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GitHub Repository: att/ast
 Path: blob/master/src/lib/libast/astsa/vmalloc.c
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/***********************************************************************

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*                                                                      *

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*               This software is part of the ast package               *

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*          Copyright (c) 1985-2011 AT&T Intellectual Property          *

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*                      and is licensed under the                       *

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*                 Eclipse Public License, Version 1.0                  *

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*                    by AT&T Intellectual Property                     *

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*                                                                      *

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*                A copy of the License is available at                 *

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*          http://www.eclipse.org/org/documents/epl-v10.html           *

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*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *

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*                                                                      *

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*              Information and Software Systems Research               *

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*                            AT&T Research                             *

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*                           Florham Park NJ                            *

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*                                                                      *

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*                 Glenn Fowler <[email protected]>                  *

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*                  David Korn <[email protected]>                   *

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*                   Phong Vo <[email protected]>                    *

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*                                                                      *

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***********************************************************************/

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#pragma prototyped

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/*

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 * standalone mini vmalloc implementation

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 * no resize, no free, no disciplines, no methods

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 */

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#include <ast.h>

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#include <vmalloc.h>

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Vmalloc_t*	Vmregion;

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Vmalloc_t*

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_vm_open(void)

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{

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	Vmalloc_t*	vp;

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	if (vp = newof(0, Vmalloc_t, 1, 0))

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	{

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		vp->current = &vp->base;

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		vp->data = vp->current->data;

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		vp->size = sizeof(vp->current->data);

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	}

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	return vp;

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}

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int

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_vm_close(register Vmalloc_t* vp)

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{

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	register Vmchunk_t*	cp;

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	register Vmchunk_t*	np;

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	if (!vp)

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		return -1;

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	np = vp->base.next;

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	while (cp = np)

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	{

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		np = cp->next;

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		free(cp);

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	}

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	free(vp);

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	return 0;

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}

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void*

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_vm_resize(register Vmalloc_t* vp, void* o, unsigned long size)

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{

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	char*		p;

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	unsigned long	n;

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	unsigned long	z;

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	z = vp->last;

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	vp->last = size;

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	if (o && size < z)

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		return o;

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	if ((o ? (size - z) : size) > vp->size)

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	{

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		n = (size > sizeof(vp->current->data)) ? (size - sizeof(vp->current->data)) : 0;

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		if (!(vp->current->next = newof(0, Vmchunk_t, 1, n)))

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			return 0;

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		vp->current = vp->current->next;

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		vp->data = vp->current->data;

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		vp->size = n ? 0 : sizeof(vp->current->data);

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		if (o)

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		{

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			memcpy(vp->data, o, z);

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			o = (void*)vp->data;

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		}

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	}

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	else if (o)

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		size -= z;

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	p = vp->data;

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	size = roundof(size, VM_ALIGN);

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	if (size >= vp->size)

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		vp->size = 0;

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	else

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	{

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		vp->size -= size;

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		vp->data += size;

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	}

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	return p;

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}

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