERE DEFINED DESCRIPTION
// value_type container The type of object, T, stored in the array
// allocator_type container Allocator to use
// pointer container Pointer to p
// const_pointer container Const pointer to p
// reference container Reference to t
// const_reference container Const reference to t
// size_type container An unsigned integral type
// difference_type container A signed integral type
// iterator [*] container Iterator used to iterate over a sparsetable
// const_iterator container Const iterator used to iterate over a table
// reverse_iterator reversible Iterator used to iterate backwards over
// container a sparsetable
// const_reverse_iterator reversible container Guess
// nonempty_iterator [+] sparsetable Iterates over assigned
// array elements only
// const_nonempty_iterator sparsetable Iterates over assigned
// array elements only
// reverse_nonempty_iterator sparsetable Iterates backwards over
// assigned array elements only
// const_reverse_nonempty_iterator sparsetable Iterates backwards over
// assigned array elements only
//
// [*] All iterators are const in a sparsetable (though nonempty_iterators
// may not be). Use get() and set() to assign values, not iterators.
//
// [+] iterators are random-access iterators. nonempty_iterators are
// bidirectional iterators.
// Iterator members
// MEMBER WHERE DEFINED DESCRIPTION
//
// iterator begin() container An iterator to the beginning of the table
// iterator end() container An iterator to the end of the table
// const_iterator container A const_iterator pointing to the
// begin() const beginning of a sparsetable
// const_iterator container A const_iterator pointing to the
// end() const end of a sparsetable
//
// reverse_iterator reversable Points to beginning of a reversed
// rbegin() container sparsetable
// reverse_iterator reversable Points to end of a reversed table
// rend() container
// const_reverse_iterator reversable Points to beginning of a
// rbegin() const container reversed sparsetable
// const_reverse_iterator reversable Points to end of a reversed table
// rend() const container
//
// nonempty_iterator sparsetable Points to first assigned element
// begin() of a sparsetable
// nonempty_iterator sparsetable Points past last assigned element
// end() of a sparsetable
// const_nonempty_iterator sparsetable Points to first assigned element
// begin() const of a sparsetable
// const_nonempty_iterator sparsetable Points past last assigned element
// end() const of a sparsetable
//
// reverse_nonempty_iterator sparsetable Points to first assigned element
// begin() of a reversed sparsetable
// reverse_nonempty_iterator sparsetable Points past last assigned element
// end() of a reversed sparsetable
// const_reverse_nonempty_iterator sparsetable Points to first assigned
// begin() const elt of a reversed sparsetable
// const_reverse_nonempty_iterator sparsetable Points past last assigned
// end() const elt of a reversed sparsetable
//
//
// Other members
// MEMBER WHERE DEFINED DESCRIPTION
// sparsetable() sparsetable A table of size 0; must resize()
// before using.
// sparsetable(size_type size) sparsetable A table of size size. All
// indices are unassigned.
// sparsetable(
// const sparsetable &tbl) sparsetable Copy constructor
// ~sparsetable() sparsetable The destructor
// sparsetable &operator=( sparsetable The assignment operator
// const sparsetable &tbl)
//
// void resize(size_type size) sparsetable Grow or shrink a table to
// have size indices [*]
//
// void swap(sparsetable &x) sparsetable Swap two sparsetables
// void swap(sparsetable &x, sparsetable Swap two sparsetables
// sparsetable &y) (global, not member, function)
//
// size_type size() const sparsetable Number of "buckets" in the table
// size_type max_size() const sparsetable Max allowed size of a sparsetable
// bool empty() const sparsetable true if size() == 0
// size_type num_nonempty() const sparsetable Number of assigned "buckets"
//
// const_reference get( sparsetable Value at index i, or default
// size_type i) const value if i is unassigned
// const_reference operator[]( sparsetable Identical to get(i) [+]
// difference_type i) const
// reference set(size_type i, sparsetable Set element at index i to
// const_reference val) be a copy of val
// bool test(size_type i) sparsetable True if element at index i
// const has been assigned to
// bool test(iterator pos) sparsetable True if element pointed to
// const by pos has been assigned to
// void erase(iterator pos) sparsetable Set element pointed to by
// pos to be unassigned [!]
// void erase(size_type i) sparsetable Set element i to be unassigned
// void erase(iterator start, sparsetable Erases all elements between
// iterator end) start and end
// void clear() sparsetable Erases all elements in the table
//
// I/O versions exist for both FILE* and for File* (Google2-style files):
// bool write_metadata(FILE *fp) sparsetable Writes a sparsetable to the
// bool write_metadata(File *fp) given file. true if write
// completes successfully
// bool read_metadata(FILE *fp) sparsetable Replaces sparsetable with
// bool read_metadata(File *fp) version read from fp. true
// if read completes sucessfully
// bool write_nopointer_data(FILE *fp) Read/write the data stored in
// bool read_nopointer_data(FILE*fp) the table, if it's simple
//
// bool operator==( forward Tests two tables for equality.
// const sparsetable &t1, container This is a global function,
// const sparsetable &t2) not a member function.
// bool operator<( forward Lexicographical comparison.
// const sparsetable &t1, container This is a global function,
// const sparsetable &t2) not a member function.
//
// [*] If you shrink a sparsetable using resize(), assigned elements
// past the end of the table are removed using erase(). If you grow
// a sparsetable, new unassigned indices are created.
//
// [+] Note that operator[] returns a const reference. You must use
// set() to change the value of a table element.
//
// [!] Unassignment also calls the destructor.
//
// Iterators are invalidated whenever an item is inserted or
// deleted (ie set() or erase() is used) or when the size of
// the table changes (ie resize() or clear() is used).
//
// See doc/sparsetable.html for more information about how to use this class.
// Note: this uses STL style for naming, rather than Google naming.
// That's because this is an STL-y container
#ifndef UTIL_GTL_SPARSETABLE_H_
#define UTIL_GTL_SPARSETABLE_H_
#include <sparsehash/internal/sparseconfig.h>
#include <stdlib.h> // for malloc/free
#include <stdio.h> // to read/write tables
#include <string.h> // for memcpy
#ifdef HAVE_STDINT_H
#include <stdint.h> // the normal place uint16_t is defined
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h> // the normal place u_int16_t is defined
#endif
#ifdef HAVE_INTTYPES_H
#include <inttypes.h> // a third place for uint16_t or u_int16_t
#endif
#include <assert.h> // for bounds checking
#include <iterator> // to define reverse_iterator for me
#include <algorithm> // equal, lexicographical_compare, swap,...
#include <memory> // uninitialized_copy, uninitialized_fill
#include <vector> // a sparsetable is a vector of groups
#include <sparsehash/type_traits.h>
#include <sparsehash/internal/hashtable-common.h>
#include <sparsehash/internal/libc_allocator_with_realloc.h>
// A lot of work to get a type that's guaranteed to be 16 bits...
#ifndef HAVE_U_INT16_T
# if defined HAVE_UINT16_T
typedef uint16_t u_int16_t; // true on solaris, possibly other C99 libc's
# elif defined HAVE___UINT16
typedef __int16 int16_t; // true on vc++7
typedef unsigned __int16 u_int16_t;
# else
// Cannot find a 16-bit integer type. Hoping for the best with "short"...
typedef short int int16_t;
typedef unsigned short int u_int16_t;
# endif
#endif
_START_GOOGLE_NAMESPACE_
namespace base { // just to make google->opensource transition easier
using GOOGLE_NAMESPACE::true_type;
using GOOGLE_NAMESPACE::false_type;
using GOOGLE_NAMESPACE::integral_constant;
using GOOGLE_NAMESPACE::has_trivial_copy;
using GOOGLE_NAMESPACE::has_trivial_destructor;
using GOOGLE_NAMESPACE::is_same;
}
// The smaller this is, the faster lookup is (because the group bitmap is
// smaller) and the faster insert is, because there's less to move.
// On the other hand, there are more groups. Since group::size_type is
// a short, this number should be of the form 32*x + 16 to avoid waste.
static const u_int16_t DEFAULT_SPARSEGROUP_SIZE = 48; // fits in 1.5 words
// Our iterator as simple as iterators can be: basically it's just
// the index into our table. Dereference, the only complicated
// thing, we punt to the table class. This just goes to show how
// much machinery STL requires to do even the most trivial tasks.
//
// A NOTE ON ASSIGNING:
// A sparse table does not actually allocate memory for entries
// that are not filled. Because of this, it becomes complicated
// to have a non-const iterator: we don't know, if the iterator points
// to a not-filled bucket, whether you plan to fill it with something
// or whether you plan to read its value (in which case you'll get
// the default bucket value). Therefore, while we can define const
// operations in a pretty 'normal' way, for non-const operations, we
// define something that returns a helper object with operator= and
// operator& that allocate a bucket lazily. We use this for table[]
// and also for regular table iterators.
template <class tabletype>
class table_element_adaptor {
public:
typedef typename tabletype::value_type value_type;
typedef typename tabletype::size_type size_type;
typedef typename tabletype::reference reference;
typedef typename tabletype::pointer pointer;
table_element_adaptor(tabletype *tbl, size_type p)
: table(tbl), pos(p) { }
table_element_adaptor& operator= (const value_type &val) {
table->set(pos, val);
return *this;
}
operator value_type() { return table->get(pos); } // we look like a value
pointer operator& () { return &table->mutating_get(pos); }
private:
tabletype* table;
size_type pos;
};
// Our iterator as simple as iterators can be: basically it's just
// the index into our table. Dereference, the only complicated
// thing, we punt to the table class. This just goes to show how
// much machinery STL requires to do even the most trivial tasks.
//
// By templatizing over tabletype, we have one iterator type which
// we can use for both sparsetables and sparsebins. In fact it
// works on any class that allows size() and operator[] (eg vector),
// as long as it does the standard STL typedefs too (eg value_type).
template <class tabletype>
class table_iterator {
public:
typedef table_iterator iterator;
typedef std::random_access_iterator_tag iterator_category;
typedef typename tabletype::value_type value_type;
typedef typename tabletype::difference_type difference_type;
typedef typename tabletype::size_type size_type;
typedef table_element_adaptor<tabletype> reference;
typedef table_element_adaptor<tabletype>* pointer;
// The "real" constructor
table_iterator(tabletype *tbl, size_type p)
: table(tbl), pos(p) { }
// The default constructor, used when I define vars of type table::iterator
table_iterator() : table(NULL), pos(0) { }
// The copy constructor, for when I say table::iterator foo = tbl.begin()
// The default destructor is fine; we don't define one
// The default operator= is fine; we don't define one
// The main thing our iterator does is dereference. If the table entry
// we point to is empty, we return the default value type.
// This is the big different function from the const iterator.
reference operator*() {
return table_element_adaptor<tabletype>(table, pos);
}
pointer operator->() { return &(operator*()); }
// Helper function to assert things are ok; eg pos is still in range
void check() const {
assert(table);
assert(pos <= table->size());
}
// Arithmetic: we just do arithmetic on pos. We don't even need to
// do bounds checking, since STL doesn't consider that its job. :-)
iterator& operator+=(size_type t) { pos += t; check(); return *this; }
iterator& operator-=(size_type t) { pos -= t; check(); return *this; }
iterator& operator++() { ++pos; check(); return *this; }
iterator& operator--() { --pos; check(); return *this; }
iterator operator++(int) { iterator tmp(*this); // for x++
++pos; check(); return tmp; }
iterator operator--(int) { iterator tmp(*this); // for x--
--pos; check(); return tmp; }
iterator operator+(difference_type i) const { iterator tmp(*this);
tmp += i; return tmp; }
iterator operator-(difference_type i) const { iterator tmp(*this);
tmp -= i; return tmp; }
difference_type operator-(iterator it) const { // for "x = it2 - it"
assert(table == it.table);
return pos - it.pos;
}
reference operator[](difference_type n) const {
return *(*this + n); // simple though not totally efficient
}
// Comparisons.
bool operator==(const iterator& it) const {
return table == it.table && pos == it.pos;
}
bool operator<(const iterator& it) const {
assert(table == it.table); // life is bad bad bad otherwise
return pos < it.pos;
}
bool operator!=(const iterator& it) const { return !(*this == it); }
bool operator<=(const iterator& it) const { return !(it < *this); }
bool operator>(const iterator& it) const { return it < *this; }
bool operator>=(const iterator& it) const { return !(*this < it); }
// Here's the info we actually need to be an iterator
tabletype *table; // so we can dereference and bounds-check
size_type pos; // index into the table
};
// support for "3 + iterator" has to be defined outside the class, alas
template<class T>
table_iterator<T> operator+(typename table_iterator<T>::difference_type i,
table_iterator<T> it) {
return it + i; // so people can say it2 = 3 + it
}
template <class tabletype>
class const_table_iterator {
public:
typedef table_iterator<tabletype> iterator;
typedef const_table_iterator const_iterator;
typedef std::random_access_iterator_tag iterator_category;
typedef typename tabletype::value_type value_type;
typedef typename tabletype::difference_type difference_type;
typedef typename tabletype::size_type size_type;
typedef typename tabletype::const_reference reference; // we're const-only
typedef typename tabletype::const_pointer pointer;
// The "real" constructor
const_table_iterator(const tabletype *tbl, size_type p)
: table(tbl), pos(p) { }
// The default constructor, used when I define vars of type table::iterator
const_table_iterator() : table(NULL), pos(0) { }
// The copy constructor, for when I say table::iterator foo = tbl.begin()
// Also converts normal iterators to const iterators
const_table_iterator(const iterator &from)
: table(from.table), pos(from.pos) { }
// The default destructor is fine; we don't define one
// The default operator= is fine; we don't define one
// The main thing our iterator does is dereference. If the table entry
// we point to is empty, we return the default value type.
reference operator*() const { return (*table)[pos]; }
pointer operator->() const { return &(operator*()); }
// Helper function to assert things are ok; eg pos is still in range
void check() const {
assert(table);
assert(pos <= table->size());
}
// Arithmetic: we just do arithmetic on pos. We don't even need to
// do bounds checking, since STL doesn't consider that its job. :-)
const_iterator& operator+=(size_type t) { pos += t; check(); return *this; }
const_iterator& operator-=(size_type t) { pos -= t; check(); return *this; }
const_iterator& operator++() { ++pos; check(); return *this; }
const_iterator& operator--() { --pos; check(); return *this; }
const_iterator operator++(int) { const_iterator tmp(*this); // for x++
++pos; check(); return tmp; }
const_iterator operator--(int) { const_iterator tmp(*this); // for x--
--pos; check(); return tmp; }
const_iterator operator+(difference_type i) const { const_iterator tmp(*this);
tmp += i; return tmp; }
const_iterator operator-(difference_type i) const { const_iterator tmp(*this);
tmp -= i; return tmp; }
difference_type operator-(const_iterator it) const { // for "x = it2 - it"
assert(table == it.table);
return pos - it.pos;
}
reference operator[](difference_type n) const {
return *(*this + n); // simple though not totally efficient
}
// Comparisons.
bool operator==(const const_iterator& it) const {
return table == it.table && pos == it.pos;
}
bool operator<(const const_iterator& it) const {
assert(table == it.table); // life is bad bad bad otherwise
return pos < it.pos;
}
bool operator!=(const const_iterator& it) const { return !(*this == it); }
bool operator<=(const const_iterator& it) const { return !(it < *this); }
bool operator>(const const_iterator& it) const { return it < *this; }
bool operator>=(const const_iterator& it) const { return !(*this < it); }
// Here's the info we actually need to be an iterator
const tabletype *table; // so we can dereference and bounds-check
size_type pos; // index into the table
};
// support for "3 + iterator" has to be defined outside the class, alas
template<class T>
const_table_iterator<T> operator+(typename
const_table_iterator<T>::difference_type i,
const_table_iterator<T> it) {
return it + i; // so people can say it2 = 3 + it
}
// ---------------------------------------------------------------------------
/*
// This is a 2-D iterator. You specify a begin and end over a list
// of *containers*. We iterate over each container by iterating over
// it. It's actually simple:
// VECTOR.begin() VECTOR[0].begin() --------> VECTOR[0].end() ---,
// | ________________________________________________/
// | \_> VECTOR[1].begin() --------> VECTOR[1].end() -,
// | ___________________________________________________/
// v \_> ......
// VECTOR.end()
//
// It's impossible to do random access on one of these things in constant
// time, so it's just a bidirectional iterator.
//
// Unfortunately, because we need to use this for a non-empty iterator,
// we use nonempty_begin() and nonempty_end() instead of begin() and end()
// (though only going across, not down).
*/
#define TWOD_BEGIN_ nonempty_begin
#define TWOD_END_ nonempty_end
#define TWOD_ITER_ nonempty_iterator
#define TWOD_CONST_ITER_ const_nonempty_iterator
template <class containertype>
class two_d_iterator {
public:
typedef two_d_iterator iterator;
typedef std::bidirectional_iterator_tag iterator_category;
// apparently some versions of VC++ have trouble with two ::'s in a typename
typedef typename containertype::value_type _tmp_vt;
typedef typename _tmp_vt::value_type value_type;
typedef typename _tmp_vt::difference_type difference_type;
typedef typename _tmp_vt::reference reference;
typedef typename _tmp_vt::pointer pointer;
// The "real" constructor. begin and end specify how many rows we have
// (in the diagram above); we always iterate over each row completely.
two_d_iterator(typename containertype::iterator begin,
typename containertype::iterator end,
typename containertype::iterator curr)
: row_begin(begin), row_end(end), row_current(curr), col_current() {
if ( row_current != row_end ) {
col_current = row_current->TWOD_BEGIN_();
advance_past_end(); // in case cur->begin() == cur->end()
}
}
// If you want to start at an arbitrary place, you can, I guess
two_d_iterator(typename containertype::iterator begin,
typename containertype::iterator end,
typename containertype::iterator curr,
typename containertype::value_type::TWOD_ITER_ col)
: row_begin(begin), row_end(end), row_current(curr), col_current(col) {
advance_past_end(); // in case cur->begin() == cur->end()
}
// The default constructor, used when I define vars of type table::iterator
two_d_iterator() : row_begin(), row_end(), row_current(), col_current() { }
// The default destructor is fine; we don't define one
// The default operator= is fine; we don't define one
// Happy dereferencer
reference operator*() const { return *col_current; }
pointer operator->() const { return &(operator*()); }
// Arithmetic: we just do arithmetic on pos. We don't even need to
// do bounds checking, since STL doesn't consider that its job. :-)
// NOTE: this is not amortized constant time! What do we do about it?
void advance_past_end() { // used when col_current points to end()
while ( col_current == row_current->TWOD_END_() ) { // end of current row
++row_current; // go to beginning of next
if ( row_current != row_end ) // col is irrelevant at end
col_current = row_current->TWOD_BEGIN_();
else
break; // don't go past row_end
}
}
iterator& operator++() {
assert(row_current != row_end); // how to ++ from there?
++col_current;
advance_past_end(); // in case col_current is at end()
return *this;
}
iterator& operator--() {
while ( row_current == row_end ||
col_current == row_current->TWOD_BEGIN_() ) {
assert(row_current != row_begin);
--row_current;
col_current = row_current->TWOD_END_(); // this is 1 too far
}
--col_current;
return *this;
}
iterator operator++(int) { iterator tmp(*this); ++*this; return tmp; }
iterator operator--(int) { iterator tmp(*this); --*this; return tmp; }
// Comparisons.
bool operator==(const iterator& it) const {
return ( row_begin == it.row_begin &&
row_end == it.row_end &&
row_current == it.row_current &&
(row_current == row_end || col_current == it.col_current) );
}
bool operator!=(const iterator& it) const { return !(*this == it); }
// Here's the info we actually need to be an iterator
// These need to be public so we convert from iterator to const_iterator
typename containertype::iterator row_begin, row_end, row_current;
typename containertype::value_type::TWOD_ITER_ col_current;
};
// The same thing again, but this time const. :-(
template <class containertype>
class const_two_d_iterator {
public:
typedef const_two_d_iterator iterator;
typedef std::bidirectional_iterator_tag iterator_category;
// apparently some versions of VC++ have trouble with two ::'s in a typename
typedef typename containertype::value_type _tmp_vt;
typedef typename _tmp_vt::value_type value_type;
typedef typename _tmp_vt::difference_type difference_type;
typedef typename _tmp_vt::const_reference reference;
typedef typename _tmp_vt::const_pointer pointer;
const_two_d_iterator(typename containertype::const_iterator begin,
typename containertype::const_iterator end,
typename containertype::const_iterator curr)
: row_begin(begin), row_end(end), row_current(curr), col_current() {
if ( curr != end ) {
col_current = curr->TWOD_BEGIN_();
advance_past_end(); // in case cur->begin() == cur->end()
}
}
const_two_d_iterator(typename containertype::const_iterator begin,
typename containertype::const_iterator end,
typename containertype::const_iterator curr,
typename containertype::value_type::TWOD_CONST_ITER_ col)
: row_begin(begin), row_end(end), row_current(curr), col_current(col) {
advance_past_end(); // in case cur->begin() == cur->end()
}
const_two_d_iterator()
: row_begin(), row_end(), row_current(), col_current() {
}
// Need this explicitly so we can convert normal iterators to const iterators
const_two_d_iterator(const two_d_iterator<containertype>& it) :
row_begin(it.row_begin), row_end(it.row_end), row_current(it.row_current),
col_current(it.col_current) { }
typename containertype::const_iterator row_begin, row_end, row_current;
typename containertype::value_type::TWOD_CONST_ITER_ col_current;
// EVERYTHING FROM HERE DOWN IS THE SAME AS THE NON-CONST ITERATOR
reference operator*() const { return *col_current; }
pointer operator->() const { return &(operator*()); }
void advance_past_end() { // used when col_current points to end()
while ( col_current == row_current->TWOD_END_() ) { // end of current row
++row_current; // go to beginning of next
if ( row_current != row_end ) // col is irrelevant at end
col_current = row_current->TWOD_BEGIN_();
else
break; // don't go past row_end
}
}
iterator& operator++() {
assert(row_current != row_end); // how to ++ from there?
++col_current;
advance_past_end(); // in case col_current is at end()
return *this;
}
iterator& operator--() {
while ( row_current == row_end ||
col_current == row_current->TWOD_BEGIN_() ) {
assert(row_current != row_begin);
--row_current;
col_current = row_current->TWOD_END_(); // this is 1 too far
}
--col_current;
return *this;
}
iterator operator++(int) { iterator tmp(*this); ++*this; return tmp; }
iterator operator--(int) { iterator tmp(*this); --*this; return tmp; }
bool operator==(const iterator& it) const {
return ( row_begin == it.row_begin &&
row_end == it.row_end &&
row_current == it.row_current &&
(row_current == row_end || col_current == it.col_current) );
}
bool operator!=(const iterator& it) const { return !(*this == it); }
};
// We provide yet another version, to be as frugal with memory as
// possible. This one frees each block of memory as it finishes
// iterating over it. By the end, the entire table is freed.
// For understandable reasons, you can only iterate over it once,
// which is why it's an input iterator
template <class containertype>
class destructive_two_d_iterator {
public:
typedef destructive_two_d_iterator iterator;
typedef std::input_iterator_tag iterator_category;
// apparently some versions of VC++ have trouble with two ::'s in a typename
typedef typename containertype::value_type _tmp_vt;
typedef typename _tmp_vt::value_type value_type;
typedef typename _tmp_vt::difference_type difference_type;
typedef typename _tmp_vt::reference reference;
typedef typename _tmp_vt::pointer pointer;
destructive_two_d_iterator(typename containertype::iterator begin,
typename containertype::iterator end,
typename containertype::iterator curr)
: row_begin(begin), row_end(end), row_current(curr), col_current() {
if ( curr != end ) {
col_current = curr->TWOD_BEGIN_();
advance_past_end(); // in case cur->begin() == cur->end()
}
}
destructive_two_d_iterator(typename containertype::iterator begin,
typename containertype::iterator end,
typename containertype::iterator curr,
typename containertype::value_type::TWOD_ITER_ col)
: row_begin(begin), row_end(end), row_current(curr), col_current(col) {
advance_past_end(); // in case cur->begin() == cur->end()
}
destructive_two_d_iterator()
: row_begin(), row_end(), row_current(), col_current() {
}
typename containertype::iterator row_begin, row_end, row_current;
typename containertype::value_type::TWOD_ITER_ col_current;
// This is the part that destroys
void advance_past_end() { // used when col_current points to end()
while ( col_current == row_current->TWOD_END_() ) { // end of current row
row_current->clear(); // the destructive part
// It would be nice if we could decrement sparsetable->num_buckets here
++row_current; // go to beginning of next
if ( row_current != row_end ) // col is irrelevant at end
col_current = row_current->TWOD_BEGIN_();
else
break; // don't go past row_end
}
}
// EVERYTHING FROM HERE DOWN IS THE SAME AS THE REGULAR ITERATOR
reference operator*() const { return *col_current; }
pointer operator->() const { return &(operator*()); }
iterator& operator++() {
assert(row_current != row_end); // how to ++ from there?
++col_current;
advance_past_end(); // in case col_current is at end()
return *this;
}
iterator operator++(int) { iterator tmp(*this); ++*this; return tmp; }
bool operator==(const iterator& it) const {
return ( row_begin == it.row_begin &&
row_end == it.row_end &&
row_current == it.row_current &&
(row_current == row_end || col_current == it.col_current) );
}
bool operator!=(const iterator& it) const { return !(*this == it); }
};
#undef TWOD_BEGIN_
#undef TWOD_END_
#undef TWOD_ITER_
#undef TWOD_CONST_ITER_
// SPARSE-TABLE
// ------------
// The idea is that a table with (logically) t buckets is divided
// into t/M *groups* of M buckets each. (M is a constant set in
// GROUP_SIZE for efficiency.) Each group is stored sparsely.
// Thus, inserting into the table causes some array to grow, which is
// slow but still constant time. Lookup involves doing a
// logical-position-to-sparse-position lookup, which is also slow but
// constant time. The larger M is, the slower these operations are
// but the less overhead (slightly).
//
// To store the sparse array, we store a bitmap B, where B[i] = 1 iff
// bucket i is non-empty. Then to look up bucket i we really look up
// array[# of 1s before i in B]. This is constant time for fixed M.
//
// Terminology: the position of an item in the overall table (from
// 1 .. t) is called its "location." The logical position in a group
// (from 1 .. M ) is called its "position." The actual location in
// the array (from 1 .. # of non-empty buckets in the group) is
// called its "offset."
template <class T, u_int16_t GROUP_SIZE, class Alloc>
class sparsegroup {
private:
typedef typename Alloc::template rebind<T>::other value_alloc_type;
public:
// Basic types
typedef T value_type;
typedef Alloc allocator_type;
typedef typename value_alloc_type::reference reference;
typedef typename value_alloc_type::const_reference const_reference;
typedef typename value_alloc_type::pointer pointer;
typedef typename value_alloc_type::const_pointer const_pointer;
typedef table_iterator<sparsegroup<T, GROUP_SIZE, Alloc> > iterator;
typedef const_table_iterator<sparsegroup<T, GROUP_SIZE, Alloc> >
const_iterator;
typedef table_element_adaptor<sparsegroup<T, GROUP_SIZE, Alloc> >
element_adaptor;
typedef u_int16_t size_type; // max # of buckets
typedef int16_t difference_type;
typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
typedef std::reverse_iterator<iterator> reverse_iterator; // from iterator.h
// These are our special iterators, that go over non-empty buckets in a
// group. These aren't const-only because you can change non-empty bcks.
typedef pointer nonempty_iterator;
typedef const_pointer const_nonempty_iterator;
typedef std::reverse_iterator<nonempty_iterator> reverse_nonempty_iterator;
typedef std::reverse_iterator<const_nonempty_iterator> const_reverse_nonempty_iterator;
// Iterator functions
iterator begin() { return iterator(this, 0); }
const_iterator begin() const { return const_iterator(this, 0); }
iterator end() { return iterator(this, size()); }
const_iterator end() const { return const_iterator(this, size()); }
reverse_iterator rbegin() { return reverse_iterator(end()); }
const_reverse_iterator rbegin() const { return const_reverse_iterator(end()); }
reverse_iterator rend() { return reverse_iterator(begin()); }
const_reverse_iterator rend() const { return const_reverse_iterator(begin()); }
// We'll have versions for our special non-empty iterator too
nonempty_iterator nonempty_begin() { return group; }
const_nonempty_iterator nonempty_begin() const { return group; }
nonempty_iterator nonempty_end() {
return group + settings.num_buckets;
}
const_nonempty_iterator nonempty_end() const {
return group + settings.num_buckets;
}
reverse_nonempty_iterator nonempty_rbegin() {
return reverse_nonempty_iterator(nonempty_end());
}
const_reverse_nonempty_iterator nonempty_rbegin() const {
return const_reverse_nonempty_iterator(nonempty_end());
}
reverse_nonempty_iterator nonempty_rend() {
return reverse_nonempty_iterator(nonempty_begin());
}
const_reverse_nonempty_iterator nonempty_rend() const {
return const_reverse_nonempty_iterator(nonempty_begin());
}
// This gives us the "default" value to return for an empty bucket.
// We just use the default constructor on T, the template type
const_reference default_value() const {
static value_type defaultval = value_type();
return defaultval;
}
private:
// We need to do all this bit manipulation, of course. ick
static size_type charbit(size_type i) { return i >> 3; }
static size_type modbit(size_type i) { return 1 << (i&7); }
int bmtest(size_type i) const { return bitmap[charbit(i)] & modbit(i); }
void bmset(size_type i) { bitmap[charbit(i)] |= modbit(i); }
void bmclear(size_type i) { bitmap[charbit(i)] &= ~modbit(i); }
pointer allocate_group(size_type n) {
pointer retval = settings.allocate(n);
if (retval == NULL) {
// We really should use PRIuS here, but I don't want to have to add
// a whole new configure option, with concomitant macro namespace
// pollution, just to print this (unlikely) error message. So I cast.
fprintf(stderr, "sparsehash FATAL ERROR: failed to allocate %lu groups\n",
static_cast<unsigned long>(n));
exit(1);
}
return retval;
}
void free_group() {
if (!group) return;
pointer end_it = group + settings.num_buckets;
for (pointer p = group; p != end_it; ++p)
p->~value_type();
settings.deallocate(group, settings.num_buckets);
group = NULL;
}
static size_type bits_in_char(unsigned char c) {
// We could make these ints. The tradeoff is size (eg does it overwhelm
// the cache?) vs efficiency in referencing sub-word-sized array elements.
static const char bits_in[256] = {
0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8,
};
return bits_in[c];
}
public: // get_iter() in sparsetable needs it
// We need a small function that tells us how many set bits there are
// in positions 0..i-1 of the bitmap. It uses a big table.
// We make it static so templates don't allocate lots of these tables.
// There are lots of ways to do this calculation (called 'popcount').
// The 8-bit table lookup is one of the fastest, though this
// implementation suffers from not doing any loop unrolling. See, eg,
// http://www.dalkescientific.com/writings/diary/archive/2008/07/03/hakmem_and_other_popcounts.html
// http://gurmeetsingh.wordpress.com/2008/08/05/fast-bit-counting-routines/
static size_type pos_to_offset(const unsigned char *bm, size_type pos) {
size_type retval = 0;
// [Note: condition pos > 8 is an optimization; convince yourself we
// give exactly the same result as if we had pos >= 8 here instead.]
for ( ; pos > 8; pos -= 8 ) // bm[0..pos/8-1]
retval += bits_in_char(*bm++); // chars we want *all* bits in
return retval + bits_in_char(*bm & ((1 << pos)-1)); // char including pos
}
size_type pos_to_offset(size_type pos) const { // not static but still const
return pos_to_offset(bitmap, pos);
}
// Returns the (logical) position in the bm[] array, i, such that
// bm[i] is the offset-th set bit in the array. It is the inverse
// of pos_to_offset. get_pos() uses this function to find the index
// of an nonempty_iterator in the table. Bit-twiddling from
// http://hackersdelight.org/basics.pdf
static size_type offset_to_pos(const unsigned char *bm, size_type offset) {
size_type retval = 0;
// This is sizeof(this->bitmap).
const size_type group_size = (GROUP_SIZE-1) / 8 + 1;
for (size_type i = 0; i < group_size; i++) { // forward scan
const size_type pop_count = bits_in_char(*bm);
if (pop_count > offset) {
unsigned char last_bm = *bm;
for (; offset > 0; offset--) {
last_bm &= (last_bm-1); // remove right-most set bit
}
// Clear all bits to the left of the rightmost bit (the &),
// and then clear the rightmost bit but set all bits to the
// right of it (the -1).
last_bm = (last_bm & -last_bm) - 1;
retval += bits_in_char(last_bm);
return retval;
}
offset -= pop_count;
retval += 8;
bm++;
}
return retval;
}
size_type offset_to_pos(size_type offset) const {
return offset_to_pos(bitmap, offset);
}
public:
// Constructors -- default and copy -- and destructor
explicit sparsegroup(allocator_type& a) :
group(0), settings(alloc_impl<value_alloc_type>(a)) {
memset(bitmap, 0, sizeof(bitmap));
}
sparsegroup(const sparsegroup& x) : group(0), settings(x.settings) {
if ( settings.num_buckets ) {
group = allocate_group(x.settings.num_buckets);
std::uninitialized_copy(x.group, x.group + x.settings.num_buckets, group);
}
memcpy(bitmap, x.bitmap, sizeof(bitmap));
}
~sparsegroup() { free_group(); }
// Operator= is just like the copy constructor, I guess
// TODO(austern): Make this exception safe. Handle exceptions in value_type's
// copy constructor.
sparsegroup &operator=(const sparsegroup& x) {
if ( &x == this ) return *this; // x = x
if ( x.settings.num_buckets == 0 ) {
free_group();
} else {
pointer p = allocate_group(x.settings.num_buckets);
std::uninitialized_copy(x.group, x.group + x.settings.num_buckets, p);
free_group();
group = p;
}
memcpy(bitmap, x.bitmap, sizeof(bitmap));
settings.num_buckets = x.settings.num_buckets;
return *this;
}
// Many STL algorithms use swap instead of copy constructors
void swap(sparsegroup& x) {
std::swap(group, x.group); // defined in <algorithm>
for ( int i = 0; i < sizeof(bitmap) / sizeof(*bitmap); ++i )
std::swap(bitmap[i], x.bitmap[i]); // swap not defined on arrays
std::swap(settings.num_buckets, x.settings.num_buckets);
// we purposefully don't swap the allocator, which may not be swap-able
}
// It's always nice to be able to clear a table without deallocating it
void clear() {
free_group();
memset(bitmap, 0, sizeof(bitmap));
settings.num_buckets = 0;
}
// Functions that tell you about size. Alas, these aren't so useful
// because our table is always fixed size.
size_type size() const { return GROUP_SIZE; }
size_type max_size() const { return GROUP_SIZE; }
bool empty() const { return false; }
// We also may want to know how many *used* buckets there are
size_type num_nonempty() const { return settings.num_buckets; }
// get()/set() are explicitly const/non-const. You can use [] if
// you want something that can be either (potentially more expensive).
const_reference get(size_type i) const {
if ( bmtest(i) ) // bucket i is occupied
return group[pos_to_offset(bitmap, i)];
else
return default_value(); // return the default reference
}
// TODO(csilvers): make protected + friend
// This is used by sparse_hashtable to get an element from the table
// when we know it exists.
const_reference unsafe_get(size_type i) const {
assert(bmtest(i));
return group[pos_to_offset(bitmap, i)];
}
// TODO(csilvers): make protected + friend
reference mutating_get(size_type i) { // fills bucket i before getting
if ( !bmtest(i) )
set(i, default_value());
return group[pos_to_offset(bitmap, i)];
}
// Syntactic sugar. It's easy to return a const reference. To
// return a non-const reference, we need to use the assigner adaptor.
const_reference operator[](size_type i) const {
return get(i);
}
element_adaptor operator[](size_type i) {
return element_adaptor(this, i);
}
private:
// Create space at group[offset], assuming value_type has trivial
// copy constructor and destructor, and the allocator_type is
// the default libc_allocator_with_alloc. (Really, we want it to have
// "trivial move", because that's what realloc and memmove both do.
// But there's no way to capture that using type_traits, so we
// pretend that move(x, y) is equivalent to "x.~T(); new(x) T(y);"
// which is pretty much correct, if a bit conservative.)
void set_aux(size_type offset, base::true_type) {
group = settings.realloc_or_die(group, settings.num_buckets+1);
// This is equivalent to memmove(), but faster on my Intel P4,
// at least with gcc4.1 -O2 / glibc 2.3.6.
for (size_type i = settings.num_buckets; i > offset; --i)
memcpy(group + i, group + i-1, sizeof(*group));
}
// Create space at group[offset], without special assumptions about value_type
// and allocator_type.
void set_aux(size_type offset, base::false_type) {
// This is valid because 0 <= offset <= num_buckets
pointer p = allocate_group(settings.num_buckets + 1);
std::uninitialized_copy(group, group + offset, p);
std::uninitialized_copy(group + offset, group + settings.num_buckets,
p + offset + 1);
free_group();
group = p;
}
public:
// This returns a reference to the inserted item (which is a copy of val).
// TODO(austern): Make this exception safe: handle exceptions from
// value_type's copy constructor.
reference set(size_type i, const_reference val) {
size_type offset = pos_to_offset(bitmap, i); // where we'll find (or insert)
if ( bmtest(i) ) {
// Delete the old value, which we're replacing with the new one
group[offset].~value_type();
} else {
typedef base::integral_constant<bool,
(base::has_trivial_copy<value_type>::value &&
base::has_trivial_destructor<value_type>::value &&
base::is_same<
allocator_type,
libc_allocator_with_realloc<value_type> >::value)>
realloc_and_memmove_ok; // we pretend mv(x,y) == "x.~T(); new(x) T(y)"
set_aux(offset, realloc_and_memmove_ok());
++settings.num_buckets;
bmset(i);
}
// This does the actual inserting. Since we made the array using
// malloc, we use "placement new" to just call the constructor.
new(&group[offset]) value_type(val);
return group[offset];
}
// We let you see if a bucket is non-empty without retrieving it
bool test(size_type i) const {
return bmtest(i) != 0;
}
bool test(iterator pos) const {
return bmtest(pos.pos) != 0;
}
private:
// Shrink the array, assuming value_type has trivial copy
// constructor and destructor, and the allocator_type is the default
// libc_allocator_with_alloc. (Really, we want it to have "trivial
// move", because that's what realloc and memmove both do. But
// there's no way to capture that using type_traits, so we pretend
// that move(x, y) is equivalent to ""x.~T(); new(x) T(y);"
// which is pretty much correct, if a bit conservative.)
void erase_aux(size_type offset, base::true_type) {
// This isn't technically necessary, since we know we have a
// trivial destructor, but is a cheap way to get a bit more safety.
group[offset].~value_type();
// This is equivalent to memmove(), but faster on my Intel P4,
// at lesat with gcc4.1 -O2 / glibc 2.3.6.
assert(settings.num_buckets > 0);
for (size_type i = offset; i < settings.num_buckets-1; ++i)
memcpy(group + i, group + i+1, sizeof(*group)); // hopefully inlined!
group = settings.realloc_or_die(group, settings.num_buckets-1);
}
// Shrink the array, without any special assumptions about value_type and
// allocator_type.
void erase_aux(size_type offset, base::false_type) {
// This is valid because 0 <= offset < num_buckets. Note the inequality.
pointer p = allocate_group(settings.num_buckets - 1);
std::uninitialized_copy(group, group + offset, p);
std::uninitialized_copy(group + offset + 1, group + settings.num_buckets,
p + offset);
free_group();
group = p;
}
public:
// This takes the specified elements out of the group. This is
// "undefining", rather than "clearing".
// TODO(austern): Make this exception safe: handle exceptions from
// value_type's copy constructor.
void erase(size_type i) {
if ( bmtest(i) ) { // trivial to erase empty bucket
size_type offset = pos_to_offset(bitmap,i); // where we'll find (or insert)
if ( settings.num_buckets == 1 ) {
free_group();
group = NULL;
} else {
typedef base::integral_constant<bool,
(base::has_trivial_copy<value_type>::value &&
base::has_trivial_destructor<value_type>::value &&
base::is_same<
allocator_type,
libc_allocator_with_realloc<value_type> >::value)>
realloc_and_memmove_ok; // pretend mv(x,y) == "x.~T(); new(x) T(y)"
erase_aux(offset, realloc_and_memmove_ok());
}
--settings.num_buckets;
bmclear(i);
}
}
void erase(iterator pos) {
erase(pos.pos);
}
void erase(iterator start_it, iterator end_it) {
// This could be more efficient, but to do so we'd need to make
// bmclear() clear a range of indices. Doesn't seem worth it.
for ( ; start_it != end_it; ++start_it )
erase(start_it);
}
// I/O
// We support reading and writing groups to disk. We don't store
// the actual array contents (which we don't know how to store),
// just the bitmap and size. Meant to be used with table I/O.
template <typename OUTPUT> bool write_metadata(OUTPUT *fp) const {
// we explicitly set to u_int16_t
assert(sizeof(settings.num_buckets) == 2);
if ( !sparsehash_internal::write_bigendian_number(fp, settings.num_buckets,
2) )
return false;
if ( !sparsehash_internal::write_data(fp, bitmap, sizeof(bitmap)) )
return false;
return true;
}
// Reading destroys the old group contents! Returns true if all was ok.
template <typename INPUT> bool read_metadata(INPUT *fp) {
clear();
if ( !sparsehash_internal::read_bigendian_number(fp, &settings.num_buckets,
2) )
return false;
if ( !sparsehash_internal::read_data(fp, bitmap, sizeof(bitmap)) )
return false;
// We'll allocate the space, but we won't fill it: it will be
// left as uninitialized raw memory.
group = allocate_group(settings.num_buckets);
return true;
}
// Again, only meaningful if value_type is a POD.
template <typename INPUT> bool read_nopointer_data(INPUT *fp) {
for ( nonempty_iterator it = nonempty_begin();
it != nonempty_end(); ++it ) {
if ( !sparsehash_internal::read_data(fp, &(*it), sizeof(*it)) )
return false;
}
return true;
}
// If your keys and values are simple enough, we can write them
// to disk for you. "simple enough" means POD and no pointers.
// However, we don't try to normalize endianness.
template <typename OUTPUT> bool write_nopointer_data(OUTPUT *fp) const {
for ( const_nonempty_iterator it = nonempty_begin();
it != nonempty_end(); ++it ) {
if ( !sparsehash_internal::write_data(fp, &(*it), sizeof(*it)) )
return false;
}
return true;
}
// Comparisons. We only need to define == and < -- we get
// != > <= >= via relops.h (which we happily included above).
// Note the comparisons are pretty arbitrary: we compare
// values of the first index that isn't equal (using default
// value for empty buckets).
bool operator==(const sparsegroup& x) const {
return ( settings.num_buckets == x.settings.num_buckets &&
memcmp(bitmap, x.bitmap, sizeof(bitmap)) == 0 &&
std::equal(begin(), end(), x.begin()) ); // from <algorithm>
}
bool operator<(const sparsegroup& x) const { // also from <algorithm>
return std::lexicographical_compare(begin(), end(), x.begin(), x.end());
}
bool operator!=(const sparsegroup& x) const { return !(*this == x); }
bool operator<=(const sparsegroup& x) const { return !(x < *this); }
bool operator>(const sparsegroup& x) const { return x < *this; }
bool operator>=(const sparsegroup& x) const { return !(*this < x); }
private:
template <class A>
class alloc_impl : public A {
public:
typedef typename A::pointer pointer;
typedef typename A::size_type size_type;
// Convert a normal allocator to one that has realloc_or_die()
alloc_impl(const A& a) : A(a) { }
// realloc_or_die should only be used when using the default
// allocator (libc_allocator_with_realloc).
pointer realloc_or_die(pointer /*ptr*/, size_type /*n*/) {
fprintf(stderr, "realloc_or_die is only supported for "
"libc_allocator_with_realloc\n");
exit(1);
return NULL;
}
};
// A template specialization of alloc_impl for
// libc_allocator_with_realloc that can handle realloc_or_die.
template <class A>
class alloc_impl<libc_allocator_with_realloc<A> >
: public libc_allocator_with_realloc<A> {
public:
typedef typename libc_allocator_with_realloc<A>::pointer pointer;
typedef typename libc_allocator_with_realloc<A>::size_type size_type;
alloc_impl(const libc_allocator_with_realloc<A>& a)
: libc_allocator_with_realloc<A>(a) { }
pointer realloc_or_die(pointer ptr, size_type n) {
pointer retval = this->reallocate(ptr, n);
if (retval == NULL) {
fprintf(stderr, "sparsehash: FATAL ERROR: failed to reallocate "
"%lu elements for ptr %p", static_cast<unsigned long>(n), ptr);
exit(1);
}
return retval;
}
};
// Package allocator with num_buckets to eliminate memory needed for the
// zero-size allocator.
// If new fields are added to this class, we should add them to
// operator= and swap.
class Settings : public alloc_impl<value_alloc_type> {
public:
Settings(const alloc_impl<value_alloc_type>& a, u_int16_t n = 0)
: alloc_impl<value_alloc_type>(a), num_buckets(n) { }
Settings(const Settings& s)
: alloc_impl<value_alloc_type>(s), num_buckets(s.num_buckets) { }
u_int16_t num_buckets; // limits GROUP_SIZE to 64K
};
// The actual data
pointer group; // (small) array of T's
Settings settings; // allocator and num_buckets
unsigned char bitmap[(GROUP_SIZE-1)/8 + 1]; // fancy math is so we round up
};
// We need a global swap as well
template <class T, u_int16_t GROUP_SIZE, class Alloc>
inline void swap(sparsegroup<T,GROUP_SIZE,Alloc> &x,
sparsegroup<T,GROUP_SIZE,Alloc> &y) {
x.swap(y);
}
// ---------------------------------------------------------------------------
template <class T, u_int16_t GROUP_SIZE = DEFAULT_SPARSEGROUP_SIZE,
class Alloc = libc_allocator_with_realloc<T> >
class sparsetable {
private:
typedef typename Alloc::template rebind<T>::other value_alloc_type;
typedef typename Alloc::template rebind<
sparsegroup<T, GROUP_SIZE, value_alloc_type> >::other vector_alloc;
public:
// Basic types
typedef T value_type; // stolen from stl_vector.h
typedef Alloc allocator_type;
typedef typename value_alloc_type::size_type size_type;
typedef typename value_alloc_type::difference_type difference_type;
typedef typename value_alloc_type::reference reference;
typedef typename value_alloc_type::const_reference const_reference;
typedef typename value_alloc_type::pointer pointer;
typedef typename value_alloc_type::const_pointer const_pointer;
typedef table_iterator<sparsetable<T, GROUP_SIZE, Alloc> > iterator;
typedef const_table_iterator<sparsetable<T, GROUP_SIZE, Alloc> >
const_iterator;
typedef table_element_adaptor<sparsetable<T, GROUP_SIZE, Alloc> >
element_adaptor;
typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
typedef std::reverse_iterator<iterator> reverse_iterator; // from iterator.h
// These are our special iterators, that go over non-empty buckets in a
// table. These aren't const only because you can change non-empty bcks.
typedef two_d_iterator< std::vector< sparsegroup<value_type, GROUP_SIZE,
value_alloc_type>,
vector_alloc> >
nonempty_iterator;
typedef const_two_d_iterator< std::vector< sparsegroup<value_type,
GROUP_SIZE,
value_alloc_type>,
vector_alloc> >
const_nonempty_iterator;
typedef std::reverse_iterator<nonempty_iterator> reverse_nonempty_iterator;
typedef std::reverse_iterator<const_nonempty_iterator> const_reverse_nonempty_iterator;
// Another special iterator: it frees memory as it iterates (used to resize)
typedef destructive_two_d_iterator< std::vector< sparsegroup<value_type,
GROUP_SIZE,
value_alloc_type>,
vector_alloc> >
destructive_iterator;
// Iterator functions
iterator begin() { return iterator(this, 0); }
const_iterator begin() const { return const_iterator(this, 0); }
iterator end() { return iterator(this, size()); }
const_iterator end() const { return const_iterator(this, size()); }
reverse_iterator rbegin() { return reverse_iterator(end()); }
const_reverse_iterator rbegin() const { return const_reverse_iterator(end()); }
reverse_iterator rend() { return reverse_iterator(begin()); }
const_reverse_iterator rend() const { return const_reverse_iterator(begin()); }
// Versions for our special non-empty iterator
nonempty_iterator nonempty_begin() {
return nonempty_iterator(groups.begin(), groups.end(), groups.begin());
}
const_nonempty_iterator nonempty_begin() const {
return const_nonempty_iterator(groups.begin(),groups.end(), groups.begin());
}
nonempty_iterator nonempty_end() {
return nonempty_iterator(groups.begin(), groups.end(), groups.end());
}
const_nonempty_iterator nonempty_end() const {
return const_nonempty_iterator(groups.begin(), groups.end(), groups.end());
}
reverse_nonempty_iterator nonempty_rbegin() {
return reverse_nonempty_iterator(nonempty_end());
}
const_reverse_nonempty_iterator nonempty_rbegin() const {
return const_reverse_nonempty_iterator(nonempty_end());
}
reverse_nonempty_iterator nonempty_rend() {
return reverse_nonempty_iterator(nonempty_begin());
}
const_reverse_nonempty_iterator nonempty_rend() const {
return const_reverse_nonempty_iterator(nonempty_begin());
}
destructive_iterator destructive_begin() {
return destructive_iterator(groups.begin(), groups.end(), groups.begin());
}
destructive_iterator destructive_end() {
return destructive_iterator(groups.begin(), groups.end(), groups.end());
}
typedef sparsegroup<value_type, GROUP_SIZE, allocator_type> group_type;
typedef std::vector<group_type, vector_alloc > group_vector_type;
typedef typename group_vector_type::reference GroupsReference;
typedef typename group_vector_type::const_reference GroupsConstReference;
typedef typename group_vector_type::iterator GroupsIterator;
typedef typename group_vector_type::const_iterator GroupsConstIterator;
// How to deal with the proper group
static size_type num_groups(size_type num) { // how many to hold num buckets
return num == 0 ? 0 : ((num-1) / GROUP_SIZE) + 1;
}
u_int16_t pos_in_group(size_type i) const {
return static_cast<u_int16_t>(i % GROUP_SIZE);
}
size_type group_num(size_type i) const {
return i / GROUP_SIZE;
}
GroupsReference which_group(size_type i) {
return groups[group_num(i)];
}
GroupsConstReference which_group(size_type i) const {
return groups[group_num(i)];
}
public:
// Constructors -- default, normal (when you specify size), and copy
explicit sparsetable(size_type sz = 0, Alloc alloc = Alloc())
: groups(vector_alloc(alloc)), settings(alloc, sz) {
groups.resize(num_groups(sz), group_type(settings));
}
// We can get away with using the default copy constructor,
// and default destructor, and hence the default operator=. Huzzah!
// Many STL algorithms use swap instead of copy constructors
void swap(sparsetable& x) {
std::swap(groups, x.groups); // defined in stl_algobase.h
std::swap(settings.table_size, x.settings.table_size);
std::swap(settings.num_buckets, x.settings.num_buckets);
}
// It's always nice to be able to clear a table without deallocating it
void clear() {
GroupsIterator group;
for ( group = groups.begin(); group != groups.end(); ++group ) {
group->clear();
}
settings.num_buckets = 0;
}
// ACCESSOR FUNCTIONS for the things we templatize on, basically
allocator_type get_allocator() const {
return allocator_type(settings);
}
// Functions that tell you about size.
// NOTE: empty() is non-intuitive! It does not tell you the number
// of not-empty buckets (use num_nonempty() for that). Instead
// it says whether you've allocated any buckets or not.
size_type size() const { return settings.table_size; }
size_type max_size() const { return settings.max_size(); }
bool empty() const { return settings.table_size == 0; }
// We also may want to know how many *used* buckets there are
size_type num_nonempty() const { return settings.num_buckets; }
// OK, we'll let you resize one of these puppies
void resize(size_type new_size) {
groups.resize(num_groups(new_size), group_type(settings));
if ( new_size < settings.table_size) {
// lower num_buckets, clear last group
if ( pos_in_group(new_size) > 0 ) // need to clear inside last group
groups.back().erase(groups.back().begin() + pos_in_group(new_size),
groups.back().end());
settings.num_buckets = 0; // refigure # of used buckets
GroupsConstIterator group;
for ( group = groups.begin(); group != groups.end(); ++group )
settings.num_buckets += group->num_nonempty();
}
settings.table_size = new_size;
}
// We let you see if a bucket is non-empty without retrieving it
bool test(size_type i) const {
assert(i < settings.table_size);
return which_group(i).test(pos_in_group(i));
}
bool test(iterator pos) const {
return which_group(pos.pos).test(pos_in_group(pos.pos));
}
bool test(const_iterator pos) const {
return which_group(pos.pos).test(pos_in_group(pos.pos));
}
// We only return const_references because it's really hard to
// return something settable for empty buckets. Use set() instead.
const_reference get(size_type i) const {
assert(i < settings.table_size);
return which_group(i).get(pos_in_group(i));
}
// TODO(csilvers): make protected + friend
// This is used by sparse_hashtable to get an element from the table
// when we know it exists (because the caller has called test(i)).
const_reference unsafe_get(size_type i) const {
assert(i < settings.table_size);
assert(test(i));
return which_group(i).unsafe_get(pos_in_group(i));
}
// TODO(csilvers): make protected + friend element_adaptor
reference mutating_get(size_type i) { // fills bucket i before getting
assert(i < settings.table_size);
typename group_type::size_type old_numbuckets = which_group(i).num_nonempty();
reference retval = which_group(i).mutating_get(pos_in_group(i));
settings.num_buckets += which_group(i).num_nonempty() - old_numbuckets;
return retval;
}
// Syntactic sugar. As in sparsegroup, the non-const version is harder
const_reference operator[](size_type i) const {
return get(i);
}
element_adaptor operator[](size_type i) {
return element_adaptor(this, i);
}
// Needed for hashtables, gets as a nonempty_iterator. Crashes for empty bcks
const_nonempty_iterator get_iter(size_type i) const {
assert(test(i)); // how can a nonempty_iterator point to an empty bucket?
return const_nonempty_iterator(
groups.begin(), groups.end(),
groups.begin() + group_num(i),
(groups[group_num(i)].nonempty_begin() +
groups[group_num(i)].pos_to_offset(pos_in_group(i))));
}
// For nonempty we can return a non-const version
nonempty_iterator get_iter(size_type i) {
assert(test(i)); // how can a nonempty_iterator point to an empty bucket?
return nonempty_iterator(
groups.begin(), groups.end(),
groups.begin() + group_num(i),
(groups[group_num(i)].nonempty_begin() +
groups[group_num(i)].pos_to_offset(pos_in_group(i))));
}
// And the reverse transformation.
size_type get_pos(const const_nonempty_iterator it) const {
difference_type current_row = it.row_current - it.row_begin;
difference_type current_col = (it.col_current -
groups[current_row].nonempty_begin());
return ((current_row * GROUP_SIZE) +
groups[current_row].offset_to_pos(current_col));
}
// This returns a reference to the inserted item (which is a copy of val)
// The trick is to figure out whether we're replacing or inserting anew
reference set(size_type i, const_reference val) {
assert(i < settings.table_size);
typename group_type::size_type old_numbuckets = which_group(i).num_nonempty();
reference retval = which_group(i).set(pos_in_group(i), val);
settings.num_buckets += which_group(i).num_nonempty() - old_numbuckets;
return retval;
}
// This takes the specified elements out of the table. This is
// "undefining", rather than "clearing".
void erase(size_type i) {
assert(i < settings.table_size);
typename group_type::size_type old_numbuckets = which_group(i).num_nonempty();
which_group(i).erase(pos_in_group(i));
settings.num_buckets += which_group(i).num_nonempty() - old_numbuckets;
}
void erase(iterator pos) {
erase(pos.pos);
}
void erase(iterator start_it, iterator end_it) {
// This could be more efficient, but then we'd need to figure
// out if we spanned groups or not. Doesn't seem worth it.
for ( ; start_it != end_it; ++start_it )
erase(start_it);
}
// We support reading and writing tables to disk. We don't store
// the actual array contents (which we don't know how to store),
// just the groups and sizes. Returns true if all went ok.
private:
// Every time the disk format changes, this should probably change too
typedef unsigned long MagicNumberType;
static const MagicNumberType MAGIC_NUMBER = 0x24687531;
// Old versions of this code write all data in 32 bits. We need to
// support these files as well as having support for 64-bit systems.
// So we use the following encoding scheme: for values < 2^32-1, we
// store in 4 bytes in big-endian order. For values > 2^32, we
// store 0xFFFFFFF followed by 8 bytes in big-endian order. This
// causes us to mis-read old-version code that stores exactly
// 0xFFFFFFF, but I don't think that is likely to have happened for
// these particular values.
template <typename OUTPUT, typename IntType>
static bool write_32_or_64(OUTPUT* fp, IntType value) {
if ( value < 0xFFFFFFFFULL ) { // fits in 4 bytes
if ( !sparsehash_internal::write_bigendian_number(fp, value, 4) )
return false;
} else {
if ( !sparsehash_internal::write_bigendian_number(fp, 0xFFFFFFFFUL, 4) )
return false;
if ( !sparsehash_internal::write_bigendian_number(fp, value, 8) )
return false;
}
return true;
}
template <typename INPUT, typename IntType>
static bool read_32_or_64(INPUT* fp, IntType *value) { // reads into value
MagicNumberType first4 = 0; // a convenient 32-bit unsigned type
if ( !sparsehash_internal::read_bigendian_number(fp, &first4, 4) )
return false;
if ( first4 < 0xFFFFFFFFULL ) {
*value = first4;
} else {
if ( !sparsehash_internal::read_bigendian_number(fp, value, 8) )
return false;
}
return true;
}
public:
// read/write_metadata() and read_write/nopointer_data() are DEPRECATED.
// Use serialize() and unserialize(), below, for new code.
template <typename OUTPUT> bool write_metadata(OUTPUT *fp) const {
if ( !write_32_or_64(fp, MAGIC_NUMBER) ) return false;
if ( !write_32_or_64(fp, settings.table_size) ) return false;
if ( !write_32_or_64(fp, settings.num_buckets) ) return false;
GroupsConstIterator group;
for ( group = groups.begin(); group != groups.end(); ++group )
if ( group->write_metadata(fp) == false ) return false;
return true;
}
// Reading destroys the old table contents! Returns true if read ok.
template <typename INPUT> bool read_metadata(INPUT *fp) {
size_type magic_read = 0;
if ( !read_32_or_64(fp, &magic_read) ) return false;
if ( magic_read != MAGIC_NUMBER ) {
clear(); // just to be consistent
return false;
}
if ( !read_32_or_64(fp, &settings.table_size) ) return false;
if ( !read_32_or_64(fp, &settings.num_buckets) ) return false;
resize(settings.table_size); // so the vector's sized ok
GroupsIterator group;
for ( group = groups.begin(); group != groups.end(); ++group )
if ( group->read_metadata(fp) == false ) return false;
return true;
}
// This code is identical to that for SparseGroup
// If your keys and values are simple enough, we can write them
// to disk for you. "simple enough" means no pointers.
// However, we don't try to normalize endianness
bool write_nopointer_data(FILE *fp) const {
for ( const_nonempty_iterator it = nonempty_begin();
it != nonempty_end(); ++it ) {
if ( !fwrite(&*it, sizeof(*it), 1, fp) ) return false;
}
return true;
}
// When reading, we have to override the potential const-ness of *it
bool read_nopointer_data(FILE *fp) {
for ( nonempty_iterator it = nonempty_begin();
it != nonempty_end(); ++it ) {
if ( !fread(reinterpret_cast<void*>(&(*it)), sizeof(*it), 1, fp) )
return false;
}
return true;
}
// INPUT and OUTPUT must be either a FILE, *or* a C++ stream
// (istream, ostream, etc) *or* a class providing
// Read(void*, size_t) and Write(const void*, size_t)
// (respectively), which writes a buffer into a stream
// (which the INPUT/OUTPUT instance presumably owns).
typedef sparsehash_internal::pod_serializer<value_type> NopointerSerializer;
// ValueSerializer: a functor. operator()(OUTPUT*, const value_type&)
template <typename ValueSerializer, typename OUTPUT>
bool serialize(ValueSerializer serializer, OUTPUT *fp) {
if ( !write_metadata(fp) )
return false;
for ( const_nonempty_iterator it = nonempty_begin();
it != nonempty_end(); ++it ) {
if ( !serializer(fp, *it) ) return false;
}
return true;
}
// ValueSerializer: a functor. operator()(INPUT*, value_type*)
template <typename ValueSerializer, typename INPUT>
bool unserialize(ValueSerializer serializer, INPUT *fp) {
clear();
if ( !read_metadata(fp) )
return false;
for ( nonempty_iterator it = nonempty_begin();
it != nonempty_end(); ++it ) {
if ( !serializer(fp, &*it) ) return false;
}
return true;
}
// Comparisons. Note the comparisons are pretty arbitrary: we
// compare values of the first index that isn't equal (using default
// value for empty buckets).
bool operator==(const sparsetable& x) const {
return ( settings.table_size == x.settings.table_size &&
settings.num_buckets == x.settings.num_buckets &&
groups == x.groups );
}
bool operator<(const sparsetable& x) const {
return std::lexicographical_compare(begin(), end(), x.begin(), x.end());
}
bool operator!=(const sparsetable& x) const { return !(*this == x); }
bool operator<=(const sparsetable& x) const { return !(x < *this); }
bool operator>(const sparsetable& x) const { return x < *this; }
bool operator>=(const sparsetable& x) const { return !(*this < x); }
private:
// Package allocator with table_size and num_buckets to eliminate memory
// needed for the zero-size allocator.
// If new fields are added to this class, we should add them to
// operator= and swap.
class Settings : public allocator_type {
public:
typedef typename allocator_type::size_type size_type;
Settings(const allocator_type& a, size_type sz = 0, size_type n = 0)
: allocator_type(a), table_size(sz), num_buckets(n) { }
Settings(const Settings& s)
: allocator_type(s),
table_size(s.table_size), num_buckets(s.num_buckets) { }
size_type table_size; // how many buckets they want
size_type num_buckets; // number of non-empty buckets
};
// The actual data
group_vector_type groups; // our list of groups
Settings settings; // allocator, table size, buckets
};
// We need a global swap as well
template <class T, u_int16_t GROUP_SIZE, class Alloc>
inline void swap(sparsetable<T,GROUP_SIZE,Alloc> &x,
sparsetable<T,GROUP_SIZE,Alloc> &y) {
x.swap(y);
}
_END_GOOGLE_NAMESPACE_
#endif // UTIL_GTL_SPARSETABLE_H_