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Make CLIST templated. Move member methods inside the class. Move helper classes (CLIST_LINK and CLIST_ITERATOR inside the list class).

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This allows us to use real C++ templates for different instantiations instead of void * emulation.
This commit is contained in:
Egor Pugin 2024-11-22 03:38:07 +03:00
parent 32fee19447
commit 3088d2eecc
2 changed files with 896 additions and 1051 deletions
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444
src/ccutil/clst.cpp
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@ -1,444 +0,0 @@
/**********************************************************************
* File: clst.cpp (Formerly clist.c)
* Description: CONS cell list handling code which is not in the include file.
* Author: Phil Cheatle
*
* (C) Copyright 1991, Hewlett-Packard Ltd.
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
** http://www.apache.org/licenses/LICENSE-2.0
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*
**********************************************************************/
#include "clst.h"
#include <cstdlib>
namespace tesseract {
/***********************************************************************
* CLIST::internal_deep_clear
*
* Used by the "deep_clear" member function of derived list
* classes to destroy all the elements on the list.
* The calling function passes a "zapper" function which can be called to
* delete each data element of the list, regardless of its class. This
* technique permits a generic clear function to destroy elements of
* different derived types correctly, without requiring virtual functions and
* the consequential memory overhead.
**********************************************************************/
void CLIST::internal_deep_clear( // destroy all links
void (*zapper)(void *)) { // ptr to zapper functn
if (!empty()) {
auto ptr = last->next; // set to first
last->next = nullptr; // break circle
last = nullptr; // set list empty
while (ptr) {
auto next = ptr->next;
zapper(ptr->data);
delete (ptr);
ptr = next;
}
}
}
/***********************************************************************
* CLIST::shallow_clear
*
* Used by the destructor and the "shallow_clear" member function of derived
* list classes to destroy the list.
* The data elements are NOT destroyed.
*
**********************************************************************/
void CLIST::shallow_clear() { // destroy all links
if (!empty()) {
auto ptr = last->next; // set to first
last->next = nullptr; // break circle
last = nullptr; // set list empty
while (ptr) {
auto next = ptr->next;
delete (ptr);
ptr = next;
}
}
}
/***********************************************************************
* CLIST::assign_to_sublist
*
* The list is set to a sublist of another list. "This" list must be empty
* before this function is invoked. The two iterators passed must refer to
* the same list, different from "this" one. The sublist removed is the
* inclusive list from start_it's current position to end_it's current
* position. If this range passes over the end of the source list then the
* source list has its end set to the previous element of start_it. The
* extracted sublist is unaffected by the end point of the source list, its
* end point is always the end_it position.
**********************************************************************/
void CLIST::assign_to_sublist( // to this list
CLIST_ITERATOR *start_it, // from list start
CLIST_ITERATOR *end_it) { // from list end
constexpr ERRCODE LIST_NOT_EMPTY("Destination list must be empty before extracting a sublist");
if (!empty()) {
LIST_NOT_EMPTY.error("CLIST.assign_to_sublist", ABORT);
}
last = start_it->extract_sublist(end_it);
}
/***********************************************************************
* CLIST::sort
*
* Sort elements on list
**********************************************************************/
void CLIST::sort( // sort elements
int comparator( // comparison routine
const void *, const void *)) {
// Allocate an array of pointers, one per list element.
auto count = length();
if (count > 0) {
// ptr array to sort
std::vector<void *> base;
base.reserve(count);
CLIST_ITERATOR it(this);
// Extract all elements, putting the pointers in the array.
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
base.push_back(it.extract());
}
// Sort the pointer array.
qsort(&base[0], count, sizeof(base[0]), comparator);
// Rebuild the list from the sorted pointers.
for (auto current : base) {
it.add_to_end(current);
}
}
}
// Assuming list has been sorted already, insert new_data to
// keep the list sorted according to the same comparison function.
// Comparison function is the same as used by sort, i.e. uses double
// indirection. Time is O(1) to add to beginning or end.
// Time is linear to add pre-sorted items to an empty list.
// If unique, then don't add duplicate entries.
// Returns true if the element was added to the list.
bool CLIST::add_sorted(int comparator(const void *, const void *), bool unique, void *new_data) {
// Check for adding at the end.
if (last == nullptr || comparator(&last->data, &new_data) < 0) {
auto *new_element = new CLIST_LINK;
new_element->data = new_data;
if (last == nullptr) {
new_element->next = new_element;
} else {
new_element->next = last->next;
last->next = new_element;
}
last = new_element;
return true;
} else if (!unique || last->data != new_data) {
// Need to use an iterator.
CLIST_ITERATOR it(this);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
void *data = it.data();
if (data == new_data && unique) {
return false;
}
if (comparator(&data, &new_data) > 0) {
break;
}
}
if (it.cycled_list()) {
it.add_to_end(new_data);
} else {
it.add_before_then_move(new_data);
}
return true;
}
return false;
}
// Assuming that the minuend and subtrahend are already sorted with
// the same comparison function, shallow clears this and then copies
// the set difference minuend - subtrahend to this, being the elements
// of minuend that do not compare equal to anything in subtrahend.
// If unique is true, any duplicates in minuend are also eliminated.
void CLIST::set_subtract(int comparator(const void *, const void *), bool unique, CLIST *minuend,
CLIST *subtrahend) {
shallow_clear();
CLIST_ITERATOR m_it(minuend);
CLIST_ITERATOR s_it(subtrahend);
// Since both lists are sorted, finding the subtras that are not
// minus is a case of a parallel iteration.
for (m_it.mark_cycle_pt(); !m_it.cycled_list(); m_it.forward()) {
void *minu = m_it.data();
void *subtra = nullptr;
if (!s_it.empty()) {
subtra = s_it.data();
while (!s_it.at_last() && comparator(&subtra, &minu) < 0) {
s_it.forward();
subtra = s_it.data();
}
}
if (subtra == nullptr || comparator(&subtra, &minu) != 0) {
add_sorted(comparator, unique, minu);
}
}
}
/***********************************************************************
* MEMBER FUNCTIONS OF CLASS: CLIST_ITERATOR
* =========================================
**********************************************************************/
/***********************************************************************
* CLIST_ITERATOR::forward
*
* Move the iterator to the next element of the list.
* REMEMBER: ALL LISTS ARE CIRCULAR.
**********************************************************************/
void *CLIST_ITERATOR::forward() {
if (list->empty()) {
return nullptr;
}
if (current) { // not removed so
// set previous
prev = current;
started_cycling = true;
// In case next is deleted by another iterator, get next from current.
current = current->next;
} else {
if (ex_current_was_cycle_pt) {
cycle_pt = next;
}
current = next;
}
next = current->next;
return current->data;
}
/***********************************************************************
* CLIST_ITERATOR::data_relative
*
* Return the data pointer to the element "offset" elements from current.
* "offset" must not be less than -1.
* (This function can't be INLINEd because it contains a loop)
**********************************************************************/
void *CLIST_ITERATOR::data_relative( // get data + or - ...
int8_t offset) { // offset from current
CLIST_LINK *ptr;
#ifndef NDEBUG
if (!list)
NO_LIST.error("CLIST_ITERATOR::data_relative", ABORT);
if (list->empty())
EMPTY_LIST.error("CLIST_ITERATOR::data_relative", ABORT);
if (offset < -1)
BAD_PARAMETER.error("CLIST_ITERATOR::data_relative", ABORT, "offset < -l");
#endif
if (offset == -1) {
ptr = prev;
} else {
for (ptr = current ? current : prev; offset-- > 0; ptr = ptr->next) {
;
}
}
return ptr->data;
}
/***********************************************************************
* CLIST_ITERATOR::move_to_last()
*
* Move current so that it is set to the end of the list.
* Return data just in case anyone wants it.
* (This function can't be INLINEd because it contains a loop)
**********************************************************************/
void *CLIST_ITERATOR::move_to_last() {
while (current != list->last) {
forward();
}
if (current == nullptr) {
return nullptr;
} else {
return current->data;
}
}
/***********************************************************************
* CLIST_ITERATOR::exchange()
*
* Given another iterator, whose current element is a different element on
* the same list list OR an element of another list, exchange the two current
* elements. On return, each iterator points to the element which was the
* other iterators current on entry.
* (This function hasn't been in-lined because its a bit big!)
**********************************************************************/
void CLIST_ITERATOR::exchange( // positions of 2 links
CLIST_ITERATOR *other_it) { // other iterator
constexpr ERRCODE DONT_EXCHANGE_DELETED("Can't exchange deleted elements of lists");
/* Do nothing if either list is empty or if both iterators reference the same
link */
if ((list->empty()) || (other_it->list->empty()) || (current == other_it->current)) {
return;
}
/* Error if either current element is deleted */
if (!current || !other_it->current) {
DONT_EXCHANGE_DELETED.error("CLIST_ITERATOR.exchange", ABORT);
}
/* Now handle the 4 cases: doubleton list; non-doubleton adjacent elements
(other before this); non-doubleton adjacent elements (this before other);
non-adjacent elements. */
// adjacent links
if ((next == other_it->current) || (other_it->next == current)) {
// doubleton list
if ((next == other_it->current) && (other_it->next == current)) {
prev = next = current;
other_it->prev = other_it->next = other_it->current;
} else { // non-doubleton with
// adjacent links
// other before this
if (other_it->next == current) {
other_it->prev->next = current;
other_it->current->next = next;
current->next = other_it->current;
other_it->next = other_it->current;
prev = current;
} else { // this before other
prev->next = other_it->current;
current->next = other_it->next;
other_it->current->next = current;
next = current;
other_it->prev = other_it->current;
}
}
} else { // no overlap
prev->next = other_it->current;
current->next = other_it->next;
other_it->prev->next = current;
other_it->current->next = next;
}
/* update end of list pointer when necessary (remember that the 2 iterators
may iterate over different lists!) */
if (list->last == current) {
list->last = other_it->current;
}
if (other_it->list->last == other_it->current) {
other_it->list->last = current;
}
if (current == cycle_pt) {
cycle_pt = other_it->cycle_pt;
}
if (other_it->current == other_it->cycle_pt) {
other_it->cycle_pt = cycle_pt;
}
/* The actual exchange - in all cases*/
auto old_current = current;
current = other_it->current;
other_it->current = old_current;
}
/***********************************************************************
* CLIST_ITERATOR::extract_sublist()
*
* This is a private member, used only by CLIST::assign_to_sublist.
* Given another iterator for the same list, extract the links from THIS to
* OTHER inclusive, link them into a new circular list, and return a
* pointer to the last element.
* (Can't inline this function because it contains a loop)
**********************************************************************/
CLIST_LINK *CLIST_ITERATOR::extract_sublist( // from this current
CLIST_ITERATOR *other_it) { // to other current
CLIST_ITERATOR temp_it = *this;
constexpr ERRCODE BAD_SUBLIST("Can't find sublist end point in original list");
#ifndef NDEBUG
constexpr ERRCODE BAD_EXTRACTION_PTS("Can't extract sublist from points on different lists");
constexpr ERRCODE DONT_EXTRACT_DELETED("Can't extract a sublist marked by deleted points");
if (list != other_it->list)
BAD_EXTRACTION_PTS.error("CLIST_ITERATOR.extract_sublist", ABORT);
if (list->empty())
EMPTY_LIST.error("CLIST_ITERATOR::extract_sublist", ABORT);
if (!current || !other_it->current)
DONT_EXTRACT_DELETED.error("CLIST_ITERATOR.extract_sublist", ABORT);
#endif
ex_current_was_last = other_it->ex_current_was_last = false;
ex_current_was_cycle_pt = false;
other_it->ex_current_was_cycle_pt = false;
temp_it.mark_cycle_pt();
do { // walk sublist
if (temp_it.cycled_list()) { // can't find end pt
BAD_SUBLIST.error("CLIST_ITERATOR.extract_sublist", ABORT);
}
if (temp_it.at_last()) {
list->last = prev;
ex_current_was_last = other_it->ex_current_was_last = true;
}
if (temp_it.current == cycle_pt) {
ex_current_was_cycle_pt = true;
}
if (temp_it.current == other_it->cycle_pt) {
other_it->ex_current_was_cycle_pt = true;
}
temp_it.forward();
} while (temp_it.prev != other_it->current);
// circularise sublist
other_it->current->next = current;
auto end_of_new_list = other_it->current;
// sublist = whole list
if (prev == other_it->current) {
list->last = nullptr;
prev = current = next = nullptr;
other_it->prev = other_it->current = other_it->next = nullptr;
} else {
prev->next = other_it->next;
current = other_it->current = nullptr;
next = other_it->next;
other_it->prev = prev;
}
return end_of_new_list;
}
} // namespace tesseract

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src/ccutil/clst.h
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