#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <limits.h>
#include <math.h>
#include <wchar.h>
#include <locale.h>
#include <langinfo.h>

#define TEST(r, f, x, m) ( \
((r) = (f)) == (x) || \
(printf(__FILE__ ":%d: %s failed (" m ")\n", __LINE__, #f, r, x), err++, 0) )

#define TEST_S(s, x, m) ( \
!wcscmp((s),(x)) || \
(printf(__FILE__ ":%d: [%ls] != [%ls] (%s)\n", __LINE__, s, x, m), err++, 0) )

static const struct {
	const wchar_t *fmt;
	int i;
	const wchar_t *expect;
} int_tests[] = {
	/* width, precision, alignment */
	{ L"%04d", 12, L"0012" },
	{ L"%.3d", 12, L"012" },
	{ L"%3d", 12, L" 12" },
	{ L"%-3d", 12, L"12 " },
	{ L"%+3d", 12, L"+12" },
	{ L"%+-5d", 12, L"+12  " },
	{ L"%+- 5d", 12, L"+12  " },
	{ L"%- 5d", 12, L" 12  " },
	{ L"% d", 12, L" 12" },
	{ L"%0-5d", 12, L"12   " },
	{ L"%-05d", 12, L"12   " },

	/* ...explicit precision of 0 shall be no characters. */
	{ L"%.0d", 0, L"" },
	{ L"%.0o", 0, L"" },
	{ L"%#.0d", 0, L"" },
	{ L"%#.0o", 0, L"" },
	{ L"%#.0x", 0, L"" },

	/* hex: test alt form and case */
	{ L"%x", 63, L"3f" },
	{ L"%#x", 63, L"0x3f" },
	{ L"%X", 63, L"3F" },

	/* octal: test alt form */
	{ L"%o", 15, L"17" },
	{ L"%#o", 15, L"017" },

	{ NULL, 0.0, NULL }
};

static const struct {
	const wchar_t *fmt;
	double f;
	const wchar_t *expect;
} fp_tests[] = {
	/* basic form, handling of exponent/precision for 0 */
	{ L"%e", 0.0, L"0.000000e+00" },
	{ L"%f", 0.0, L"0.000000" },
	{ L"%g", 0.0, L"0" },
	{ L"%#g", 0.0, L"0.00000" },

	/* rounding */
	{ L"%f", 1.1, L"1.100000" },
	{ L"%f", 1.2, L"1.200000" },
	{ L"%f", 1.3, L"1.300000" },
	{ L"%f", 1.4, L"1.400000" },
	{ L"%f", 1.5, L"1.500000" },
	
	/* correctness in DBL_DIG places */
	{ L"%.15g", 1.23456789012345, L"1.23456789012345" },

	/* correct choice of notation for %g */
	{ L"%g", 0.0001, L"0.0001" },
	{ L"%g", 0.00001, L"1e-05" },
	{ L"%g", 123456, L"123456" },
	{ L"%g", 1234567, L"1.23457e+06" },
	{ L"%.7g", 1234567, L"1234567" },
	{ L"%.7g", 12345678, L"1.234568e+07" },

	/* pi in double precision, printed to a few extra places */
	{ L"%.15f", M_PI, L"3.141592653589793" },
	{ L"%.18f", M_PI, L"3.141592653589793116" },

	/* exact conversion of large integers */
	{ L"%.0f", 340282366920938463463374607431768211456.0,
	         L"340282366920938463463374607431768211456" },

	{ NULL, 0.0, NULL }
};

int test_swprintf(void)
{
	int i, j;
	int err=0;
	wchar_t b[500], *s;

	setlocale(LC_CTYPE, "en_US.UTF-8") ||
	setlocale(LC_CTYPE, "en_GB.UTF-8") ||
	setlocale(LC_CTYPE, "en.UTF-8") ||
	setlocale(LC_CTYPE, "POSIX.UTF-8") ||
	setlocale(LC_CTYPE, "C.UTF-8") ||
	setlocale(LC_CTYPE, "UTF-8") ||
	setlocale(LC_CTYPE, "");

	TEST(i, strcmp(nl_langinfo(CODESET), "UTF-8"), 0, "no UTF-8 locale; tests might fail");

	TEST(i, swprintf(0, 0, L"%d", 123456)<0, 1, "%d != %d");

	TEST(i, swprintf(b, 2, L"%lc", 0xc0), 1, "%d != %d");
	TEST(i, b[0], 0xc0, "wrong character %x != %x");
	TEST(i, swprintf(b, 2, L"%lc", 0x20ac), 1, "%d != %d");
	TEST(i, b[0], 0x20ac, "wrong character %x != %x");
	TEST(i, swprintf(b, 3, L"%s", "\xc3\x80!"), 2, "%d != %d");
	TEST(i, b[0], 0xc0, "wrong character %x != %x");
	TEST(i, swprintf(b, 2, L"%.1s", "\xc3\x80!"), 1, "%d != %d");
	TEST(i, b[0], 0xc0, "wrong character %x != %x");

	wcscpy(b, L"xxxxxxxx");
	TEST(i, swprintf(b, 4, L"%d", 123456)<0, 1, "%d != %d");
	TEST_S(b, L"123", "incorrect output");
	TEST(i, b[5], 'x', "buffer overrun");

	for (j=0; int_tests[j].fmt; j++) {
		TEST(i, swprintf(b, sizeof b/sizeof *b, int_tests[j].fmt, int_tests[j].i), wcslen(b), "%d != %d");
		TEST_S(b, int_tests[j].expect, "bad integer conversion");
	}

	for (j=0; fp_tests[j].fmt; j++) {
		TEST(i, swprintf(b, sizeof b/sizeof *b, fp_tests[j].fmt, fp_tests[j].f), wcslen(b), "%d != %d");
		TEST_S(b, fp_tests[j].expect, "bad floating point conversion");
	}

	return err;
}