/* Copyright (C) 1989, 1995, 1997, 1998, 1999 Aladdin Enterprises.  All rights reserved.
  
  This file is part of GNU Ghostscript.
  
  GNU Ghostscript is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY.  No author or distributor accepts responsibility
  to anyone for the consequences of using it or for whether it serves any
  particular purpose or works at all, unless he says so in writing.  Refer
  to the GNU General Public License for full details.
  
  Everyone is granted permission to copy, modify and redistribute GNU
  Ghostscript, but only under the conditions described in the GNU General
  Public License.  A copy of this license is supposed to have been given
  to you along with GNU Ghostscript so you can know your rights and
  responsibilities.  It should be in a file named COPYING.  Among other
  things, the copyright notice and this notice must be preserved on all
  copies.
*/

/*$RCSfile: zrelbit.c,v $ $Revision: 1.2.2.1 $ */
/* Relational, boolean, and bit operators */
#include "ghost.h"
#include "oper.h"
#include "gsutil.h"
#include "idict.h"
#include "store.h"

/*
 * Many of the procedures in this file are public only so they can be
 * called from the FunctionType 4 interpreter (zfunc4.c).
 */

/* ------ Standard operators ------ */

/* Define the type test for eq and its relatives. */
#define EQ_CHECK_READ(opp, dflt)\
    switch ( r_type(opp) ) {\
	case t_string:\
	    check_read(*(opp));\
	    break;\
	default:\
	    dflt;\
  }

/* Forward references */
private int obj_le(P2(os_ptr, os_ptr));

/* <obj1> <obj2> eq <bool> */
int
zeq(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    EQ_CHECK_READ(op - 1, check_op(2));
    EQ_CHECK_READ(op, DO_NOTHING);
    make_bool(op - 1, (obj_eq(op - 1, op) ? 1 : 0));
    pop(1);
    return 0;
}

/* <obj1> <obj2> ne <bool> */
int
zne(i_ctx_t *i_ctx_p)
{	/* We'll just be lazy and use eq. */
    int code = zeq(i_ctx_p);

    if (!code)
	osp->value.boolval ^= 1;
    return code;
}

/* <num1> <num2> ge <bool> */
/* <str1> <str2> ge <bool> */
int
zge(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    int code = obj_le(op, op - 1);

    if (code < 0)
	return code;
    make_bool(op - 1, code);
    pop(1);
    return 0;
}

/* <num1> <num2> gt <bool> */
/* <str1> <str2> gt <bool> */
int
zgt(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    int code = obj_le(op - 1, op);

    if (code < 0)
	return code;
    make_bool(op - 1, code ^ 1);
    pop(1);
    return 0;
}

/* <num1> <num2> le <bool> */
/* <str1> <str2> le <bool> */
int
zle(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    int code = obj_le(op - 1, op);

    if (code < 0)
	return code;
    make_bool(op - 1, code);
    pop(1);
    return 0;
}

/* <num1> <num2> lt <bool> */
/* <str1> <str2> lt <bool> */
int
zlt(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    int code = obj_le(op, op - 1);

    if (code < 0)
	return code;
    make_bool(op - 1, code ^ 1);
    pop(1);
    return 0;
}

/* <num1> <num2> .max <num> */
/* <str1> <str2> .max <str> */
private int
zmax(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    int code = obj_le(op - 1, op);

    if (code < 0)
	return code;
    if (code) {
	ref_assign(op - 1, op);
    }
    pop(1);
    return 0;
}

/* <num1> <num2> .min <num> */
/* <str1> <str2> .min <str> */
private int
zmin(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    int code = obj_le(op - 1, op);

    if (code < 0)
	return code;
    if (!code) {
	ref_assign(op - 1, op);
    }
    pop(1);
    return 0;
}

/* <bool1> <bool2> and <bool> */
/* <int1> <int2> and <int> */
int
zand(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    switch (r_type(op)) {
	case t_boolean:
	    check_type(op[-1], t_boolean);
	    op[-1].value.boolval &= op->value.boolval;
	    break;
	case t_integer:
	    check_type(op[-1], t_integer);
	    op[-1].value.intval &= op->value.intval;
	    break;
	default:
	    return_op_typecheck(op);
    }
    pop(1);
    return 0;
}

/* <bool> not <bool> */
/* <int> not <int> */
int
znot(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    switch (r_type(op)) {
	case t_boolean:
	    op->value.boolval = !op->value.boolval;
	    break;
	case t_integer:
	    op->value.intval = ~op->value.intval;
	    break;
	default:
	    return_op_typecheck(op);
    }
    return 0;
}

/* <bool1> <bool2> or <bool> */
/* <int1> <int2> or <int> */
int
zor(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    switch (r_type(op)) {
	case t_boolean:
	    check_type(op[-1], t_boolean);
	    op[-1].value.boolval |= op->value.boolval;
	    break;
	case t_integer:
	    check_type(op[-1], t_integer);
	    op[-1].value.intval |= op->value.intval;
	    break;
	default:
	    return_op_typecheck(op);
    }
    pop(1);
    return 0;
}

/* <bool1> <bool2> xor <bool> */
/* <int1> <int2> xor <int> */
int
zxor(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    switch (r_type(op)) {
	case t_boolean:
	    check_type(op[-1], t_boolean);
	    op[-1].value.boolval ^= op->value.boolval;
	    break;
	case t_integer:
	    check_type(op[-1], t_integer);
	    op[-1].value.intval ^= op->value.intval;
	    break;
	default:
	    return_op_typecheck(op);
    }
    pop(1);
    return 0;
}

/* <int> <shift> bitshift <int> */
int
zbitshift(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    int shift;

    check_type(*op, t_integer);
    check_type(op[-1], t_integer);
#define MAX_SHIFT (arch_sizeof_long * 8 - 1)
    if (op->value.intval < -MAX_SHIFT || op->value.intval > MAX_SHIFT)
	op[-1].value.intval = 0;
#undef MAX_SHIFT
    else if ((shift = op->value.intval) < 0)
	op[-1].value.intval = ((ulong)(op[-1].value.intval)) >> -shift;
    else
	op[-1].value.intval <<= shift;
    pop(1);
    return 0;
}

/* ------ Extensions ------ */

/* <obj1> <obj2> .identeq <bool> */
private int
zidenteq(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    EQ_CHECK_READ(op - 1, check_op(2));
    EQ_CHECK_READ(op, DO_NOTHING);
    make_bool(op - 1, (obj_ident_eq(op - 1, op) ? 1 : 0));
    pop(1);
    return 0;

}

/* <obj1> <obj2> .identne <bool> */
private int
zidentne(i_ctx_t *i_ctx_p)
{
	/* We'll just be lazy and use .identeq. */
    int code = zidenteq(i_ctx_p);

    if (!code)
	osp->value.boolval ^= 1;
    return code;
}

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

const op_def zrelbit_op_defs[] =
{
    {"2and", zand},
    {"2bitshift", zbitshift},
    {"2eq", zeq},
    {"2ge", zge},
    {"2gt", zgt},
    {"2le", zle},
    {"2lt", zlt},
    {"2.max", zmax},
    {"2.min", zmin},
    {"2ne", zne},
    {"1not", znot},
    {"2or", zor},
    {"2xor", zxor},
		/* Extensions */
    {"2.identeq", zidenteq},
    {"2.identne", zidentne},
    op_def_end(0)
};

/* ------ Internal routines ------ */

/* Compare two operands (both numeric, or both strings). */
/* Return 1 if op[-1] <= op[0], 0 if op[-1] > op[0], */
/* or a (negative) error code. */
private int
obj_le(register os_ptr op1, register os_ptr op)
{
    switch (r_type(op1)) {
	case t_integer:
	    switch (r_type(op)) {
		case t_integer:
		    return (op1->value.intval <= op->value.intval);
		case t_real:
		    return ((double)op1->value.intval <= op->value.realval);
		default:
		    return_op_typecheck(op);
	    }
	case t_real:
	    switch (r_type(op)) {
		case t_real:
		    return (op1->value.realval <= op->value.realval);
		case t_integer:
		    return (op1->value.realval <= (double)op->value.intval);
		default:
		    return_op_typecheck(op);
	    }
	case t_string:
	    check_read(*op1);
	    check_read_type(*op, t_string);
	    return (bytes_compare(op1->value.bytes, r_size(op1),
				  op->value.bytes, r_size(op)) <= 0);
	default:
	    return_op_typecheck(op1);
    }
}
