/*
 *  M_APM  -  mapm_sin.c
 *
 *  Copyright (C) 1999 - 2007   Michael C. Ring
 *
 *  Permission to use, copy, and distribute this software and its
 *  documentation for any purpose with or without fee is hereby granted,
 *  provided that the above copyright notice appear in all copies and
 *  that both that copyright notice and this permission notice appear
 *  in supporting documentation.
 *
 *  Permission to modify the software is granted. Permission to distribute
 *  the modified code is granted. Modifications are to be distributed by
 *  using the file 'license.txt' as a template to modify the file header.
 *  'license.txt' is available in the official MAPM distribution.
 *
 *  This software is provided "as is" without express or implied warranty.
 */

/*
 *
 *      This file contains the top level (user callable) SIN / COS / TAN
 *	functions.
 *
 */

#include "pgAdmin3.h"
#include "pgscript/utilities/mapm-lib/m_apm_lc.h"

/****************************************************************************/
void	m_apm_sin(M_APM r, int places, M_APM a)
{
	M_APM	tmp3;

	tmp3 = M_get_stack_var();
	M_limit_angle_to_pi(tmp3, (places + 6), a);
	M_5x_sin(r, places, tmp3);
	M_restore_stack(1);
}
/****************************************************************************/
void	m_apm_cos(M_APM r, int places, M_APM a)
{
	M_APM	tmp3;

	tmp3 = M_get_stack_var();
	M_limit_angle_to_pi(tmp3, (places + 6), a);
	M_4x_cos(r, places, tmp3);
	M_restore_stack(1);
}
/****************************************************************************/
void	m_apm_sin_cos(M_APM sinv, M_APM cosv, int places, M_APM aa)
{
	M_APM	tmp5, tmp6, tmp7;

	tmp5 = M_get_stack_var();
	tmp6 = M_get_stack_var();
	tmp7 = M_get_stack_var();

	M_limit_angle_to_pi(tmp5, (places + 6), aa);
	M_4x_cos(tmp7, (places + 6), tmp5);

	/*
	 *   compute sin(x) = sqrt(1 - cos(x) ^ 2).
	 *
	 *   note that the sign of 'sin' will always be positive after the
	 *   sqrt call. we need to adjust the sign based on what quadrant
	 *   the original angle is in.
	 */

	M_cos_to_sin(tmp6, (places + 6), tmp7);
	if (tmp6->m_apm_sign != 0)
		tmp6->m_apm_sign = tmp5->m_apm_sign;

	m_apm_round(sinv, places, tmp6);
	m_apm_round(cosv, places, tmp7);
	M_restore_stack(3);
}
/****************************************************************************/
void	m_apm_tan(M_APM r, int places, M_APM a)
{
	M_APM	tmps, tmpc, tmp0;

	tmps = M_get_stack_var();
	tmpc = M_get_stack_var();
	tmp0 = M_get_stack_var();

	m_apm_sin_cos(tmps, tmpc, (places + 4), a);

	/* tan(x) = sin(x) / cos(x) */

	m_apm_divide(tmp0, (places + 4), tmps, tmpc);
	m_apm_round(r, places, tmp0);
	M_restore_stack(3);
}
/****************************************************************************/
void	M_limit_angle_to_pi(M_APM rr, int places, M_APM aa)
{
	M_APM	tmp7, tmp8, tmp9;

	M_check_PI_places(places);

	tmp9 = M_get_stack_var();
	m_apm_copy(tmp9, MM_lc_PI);

	if (m_apm_compare(aa, tmp9) == 1)       /*  > PI  */
	{
		tmp7 = M_get_stack_var();
		tmp8 = M_get_stack_var();

		m_apm_add(tmp7, aa, tmp9);
		m_apm_integer_divide(tmp9, tmp7, MM_lc_2_PI);
		m_apm_multiply(tmp8, tmp9, MM_lc_2_PI);
		m_apm_subtract(tmp9, aa, tmp8);
		m_apm_round(rr, places, tmp9);

		M_restore_stack(3);
		return;
	}

	tmp9->m_apm_sign = -1;
	if (m_apm_compare(aa, tmp9) == -1)       /*  < -PI  */
	{
		tmp7 = M_get_stack_var();
		tmp8 = M_get_stack_var();

		m_apm_add(tmp7, aa, tmp9);
		m_apm_integer_divide(tmp9, tmp7, MM_lc_2_PI);
		m_apm_multiply(tmp8, tmp9, MM_lc_2_PI);
		m_apm_subtract(tmp9, aa, tmp8);
		m_apm_round(rr, places, tmp9);

		M_restore_stack(3);
		return;
	}

	m_apm_copy(rr, aa);
	M_restore_stack(1);
}
/****************************************************************************/