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 http://www.opensolaris.org/os/licensing.
  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
  31 /*
  32  * Return B_TRUE if "str" is a number string, B_FALSE otherwise.
  33  * Works for integer and floating point numbers.
  34  */
  35 boolean_t
  36 zfs_isnumber(const char *str)
  37 {
  38         if (!*str)
  39                 return (B_FALSE);
  40
  41         for (; *str; str++)
  42                 if (!(isdigit(*str) || (*str == '.')))
  43                         return (B_FALSE);
  44
  45         return (B_TRUE);
  46 }
  47
  48 /*
  49  * Convert a number to an appropriately human-readable output.
  50  */
  51 void
  52 zfs_nicenum_format(uint64_t num, char *buf, size_t buflen,
  53     enum zfs_nicenum_format format)
  54 {
  55         uint64_t n = num;
  56         int index = 0;
  57         const char *u;
  58         const char *units[3][7] = {
  59             [ZFS_NICENUM_1024] = {"", "K", "M", "G", "T", "P", "E"},
  60             [ZFS_NICENUM_BYTES] = {"B", "K", "M", "G", "T", "P", "E"},
  61             [ZFS_NICENUM_TIME] = {"ns", "us", "ms", "s", "?", "?", "?"}
  62         };
  63
  64         const int units_len[] = {[ZFS_NICENUM_1024] = 6,
  65             [ZFS_NICENUM_BYTES] = 6,
  66             [ZFS_NICENUM_TIME] = 4};
  67
  68         const int k_unit[] = {  [ZFS_NICENUM_1024] = 1024,
  69             [ZFS_NICENUM_BYTES] = 1024,
  70             [ZFS_NICENUM_TIME] = 1000};
  71
  72         double val;
  73
  74         if (format == ZFS_NICENUM_RAW) {
  75                 snprintf(buf, buflen, "%llu", (u_longlong_t)num);
  76                 return;
  77         } else if (format == ZFS_NICENUM_RAWTIME && num > 0) {
  78                 snprintf(buf, buflen, "%llu", (u_longlong_t)num);
  79                 return;
  80         } else if (format == ZFS_NICENUM_RAWTIME && num == 0) {
  81                 snprintf(buf, buflen, "%s", "-");
  82                 return;
  83         }
  84
  85         while (n >= k_unit[format] && index < units_len[format]) {
  86                 n /= k_unit[format];
  87                 index++;
  88         }
  89
  90         u = units[format][index];
  91
  92         /* Don't print zero latencies since they're invalid */
  93         if ((format == ZFS_NICENUM_TIME) && (num == 0)) {
  94                 (void) snprintf(buf, buflen, "-");
  95         } else if ((index == 0) || ((num %
  96             (uint64_t)powl(k_unit[format], index)) == 0)) {
  97                 /*
  98                  * If this is an even multiple of the base, always display
  99                  * without any decimal precision.
 100                  */
 101                 (void) snprintf(buf, buflen, "%llu%s", (u_longlong_t)n, u);
 102
 103         } else {
 104                 /*
 105                  * We want to choose a precision that reflects the best choice
 106                  * for fitting in 5 characters.  This can get rather tricky when
 107                  * we have numbers that are very close to an order of magnitude.
 108                  * For example, when displaying 10239 (which is really 9.999K),
 109                  * we want only a single place of precision for 10.0K.  We could
 110                  * develop some complex heuristics for this, but it's much
 111                  * easier just to try each combination in turn.
 112                  */
 113                 int i;
 114                 for (i = 2; i >= 0; i--) {
 115                         val = (double)num /
 116                             (uint64_t)powl(k_unit[format], index);
 117
 118                         /*
 119                          * Don't print floating point values for time.  Note,
 120                          * we use floor() instead of round() here, since
 121                          * round can result in undesirable results.  For
 122                          * example, if "num" is in the range of
 123                          * 999500-999999, it will print out "1000us".  This
 124                          * doesn't happen if we use floor().
 125                          */
 126                         if (format == ZFS_NICENUM_TIME) {
 127                                 if (snprintf(buf, buflen, "%d%s",
 128                                     (unsigned int) floor(val), u) <= 5)
 129                                         break;
 130
 131                         } else {
 132                                 if (snprintf(buf, buflen, "%.*f%s", i,
 133                                     val, u) <= 5)
 134                                         break;
 135                         }
 136                 }
 137         }
 138 }
 139
 140 /*
 141  * Convert a number to an appropriately human-readable output.
 142  */
 143 void
 144 zfs_nicenum(uint64_t num, char *buf, size_t buflen)
 145 {
 146         zfs_nicenum_format(num, buf, buflen, ZFS_NICENUM_1024);
 147 }
 148
 149 /*
 150  * Convert a time to an appropriately human-readable output.
 151  * @num:        Time in nanoseconds
 152  */
 153 void
 154 zfs_nicetime(uint64_t num, char *buf, size_t buflen)
 155 {
 156         zfs_nicenum_format(num, buf, buflen, ZFS_NICENUM_TIME);
 157 }
 158
 159 /*
 160  * Print out a raw number with correct column spacing
 161  */
 162 void
 163 zfs_niceraw(uint64_t num, char *buf, size_t buflen)
 164 {
 165         zfs_nicenum_format(num, buf, buflen, ZFS_NICENUM_RAW);
 166 }
 167
 168 /*
 169  * Convert a number of bytes to an appropriately human-readable output.
 170  */
 171 void
 172 zfs_nicebytes(uint64_t num, char *buf, size_t buflen)
 173 {
 174         zfs_nicenum_format(num, buf, buflen, ZFS_NICENUM_BYTES);
 175 }