/* List implementation of a partition of consecutive integers. Copyright (C) 2000-2024 Free Software Foundation, Inc. Contributed by CodeSourcery, LLC. This file is part of GNU CC. GNU CC 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 2, or (at your option) any later version. GNU CC 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 GNU CC; see the file COPYING. If not, write to the Free Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #ifdef HAVE_STDLIB_H #include <stdlib.h> #endif #ifdef HAVE_STRING_H #include <string.h> #endif #include "libiberty.h" #include "partition.h" static int elem_compare (const void *, const void *); /* Creates a partition of NUM_ELEMENTS elements. Initially each element is in a class by itself. */ partition partition_new (int num_elements) { int e; partition part = (partition) xmalloc (sizeof (struct partition_def) + (num_elements - 1) * sizeof (struct partition_elem)); part->num_elements = num_elements; for (e = 0; e < num_elements; ++e) { part->elements[e].class_element = e; part->elements[e].next = &(part->elements[e]); part->elements[e].class_count = 1; } return part; } /* Freeds a partition. */ void partition_delete (partition part) { free (part); } /* Unites the classes containing ELEM1 and ELEM2 into a single class of partition PART. If ELEM1 and ELEM2 are already in the same class, does nothing. Returns the canonical element of the resulting union class. */ int partition_union (partition part, int elem1, int elem2) { struct partition_elem *elements = part->elements; struct partition_elem *e1; struct partition_elem *e2; struct partition_elem *p; struct partition_elem *old_next; /* The canonical element of the resulting union class. */ int class_element = elements[elem1].class_element; /* If they're already in the same class, do nothing. */ if (class_element == elements[elem2].class_element) return class_element; /* Make sure ELEM1 is in the larger class of the two. If not, swap them. This way we always scan the shorter list. */ if (elements[elem1].class_count < elements[elem2].class_count) { int temp = elem1; elem1 = elem2; elem2 = temp; class_element = elements[elem1].class_element; } e1 = &(elements[elem1]); e2 = &(elements[elem2]); /* Keep a count of the number of elements in the list. */ elements[class_element].class_count += elements[e2->class_element].class_count; /* Update the class fields in elem2's class list. */ e2->class_element = class_element; for (p = e2->next; p != e2; p = p->next) p->class_element = class_element; /* Splice ELEM2's class list into ELEM1's. These are circular lists. */ old_next = e1->next; e1->next = e2->next; e2->next = old_next; return class_element; } /* Compare elements ELEM1 and ELEM2 from array of integers, given a pointer to each. Used to qsort such an array. */ static int elem_compare (const void *elem1, const void *elem2) { int e1 = * (const int *) elem1; int e2 = * (const int *) elem2; if (e1 < e2) return -1; else if (e1 > e2) return 1; else return 0; } /* Prints PART to the file pointer FP. The elements of each class are sorted. */ void partition_print (partition part, FILE *fp) { char *done; int num_elements = part->num_elements; struct partition_elem *elements = part->elements; int *class_elements; int e; /* Flag the elements we've already printed. */ done = (char *) xmalloc (num_elements); memset (done, 0, num_elements); /* A buffer used to sort elements in a class. */ class_elements = (int *) xmalloc (num_elements * sizeof (int)); fputc ('[', fp); for (e = 0; e < num_elements; ++e) /* If we haven't printed this element, print its entire class. */ if (! done[e]) { int c = e; int count = elements[elements[e].class_element].class_count; int i; /* Collect the elements in this class. */ for (i = 0; i < count; ++i) { class_elements[i] = c; done[c] = 1; c = elements[c].next - elements; } /* Sort them. */ qsort ((void *) class_elements, count, sizeof (int), elem_compare); /* Print them. */ fputc ('(', fp); for (i = 0; i < count; ++i) fprintf (fp, i == 0 ? "%d" : " %d", class_elements[i]); fputc (')', fp); } fputc (']', fp); free (class_elements); free (done); }