1 /* List implementation of a partition of consecutive integers.
2 Copyright (C) 2000-2019 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, 51 Franklin Street - Fifth Floor,
20 Boston, MA 02110-1301, USA. */
34 #include "libiberty.h"
35 #include "partition.h"
37 static int elem_compare (const void *, const void *);
39 /* Creates a partition of NUM_ELEMENTS elements. Initially each
40 element is in a class by itself. */
43 partition_new (int num_elements
)
47 partition part
= (partition
)
48 xmalloc (sizeof (struct partition_def
) +
49 (num_elements
- 1) * sizeof (struct partition_elem
));
50 part
->num_elements
= num_elements
;
51 for (e
= 0; e
< num_elements
; ++e
)
53 part
->elements
[e
].class_element
= e
;
54 part
->elements
[e
].next
= &(part
->elements
[e
]);
55 part
->elements
[e
].class_count
= 1;
61 /* Freeds a partition. */
64 partition_delete (partition part
)
69 /* Unites the classes containing ELEM1 and ELEM2 into a single class
70 of partition PART. If ELEM1 and ELEM2 are already in the same
71 class, does nothing. Returns the canonical element of the
72 resulting union class. */
75 partition_union (partition part
, int elem1
, int elem2
)
77 struct partition_elem
*elements
= part
->elements
;
78 struct partition_elem
*e1
;
79 struct partition_elem
*e2
;
80 struct partition_elem
*p
;
81 struct partition_elem
*old_next
;
82 /* The canonical element of the resulting union class. */
83 int class_element
= elements
[elem1
].class_element
;
85 /* If they're already in the same class, do nothing. */
86 if (class_element
== elements
[elem2
].class_element
)
89 /* Make sure ELEM1 is in the larger class of the two. If not, swap
90 them. This way we always scan the shorter list. */
91 if (elements
[elem1
].class_count
< elements
[elem2
].class_count
)
96 class_element
= elements
[elem1
].class_element
;
99 e1
= &(elements
[elem1
]);
100 e2
= &(elements
[elem2
]);
102 /* Keep a count of the number of elements in the list. */
103 elements
[class_element
].class_count
104 += elements
[e2
->class_element
].class_count
;
106 /* Update the class fields in elem2's class list. */
107 e2
->class_element
= class_element
;
108 for (p
= e2
->next
; p
!= e2
; p
= p
->next
)
109 p
->class_element
= class_element
;
111 /* Splice ELEM2's class list into ELEM1's. These are circular
117 return class_element
;
120 /* Compare elements ELEM1 and ELEM2 from array of integers, given a
121 pointer to each. Used to qsort such an array. */
124 elem_compare (const void *elem1
, const void *elem2
)
126 int e1
= * (const int *) elem1
;
127 int e2
= * (const int *) elem2
;
136 /* Prints PART to the file pointer FP. The elements of each
140 partition_print (partition part
, FILE *fp
)
143 int num_elements
= part
->num_elements
;
144 struct partition_elem
*elements
= part
->elements
;
148 /* Flag the elements we've already printed. */
149 done
= (char *) xmalloc (num_elements
);
150 memset (done
, 0, num_elements
);
152 /* A buffer used to sort elements in a class. */
153 class_elements
= (int *) xmalloc (num_elements
* sizeof (int));
156 for (e
= 0; e
< num_elements
; ++e
)
157 /* If we haven't printed this element, print its entire class. */
161 int count
= elements
[elements
[e
].class_element
].class_count
;
164 /* Collect the elements in this class. */
165 for (i
= 0; i
< count
; ++i
) {
166 class_elements
[i
] = c
;
168 c
= elements
[c
].next
- elements
;
171 qsort ((void *) class_elements
, count
, sizeof (int), elem_compare
);
174 for (i
= 0; i
< count
; ++i
)
175 fprintf (fp
, i
== 0 ? "%d" : " %d", class_elements
[i
]);
180 free (class_elements
);
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