/* Copyright (C) 2001-2023 Artifex Software, Inc.
   All Rights Reserved.

   This software is provided AS-IS with no warranty, either express or
   implied.

   This software is distributed under license and may not be copied,
   modified or distributed except as expressly authorized under the terms
   of the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact
   Artifex Software, Inc.,  39 Mesa Street, Suite 108A, San Francisco,
   CA 94129, USA, for further information.
*/


/* Level 2 "Virtual memory" operators */
#include "ghost.h"
#include "oper.h"
#include "estack.h"
#include "ialloc.h"		/* for ivmspace.h */
#include "ivmspace.h"
#include "ivmem2.h"
#include "store.h"

/* Garbage collector control parameters. */
#define DEFAULT_VM_THRESHOLD_SMALL 100000
#define DEFAULT_VM_THRESHOLD_LARGE 8000000

/* ------ Local/global VM control ------ */

/* <bool> .setglobal - */
static int
zsetglobal(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    check_type(*op, t_boolean);
    ialloc_set_space(idmemory,
                     (op->value.boolval ? avm_global : avm_local));
    pop(1);
    return 0;
}

/* - .currentglobal <bool> */
static int
zcurrentglobal(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    push(1);
    make_bool(op, ialloc_space(idmemory) != avm_local);
    return 0;
}

/* <any> gcheck/scheck <bool> */
static int
zgcheck(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    check_op(1);
    make_bool(op, (r_is_local(op) ? false : true));
    return 0;
}

/* ------ Garbage collector control ------ */

/* These routines are exported for setuserparams. */

/*
 * <int> setvmthreshold -
 *
 * This is implemented as a PostScript procedure that calls setuserparams.
 */
int
set_vm_threshold(i_ctx_t *i_ctx_p, int64_t val)
{
    if (val < -1)
        return_error(gs_error_rangecheck);
    else if (val == -1)
        val = (gs_debug_c('.') ? DEFAULT_VM_THRESHOLD_SMALL :
               DEFAULT_VM_THRESHOLD_LARGE);
#if PSINT32BIT==1
    else if (val > max_int)
        val = max_int
#endif
    gs_memory_set_vm_threshold(idmemory->space_system, val);
    gs_memory_set_vm_threshold(idmemory->space_global, val);
    gs_memory_set_vm_threshold(idmemory->space_local, val);
    return 0;
}

int
set_vm_reclaim(i_ctx_t *i_ctx_p, long val)
{
    if (val >= -2 && val <= 0) {
        gs_memory_set_vm_reclaim(idmemory->space_system, (val >= -1));
        gs_memory_set_vm_reclaim(idmemory->space_global, (val >= -1));
        gs_memory_set_vm_reclaim(idmemory->space_local, (val == 0));
        return 0;
    } else
        return_error(gs_error_rangecheck);
}

/*
 * <int> .vmreclaim -
 *
 * This implements only immediate garbage collection: enabling and
 * disabling GC is implemented by calling setuserparams.
 */
static int
zvmreclaim(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    check_type(*op, t_integer);
    if (op->value.intval == 1 || op->value.intval == 2) {
        /* Force the interpreter to store its state and exit. */
        /* The interpreter's caller will do the actual GC. */
        return_error(gs_error_VMreclaim);
    }
    return_error(gs_error_rangecheck);
}

/* ------ Initialization procedure ------ */

/* The VM operators are defined even if the initial language level is 1, */
/* because we need them during initialization. */
const op_def zvmem2_op_defs[] =
{
    {"0.currentglobal", zcurrentglobal},
    {"1.gcheck", zgcheck},
    {"1.setglobal", zsetglobal},
                /* The rest of the operators are defined only in Level 2. */
    op_def_begin_level2(),
    {"1.vmreclaim", zvmreclaim},
    op_def_end(0)
};