| 1 | /* List implementation of a partition of consecutive integers. |
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| 2 | Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc. |
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| 3 | Contributed by CodeSourcery, LLC. |
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| 4 | |
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| 5 | This file is part of GCC. |
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| 6 | |
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| 7 | GCC is free software; you can redistribute it and/or modify |
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| 8 | it under the terms of the GNU General Public License as published by |
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| 9 | the Free Software Foundation; either version 2, or (at your option) |
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| 10 | any later version. |
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| 11 | |
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| 12 | GCC is distributed in the hope that it will be useful, |
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| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 15 | GNU General Public License for more details. |
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| 16 | |
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| 17 | You should have received a copy of the GNU General Public License |
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| 18 | along with GCC; see the file COPYING. If not, write to |
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| 19 | the Free Software Foundation, 51 Franklin Street - Fifth Floor, |
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| 20 | Boston, MA 02110-1301, USA. */ |
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| 21 | |
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| 22 | /* This package implements a partition of consecutive integers. The |
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| 23 | elements are partitioned into classes. Each class is represented |
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| 24 | by one of its elements, the canonical element, which is chosen |
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| 25 | arbitrarily from elements in the class. The principal operations |
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| 26 | on a partition are FIND, which takes an element, determines its |
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| 27 | class, and returns the canonical element for that class, and UNION, |
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| 28 | which unites the two classes that contain two given elements into a |
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| 29 | single class. |
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| 30 | |
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| 31 | The list implementation used here provides constant-time finds. By |
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| 32 | storing the size of each class with the class's canonical element, |
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| 33 | it is able to perform unions over all the classes in the partition |
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| 34 | in O (N log N) time. */ |
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| 35 | |
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| 36 | #ifndef _PARTITION_H |
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| 37 | #define _PARTITION_H |
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| 38 | |
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| 39 | #ifdef __cplusplus |
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| 40 | extern "C" { |
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| 41 | #endif /* __cplusplus */ |
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| 42 | |
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| 43 | #include "ansidecl.h" |
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| 44 | #include <stdio.h> |
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| 45 | |
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| 46 | struct partition_elem |
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| 47 | { |
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| 48 | /* The next element in this class. Elements in each class form a |
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| 49 | circular list. */ |
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| 50 | struct partition_elem* next; |
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| 51 | /* The canonical element that represents the class containing this |
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| 52 | element. */ |
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| 53 | int class_element; |
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| 54 | /* The number of elements in this class. Valid only if this is the |
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| 55 | canonical element for its class. */ |
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| 56 | unsigned class_count; |
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| 57 | }; |
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| 58 | |
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| 59 | typedef struct partition_def |
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| 60 | { |
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| 61 | /* The number of elements in this partition. */ |
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| 62 | int num_elements; |
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| 63 | /* The elements in the partition. */ |
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| 64 | struct partition_elem elements[1]; |
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| 65 | } *partition; |
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| 66 | |
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| 67 | extern partition partition_new (int); |
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| 68 | extern void partition_delete (partition); |
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| 69 | extern int partition_union (partition, int, int); |
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| 70 | extern void partition_print (partition, FILE*); |
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| 71 | |
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| 72 | /* Returns the canonical element corresponding to the class containing |
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| 73 | ELEMENT__ in PARTITION__. */ |
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| 74 | |
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| 75 | #define partition_find(partition__, element__) \ |
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| 76 | ((partition__)->elements[(element__)].class_element) |
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| 77 | |
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| 78 | #ifdef __cplusplus |
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| 79 | } |
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| 80 | #endif /* __cplusplus */ |
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| 81 | |
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| 82 | #endif /* _PARTITION_H */ |
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