memory.c   [plain text]

/*
    This software may only be used by you under license from AT&T Corp.
    ("AT&T").  A copy of AT&T's Source Code Agreement is available at
    AT&T's Internet website having the URL:
    <http://www.research.att.com/sw/tools/graphviz/license/source.html>
    If you received this software without first entering into a license
    with AT&T, you have an infringing copy of this software and cannot use
    it without violating AT&T's intellectual property rights.
*/
#pragma prototyped
#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;
}