| 1 | /* List implementation of a partition of consecutive integers. |
| 2 | Copyright (C) 2000, 2001, 2002 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 canonical element that represents the class containing this |
| 49 | element. */ |
| 50 | int class_element; |
| 51 | /* The next element in this class. Elements in each class form a |
| 52 | circular list. */ |
| 53 | struct partition_elem* next; |
| 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 */ |