/*-
 * 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.
 */

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

#include <sys/param.h>
#include <fenv.h>
#include <float.h>
#include <math.h>
#include <stdio.h>

#ifdef __i386__
#include <ieeefp.h>
#endif

#include "test-utils.h"

#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;                           \
        ATF_CHECK_EQ(0, feclearexcept(FE_ALL_EXCEPT));                  \
        CHECK_FPEQUAL((func)(_d), (result));                    \
        CHECK_FP_EXCEPTIONS_MSG(excepts, exceptmask, "for %s(%s)",      \
            #func, #x);                                                 \
} while (0)

#define test_tol(func, z, result, tol)                  do {            \
        volatile long double _d = z;                                    \
        debug("  testing %6s(%15La) ~= % .36Le\n", #func, _d, result);  \
        CHECK_FPEQUAL_TOL((func)(_d), (result), (tol), CS_BOTH);        \
} 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(logl, x, result, exceptmask, excepts);                     \
        test(log2, x, result, exceptmask, excepts);                     \
        test(log2f, x, result, exceptmask, excepts);                    \
        test(log2l, x, result, exceptmask, excepts);                    \
        test(log10, x, result, exceptmask, excepts);                    \
        test(log10f, x, result, exceptmask, excepts);                   \
        test(log10l, 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);                   \
        test(log1pl, x, result, exceptmask, excepts);                   \
} while (0)

ATF_TC_WITHOUT_HEAD(generic_tests);
ATF_TC_BODY(generic_tests, tc)
{
#if defined(__aarch64__) || defined(__riscv)
        atf_tc_expect_fail("https://bugs.freebsd.org/290099");
#endif
        /* 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);
}

ATF_TC_WITHOUT_HEAD(log2_tests);
ATF_TC_BODY(log2_tests, tc)
{
        unsigned i;

        /*
         * We should insist that log2() return exactly the correct
         * result and not raise an inexact exception for powers of 2.
         */
        ATF_REQUIRE_EQ(0, feclearexcept(FE_ALL_EXCEPT));
        for (i = FLT_MIN_EXP - FLT_MANT_DIG; i < FLT_MAX_EXP; i++) {
                ATF_CHECK_EQ(i, log2f(ldexpf(1.0, i)));
                CHECK_FP_EXCEPTIONS(0, ALL_STD_EXCEPT);
        }
        for (i = DBL_MIN_EXP - DBL_MANT_DIG; i < DBL_MAX_EXP; i++) {
                ATF_CHECK_EQ(i, log2(ldexp(1.0, i)));
                CHECK_FP_EXCEPTIONS(0, ALL_STD_EXCEPT);
        }
        for (i = LDBL_MIN_EXP - LDBL_MANT_DIG; i < LDBL_MAX_EXP; i++) {
                ATF_CHECK_EQ(i, log2l(ldexpl(1.0, i)));
                CHECK_FP_EXCEPTIONS(0, ALL_STD_EXCEPT);
        }
}

ATF_TC_WITHOUT_HEAD(roundingmode_tests);
ATF_TC_BODY(roundingmode_tests, tc)
{

        /*
         * Corner cases in other rounding modes.
         */
        fesetround(FE_DOWNWARD);
        /* These are still positive per IEEE 754R */
#if 0
        testall0(1.0, 0.0, ALL_STD_EXCEPT, 0);
#else
        /* logl, log2l, and log10l don't pass yet. */
        test(log, 1.0, 0.0, ALL_STD_EXCEPT, 0);
        test(logf, 1.0, 0.0, ALL_STD_EXCEPT, 0);
        test(log2, 1.0, 0.0, ALL_STD_EXCEPT, 0);
        test(log2f, 1.0, 0.0, ALL_STD_EXCEPT, 0);
        test(log10, 1.0, 0.0, ALL_STD_EXCEPT, 0);
        test(log10f, 1.0, 0.0, ALL_STD_EXCEPT, 0);
#endif
        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);
}

ATF_TC_WITHOUT_HEAD(accuracy_tests);
ATF_TC_BODY(accuracy_tests, tc)
{
#if defined(__riscv)
        atf_tc_expect_death("https://bugs.freebsd.org/290099");
#endif
        static const struct {
                float x;
                long double log2x;
                long double logex;
                long double log10x;
        } tests[] = {
                {  0x1p-120 + 0x1p-140,
                  -1.19999998624139449158861798943319717e2L,
                  -8.31776607135195754708796206665656732e1L,
                  -3.61235990655024477716980559136055915e1L,
                },
                {  1.0 - 0x1p-20,
                  -1.37586186296463416424364914705656460e-6L,
                  -9.53674771153890007250243736279163253e-7L,
                  -4.14175690642480911859354110516159131e-7L, },
                {  1.0 + 0x1p-20,
                   1.37586055084113820105668028340371476e-6L,
                   9.53673861659188233908415514963336144e-7L,
                   4.14175295653950611453333571759200697e-7L },
                {  19.75,
                   4.30378074817710292442728634194115348e0L,
                   2.98315349134713087533848129856505779e0L,
                   1.29556709996247903756734359702926363e0L },
                {  19.75 * 0x1p100,
                   1.043037807481771029244272863419411534e2L,
                   72.29787154734166181706169344438271459357255439172762452L,
                   3.139856666636059855894123306947856631e1L },
        };
        unsigned i;

        long double log1p_ldbl_ulp = LDBL_ULP();
#if LDBL_MANT_DIG > 64
        /*
         * On ld128 platforms the log1p() implementation provides less accuracy,
         * but does still match the ld80 precision. Use the ld80 LDBL_ULP()
         * value for now to avoid losing test coverage for the other functions.
         * Reported as https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=253984
         */
        log1p_ldbl_ulp = ldexpl(1.0, 1 - 64);
#endif

        for (i = 0; i < nitems(tests); i++) {
                test_tol(log2, tests[i].x, tests[i].log2x, DBL_ULP());
                test_tol(log2f, tests[i].x, tests[i].log2x, FLT_ULP());
                test_tol(log2l, tests[i].x, tests[i].log2x, LDBL_ULP());
                test_tol(log, tests[i].x, tests[i].logex, DBL_ULP());
                test_tol(logf, tests[i].x, tests[i].logex, FLT_ULP());
                test_tol(logl, tests[i].x, tests[i].logex, LDBL_ULP());
                test_tol(log10, tests[i].x, tests[i].log10x, DBL_ULP());
                test_tol(log10f, tests[i].x, tests[i].log10x, FLT_ULP());
                test_tol(log10l, tests[i].x, tests[i].log10x, LDBL_ULP());
                if (tests[i].x >= 0.5) {
                        test_tol(log1p, tests[i].x - 1, tests[i].logex,
                                 DBL_ULP());
                        test_tol(log1pf, tests[i].x - 1, tests[i].logex,
                                 FLT_ULP());
                        test_tol(log1pl, tests[i].x - 1, tests[i].logex,
                                 log1p_ldbl_ulp);
                }
        }
}

ATF_TC_WITHOUT_HEAD(log1p_accuracy_tests);
ATF_TC_BODY(log1p_accuracy_tests, tc)
{
#if LDBL_MANT_DIG > 64
        if (atf_tc_get_config_var_as_bool_wd(tc, "ci", false))
                atf_tc_expect_fail("https://bugs.freebsd.org/253984");
#endif
#if defined(__riscv)
        atf_tc_expect_death("https://bugs.freebsd.org/290099");
#endif
        test_tol(log1pf, 0x0.333333p0F,
                 1.82321546859847114303367992804596800640e-1L, FLT_ULP());
        test_tol(log1p, 0x0.3333333333333p0,
                 1.82321556793954589204283870982629267635e-1L, DBL_ULP());
        test_tol(log1pl, 0x0.33333333333333332p0L,
                 1.82321556793954626202683007050468762914e-1L, LDBL_ULP());

        test_tol(log1pf, -0x0.333333p0F,
                 -2.23143536413048672940940199918017467652e-1L, FLT_ULP());
        test_tol(log1p, -0x0.3333333333333p0,
                 -2.23143551314209700255143859052009022937e-1L, DBL_ULP());
        test_tol(log1pl, -0x0.33333333333333332p0L,
                 -2.23143551314209755752742563153765697950e-1L, LDBL_ULP());
}

ATF_TP_ADD_TCS(tp)
{

        ATF_TP_ADD_TC(tp, generic_tests);
        ATF_TP_ADD_TC(tp, log2_tests);
        ATF_TP_ADD_TC(tp, roundingmode_tests);
        ATF_TP_ADD_TC(tp, accuracy_tests);
        ATF_TP_ADD_TC(tp, log1p_accuracy_tests);

        return (atf_no_error());
}