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/* Keyword list.
Copyright (C) 2002 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>.
This file is part of GNU GPERF.
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/>. */
/* Specification. */
#include "keyword-list.h"
#include <stddef.h>
/* -------------------------- Keyword_List class --------------------------- */
/* Constructor. */
Keyword_List::Keyword_List (Keyword *car)
: _cdr (NULL), _car (car)
{
}
/* ------------------------- KeywordExt_List class ------------------------- */
/* Constructor. */
KeywordExt_List::KeywordExt_List (KeywordExt *car)
: Keyword_List (car)
{
}
/* ------------------------ Keyword_List functions ------------------------- */
/* Copies a linear list, sharing the list elements. */
Keyword_List *
copy_list (Keyword_List *list)
{
Keyword_List *result;
Keyword_List **lastp = &result;
while (list != NULL)
{
Keyword_List *new_cons = new Keyword_List (list->first());
*lastp = new_cons;
lastp = &new_cons->rest();
list = list->rest();
}
*lastp = NULL;
return result;
}
/* Copies a linear list, sharing the list elements. */
KeywordExt_List *
copy_list (KeywordExt_List *list)
{
return static_cast<KeywordExt_List *> (copy_list (static_cast<Keyword_List *> (list)));
}
/* Deletes a linear list, keeping the list elements in memory. */
void
delete_list (Keyword_List *list)
{
while (list != NULL)
{
Keyword_List *rest = list->rest();
delete list;
list = rest;
}
}
/* Type of a comparison function. */
typedef bool (*Keyword_Comparison) (Keyword *keyword1, Keyword *keyword2);
/* Merges two sorted lists together to form one sorted list. */
static Keyword_List *
merge (Keyword_List *list1, Keyword_List *list2, Keyword_Comparison less)
{
Keyword_List *result;
Keyword_List **resultp = &result;
for (;;)
{
if (!list1)
{
*resultp = list2;
break;
}
if (!list2)
{
*resultp = list1;
break;
}
if (less (list2->first(), list1->first()))
{
*resultp = list2;
resultp = &list2->rest();
/* We would have a stable sorting if the next line would read:
list2 = *resultp; */
list2 = list1; list1 = *resultp;
}
else
{
*resultp = list1;
resultp = &list1->rest();
list1 = *resultp;
}
}
return result;
}
/* Sorts a linear list, given a comparison function.
Note: This uses a variant of mergesort that is *not* a stable sorting
algorithm. */
Keyword_List *
mergesort_list (Keyword_List *list, Keyword_Comparison less)
{
if (list == NULL || list->rest() == NULL)
/* List of length 0 or 1. Nothing to do. */
return list;
else
{
/* Determine a list node in the middle. */
Keyword_List *middle = list;
for (Keyword_List *temp = list->rest();;)
{
temp = temp->rest();
if (temp == NULL)
break;
temp = temp->rest();
middle = middle->rest();
if (temp == NULL)
break;
}
/* Cut the list into two halves.
If the list has n elements, the left half has ceiling(n/2) elements
and the right half has floor(n/2) elements. */
Keyword_List *right_half = middle->rest();
middle->rest() = NULL;
/* Sort the two halves, then merge them. */
return merge (mergesort_list (list, less),
mergesort_list (right_half, less),
less);
}
}
KeywordExt_List *
mergesort_list (KeywordExt_List *list,
bool (*less) (KeywordExt *keyword1, KeywordExt *keyword2))
{
return
static_cast<KeywordExt_List *>
(mergesort_list (static_cast<Keyword_List *> (list),
reinterpret_cast<Keyword_Comparison> (less)));
}
#ifndef __OPTIMIZE__
#define INLINE /* not inline */
#include "keyword-list.icc"
#undef INLINE
#endif /* not defined __OPTIMIZE__ */
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