1 /* List implementation of a partition of consecutive integers. 2 Copyright (C) 2000, 2001 Free Software Foundation, Inc. 3 Contributed by CodeSourcery, LLC. 4 5 This file is part of GNU CC. 6 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) 10 any later version. 11 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. 16 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. */ 21 22 #ifdef HAVE_CONFIG_H 23 #include "config.h" 24 #endif 25 26 #ifdef HAVE_STDLIB_H 27 #include <stdlib.h> 28 #endif 29 30 #ifdef HAVE_STRING_H 31 #include <string.h> 32 #endif 33 34 #include "libiberty.h" 35 #include "partition.h" 36 37 static int elem_compare (const void *, const void *); 38 39 /* Creates a partition of NUM_ELEMENTS elements. Initially each 40 element is in a class by itself. */ 41 42 partition 43 partition_new (int num_elements) 44 { 45 int e; 46 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) 52 { 53 part->elements[e].class_element = e; 54 part->elements[e].next = &(part->elements[e]); 55 part->elements[e].class_count = 1; 56 } 57 58 return part; 59 } 60 61 /* Freeds a partition. */ 62 63 void 64 partition_delete (partition part) 65 { 66 free (part); 67 } 68 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. */ 73 74 int 75 partition_union (partition part, int elem1, int elem2) 76 { 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; 84 85 /* If they're already in the same class, do nothing. */ 86 if (class_element == elements[elem2].class_element) 87 return class_element; 88 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) 92 { 93 int temp = elem1; 94 elem1 = elem2; 95 elem2 = temp; 96 class_element = elements[elem1].class_element; 97 } 98 99 e1 = &(elements[elem1]); 100 e2 = &(elements[elem2]); 101 102 /* Keep a count of the number of elements in the list. */ 103 elements[class_element].class_count 104 += elements[e2->class_element].class_count; 105 106 /* 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; 110 111 /* Splice ELEM2's class list into ELEM1's. These are circular 112 lists. */ 113 old_next = e1->next; 114 e1->next = e2->next; 115 e2->next = old_next; 116 117 return class_element; 118 } 119 120 /* Compare elements ELEM1 and ELEM2 from array of integers, given a 121 pointer to each. Used to qsort such an array. */ 122 123 static int 124 elem_compare (const void *elem1, const void *elem2) 125 { 126 int e1 = * (const int *) elem1; 127 int e2 = * (const int *) elem2; 128 if (e1 < e2) 129 return -1; 130 else if (e1 > e2) 131 return 1; 132 else 133 return 0; 134 } 135 136 /* Prints PART to the file pointer FP. The elements of each 137 class are sorted. */ 138 139 void 140 partition_print (partition part, FILE *fp) 141 { 142 char *done; 143 int num_elements = part->num_elements; 144 struct partition_elem *elements = part->elements; 145 int *class_elements; 146 int e; 147 148 /* Flag the elements we've already printed. */ 149 done = (char *) xmalloc (num_elements); 150 memset (done, 0, num_elements); 151 152 /* A buffer used to sort elements in a class. */ 153 class_elements = (int *) xmalloc (num_elements * sizeof (int)); 154 155 fputc ('[', fp); 156 for (e = 0; e < num_elements; ++e) 157 /* If we haven't printed this element, print its entire class. */ 158 if (! done[e]) 159 { 160 int c = e; 161 int count = elements[elements[e].class_element].class_count; 162 int i; 163 164 /* Collect the elements in this class. */ 165 for (i = 0; i < count; ++i) { 166 class_elements[i] = c; 167 done[c] = 1; 168 c = elements[c].next - elements; 169 } 170 /* Sort them. */ 171 qsort ((void *) class_elements, count, sizeof (int), elem_compare); 172 /* Print them. */ 173 fputc ('(', fp); 174 for (i = 0; i < count; ++i) 175 fprintf (fp, i == 0 ? "%d" : " %d", class_elements[i]); 176 fputc (')', fp); 177 } 178 fputc (']', fp); 179 180 free (class_elements); 181 free (done); 182 } 183 184
