/* Copyright (C) 2001-2006 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 that
   license.  Refer to licensing information at http://www.artifex.com/
   or contact Artifex Software, Inc.,  7 Mt. Lassen Drive - Suite A-134,
   San Rafael, CA  94903, U.S.A., +1(415)492-9861, for further information.
*/

/* $Id: zrelbit.c 8250 2007-09-25 13:31:24Z giles $ */
/* 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 */
static int obj_le(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(imemory, 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> */
static 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> */
static 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> */
static 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(imemory, op - 1, op) ? 1 : 0));
    pop(1);
    return 0;

}

/* <obj1> <obj2> .identne <bool> */
static 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. */
static 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);
    }
}
