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
]);
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