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Annotation of 43BSDReno/pgrm/dbx/lists.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1983 The Regents of the University of California.
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * Redistribution and use in source and binary forms are permitted
        !             6:  * provided that: (1) source distributions retain this entire copyright
        !             7:  * notice and comment, and (2) distributions including binaries display
        !             8:  * the following acknowledgement:  ``This product includes software
        !             9:  * developed by the University of California, Berkeley and its contributors''
        !            10:  * in the documentation or other materials provided with the distribution
        !            11:  * and in all advertising materials mentioning features or use of this
        !            12:  * software. Neither the name of the University nor the names of its
        !            13:  * contributors may be used to endorse or promote products derived
        !            14:  * from this software without specific prior written permission.
        !            15:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
        !            16:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
        !            17:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            18:  */
        !            19: 
        !            20: #ifndef lint
        !            21: static char sccsid[] = "@(#)lists.c    5.3 (Berkeley) 6/1/90";
        !            22: #endif /* not lint */
        !            23: 
        !            24: /*
        !            25:  * General list definitions.
        !            26:  *
        !            27:  * The assumption is that the elements in a list are words,
        !            28:  * usually pointers to the actual information.
        !            29:  */
        !            30: 
        !            31: #include "defs.h"
        !            32: #include "lists.h"
        !            33: 
        !            34: #ifndef public
        !            35: 
        !            36: typedef struct List *List;
        !            37: typedef struct ListItem *ListItem;
        !            38: typedef char *ListElement;
        !            39: 
        !            40: #define list_item(element) generic_list_item((ListElement) (element))
        !            41: #define list_element(type, item) ((type) (item == nil ? nil : (item)->element))
        !            42: #define list_head(list) ((list == nil) ? nil : (list)->head)
        !            43: #define list_tail(list) ((list == nil) ? nil : (list)->tail)
        !            44: #define list_next(item) ((item == nil) ? nil : (item)->next)
        !            45: #define list_prev(item) ((item == nil) ? nil : (item)->prev)
        !            46: #define list_size(list) (((list) == nil) ? 0 : (list)->nitems)
        !            47: 
        !            48: #define foreach(type, i, list) \
        !            49: { \
        !            50:     register ListItem _item; \
        !            51:  \
        !            52:     _item = list_head(list); \
        !            53:     while (_item != nil) { \
        !            54:        i = list_element(type, _item); \
        !            55:        _item = list_next(_item);
        !            56: 
        !            57: #define endfor \
        !            58:     } \
        !            59: }
        !            60: 
        !            61: /*
        !            62:  * Iterate through two equal-sized lists.
        !            63:  */
        !            64: 
        !            65: #define foreach2(type1, i, list1, type2, j, list2) \
        !            66: { \
        !            67:     register ListItem _item1, _item2; \
        !            68:  \
        !            69:     _item1 = list_head(list1); \
        !            70:     _item2 = list_head(list2); \
        !            71:     while (_item1 != nil) { \
        !            72:        i = list_element(type1, _item1); \
        !            73:        j = list_element(type2, _item2); \
        !            74:        _item1 = list_next(_item1); \
        !            75:        _item2 = list_next(_item2);
        !            76: 
        !            77: #define list_islast() (_item == nil)
        !            78: #define list_curitem(list) (_item == nil ? list_tail(list) : list_prev(_item))
        !            79: 
        !            80: /*
        !            81:  * Representation should not be used outside except through macros.
        !            82:  */
        !            83: 
        !            84: struct List {
        !            85:     Integer nitems;
        !            86:     ListItem head;
        !            87:     ListItem tail;
        !            88: };
        !            89: 
        !            90: struct ListItem {
        !            91:     ListElement element;
        !            92:     ListItem next;
        !            93:     ListItem prev;
        !            94: };
        !            95: 
        !            96: #endif
        !            97: 
        !            98: /*
        !            99:  * Allocate and initialize a list.
        !           100:  */
        !           101: 
        !           102: public List list_alloc()
        !           103: {
        !           104:     List list;
        !           105: 
        !           106:     list = new(List);
        !           107:     list->nitems = 0;
        !           108:     list->head = nil;
        !           109:     list->tail = nil;
        !           110:     return list;
        !           111: }
        !           112: 
        !           113: /*
        !           114:  * Create a list item from an object (represented as pointer or integer).
        !           115:  */
        !           116: 
        !           117: public ListItem generic_list_item(element)
        !           118: ListElement element;
        !           119: {
        !           120:     ListItem i;
        !           121: 
        !           122:     i = new(ListItem);
        !           123:     i->element = element;
        !           124:     i->next = nil;
        !           125:     i->prev = nil;
        !           126:     return i;
        !           127: }
        !           128: 
        !           129: /*
        !           130:  * Insert an item before the item in a list.
        !           131:  */
        !           132: 
        !           133: public list_insert(item, after, list)
        !           134: ListItem item;
        !           135: ListItem after;
        !           136: List list;
        !           137: {
        !           138:     ListItem a;
        !           139: 
        !           140:     checkref(list);
        !           141:     list->nitems = list->nitems + 1;
        !           142:     if (list->head == nil) {
        !           143:        list->head = item;
        !           144:        list->tail = item;
        !           145:     } else {
        !           146:        if (after == nil) {
        !           147:            a = list->head;
        !           148:        } else {
        !           149:            a = after;
        !           150:        }
        !           151:        item->next = a;
        !           152:        item->prev = a->prev;
        !           153:        if (a->prev != nil) {
        !           154:            a->prev->next = item;
        !           155:        } else {
        !           156:            list->head = item;
        !           157:        }
        !           158:        a->prev = item;
        !           159:     }
        !           160: }
        !           161: 
        !           162: /*
        !           163:  * Append an item after the given item in a list.
        !           164:  */
        !           165: 
        !           166: public list_append(item, before, list)
        !           167: ListItem item;
        !           168: ListItem before;
        !           169: List list;
        !           170: {
        !           171:     ListItem b;
        !           172: 
        !           173:     checkref(list);
        !           174:     list->nitems = list->nitems + 1;
        !           175:     if (list->head == nil) {
        !           176:        list->head = item;
        !           177:        list->tail = item;
        !           178:     } else {
        !           179:        if (before == nil) {
        !           180:            b = list->tail;
        !           181:        } else {
        !           182:            b = before;
        !           183:        }
        !           184:        item->next = b->next;
        !           185:        item->prev = b;
        !           186:        if (b->next != nil) {
        !           187:            b->next->prev = item;
        !           188:        } else {
        !           189:            list->tail = item;
        !           190:        }
        !           191:        b->next = item;
        !           192:     }
        !           193: }
        !           194: 
        !           195: /*
        !           196:  * Delete an item from a list.
        !           197:  */
        !           198: 
        !           199: public list_delete(item, list)
        !           200: ListItem item;
        !           201: List list;
        !           202: {
        !           203:     checkref(item);
        !           204:     checkref(list);
        !           205:     assert(list->nitems > 0);
        !           206:     if (item->next == nil) {
        !           207:        list->tail = item->prev;
        !           208:     } else {
        !           209:        item->next->prev = item->prev;
        !           210:     }
        !           211:     if (item->prev == nil) {
        !           212:        list->head = item->next;
        !           213:     } else {
        !           214:        item->prev->next = item->next;
        !           215:     }
        !           216:     list->nitems = list->nitems - 1;
        !           217: }
        !           218: 
        !           219: /*
        !           220:  * Concatenate one list onto the end of another.
        !           221:  */
        !           222: 
        !           223: public List list_concat(first, second)
        !           224: List first, second;
        !           225: {
        !           226:     List r;
        !           227: 
        !           228:     if (first == nil) {
        !           229:        r = second;
        !           230:     } else if (second == nil) {
        !           231:        r = first;
        !           232:     } else {
        !           233:        second->head->prev = first->tail;
        !           234:        first->tail->next = second->head;
        !           235:        first->tail = second->tail;
        !           236:        first->nitems = first->nitems + second->nitems;
        !           237:        r = first;
        !           238:     }
        !           239:     return r;
        !           240: }

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