e_ll.c

对于研究FPGA结构的人来说

/*------------------------------------------------------------------------*
* Copyright 1998 by Paul Leventis, Jonathan Rose and the University of    *
* Toronto.  Use is permitted, provided that this attribution is retained  *
* and no part of the code is re-distributed or included in any commercial *
* product except by written agreement with the above parties.             *
*                                                                         *
* For more information, contact us directly:                              *
*    Paul Leventis ([e-mail])                             *
*    Jonathan Rose  ([e-mail])                              *
*    Department of Electrical and Computer Engineering                    *
*    University of Toronto, 10 King's College Rd.,                        *
*    Toronto, Ontario, CANADA M5S 1A4                                     *
*    Phone: [phone]  Fax: [phone]                           *
*------------------------------------------------------------------------*/

/* 
 * e_ll.c
 * Generalised linked list functions
 *
 * P. Leventis, July 1997
*/

#include <stdlib.h>
#include "e_ll.h"
#include "e_shared.h"

#define MAIN 0

struct dummyStruct {
    char *name;
};

void ll_restart(LL *pLL)
{
	pLL->ppCurrEntry = &(pLL->pFirstEntry);
}

void ll_insert(LL *pLL, void *payload)
{
	LL_ENTRY *pNewEntry;
	
	pNewEntry = (LL_ENTRY*) malloc(sizeof(LL_ENTRY));
	mem_assert(pNewEntry);
	pNewEntry->pPayload = payload;
	pNewEntry->pNextEntry = *(pLL->ppCurrEntry);
	*(pLL->ppCurrEntry) = pNewEntry;
	pLL->nEntries++;
}

void* ll_alloc(void (*free_payload)(void *)) 
{
    LL *pLL;

    pLL = malloc(sizeof(LL));
	mem_assert(pLL);
    pLL->pFirstEntry = NULL;
    pLL->ppCurrEntry = &(pLL->pFirstEntry);
    pLL->free_payload = free_payload;
    pLL->nEntries = 0;

    return pLL;
}

int ll_add(LL *pLL, void *payload)
{
	ll_restart(pLL);
	ll_insert(pLL, payload);
	return 1;
}

int ll_inc(LL *pLL)
{
	if(*(pLL->ppCurrEntry) == NULL)
		return 0;
	pLL->ppCurrEntry = &(*(pLL->ppCurrEntry))->pNextEntry;
	if(*(pLL->ppCurrEntry) == NULL)
		return 0;
	return 1;
}

void *ll_get(LL *pLL)
{
	return (*(pLL->ppCurrEntry))->pPayload;
}

void *ll_take(LL *pLL)
{
	LL_ENTRY *pTemp;
	
	pTemp = *(pLL->ppCurrEntry);
	if(pTemp != NULL) {
	    *(pLL->ppCurrEntry) = (*(pLL->ppCurrEntry))->pNextEntry;
	    pLL->nEntries--;
	}
	return pTemp;
}

void ll_remove(LL *pLL)
{
    LL_ENTRY *pTemp = ll_take(pLL);
    
    pLL->free_payload(pTemp->pPayload);
    free(pTemp);
}

void ll_free_helper(LL *pLL)
{
	LL_ENTRY *pCurr;

	if(!pLL)
		return;
	pCurr = pLL->pFirstEntry;
	while(pCurr) {
		LL_ENTRY *pTemp = pCurr;
		pCurr = pCurr->pNextEntry;
		pLL->free_payload(pTemp->pPayload);
		free(pTemp);
	}	
	free(pLL);
}

/* Assumes that the first entry is the name!!! */
void *ll_search(LL *pLL, char *name)
{
    LL_LOOP(pLL) {
	struct dummyStruct *stringStruct = (struct dummyStruct *) ll_get(pLL);

	my_assert(stringStruct);
	if(!strcmp(stringStruct->name, name))
	    return stringStruct;
    }
    return NULL;
}
    

#if MAIN

void free_payload(void *payload)
{
	free( (int *) payload);
}

int main(void)
{
	LL my_LL;
	char command;
	int val, *pPayload;

	printf(
		"a: add iVal\n"
		"b: back to beginning\n"
		"d: dump list to screen\n"
		"h: get help\n"
		"i: insert entry\n"
		"n: next entry\n"
		"p: print current entry\n"
		"q: quit\n"
		"r: remove entry\n\n"
	);
	ll_init(&my_LL, free_payload);
	while(1) {
		scanf("%c", &command);
		switch(command) {
		case 'a':
			scanf("%d", &val);
			pPayload = (int *) malloc(sizeof(int));
			*pPayload = val;
			printf("Adding value %d to list.\n", *pPayload);
			ll_add(&my_LL, pPayload);
			break;
		case 'd':
			printf("Dumping list contents...\n");
			ll_restart(&my_LL);
			while(*(my_LL.ppCurrEntry)) {
				printf("%d ", *((int *) ll_get(&my_LL)));
				ll_inc(&my_LL);
			}
			printf("\n");
			break;
		case 'p':
			if(ll_at_end(&my_LL))
				printf("At end of list.\n");
			else
				printf("Current entry: %d\n", *((int *) ll_get(&my_LL)));
			break;
		case 'b':
			printf("Restarting at head of list.\n");
			ll_restart(&my_LL);
			break;
		case 'h':
			printf(
				"a: add iVal\n"
				"b: back to beginning\n"
				"d: dump list to screen\n"
				"h: get help\n"
				"i: insert iVal\n"
				"n: next entry\n"
				"p: print current entry\n"
				"q: quit\n"
				"r: remove entry\n\n"
			);
			break;
		case 'n':
			printf("Incrementing position.\n");
			if(!ll_inc(&my_LL))
				printf("At end of list.\n");
			break;
		case 'i':
			scanf("%d", &val);
			pPayload = (int *) malloc(sizeof(int));
			*pPayload = val;
			printf("Adding value %d to list.\n", *pPayload);
			ll_insert(&my_LL, pPayload);
			break;
		case 'r':
			if(ll_at_end(&my_LL))
				printf("At end of list.\n");
			else
				printf("Removing current entry.\n");
			ll_remove(&my_LL);
			break;
		case 'q':
			ll_free(&my_LL);
			exit(1);
		default:
			printf("Unsupported command.\n");
			break;
		}
		scanf("%c", &command);
	}
	return 0;
}

#endif