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cosmopolitan/test/libc/stdio/snprintf_test.c
Gabriel Ravier 4d05060aac
Partially fix printf hex float numbers/%a rounding (#1286) 
Hexadecimal printing of floating-point numbers in cosmopolitan (that is,
using the the conversion specifier) is improved to have correct rounding
of results in rounding modes other than the default one (ie. FE_NEAREST)

This commit fixes that, and adds tests for the change (note that there's
still some rounding issues with the a conversion specifier in general in
relatively rare cases (that is without non-default rounding modes) where
I've left commented-out tests for anyone interested in improving it more
2024-09-10 20:42:52 -07:00

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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2023 Gabriel Ravier │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/runtime/fenv.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/testlib/testlib.h"
TEST(snprintf, testVeryLargePrecision) {
char buf[512] = {};
int i = snprintf(buf, sizeof(buf), "%.9999u", 10);
ASSERT_EQ(9999, i);
ASSERT_EQ(511, strlen(buf));
}
TEST(snprintf, testPlusFlagOnChar) {
char buf[10] = {};
int i = snprintf(buf, sizeof(buf), "%+c", '=');
ASSERT_EQ(1, i);
ASSERT_STREQ("=", buf);
}
TEST(snprintf, testInf) {
char buf[10] = {};
int i = snprintf(buf, sizeof(buf), "%f", 1.0 / 0.0);
ASSERT_EQ(3, i);
ASSERT_STREQ("inf", buf);
memset(buf, '\0', 4);
i = snprintf(buf, sizeof(buf), "%Lf", 1.0L / 0.0L);
ASSERT_EQ(3, i);
ASSERT_STREQ("inf", buf);
memset(buf, '\0', 4);
i = snprintf(buf, sizeof(buf), "%e", 1.0 / 0.0);
ASSERT_EQ(3, i);
ASSERT_STREQ("inf", buf);
memset(buf, '\0', 4);
i = snprintf(buf, sizeof(buf), "%Le", 1.0L / 0.0L);
ASSERT_EQ(3, i);
ASSERT_STREQ("inf", buf);
memset(buf, '\0', 4);
i = snprintf(buf, sizeof(buf), "%g", 1.0 / 0.0);
ASSERT_EQ(3, i);
ASSERT_STREQ("inf", buf);
memset(buf, '\0', 4);
i = snprintf(buf, sizeof(buf), "%Lg", 1.0L / 0.0L);
ASSERT_EQ(3, i);
ASSERT_STREQ("inf", buf);
for (i = 4; i < 10; ++i)
ASSERT_EQ('\0', buf[i]);
}
TEST(snprintf, testUppercaseCConversionSpecifier) {
char buf[10] = {};
int i = snprintf(buf, sizeof(buf), "%C", L'a');
ASSERT_EQ(1, i);
ASSERT_STREQ("a", buf);
i = snprintf(buf, sizeof(buf), "%C", L'☺');
ASSERT_EQ(3, i);
ASSERT_STREQ("☺", buf);
}
// Make sure we don't va_arg the wrong argument size on wide character
// conversion specifiers
TEST(snprintf,
testWideCConversionSpecifierWithLotsOfArgumentsBeforeAndOneAfter) {
char buf[20] = {};
int i = snprintf(buf, sizeof(buf), "%d%d%d%d%d%d%d%d%lc%d", 0, 0, 0, 0, 0, 0,
0, 0, L'x', 1);
ASSERT_EQ(10, i);
ASSERT_STREQ("00000000x1", buf);
memset(buf, 0, sizeof(buf));
i = snprintf(buf, sizeof(buf), "%d%d%d%d%d%d%d%d%C%d", 0, 0, 0, 0, 0, 0, 0, 0,
L'x', 1);
ASSERT_EQ(10, i);
ASSERT_STREQ("00000000x1", buf);
}
static void check_n_buffer_contents(char buf[350]) {
for (int i = 0; i < 284; ++i)
ASSERT_EQ(' ', buf[i]);
ASSERT_STREQ("428463", &buf[284]);
for (int i = 290; i < 350; ++i)
ASSERT_EQ('\0', buf[i]);
}
TEST(snprintf, testNConversionSpecifier) {
char buf[350] = {};
int n_res_int = -1;
int i = snprintf(buf, sizeof(buf), "%286d%d%n%d", 42, 84, &n_res_int, 63);
ASSERT_EQ(290, i);
check_n_buffer_contents(buf);
ASSERT_EQ(288, n_res_int);
memset(&buf, '\0', sizeof(buf));
long n_res_long = -1;
i = snprintf(buf, sizeof(buf), "%286ld%ld%ln%ld", 42L, 84L, &n_res_long, 63L);
ASSERT_EQ(290, i);
check_n_buffer_contents(buf);
ASSERT_EQ(288, n_res_long);
memset(&buf, '\0', sizeof(buf));
long long n_res_long_long = -1;
i = snprintf(buf, sizeof(buf), "%286lld%lld%lln%lld", 42LL, 84LL,
&n_res_long_long, 63LL);
ASSERT_EQ(290, i);
check_n_buffer_contents(buf);
ASSERT_EQ(288, n_res_long_long);
ASSERT_EQ(sizeof(short), 2);
ASSERT_EQ(sizeof(int), 4);
memset(&buf, '\0', sizeof(buf));
short n_res_short = -1;
i = snprintf(buf, sizeof(buf), "%286hd%hd%hn%hd", (42 | 0xFFFF0000),
(84 | 0xFFFF0000), &n_res_short, (63 | 0xFFFF0000));
ASSERT_EQ(290, i);
check_n_buffer_contents(buf);
ASSERT_EQ(288, n_res_short);
ASSERT_EQ(sizeof(unsigned char), 1);
memset(&buf, '\0', sizeof(buf));
signed char n_res_char = -1;
i = snprintf(buf, sizeof(buf), "%286hhd%hhd%hhn%hhd", (42 | 0xFFFFFF00),
(84 | 0xFFFFFF00), &n_res_char, (63 | 0xFFFFFF00));
ASSERT_EQ(290, i);
check_n_buffer_contents(buf);
ASSERT_EQ((signed char)288, n_res_char);
memset(&buf, '\0', sizeof(buf));
ssize_t n_res_size_t = -1;
i = snprintf(buf, sizeof(buf), "%286zd%zd%zn%zd", (ssize_t)42, (ssize_t)84,
&n_res_size_t, (ssize_t)63);
ASSERT_EQ(290, i);
check_n_buffer_contents(buf);
ASSERT_EQ(288, n_res_size_t);
memset(&buf, '\0', sizeof(buf));
intmax_t n_res_intmax_t = -1;
i = snprintf(buf, sizeof(buf), "%286jd%jd%jn%jd", (intmax_t)42, (intmax_t)84,
&n_res_intmax_t, (intmax_t)63);
ASSERT_EQ(290, i);
check_n_buffer_contents(buf);
ASSERT_EQ(288, n_res_intmax_t);
memset(&buf, '\0', sizeof(buf));
int128_t n_res_int128_t = -1;
i = snprintf(buf, sizeof(buf), "%286jjd%jjd%jjn%jjd", (int128_t)42,
(int128_t)84, &n_res_int128_t, (int128_t)63);
ASSERT_EQ(290, i);
check_n_buffer_contents(buf);
ASSERT_EQ(288, n_res_int128_t);
memset(&buf, '\0', sizeof(buf));
ptrdiff_t n_res_ptrdiff_t = -1;
i = snprintf(buf, sizeof(buf), "%286td%td%tn%td", (ptrdiff_t)42,
(ptrdiff_t)84, &n_res_ptrdiff_t, (ptrdiff_t)63);
ASSERT_EQ(290, i);
check_n_buffer_contents(buf);
ASSERT_EQ(288, n_res_ptrdiff_t);
}
TEST(snprintf, testLongDoubleEConversionSpecifier) {
char buf[20] = {};
int i = snprintf(buf, sizeof(buf), "%Le", 1234567.8L);
ASSERT_EQ(12, i);
ASSERT_STREQ("1.234568e+06", buf);
}
TEST(snprintf, testLongDoubleRounding) {
int previous_rounding = fegetround();
ASSERT_EQ(0, fesetround(FE_DOWNWARD));
char buf[20];
int i = snprintf(buf, sizeof(buf), "%.3Lf", 4.4375L);
ASSERT_EQ(5, i);
ASSERT_STREQ("4.437", buf);
i = snprintf(buf, sizeof(buf), "%.3Lf", -4.4375L);
ASSERT_EQ(6, i);
ASSERT_STREQ("-4.438", buf);
ASSERT_EQ(0, fesetround(FE_TOWARDZERO));
i = snprintf(buf, sizeof(buf), "%.3Lf", -4.4375L);
ASSERT_EQ(6, i);
ASSERT_STREQ("-4.437", buf);
ASSERT_EQ(0, fesetround(previous_rounding));
}
TEST(snprintf, testAConversionSpecifierRounding) {
int previous_rounding = fegetround();
ASSERT_EQ(0, fesetround(FE_DOWNWARD));
char buf[20];
int i = snprintf(buf, sizeof(buf), "%.1a", 0x1.fffffp+4);
ASSERT_EQ(8, i);
ASSERT_STREQ("0x1.fp+4", buf);
ASSERT_EQ(0, fesetround(FE_UPWARD));
i = snprintf(buf, sizeof(buf), "%.1a", 0x1.f8p+4);
ASSERT_EQ(8, i);
ASSERT_STREQ("0x2.0p+4", buf);
ASSERT_EQ(0, fesetround(previous_rounding));
}
// This test currently fails because of rounding issues
// If that ever gets fixed, uncomment this
/*
TEST(snprintf, testAConversionSpecifier) {
char buf[20];
int i = snprintf(buf, sizeof(buf), "%.1a", 0x1.7800000000001p+4);
ASSERT_EQ(8, i);
ASSERT_STREQ("0x1.8p+4", buf);
memset(buf, 0, sizeof(buf));
i = snprintf(buf, sizeof(buf), "%.1a", 0x1.78p+4);
ASSERT_EQ(8, i);
ASSERT_STREQ("0x1.8p+4", buf);
}
*/
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