1/*
2 * This file and its contents are supplied under the terms of the
3 * Common Development and Distribution License ("CDDL"), version 1.0.
4 * You may only use this file in accordance with the terms of version
5 * 1.0 of the CDDL.
6 *
7 * A full copy of the text of the CDDL should have accompanied this
8 * source.  A copy of the CDDL is also available via the Internet at
9 * http://www.illumos.org/license/CDDL.
10 */
11
12/*
13 * Copyright 2014 PALO, Richard. All rights reserved.
14 * Copyright 2014 OmniTI Computer Consulting, Inc. All rights reserved.
15 */
16
17/*
18 * Test rounding of floating point numbers in libc's *printf() routines.
19 *
20 * C99 must be enabled to get DECIMAL_DIG defined, but it looks like all
21 * of usr/src/test/libc is compiled that way.
22 */
23
24#include <float.h>
25#include <fenv.h>
26#include <stdio.h>
27#include <strings.h>
28#include "test_common.h"
29
30/*
31 * Returns negative if snprintf() fails.  Returns 0 upon
32 * successful execution of the test, return 1 upon a failure.
33 * Spews output if verbose is TRUE.
34 */
35int
36run_one(test_t t, int i, int j, int precision, boolean_t verbose)
37{
38	const int size = 100;
39	char buffer[size], check[size];
40	double val;
41	int status;
42
43	val = (double)(0.0 + j) / i;
44	/* first get max precision for control check */
45	status = snprintf(check, size, "%+-.*f", DECIMAL_DIG, val);
46	if (status < 0) {
47		test_failed(t, "Max precision snprintf() "
48		    "(i = %d, j = %d) returned %d\n", i, j, status);
49		return (status);
50	}
51	/* then get specific precision */
52	status = snprintf(buffer, size, "%+-#.*f", precision, val);
53	if (status < 0) {
54		test_failed(t, "Specific precision snprintf() "
55		    "(i = %d, j = %d, precision = %d) returned %d\n", i, j,
56		    precision, status);
57		return (status);
58	}
59
60	if (strlen(check) > strlen(buffer) &&
61	    strncmp(buffer, check, strlen(buffer))) {
62		/* last check if correctly rounded up */
63		if (check[strlen(buffer)] < '5' &&
64		    buffer[strlen(buffer) - 1] > check[strlen(buffer) - 1]) {
65			if (verbose)
66				(void) printf("failure:f precision %d "
67				    "for %02d/%02d => %s (%s)\n",
68				    precision, j, i, buffer, check);
69			return (1);
70		}
71	}
72
73	return (0);
74}
75
76int
77main(int argc, char *argv[])
78{
79	int status, i, j, precision;
80	int failures = 0;
81	int runs = 0;
82	test_t t;
83	/* NOTE:  Any argument after the command enables "VERBOSE" mode. */
84	boolean_t verbose = (argc > 1);
85
86	t = test_start("*printf() floating-point rounding tests.");
87
88	(void) fesetround(FE_TONEAREST);
89
90	for (j = 1; j < 100; j++) {
91		for (i = 2; i < 100; i++) {
92			for (precision = DBL_DIG - 1; precision <= DECIMAL_DIG;
93			    precision++) {
94				runs++;
95				status = run_one(t, i, j, precision, verbose);
96				if (status < 0)
97					return (status);
98				failures += status;
99			}
100		}
101	}
102
103	if (failures > 0) {
104		test_failed(t, "Tests failed %d times out of %d attempts.\n"
105		    "Run '%s full' to see the %d failures individually.\n",
106		    failures, runs, argv[0], failures);
107	} else
108		test_passed(t);
109
110	return (0);
111}
112