/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1988 AT&T */
/*        All Rights Reserved   */

#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <memory.h>
#include <thread.h>
#include <pthread.h>
#include <synch.h>
#include <procfs.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/stat.h>

/* debugging macros */
#ifdef  DEBUG
#define ASSERT(p)       ((void) ((p) || (abort(), 0)))
#define COUNT(n)        ((void) n++)
static int              nmalloc, nrealloc, nfree;
#else
#define ASSERT(p)       ((void)0)
#define COUNT(n)        ((void)0)
#endif /* DEBUG */

/* for conveniences */
#ifndef NULL
#define NULL            (0)
#endif

#define WORDSIZE        (sizeof (WORD))
#define MINSIZE         (sizeof (TREE) - sizeof (WORD))
#define ROUND(s)        if ((s)%WORDSIZE) (s) += (WORDSIZE - ((s)%WORDSIZE))

/*
 * All of our allocations will be aligned on the least multiple of 4,
 * at least, so the two low order bits are guaranteed to be available.
 */
#ifdef _LP64
#define ALIGN           16
#else
#define ALIGN           8
#endif

/* the proto-word; size must be ALIGN bytes */
typedef union _w_ {
        size_t          w_i;            /* an unsigned int */
        struct _t_      *w_p[2];        /* two pointers */
} WORD;

/* structure of a node in the free tree */
typedef struct _t_ {
        WORD    t_s;    /* size of this element */
        WORD    t_p;    /* parent node */
        WORD    t_l;    /* left child */
        WORD    t_r;    /* right child */
        WORD    t_n;    /* next in link list */
        WORD    t_d;    /* dummy to reserve space for self-pointer */
} TREE;

/* usable # of bytes in the block */
#define SIZE(b)         (((b)->t_s).w_i)
#define RSIZE(b)        (((b)->t_s).w_i & ~BITS01)

/* free tree pointers */
#define PARENT(b)       (((b)->t_p).w_p[0])
#define LEFT(b)         (((b)->t_l).w_p[0])
#define RIGHT(b)        (((b)->t_r).w_p[0])

/* forward link in lists of small blocks */
#define AFTER(b)        (((b)->t_p).w_p[0])

/* forward and backward links for lists in the tree */
#define LINKFOR(b)      (((b)->t_n).w_p[0])
#define LINKBAK(b)      (((b)->t_p).w_p[0])

/* set/test indicator if a block is in the tree or in a list */
#define SETNOTREE(b)    (LEFT(b) = (TREE *)(-1))
#define ISNOTREE(b)     (LEFT(b) == (TREE *)(-1))

/* functions to get information on a block */
#define DATA(b)         (((char *)(b)) + WORDSIZE)
#define BLOCK(d)        ((TREE *)(((char *)(d)) - WORDSIZE))
#define SELFP(b)        (&(NEXT(b)->t_s.w_p[1]))
#define LAST(b)         ((b)->t_s.w_p[1])
#define NEXT(b)         ((TREE *)(((char *)(b)) + RSIZE(b) + WORDSIZE))
#define BOTTOM(b)       ((DATA(b) + RSIZE(b) + WORDSIZE) == Baddr)

/* functions to set and test the lowest two bits of a word */
#define BIT0            (01)            /* ...001 */
#define BIT1            (02)            /* ...010 */
#define BITS01          (03)            /* ...011 */
#define ISBIT0(w)       ((w) & BIT0)    /* Is busy? */
#define ISBIT1(w)       ((w) & BIT1)    /* Is the preceding free? */
#define SETBIT0(w)      ((w) |= BIT0)   /* Block is busy */
#define SETBIT1(w)      ((w) |= BIT1)   /* The preceding is free */
#define CLRBIT0(w)      ((w) &= ~BIT0)  /* Clean bit0 */
#define CLRBIT1(w)      ((w) &= ~BIT1)  /* Clean bit1 */
#define SETBITS01(w)    ((w) |= BITS01) /* Set bits 0 & 1 */
#define CLRBITS01(w)    ((w) &= ~BITS01) /* Clean bits 0 & 1 */
#define SETOLD01(n, o)  ((n) |= (BITS01 & (o)))

/* system call to get more memory */
#define GETCORE         sbrk
#define ERRCORE         ((char *)(-1))
#define CORESIZE        (1024*ALIGN)
#define MAX_GETCORE (size_t)(SSIZE_MAX & ~(ALIGN - 1)) /* round down ALIGN */
#define MAX_MALLOC (size_t)(SIZE_MAX - CORESIZE - 3 * ALIGN) /* overflow chk */
#define MAX_ALIGN       (1 + (size_t)SSIZE_MAX)