/*-
 * Copyright (c) 2008-2010 David Schultz <das@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: src/tools/regression/lib/msun/test-logarithm.c,v 1.3 2011/10/15 05:28:13 das Exp $
 */

/*
 * Tests for corner cases in log*().
 */

#include <assert.h>
#include <fenv.h>
#include <float.h>
#include <math.h>
#include <stdio.h>

#define ALL_STD_EXCEPT  (FE_DIVBYZERO | FE_INEXACT | FE_INVALID | \
                         FE_OVERFLOW | FE_UNDERFLOW)

#pragma STDC FENV_ACCESS ON

/*
 * Test that a function returns the correct value and sets the
 * exception flags correctly. The exceptmask specifies which
 * exceptions we should check. We need to be lenient for several
 * reasoons, but mainly because on some architectures it's impossible
 * to raise FE_OVERFLOW without raising FE_INEXACT.
 *
 * These are macros instead of functions so that assert provides more
 * meaningful error messages.
 *
 * XXX The volatile here is to avoid gcc's bogus constant folding and work
 *     around the lack of support for the FENV_ACCESS pragma.
 */
#define test(func, x, result, exceptmask, excepts)      do {            \
        volatile long double _d = x;                                    \
        assert(feclearexcept(FE_ALL_EXCEPT) == 0);                      \
        assert(fpequal((func)(_d), (result)));                           \
        assert(((func), fetestexcept(exceptmask) == (excepts)));        \
} while (0)

/* Test all the functions that compute log(x). */
#define testall0(x, result, exceptmask, excepts)        do {            \
        test(log, x, result, exceptmask, excepts);                      \
        test(logf, x, result, exceptmask, excepts);                     \
        test(log2, x, result, exceptmask, excepts);                     \
        test(log2f, x, result, exceptmask, excepts);                    \
        test(log10, x, result, exceptmask, excepts);                    \
        test(log10f, x, result, exceptmask, excepts);                   \
} while (0)

/* Test all the functions that compute log(1+x). */
#define testall1(x, result, exceptmask, excepts)        do {            \
        test(log1p, x, result, exceptmask, excepts);                    \
        test(log1pf, x, result, exceptmask, excepts);                   \
} while (0)

/*
 * Determine whether x and y are equal, with two special rules:
 *      +0.0 != -0.0
 *       NaN == NaN
 */
int
fpequal(long double x, long double y)
{
        return ((x == y && !signbit(x) == !signbit(y)) || isnan(x) && isnan(y));
}

void
run_generic_tests(void)
{

        /* log(1) == 0, no exceptions raised */
        testall0(1.0, 0.0, ALL_STD_EXCEPT, 0);
        testall1(0.0, 0.0, ALL_STD_EXCEPT, 0);
        testall1(-0.0, -0.0, ALL_STD_EXCEPT, 0);

        /* log(NaN) == NaN, no exceptions raised */
        testall0(NAN, NAN, ALL_STD_EXCEPT, 0);
        testall1(NAN, NAN, ALL_STD_EXCEPT, 0);

        /* log(Inf) == Inf, no exceptions raised */
        testall0(INFINITY, INFINITY, ALL_STD_EXCEPT, 0);
        testall1(INFINITY, INFINITY, ALL_STD_EXCEPT, 0);

        /* log(x) == NaN for x < 0, invalid exception raised */
        testall0(-INFINITY, NAN, ALL_STD_EXCEPT, FE_INVALID);
        testall1(-INFINITY, NAN, ALL_STD_EXCEPT, FE_INVALID);
        testall0(-1.0, NAN, ALL_STD_EXCEPT, FE_INVALID);
        testall1(-1.5, NAN, ALL_STD_EXCEPT, FE_INVALID);

        /* log(0) == -Inf, divide-by-zero exception */
        testall0(0.0, -INFINITY, ALL_STD_EXCEPT & ~FE_INEXACT, FE_DIVBYZERO);
        testall0(-0.0, -INFINITY, ALL_STD_EXCEPT & ~FE_INEXACT, FE_DIVBYZERO);
        testall1(-1.0, -INFINITY, ALL_STD_EXCEPT & ~FE_INEXACT, FE_DIVBYZERO);
}

void
run_log2_tests(void)
{
        int i;

        /*
         * We should insist that log2() return exactly the correct
         * result and not raise an inexact exception for powers of 2.
         */
        feclearexcept(FE_ALL_EXCEPT);
        for (i = FLT_MIN_EXP - FLT_MANT_DIG; i < FLT_MAX_EXP; i++) {
                assert(log2f(ldexpf(1.0, i)) == i);
                assert(fetestexcept(ALL_STD_EXCEPT) == 0);
        }
        for (i = DBL_MIN_EXP - DBL_MANT_DIG; i < DBL_MAX_EXP; i++) {
                assert(log2(ldexp(1.0, i)) == i);
                assert(fetestexcept(ALL_STD_EXCEPT) == 0);
        }
}

void
run_roundingmode_tests(void)
{

        /*
         * Corner cases in other rounding modes.
         */
        fesetround(FE_DOWNWARD);
        /* These are still positive per IEEE 754R */
        testall0(1.0, 0.0, ALL_STD_EXCEPT, 0);
        testall1(0.0, 0.0, ALL_STD_EXCEPT, 0);
        fesetround(FE_TOWARDZERO);
        testall0(1.0, 0.0, ALL_STD_EXCEPT, 0);
        testall1(0.0, 0.0, ALL_STD_EXCEPT, 0);

        fesetround(FE_UPWARD);
        testall0(1.0, 0.0, ALL_STD_EXCEPT, 0);
        testall1(0.0, 0.0, ALL_STD_EXCEPT, 0);
        /* log1p(-0.0) == -0.0 even when rounding upwards */
        testall1(-0.0, -0.0, ALL_STD_EXCEPT, 0);

        fesetround(FE_TONEAREST);
}

int
main(int argc, char *argv[])
{

        printf("1..3\n");

        run_generic_tests();
        printf("ok 1 - logarithm\n");

        run_log2_tests();
        printf("ok 2 - logarithm\n");

        run_roundingmode_tests();
        printf("ok 3 - logarithm\n");

        return (0);
}