/* Copyright (C) 1995 Aladdin Enterprises.  All rights reserved.
  
  This file is part of Aladdin Ghostscript.
  
  Aladdin Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author
  or distributor accepts any responsibility for the consequences of using it,
  or for whether it serves any particular purpose or works at all, unless he
  or she says so in writing.  Refer to the Aladdin Ghostscript Free Public
  License (the "License") for full details.
  
  Every copy of Aladdin Ghostscript must include a copy of the License,
  normally in a plain ASCII text file named PUBLIC.  The License grants you
  the right to copy, modify and redistribute Aladdin Ghostscript, but only
  under certain conditions described in the License.  Among other things, the
  License requires that the copyright notice and this notice be preserved on
  all copies.
*/

/* zdouble.c */
/* Double-precision floating point arithmetic operators */
#include "math_.h"
#include "memory_.h"
#include "string_.h"
#include "ctype_.h"
#include "ghost.h"
#include "gxfarith.h"
#include "errors.h"
#include "oper.h"
#include "store.h"

/*
 * Thanks to Jean-Pierre Demailly of the Institut Fourier of the
 * Universit\'e de Grenoble I <demailly@fourier.grenet.fr> for proposing
 * this package and for arranging the funding for its creation.
 *
 * These operators work with doubles represented as 8-byte strings.  When
 * applicable, they write their result into a string supplied as an argument.
 * They also accept ints and reals as arguments.
 */

/******
 ****** Time expended: 2.75 hours.
 ******/

/* Forward references */
private int near double_params_result(P3(os_ptr, int, double *));
private int near double_params(P3(os_ptr, int, double *));
private int near double_result(P3(os_ptr, int, double));
private int near double_unary(P2(os_ptr, double (*)(P1(double))));

#define dbegin_unary()\
	double num;\
	int code = double_params_result(op, 1, &num);\
	if ( code < 0 )\
	  return code

#define dbegin_binary()\
	double num[2];\
	int code = double_params_result(op, 2, num);\
	if ( code < 0 )\
	  return code

/* ------ Arithmetic ------ */

/* <dnum1> <dnum2> <dresult> .dadd <dresult> */
private int
zdadd(os_ptr op)
{	dbegin_binary();
	return double_result(op, 2, num[0] + num[1]);
}

/* <dnum1> <dnum2> <dresult> .ddiv <dresult> */
private int
zddiv(os_ptr op)
{	dbegin_binary();
	if ( num[1] == 0.0 )
	  return_error(e_undefinedresult);
	return double_result(op, 2, num[0] / num[1]);
}

/* <dnum1> <dnum2> <dresult> .dmul <dresult> */
private int
zdmul(os_ptr op)
{	dbegin_binary();
	return double_result(op, 2, num[0] * num[1]);
}

/* <dnum1> <dnum2> <dresult> .dsub <dresult> */
private int
zdsub(os_ptr op)
{	dbegin_binary();
	return double_result(op, 2, num[0] - num[1]);
}

/* ------ Simple functions ------ */

/* <dnum> <dresult> .dabs <dresult> */
private int
zdabs(os_ptr op)
{	return double_unary(op, fabs);
}

/* <dnum> <dresult> .dceiling <dresult> */
private int
zdceiling(os_ptr op)
{	return double_unary(op, ceil);
}

/* <dnum> <dresult> .dfloor <dresult> */
private int
zdfloor(os_ptr op)
{	return double_unary(op, floor);
}

/* <dnum> <dresult> .dneg <dresult> */
private int
zdneg(os_ptr op)
{	dbegin_unary();
	return double_result(op, 1, -num);
}

/* <dnum> <dresult> .dround <dresult> */
private int
zdround(os_ptr op)
{	dbegin_unary();
	return double_result(op, 1, floor(num + 0.5));
}

/* <dnum> <dresult> .dsqrt <dresult> */
private int
zdsqrt(os_ptr op)
{	dbegin_unary();
	if ( num < 0.0 )
	  return_error(e_rangecheck);
	return double_result(op, 1, sqrt(num));
}

/* <dnum> <dresult> .dtruncate <dresult> */
private int
zdtruncate(os_ptr op)
{	dbegin_unary();
	return double_result(op, 1, (num < 0 ? ceil(num) : floor(num)));
}

/* ------ Transcendental functions ------ */

private int near
darc(os_ptr op, double (*afunc)(P1(double)))
{	dbegin_unary();
	return double_result(op, 1, (*afunc)(num) * radians_to_degrees);
}
/* <dnum> <dresult> .darccos <dresult> */
private int
zdarccos(os_ptr op)
{	return darc(op, acos);
}
/* <dnum> <dresult> .darcsin <dresult> */
private int
zdarcsin(os_ptr op)
{	return darc(op, asin);
}

/* <dnum> <ddenom> <dresult> .datan <dresult> */
private int
zdatan(register os_ptr op)
{	double result;
	dbegin_binary();
	if ( num[0] == 0 )		/* on X-axis, special case */
	   {	if ( num[1] == 0 )
		  return_error(e_undefinedresult);
		result = (num[1] < 0 ? 180 : 0);
	   }
	else
	   {	result = atan2(num[0], num[1]) * radians_to_degrees;
		if ( result < 0 )
		  result += 360;
	   }
	return double_result(op, 2, result);
}

/* <dnum> <dresult> .dcos <dresult> */
private int
zdcos(os_ptr op)
{	return double_unary(op, gs_cos_degrees);
}

/* <dbase> <dexponent> <dresult> .dexp <dresult> */
private int
zdexp(os_ptr op)
{	double ipart;
	dbegin_binary();
	if ( num[0] == 0.0 && num[1] == 0.0 )
	  return_error(e_undefinedresult);
	if ( num[0] < 0.0 && modf(num[1], &ipart) != 0.0 )
	  return_error(e_undefinedresult);
	return double_result(op, 2, pow(num[0], num[1]));
}

private int near
dlog(os_ptr op, double (*lfunc)(P1(double)))
{	dbegin_unary();
	if ( num <= 0.0 )
	  return_error(e_rangecheck);
	return double_result(op, 1, (*lfunc)(num));
}
/* <dposnum> <dresult> .dln <dresult> */
private int
zdln(os_ptr op)
{	return dlog(op, log);
}
/* <dposnum> <dresult> .dlog <dresult> */
private int
zdlog(os_ptr op)
{	return dlog(op, log10);
}

/* <dnum> <dresult> .dsin <dresult> */
private int
zdsin(os_ptr op)
{	return double_unary(op, gs_sin_degrees);
}

/* ------ Comparison ------ */

private int near
dcompare(os_ptr op, int mask)
{	double num[2];
	int code = double_params(op, 2, num);
	if ( code < 0 )
	  return code;
	make_bool(op - 1,
		  (mask & (num[0] < num[1] ? 1 : num[0] > num[1] ? 4 : 2))
		   != 0);
	pop(1);
	return 0;
}
/* <dnum1> <dnum2> .deq <bool> */
private int
zdeq(os_ptr op)
{	return dcompare(op, 2);
}
/* <dnum1> <dnum2> .dge <bool> */
private int
zdge(os_ptr op)
{	return dcompare(op, 6);
}
/* <dnum1> <dnum2> .dgt <bool> */
private int
zdgt(os_ptr op)
{	return dcompare(op, 4);
}
/* <dnum1> <dnum2> .dle <bool> */
private int
zdle(os_ptr op)
{	return dcompare(op, 3);
}
/* <dnum1> <dnum2> .dlt <bool> */
private int
zdlt(os_ptr op)
{	return dcompare(op, 1);
}
/* <dnum1> <dnum2> .dne <bool> */
private int
zdne(os_ptr op)
{	return dcompare(op, 5);
}

/* ------ Conversion ------ */

/* Take the easy way out.... */
#define max_chars 50

/* <dnum> <dresult> .cvd <dresult> */
private int
zcvd(os_ptr op)
{	dbegin_unary();
	return double_result(op, 1, num);
}

/* <string> <dresult> .cvsd <dresult> */
private int
zcvsd(os_ptr op)
{	int code = double_params_result(op, 0, NULL);
	double num;
	char buf[max_chars + 2];
	char *str = buf;
	uint len;
	char end;

	if ( code < 0 )
	  return code;
	check_read_type(op[-1], t_string);
	len = r_size(op - 1);
	if ( len > max_chars )
	  return_error(e_limitcheck);
	memcpy(str, op[-1].value.bytes, len);
	/*
	 * We check syntax in the following way: we remove whitespace,
	 * verify that the string contains only [0123456789+-.dDeE],
	 * then append a $ and then check that the next character after
	 * the scanned number is a $.
	 */
	while ( len > 0 && isspace(*str) )
	  ++str, --len;
	while ( len > 0 && isspace(str[len - 1]) )
	  --len;
	str[len] = 0;
	if ( strspn(str, "0123456789+-.dDeE") != len )
	  return_error(e_syntaxerror);
	strcat(str, "$");
	if ( sscanf(str, "%lg%c", &num, &end) != 2 || end != '$' )
	  return_error(e_syntaxerror);
	return double_result(op, 1, num);
}

/* <dnum> .dcvi <int> */
private int
zdcvi(os_ptr op)
{
#define alt_min_long (-1L << (arch_sizeof_long * 8 - 1))
#define alt_max_long (~(alt_min_long))
	static const double min_int_real = (alt_min_long * 1.0 - 1);
	static const double max_int_real = (alt_max_long * 1.0 + 1);
	double num;
	int code = double_params(op, 1, &num);
	if ( code < 0 )
	  return code;

	if ( num < min_int_real || num > max_int_real )
	  return_error(e_rangecheck);
	make_int(op, (long)num);	/* truncates toward 0 */
	return 0;
}

/* <dnum> .dcvr <real> */
private int
zdcvr(os_ptr op)
{
#define b30 (0x40000000L * 1.0)
#define max_mag (0xffffff * b30 * b30 * b30 * 0x4000)
	static const float min_real = -max_mag;
	static const float max_real = max_mag;
#undef b30
#undef max_mag
	double num;
	int code = double_params(op, 1, &num);
	if ( code < 0 )
	  return code;
	if ( num < min_real || num > max_real )
	  return_error(e_rangecheck);
	make_real(op, (float)num);
	return 0;
}

/* <dnum> <string> .dcvs <substring> */
private int
zdcvs(os_ptr op)
{	double num;
	int code = double_params(op - 1, 1, &num);
	char str[max_chars + 1];
	int len;

	if ( code < 0 )
	  return code;
	check_write_type(*op, t_string);
	/*
	 * To get fully accurate output results for IEEE double-
	 * precision floats (53 bits of mantissa), the ANSI
	 * %g default of 6 digits is not enough; 16 are needed.
	 * Unfortunately, using %.16g produces unfortunate artifacts such as
	 * 1.2 printing as 1.200000000000005.  Therefore, we print using %g,
	 * and if the result isn't accurate enough, print again
	 * using %.16g.
	 */
	   {	double scanned;
		sprintf(str, "%g", num);
		sscanf(str, "%lg", &scanned);
		if ( scanned != num )
		  sprintf(str, "%.16g", num);
	   }
	len = strlen(str);
	if ( len > r_size(op) )
	  return_error(e_rangecheck);
	memcpy(op->value.bytes, str, len);
	op[-1] = *op;
	r_set_size(op - 1, len);
	pop(1);
	return 0;
}

/* ------ Initialization table ------ */

BEGIN_OP_DEFS(zdouble_op_defs) {
		/* Arithmetic */
	{"3.dadd", zdadd},
	{"3.ddiv", zddiv},
	{"3.dmul", zdmul},
	{"3.dsub", zdsub},
		/* Simple functions */
	{"2.dabs", zdabs},
	{"2.dceiling", zdceiling},
	{"2.dfloor", zdfloor},
	{"2.dneg", zdneg},
	{"2.dround", zdround},
	{"2.dsqrt", zdsqrt},
	{"2.dtruncate", zdtruncate},
		/* Transcendental functions */
	{"2.darccos", zdarccos},
	{"2.darcsin", zdarcsin},
	{"3.datan", zdatan},
	{"2.dcos", zdcos},
	{"3.dexp", zdexp},
	{"2.dln", zdln},
	{"2.dlog", zdlog},
	{"2.dsin", zdsin},
		/* Comparison */
	{"2.deq", zdeq},
	{"2.dge", zdge},
	{"2.dgt", zdgt},
	{"2.dle", zdle},
	{"2.dlt", zdlt},
	{"2.dne", zdne},
		/* Conversion */
	{"2.cvd", zcvd},
	{"2.cvsd", zcvsd},
	{"1.dcvi", zdcvi},
	{"1.dcvr", zdcvr},
	{"2.dcvs", zdcvs},
END_OP_DEFS(0) }

/* ------ Internal procedures ------ */

/* Get some double arguments. */
private int near
double_params(os_ptr op, int count, double *pval)
{	pval += count;
	while ( --count >= 0 )
	   {	switch ( r_type(op) )
		   {
		case t_real:
			*--pval = op->value.realval;
			break;
		case t_integer:
			*--pval = op->value.intval;
			break;
		case t_string:
			if ( !r_has_attr(op, a_read) ||
			     r_size(op) != sizeof(double)
			   )
			  return_error(e_typecheck);
			--pval;
			memcpy(pval, op->value.bytes, sizeof(double));
			break;
		case t__invalid:
			return_error(e_stackunderflow);
		default:
			return_error(e_typecheck);
		   }
		op--;
	   }
	return 0;
}

/* Get some double arguments, and check for a double result. */
private int near
double_params_result(os_ptr op, int count, double *pval)
{	check_write_type(*op, t_string);
	if ( r_size(op) != sizeof(double) )
	  return_error(e_typecheck);
	return double_params(op - 1, count, pval);
}

/* Return a double result. */
private int near
double_result(os_ptr op, int count, double result)
{	os_ptr op1 = op - count;
	ref_assign_inline(op1, op);
	memcpy(op1->value.bytes, &result, sizeof(double));
	pop(count);
	return 0;
}

/* Apply a unary function to a double operand. */
private int near
double_unary(os_ptr op, double (*func)(P1(double)))
{	dbegin_unary();
	return double_result(op, 1, (*func)(num));
}
