bag.c

来自「This is a resource based on j2me embedde」· C语言 代码 · 共 152 行

/*
 * @(#)bag.c	1.14 06/10/25
 *
 * Copyright  1990-2008 Sun Microsystems, Inc. All Rights Reserved.  
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER  
 *   
 * This program is free software; you can redistribute it and/or  
 * modify it under the terms of the GNU General Public License version  
 * 2 only, as published by the Free Software Foundation.   
 *   
 * This program is distributed in the hope that it will be useful, but  
 * WITHOUT ANY WARRANTY; without even the implied warranty of  
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU  
 * General Public License version 2 for more details (a copy is  
 * included at /legal/license.txt).   
 *   
 * You should have received a copy of the GNU General Public License  
 * version 2 along with this work; if not, write to the Free Software  
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  
 * 02110-1301 USA   
 *   
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa  
 * Clara, CA 95054 or visit www.sun.com if you need additional  
 * information or have any questions. 
 *
 */

/* General routines for manipulating a bag data structure */

#ifdef CVM_JVMTI

#include "javavm/include/clib.h"
#include "javavm/include/bag.h"

struct CVMBag {
    void *items;    /* hold items in bag, must align on itemSize */
    int used;       /* number of items in bag */
    int allocated;  /* space reserved */
    int itemSize;   /* size of each item, should init to sizeof item */
};

struct CVMBag * 
CVMbagCreateBag(int itemSize, int initialAllocation) {   
    struct CVMBag *theBag = (struct CVMBag *)malloc(sizeof(struct CVMBag));
    if (theBag == NULL) {
        return NULL;
    }
    itemSize = (itemSize + 7) & ~7;    /* fit 8 byte Boundary */
    theBag->items = malloc(initialAllocation * itemSize);
    if (theBag->items == NULL) {
        free(theBag);
        return NULL;
    }
    theBag->used = 0;
    theBag->allocated = initialAllocation;
    theBag->itemSize = itemSize;
    return theBag;
}

void
CVMbagDestroyBag(struct CVMBag *theBag) 
{
    free(theBag->items);
    free(theBag);
}

void *
CVMbagFind(struct CVMBag *theBag, void *key) 
{
    char *items = theBag->items;
    int itemSize = theBag->itemSize;
    char *itemsEnd = items + (itemSize * theBag->used);
    
    for (; items < itemsEnd; items += itemSize) {
        if (*((void**)items) == key) {
            return items;
        }
    }
    return NULL;
}

void *
CVMbagAdd(struct CVMBag *theBag) 
{
    int allocated = theBag->allocated;
    int itemSize = theBag->itemSize;
    void *items = theBag->items;
    void *ret;

    /* if there are no unused slots reallocate */
    if (theBag->used >= allocated) {
        allocated *= 2;
        items = realloc(items, allocated * itemSize);
        if (items == NULL) {
            return NULL;
        }
        theBag->allocated = allocated;
        theBag->items = items;
    }
    ret = ((char *)items) + (itemSize * (theBag->used)++);
    memset(ret, 0, itemSize);
    return ret;
}
    
void
CVMbagDelete(struct CVMBag *theBag, void *condemned) 
{
    int used;
    int itemSize = theBag->itemSize;
    void *items = theBag->items;
    void *tailItem;

    --theBag->used;
    used = theBag->used;
    tailItem = ((char *)items) + (used * itemSize);
    
    if (condemned != tailItem) {
        memcpy(condemned, tailItem, itemSize);
    }
}

void
CVMbagDeleteAll(struct CVMBag *theBag) 
{
    theBag->used = 0;
}

    
int
CVMbagSize(struct CVMBag *theBag) 
{
    return theBag->used;
}    

CVMBool
CVMbagEnumerateOver(struct CVMBag *theBag,
		    CVMBagEnumerateFunction func, void *arg) 
{
    char *items = theBag->items;
    int itemSize = theBag->itemSize;
    char *itemsEnd = items + (itemSize * theBag->used);
    
    for (; items < itemsEnd; items += itemSize) {
        if (!(func)((void *)items, arg)) {
            return CVM_FALSE;
        }
    }
    return CVM_TRUE;
}

#endif /* CVM_JVMTI */