1 /* $NetBSD: humanize_number.c,v 1.18 2019/03/11 15:10:51 kre Exp $ */ 2 3 /* 4 * Copyright (c) 1997, 1998, 1999, 2002 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center, by Luke Mewburn and by Tomas Svensson. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 #if defined(LIBC_SCCS) && !defined(lint) 35 __RCSID("$NetBSD: humanize_number.c,v 1.18 2019/03/11 15:10:51 kre Exp $"); 36 #endif /* LIBC_SCCS and not lint */ 37 38 #include "namespace.h" 39 #include <assert.h> 40 #include <inttypes.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <locale.h> 45 46 int 47 humanize_number(char *buf, size_t len, int64_t bytes, 48 const char *suffix, int scale, int flags) 49 { 50 const char *prefixes, *sep; 51 int b, i, r, s1, s2, sign; 52 int64_t divisor, max, post = 1; 53 size_t baselen; 54 int maxscale; 55 56 _DIAGASSERT(buf != NULL); 57 _DIAGASSERT(scale >= 0); 58 59 if (suffix == NULL) 60 suffix = ""; 61 62 if (flags & HN_DIVISOR_1000) { 63 /* SI for decimal multiplies */ 64 divisor = 1000; 65 if (flags & HN_B) 66 prefixes = "B\0k\0M\0G\0T\0P\0E"; 67 else 68 prefixes = "\0\0k\0M\0G\0T\0P\0E"; 69 } else { 70 /* 71 * binary multiplies 72 * XXX IEC 60027-2 recommends Ki, Mi, Gi... 73 */ 74 divisor = 1024; 75 if (flags & HN_B) 76 prefixes = "B\0K\0M\0G\0T\0P\0E"; 77 else 78 prefixes = "\0\0K\0M\0G\0T\0P\0E"; 79 } 80 81 #define SCALE2PREFIX(scale) (&prefixes[(scale) << 1]) 82 maxscale = 6; 83 84 if (scale < 0 || (scale > maxscale && 85 (scale & (HN_AUTOSCALE | HN_GETSCALE)) == 0)) 86 return (-1); 87 88 if (buf == NULL) 89 return (-1); 90 91 if (len > 0) 92 buf[0] = '\0'; 93 94 if (bytes < 0) { 95 sign = -1; 96 baselen = 3; /* sign, digit, prefix */ 97 if (-bytes < INT64_MAX / 100) 98 bytes *= -100; 99 else { 100 bytes = -bytes; 101 post = 100; 102 baselen += 2; 103 } 104 } else { 105 sign = 1; 106 baselen = 2; /* digit, prefix */ 107 if (bytes < INT64_MAX / 100) 108 bytes *= 100; 109 else { 110 post = 100; 111 baselen += 2; 112 } 113 } 114 if (flags & HN_NOSPACE) 115 sep = ""; 116 else { 117 sep = " "; 118 baselen++; 119 } 120 baselen += strlen(suffix); 121 122 /* Check if enough room for `x y' + suffix + `\0' */ 123 if (len < baselen + 1) 124 return (-1); 125 126 if (scale & (HN_AUTOSCALE | HN_GETSCALE)) { 127 /* 128 * 19 is number of digits in biggest possible int64_t 129 * If we don't do this, the calc of max just below can 130 * overflow, leading to absurd results. If the buffer 131 * is big enough for the number, simply use it, no scaling. 132 */ 133 if (len - baselen > 19) 134 i = 0; 135 else { 136 /* See if there are additional columns to be used. */ 137 for (max = 100, i = len - baselen; i-- > 0;) 138 max *= 10; 139 140 /* 141 * Divide the number until it fits the avail buffer. 142 * If there will be an overflow by the rounding below, 143 * (the "-50") divide once more. 144 */ 145 for (i = 0; bytes >= max - 50 && i < maxscale; i++) 146 bytes /= divisor; 147 } 148 if (scale & HN_GETSCALE) { 149 _DIAGASSERT(__type_fit(int, i)); 150 return i; 151 } 152 } else { 153 /* XXX 154 * we already know scale <= maxscale, so 155 * i < scale ==> i < maxscale 156 */ 157 for (i = 0; i < scale && i < maxscale; i++) 158 bytes /= divisor; 159 } 160 161 if (i == 0) { 162 /* 163 * Cannot go the bytes *= post route, as 164 * that can cause overflow of bytes 165 * 166 * but if we already scaled up, undo that. 167 */ 168 if (post == 1) 169 bytes /= 100; 170 171 r = snprintf(buf, len, "%" PRId64 "%s%s%s", 172 sign * bytes, sep, SCALE2PREFIX(0), suffix); 173 } else { 174 /* 175 * Here this is safe, as if i > 0, we have already 176 * divided bytes by at least 1000, post <= 100, so ... 177 */ 178 bytes *= post; 179 180 /* If a value <= 9.9 after rounding and ... */ 181 if (bytes < 995 && i > 0 && flags & HN_DECIMAL) { 182 /* baselen + \0 + .N */ 183 if (len < baselen + 1 + 1 + 184 strlen(localeconv()->decimal_point)) 185 return (-1); 186 b = ((int)bytes + 5) / 10; 187 s1 = b / 10; 188 s2 = b % 10; 189 r = snprintf(buf, len, "%d%s%d%s%s%s", 190 sign * s1, localeconv()->decimal_point, s2, 191 sep, SCALE2PREFIX(i), suffix); 192 } else 193 r = snprintf(buf, len, "%" PRId64 "%s%s%s", 194 sign * ((bytes + 50) / 100), 195 sep, SCALE2PREFIX(i), suffix); 196 } 197 198 if ((size_t)r > len) 199 r = -1; 200 201 return (r); 202 } 203