1 /* List implementation of a partition of consecutive integers. 2 Copyright (C) 2000-2016 Free Software Foundation, Inc. 3 Contributed by CodeSourcery, LLC. 4 5 This file is part of GCC. 6 7 GCC 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 GCC 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 GCC; 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 /* This package implements a partition of consecutive integers. The 23 elements are partitioned into classes. Each class is represented 24 by one of its elements, the canonical element, which is chosen 25 arbitrarily from elements in the class. The principal operations 26 on a partition are FIND, which takes an element, determines its 27 class, and returns the canonical element for that class, and UNION, 28 which unites the two classes that contain two given elements into a 29 single class. 30 31 The list implementation used here provides constant-time finds. By 32 storing the size of each class with the class's canonical element, 33 it is able to perform unions over all the classes in the partition 34 in O (N log N) time. */ 35 36 #ifndef _PARTITION_H 37 #define _PARTITION_H 38 39 #ifdef __cplusplus 40 extern "C" { 41 #endif /* __cplusplus */ 42 43 #include "ansidecl.h" 44 #include <stdio.h> 45 46 struct partition_elem 47 { 48 /* The next element in this class. Elements in each class form a 49 circular list. */ 50 struct partition_elem* next; 51 /* The canonical element that represents the class containing this 52 element. */ 53 int class_element; 54 /* The number of elements in this class. Valid only if this is the 55 canonical element for its class. */ 56 unsigned class_count; 57 }; 58 59 typedef struct partition_def 60 { 61 /* The number of elements in this partition. */ 62 int num_elements; 63 /* The elements in the partition. */ 64 struct partition_elem elements[1]; 65 } *partition; 66 67 extern partition partition_new (int); 68 extern void partition_delete (partition); 69 extern int partition_union (partition, int, int); 70 extern void partition_print (partition, FILE*); 71 72 /* Returns the canonical element corresponding to the class containing 73 ELEMENT__ in PARTITION__. */ 74 75 #define partition_find(partition__, element__) \ 76 ((partition__)->elements[(element__)].class_element) 77 78 #ifdef __cplusplus 79 } 80 #endif /* __cplusplus */ 81 82 #endif /* _PARTITION_H */ 83
