xref: /dragonfly/lib/libtcplay/humanize.c (revision 67640b13)
1 /*
2  * Copyright (c) 2011 Alex Hornung <alex@alexhornung.com>.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in
13  *    the documentation and/or other materials provided with the
14  *    distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
19  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
20  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
22  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
24  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
25  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
26  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <string.h>
31 #include <stdlib.h>
32 #include <stdio.h>
33 #include <inttypes.h>
34 #include <ctype.h>
35 #include <errno.h>
36 
37 #include "humanize.h"
38 
39 static const char prefixes[] = " KMGTPE";
40 int
41 _humanize_number(char *buf, size_t bufsz, uint64_t num)
42 {
43 	const char *prefixp;
44 	int ret;
45 	uint64_t i, d;
46 
47 	prefixp = prefixes;
48 	i = num;
49 	d = 0;
50 
51 	while ((i > 1024) && (*prefixp != '\0')) {
52 		d = (i % 1024)/10;
53 		i /= 1024;
54 		++prefixp;
55 	}
56 
57 	if (d > 0)
58 		ret = snprintf(buf, bufsz, "%"PRIu64".%"PRIu64" %c",
59 		    i, d, *prefixp);
60 	else
61 		ret = snprintf(buf, bufsz, "%"PRIu64" %c", i, *prefixp);
62 
63 
64 	if ((ret < 0) || ((size_t)ret >= bufsz)) {
65 		errno = ENOMEM;
66 		return -1;
67 	} else {
68 		return 0;
69 	}
70 }
71 
72 int
73 _dehumanize_number(const char *buf, uint64_t *dest)
74 {
75 	char *endptr;
76 	uint64_t n, n_check, d;
77 	uint64_t multiplier;
78 	size_t len;
79 
80 	if (*buf == '\0') {
81 		errno = EINVAL;
82 		return -1;
83 	}
84 
85 	len = strlen(buf);
86 	if (tolower(buf[len-1]) == 'b')
87 		--len;
88 
89 	multiplier = 1;
90 
91 	switch (tolower(buf[len-1])) {
92 	case 'y':
93 		multiplier *= 1024;
94 	case 'z':
95 		multiplier *= 1024;
96 	case 'e':
97 		multiplier *= 1024;
98 	case 'p':
99 		multiplier *= 1024;
100 	case 't':
101 		multiplier *= 1024;
102 	case 'g':
103 		multiplier *= 1024;
104 	case 'm':
105 		multiplier *= 1024;
106 	case 'k':
107 		multiplier *= 1024;
108 		break;
109 	default:
110 		/*
111 		 * only set error if string ends in a character that
112 		 * is not a valid unit.
113 		 */
114 		if (isalpha(buf[len-1])) {
115 			errno = EINVAL;
116 			return -1;
117 		}
118 	}
119 
120 	d = 0;
121 	n = n_check = strtoull(buf, &endptr, 10);
122 	if (endptr) {
123 		if ((*endptr != '.') && (*endptr != '\0') &&
124 		    (*endptr != ' ') && (endptr != &buf[len-1])) {
125 			errno = EINVAL;
126 			return -1;
127 		}
128 
129 		if (*endptr == '.') {
130 			d = strtoull(endptr+1, &endptr, 10);
131 			if (endptr && (*endptr != '\0') &&
132 			    (*endptr != ' ') &&
133 			    (endptr != &buf[len-1])) {
134 				errno = EINVAL;
135 				return -1;
136 			}
137 		}
138 	}
139 
140 	if (d != 0) {
141 		while (d < 100)
142 			d *= 10;
143 
144 		while (d > 1000)
145 			d /= 10;
146 	}
147 
148 	d *= (multiplier/1024);
149 	n *= multiplier;
150 
151 	if ((uint64_t)(n/multiplier) != n_check) {
152 		errno = ERANGE;
153 		return -1;
154 	}
155 
156 	n += d;
157 	*dest = n;
158 
159 	return 0;
160 }
161 
162 #ifdef __TEST_HUMANIZE__
163 
164 #include <assert.h>
165 int main(int argc, char *argv[])
166 {
167 	char buf[1024];
168 	uint64_t n, out;
169 	int err;
170 
171 	if (argc < 3)
172 		return -1;
173 
174 	n = strtoull(argv[1], NULL, 10);
175 
176 	err = _humanize_number(buf, 1024, n);
177 	assert(err == 0);
178 
179 	err = _dehumanize_number(buf, &out);
180 	assert(err == 0);
181 
182 	printf("Converting: %"PRIu64" => %s => %"PRIu64"\n", n, buf, out);
183 
184 	err = _dehumanize_number(argv[2], &out);
185 	assert (err == 0);
186 
187 	printf("Converting: %s => %"PRIu64"\n", argv[2], out);
188 
189 	return 0;
190 }
191 
192 #endif
193