/* absolute value
 *
 * Copyright: 1990, N. Dessipris, based on im_powtra()
 * Author: Nicos Dessipris
 * Written on: 02/05/1990
 * Modified on:
 * 5/5/93 J.Cupitt
 *	- adapted from im_lintra to work with partial images
 *	- complex and signed support added
 * 30/6/93 JC
 *	- adapted for partial v2
 *	- ANSI conversion
 *	- spe29873r6k3h()**!@lling errors removed
 * 9/2/95 JC
 *	- adapted for im_wrap...
 * 20/6/02 JC
 *	- tiny speed up
 * 8/12/06
 * 	- add liboil support
 * 28/8/09
 * 	- gtkdoc
 * 	- tiny polish
 * 31/7/10
 * 	- remove liboil
 * 6/11/11
 * 	- redone as a class
 * 3/12/13
 * 	- add orc, though the speed improvement vs. gcc's auto-vectorizer
 * 	  seems very marginal
 * 21/2/19
 * 	- move orc init to first use of abs
 */

/*

	Copyright (C) 1991-2005 The National Gallery

	This library is free software; you can redistribute it and/or
	modify it under the terms of the GNU Lesser General Public
	License as published by the Free Software Foundation; either
	version 2.1 of the License, or (at your option) any later version.

	This library is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
	Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public
	License along with this library; if not, write to the Free Software
	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
	02110-1301  USA

 */

/*

	These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk

 */

/*
#define DEBUG
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <glib/gi18n-lib.h>

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#include <vips/vips.h>

#include "unary.h"

typedef VipsUnary VipsAbs;
typedef VipsUnaryClass VipsAbsClass;

G_DEFINE_TYPE(VipsAbs, vips_abs, VIPS_TYPE_UNARY);

static int
vips_abs_build(VipsObject *object)
{
	VipsUnary *unary = (VipsUnary *) object;

	if (unary->in &&
		vips_band_format_isuint(unary->in->BandFmt))
		return vips_unary_copy(unary);

	if (VIPS_OBJECT_CLASS(vips_abs_parent_class)->build(object))
		return -1;

	return 0;
}

/* Integer abs operation: just test and negate.
 */
#define ABS_INT(TYPE) \
	{ \
		TYPE *restrict p = (TYPE *) in[0]; \
		TYPE *restrict q = (TYPE *) out; \
		int x; \
\
		for (x = 0; x < sz; x++) \
			q[x] = p[x] < 0 ? 0 - p[x] : p[x]; \
	}

/* Float abs operation: call fabs().
 */
#define ABS_FLOAT(TYPE) \
	{ \
		TYPE *restrict p = (TYPE *) in[0]; \
		TYPE *restrict q = (TYPE *) out; \
		int x; \
\
		for (x = 0; x < sz; x++) \
			q[x] = VIPS_FABS(p[x]); \
	}

/* Complex abs operation: calculate modulus.
 */

#ifdef HAVE_HYPOT

#define ABS_COMPLEX(TYPE) \
	{ \
		TYPE *restrict p = (TYPE *) in[0]; \
		TYPE *restrict q = (TYPE *) out; \
		int x; \
\
		for (x = 0; x < sz; x++) { \
			q[x] = hypot(p[0], p[1]); \
			p += 2; \
		} \
	}

#else /*HAVE_HYPOT*/

#define ABS_COMPLEX(TYPE) \
	{ \
		TYPE *restrict p = (TYPE *) in[0]; \
		TYPE *restrict q = (TYPE *) out; \
		int x; \
\
		for (x = 0; x < sz; x++) { \
			double rp = p[0]; \
			double ip = p[1]; \
			double abs_rp = VIPS_FABS(rp); \
			double abs_ip = VIPS_FABS(ip); \
\
			if (abs_rp > abs_ip) { \
				double temp = ip / rp; \
\
				q[x] = abs_rp * sqrt(1.0 + temp * temp); \
			} \
			else { \
				double temp = rp / ip; \
\
				q[x] = abs_ip * sqrt(1.0 + temp * temp); \
			} \
\
			p += 2; \
		} \
	}

#endif /*HAVE_HYPOT*/

static void
vips_abs_buffer(VipsArithmetic *arithmetic,
	VipsPel *out, VipsPel **in, int width)
{
	VipsImage *im = arithmetic->ready[0];
	const int bands = vips_image_get_bands(im);
	int sz = width * bands;

	switch (vips_image_get_format(im)) {
	case VIPS_FORMAT_CHAR:
		ABS_INT(signed char);
		break;
	case VIPS_FORMAT_SHORT:
		ABS_INT(signed short);
		break;
	case VIPS_FORMAT_INT:
		ABS_INT(signed int);
		break;
	case VIPS_FORMAT_FLOAT:
		ABS_FLOAT(float);
		break;
	case VIPS_FORMAT_DOUBLE:
		ABS_FLOAT(double);
		break;
	case VIPS_FORMAT_COMPLEX:
		ABS_COMPLEX(float);
		break;
	case VIPS_FORMAT_DPCOMPLEX:
		ABS_COMPLEX(double);
		break;

	default:
		g_assert_not_reached();
	}
}

/* Save a bit of typing.
 */
#define UC VIPS_FORMAT_UCHAR
#define C VIPS_FORMAT_CHAR
#define US VIPS_FORMAT_USHORT
#define S VIPS_FORMAT_SHORT
#define UI VIPS_FORMAT_UINT
#define I VIPS_FORMAT_INT
#define F VIPS_FORMAT_FLOAT
#define X VIPS_FORMAT_COMPLEX
#define D VIPS_FORMAT_DOUBLE
#define DX VIPS_FORMAT_DPCOMPLEX

/* Format doesn't change with abs, other than complex -> real.
 */
static const VipsBandFormat vips_abs_format_table[10] = {
	/* Band format:  UC  C  US  S  UI  I  F  X  D  DX */
	/* Promotion: */ UC, C, US, S, UI, I, F, F, D, D
};

static void
vips_abs_class_init(VipsAbsClass *class)
{
	VipsObjectClass *object_class = (VipsObjectClass *) class;
	VipsArithmeticClass *aclass = VIPS_ARITHMETIC_CLASS(class);

	object_class->nickname = "abs";
	object_class->description = _("absolute value of an image");
	object_class->build = vips_abs_build;

	aclass->process_line = vips_abs_buffer;

	vips_arithmetic_set_format_table(aclass, vips_abs_format_table);
}

static void
vips_abs_init(VipsAbs *abs)
{
}

/**
 * vips_abs: (method)
 * @in: input #VipsImage
 * @out: (out): output #VipsImage
 * @...: %NULL-terminated list of optional named arguments
 *
 * This operation finds the absolute value of an image. It does a copy for
 * unsigned integer types, negate for negative values in
 * signed integer types, <function>fabs(3)</function> for
 * float types, and calculates modulus for complex
 * types.
 *
 * See also: vips_sign().
 *
 * Returns: 0 on success, -1 on error
 */
int
vips_abs(VipsImage *in, VipsImage **out, ...)
{
	va_list ap;
	int result;

	va_start(ap, out);
	result = vips_call_split("abs", ap, in, out);
	va_end(ap);

	return result;
}
