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    Length: 2094 (0x82e)
    Types: TextFile
    Notes: UNIX file
    Names: »alloc.c«

└─⟦f27320a65⟧ Bits:30001972 Commodore 900 hard disk image with partial source code
    └─⟦2d53db1df⟧ UNIX V7 Filesystem
        └─ ⟦this⟧ »sys/coh/alloc.c« 

TextFile

/* (-lgl
 * 	The information contained herein is a trade secret of Mark Williams
 * 	Company, and  is confidential information.  It is provided  under a
 * 	license agreement,  and may be  copied or disclosed  only under the
 * 	terms of  that agreement.  Any  reproduction or disclosure  of this
 * 	material without the express written authorization of Mark Williams
 * 	Company or persuant to the license agreement is unlawful.
 * 
 * 	COHERENT Version 0.7.3
 * 	Copyright (c) 1982, 1983, 1984.
 * 	An unpublished work by Mark Williams Company, Chicago.
 * 	All rights reserved.
 -lgl) */
/*
 * Coherent.
 * Storage allocator.
 */
#include <coherent.h>
#include <alloc.h>
#include <errno.h>
#include <proc.h>
#include <uproc.h>

/*
 * Create an arena.
 */
ALL *
setarena(cp, n)
register char *cp;
{
	register ALL *ap1;
	register ALL *ap2;

	if ((char *)(ap1=align(cp)) < (char *)cp)
		ap1++;
	if ((ap2=align(&cp[n])-1) < ap1)
		panic("Arena %o too small", (int) cp);
	ap1->a_link = (char *)ap2;
	ap2->a_link = (char *)ap1;
	setused(ap2);
	return (ap1);
}

/*
 * Allocate `l' bytes of memory.
 */
char *
alloc(apq, l)
ALL *apq;
unsigned l;
{
	register ALL *ap;
	register ALL *ap1;
	register ALL *ap2;
	register unsigned i;
	register unsigned n;
	register unsigned s;

	n = 1 + (l + sizeof(ALL) - 1) / sizeof(ALL);
	for (i=0; i<2; i++) {
		for (ap1=apq; link(ap1)!=apq; ap1=link(ap1)) {
			if (ap1 == NULL)
				panic("Corrupt arena");
			if (tstfree(ap1)) {
			       for (ap2=link(ap1); tstfree(ap2); ap2=link(ap2))
					if (ap2 == apq)
						break;
				ap1->a_link = (char *)ap2;
				if ((s=ap2-ap1) >= n) {
					if (s > n) {
						if (i == 0)
							continue;
						ap = &ap1[n];
						ap->a_link = (char *)ap2;
						ap1->a_link = (char *)ap;
					}
					setused(ap1);
					kclear((char *)ap1->a_data, l);
					return (ap1->a_data);
				}
			}
		}
	}
	u.u_error = EKSPACE;
	return (NULL);
}

/*
 * Free memory.
 */
free(cp)
char *cp;
{
	register ALL *ap;
	extern char end;

	ap = ((ALL *)cp) - 1;
	if (ap<(ALL *)&end || tstfree(ap))
		panic("Bad free %o\n", (unsigned)cp);
	setfree(ap);
}