1 /* List implentation of a partition of consecutive integers.
2 Copyright (C) 2000 Free Software Foundation, Inc.
3 Contributed by CodeSourcery, LLC.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
30 #include "libiberty.h"
31 #include "partition.h"
33 /* Creates a partition of NUM_ELEMENTS elements. Initially each
34 element is in a class by itself. */
37 partition_new (num_elements)
42 partition part = (partition)
43 xmalloc (sizeof (struct partition_def) +
44 (num_elements - 1) * sizeof (struct partition_elem));
45 part->num_elements = num_elements;
46 for (e = 0; e < num_elements; ++e)
48 part->elements[e].class_element = e;
49 part->elements[e].next = &(part->elements[e]);
50 part->elements[e].class_count = 1;
56 /* Freeds a partition. */
59 partition_delete (part)
65 /* Unites the classes containing ELEM1 and ELEM2 into a single class
66 of partition PART. If ELEM1 and ELEM2 are already in the same
67 class, does nothing. Returns the canonical element of the
68 resulting union class. */
71 partition_union (part, elem1, elem2)
76 struct partition_elem *elements = part->elements;
77 struct partition_elem *e1;
78 struct partition_elem *e2;
79 struct partition_elem *p;
80 struct partition_elem *old_next;
81 /* The canonical element of the resulting union class. */
82 int class_element = elements[elem1].class_element;
84 /* If they're already in the same class, do nothing. */
85 if (class_element == elements[elem2].class_element)
88 /* Make sure ELEM1 is in the larger class of the two. If not, swap
89 them. This way we always scan the shorter list. */
90 if (elements[elem1].class_count < elements[elem2].class_count)
95 class_element = elements[elem1].class_element;
98 e1 = &(elements[elem1]);
99 e2 = &(elements[elem2]);
101 /* Keep a count of the number of elements in the list. */
102 elements[class_element].class_count
103 += elements[e2->class_element].class_count;
105 /* Update the class fields in elem2's class list. */
106 e2->class_element = class_element;
107 for (p = e2->next; p != e2; p = p->next)
108 p->class_element = class_element;
110 /* Splice ELEM2's class list into ELEM1's. These are circular
116 return class_element;
119 /* Compare elements ELEM1 and ELEM2 from array of integers, given a
120 pointer to each. Used to qsort such an array. */
123 elem_compare (elem1, elem2)
127 int e1 = * (int *) elem1;
128 int e2 = * (int *) elem2;
137 /* Prints PART to the file pointer FP. The elements of each
141 partition_print (part, fp)
146 int num_elements = part->num_elements;
147 struct partition_elem *elements = part->elements;
151 /* Flag the elements we've already printed. */
152 done = (char *) xmalloc (num_elements);
153 memset (done, 0, num_elements);
155 /* A buffer used to sort elements in a class. */
156 class_elements = (int *) xmalloc (num_elements * sizeof (int));
159 for (e = 0; e < num_elements; ++e)
160 /* If we haven't printed this element, print its entire class. */
164 int count = elements[elements[e].class_element].class_count;
167 /* Collect the elements in this class. */
168 for (i = 0; i < count; ++i) {
169 class_elements[i] = c;
171 c = elements[c].next - elements;
174 qsort ((void *) class_elements, count, sizeof (int), &elem_compare);
177 for (i = 0; i < count; ++i)
178 fprintf (fp, i == 0 ? "%d" : " %d", class_elements[i]);