lib/libzutil/zutil_nicenum.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or https://opensource.org/licenses/CDDL-1.0.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  24  */
  25
  26 #include <ctype.h>
  27 #include <math.h>
  28 #include <stdio.h>
  29 #include <libzutil.h>
  30 #include <string.h>
  31
  32 /*
  33  * Return B_TRUE if "str" is a number string, B_FALSE otherwise.
  34  * Works for integer and floating point numbers.
  35  */
  36 boolean_t
  37 zfs_isnumber(const char *str)
  38 {
  39         if (!*str)
  40                 return (B_FALSE);
  41
  42         for (; *str; str++)
  43                 if (!(isdigit(*str) || (*str == '.')))
  44                         return (B_FALSE);
  45
  46         /*
  47          * Numbers should not end with a period ("." ".." or "5." are
  48          * not valid)
  49          */
  50         if (str[strlen(str) - 1] == '.') {
  51                 return (B_FALSE);
  52         }
  53
  54         return (B_TRUE);
  55 }
  56
  57 /*
  58  * Convert a number to an appropriately human-readable output.
  59  */
  60 void
  61 zfs_nicenum_format(uint64_t num, char *buf, size_t buflen,
  62     enum zfs_nicenum_format format)
  63 {
  64         uint64_t n = num;
  65         int index = 0;
  66         const char *u;
  67         const char *units[3][7] = {
  68             [ZFS_NICENUM_1024] = {"", "K", "M", "G", "T", "P", "E"},
  69             [ZFS_NICENUM_BYTES] = {"B", "K", "M", "G", "T", "P", "E"},
  70             [ZFS_NICENUM_TIME] = {"ns", "us", "ms", "s", "?", "?", "?"}
  71         };
  72
  73         const int units_len[] = {[ZFS_NICENUM_1024] = 6,
  74             [ZFS_NICENUM_BYTES] = 6,
  75             [ZFS_NICENUM_TIME] = 4};
  76
  77         const int k_unit[] = {  [ZFS_NICENUM_1024] = 1024,
  78             [ZFS_NICENUM_BYTES] = 1024,
  79             [ZFS_NICENUM_TIME] = 1000};
  80
  81         double val;
  82
  83         if (format == ZFS_NICENUM_RAW) {
  84                 snprintf(buf, buflen, "%llu", (u_longlong_t)num);
  85                 return;
  86         } else if (format == ZFS_NICENUM_RAWTIME && num > 0) {
  87                 snprintf(buf, buflen, "%llu", (u_longlong_t)num);
  88                 return;
  89         } else if (format == ZFS_NICENUM_RAWTIME && num == 0) {
  90                 snprintf(buf, buflen, "%s", "-");
  91                 return;
  92         }
  93
  94         while (n >= k_unit[format] && index < units_len[format]) {
  95                 n /= k_unit[format];
  96                 index++;
  97         }
  98
  99         u = units[format][index];
 100
 101         /* Don't print zero latencies since they're invalid */
 102         if ((format == ZFS_NICENUM_TIME) && (num == 0)) {
 103                 (void) snprintf(buf, buflen, "-");
 104         } else if ((index == 0) || ((num %
 105             (uint64_t)powl(k_unit[format], index)) == 0)) {
 106                 /*
 107                  * If this is an even multiple of the base, always display
 108                  * without any decimal precision.
 109                  */
 110                 (void) snprintf(buf, buflen, "%llu%s", (u_longlong_t)n, u);
 111
 112         } else {
 113                 /*
 114                  * We want to choose a precision that reflects the best choice
 115                  * for fitting in 5 characters.  This can get rather tricky when
 116                  * we have numbers that are very close to an order of magnitude.
 117                  * For example, when displaying 10239 (which is really 9.999K),
 118                  * we want only a single place of precision for 10.0K.  We could
 119                  * develop some complex heuristics for this, but it's much
 120                  * easier just to try each combination in turn.
 121                  */
 122                 int i;
 123                 for (i = 2; i >= 0; i--) {
 124                         val = (double)num /
 125                             (uint64_t)powl(k_unit[format], index);
 126
 127                         /*
 128                          * Don't print floating point values for time.  Note,
 129                          * we use floor() instead of round() here, since
 130                          * round can result in undesirable results.  For
 131                          * example, if "num" is in the range of
 132                          * 999500-999999, it will print out "1000us".  This
 133                          * doesn't happen if we use floor().
 134                          */
 135                         if (format == ZFS_NICENUM_TIME) {
 136                                 if (snprintf(buf, buflen, "%d%s",
 137                                     (unsigned int) floor(val), u) <= 5)
 138                                         break;
 139
 140                         } else {
 141                                 if (snprintf(buf, buflen, "%.*f%s", i,
 142                                     val, u) <= 5)
 143                                         break;
 144                         }
 145                 }
 146         }
 147 }
 148
 149 /*
 150  * Convert a number to an appropriately human-readable output.
 151  */
 152 void
 153 zfs_nicenum(uint64_t num, char *buf, size_t buflen)
 154 {
 155         zfs_nicenum_format(num, buf, buflen, ZFS_NICENUM_1024);
 156 }
 157
 158 /*
 159  * Convert a time to an appropriately human-readable output.
 160  * @num:        Time in nanoseconds
 161  */
 162 void
 163 zfs_nicetime(uint64_t num, char *buf, size_t buflen)
 164 {
 165         zfs_nicenum_format(num, buf, buflen, ZFS_NICENUM_TIME);
 166 }
 167
 168 /*
 169  * Print out a raw number with correct column spacing
 170  */
 171 void
 172 zfs_niceraw(uint64_t num, char *buf, size_t buflen)
 173 {
 174         zfs_nicenum_format(num, buf, buflen, ZFS_NICENUM_RAW);
 175 }
 176
 177 /*
 178  * Convert a number of bytes to an appropriately human-readable output.
 179  */
 180 void
 181 zfs_nicebytes(uint64_t num, char *buf, size_t buflen)
 182 {
 183         zfs_nicenum_format(num, buf, buflen, ZFS_NICENUM_BYTES);
 184 }