memory.c

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/* $Id$ $Revision$ */
/* vim:set shiftwidth=4 ts=8: */

/*************************************************************************
 * Copyright (c) 2011 AT&T Intellectual Property 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: See CVS logs. Details at http://www.graphviz.org/
 *************************************************************************/

#include "geometry.h"
#include "render.h"

typedef struct freenode {
    struct freenode *nextfree;
} Freenode;

typedef struct freeblock {
    struct freeblock *next;
    struct freenode *nodes;
} Freeblock;

#include "mem.h"
#include <stdlib.h>
#include <stdio.h>

static int gcd(int y, int x)
{
    while (x != y) {
        if (y < x)
            x = x - y;
        else
            y = y - x;
    }
    return x;
}

#define LCM(x,y) ((x)%(y) == 0 ? (x) : (y)%(x) == 0 ? (y) : x*(y/gcd(x,y)))

void freeinit(Freelist * fl, int size)
{

    fl->head = NULL;
    fl->nodesize = LCM(size, sizeof(Freenode));
    if (fl->blocklist != NULL) {
        Freeblock *bp, *np;

        bp = fl->blocklist;
        while (bp != NULL) {
            np = bp->next;
            free(bp->nodes);
            free(bp);
            bp = np;
        }
    }
    fl->blocklist = NULL;
}

void *getfree(Freelist * fl)
{
    int i;
    Freenode *t;
    Freeblock *mem;

    if (fl->head == NULL) {
        int size = fl->nodesize;
        char *cp;

        mem = GNEW(Freeblock);
        mem->nodes = gmalloc(sqrt_nsites * size);
        cp = (char *) (mem->nodes);
        for (i = 0; i < sqrt_nsites; i++) {
            makefree(cp + i * size, fl);
        }
        mem->next = fl->blocklist;
        fl->blocklist = mem;
    }
    t = fl->head;
    fl->head = t->nextfree;
    return ((void *) t);
}

void makefree(void *curr, Freelist * fl)
{
    ((Freenode *) curr)->nextfree = fl->head;
    fl->head = (Freenode *) curr;
}