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/* Copyright (c) 1998 Silicon Graphics, Inc. */ |
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|
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#ifndef lint |
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static char SCCSid[] = "$SunId$ SGI"; |
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#endif |
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|
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/* |
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* sm_list.c |
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* Routines for handling linked generic linked lists, stack, and |
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* circular lists. Data element is an int (can be cast to hold |
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* pointer to more general data element) |
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*/ |
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|
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#include "standard.h" |
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#include "sm_list.h" |
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|
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/* List of available edges */ |
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static LIST *free_lists = NULL; |
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#ifdef DEBUG |
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extern int Malloc_cnt; |
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#endif |
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LIST |
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*new_list() |
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{ |
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LIST *l; |
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|
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/* check free list for available edges */ |
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if( free_lists ) |
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{ |
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l = free_lists; |
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free_lists = LIST_NEXT(free_lists); |
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} |
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/* if no free edges- allocate the memory */ |
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else |
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{ |
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if( !(l = (LIST *)malloc(sizeof(LIST)))) |
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error(SYSTEM,"new_list():Unable to allocate memory"); |
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} |
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/* clear the memory */ |
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bzero(l, sizeof(LIST)); |
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|
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return(l); |
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} |
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|
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|
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/* attaches list a at the end of list b */ |
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LIST |
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*append_list(a,b) |
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LIST *a,*b; |
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{ |
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LIST * l; |
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|
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if(!b) |
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return(a); |
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|
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l = b; |
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while(LIST_NEXT(l) && LIST_NEXT(l) != b) |
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l = LIST_NEXT(l); |
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|
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SET_LIST_NEXT(l,a); |
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|
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return(b); |
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} |
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|
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/* Adds data to the end of a circular list. If set, "end" |
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* is a pointer to the last element in the list |
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*/ |
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LIST |
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*add_data_to_circular_list(l,end,d) |
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LIST *l,**end; |
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int d; |
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{ |
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LIST *list; |
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|
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list = new_list(); |
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SET_LIST_DATA(list,d); |
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|
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if(!l) |
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l = list; |
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else |
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{ |
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if(*end) |
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SET_LIST_NEXT(*end,list); |
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else |
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l = append_list(list,l); |
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} |
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|
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*end = list; |
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SET_LIST_NEXT(list,l); |
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return(l); |
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} |
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|
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/* Pushes data element d at the top of the list- returns pointer |
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to new top of list |
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*/ |
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LIST |
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*push_data(l,d) |
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LIST *l; |
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int d; |
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{ |
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LIST * list; |
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|
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list = new_list(); |
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SET_LIST_DATA(list,d); |
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SET_LIST_NEXT(list,l); |
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return(list); |
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} |
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|
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/* frees the list */ |
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LIST |
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*free_list(l) |
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LIST * l; |
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{ |
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if(!l) |
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return(NULL); |
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|
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free_lists = append_list(free_lists,l); |
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|
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return(NULL); |
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} |
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|
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/* Returns data element d at the top of the list- returns pointer |
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to new top of list |
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*/ |
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int |
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pop_list(l) |
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LIST **l; |
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{ |
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LIST *p; |
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int d; |
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|
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if(!l) |
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return(NULL); |
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if(!(p = *l)) |
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return(NULL); |
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|
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d = LIST_DATA(p); |
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|
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*l = LIST_NEXT(p); |
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|
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LIST_NEXT(p) =NULL; |
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free_list(p); |
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|
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return(d); |
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} |
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|
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/* Search through list for data element "d", and remove from |
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* list: Returns TRUE if found, false otherwise |
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*/ |
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int |
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remove_from_list(d,list) |
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int d; |
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LIST **list; |
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{ |
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LIST *l,*prev; |
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|
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l = *list; |
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prev = NULL; |
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|
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while(l) |
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{ |
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if(LIST_DATA(l) == d) |
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{ |
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if(l == *list) |
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*list = LIST_NEXT(*list); |
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else |
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SET_LIST_NEXT(prev,LIST_NEXT(l)); |
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|
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SET_LIST_NEXT(l,NULL); |
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free_list(l); |
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return(TRUE); |
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} |
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prev = l; |
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l = LIST_NEXT(l); |
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} |
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return(FALSE); |
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} |
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