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 <math.h>
  27 #include <stdio.h>
  28 #include <libzutil.h>
  29
  30 /*
  31  * Convert a number to an appropriately human-readable output.
  32  */
  33 void
  34 zfs_nicenum_format(uint64_t num, char *buf, size_t buflen,
  35     enum zfs_nicenum_format format)
  36 {
  37         uint64_t n = num;
  38         int index = 0;
  39         const char *u;
  40         const char *units[3][7] = {
  41             [ZFS_NICENUM_1024] = {"", "K", "M", "G", "T", "P", "E"},
  42             [ZFS_NICENUM_BYTES] = {"B", "K", "M", "G", "T", "P", "E"},
  43             [ZFS_NICENUM_TIME] = {"ns", "us", "ms", "s", "?", "?", "?"}
  44         };
  45
  46         const int units_len[] = {[ZFS_NICENUM_1024] = 6,
  47             [ZFS_NICENUM_BYTES] = 6,
  48             [ZFS_NICENUM_TIME] = 4};
  49
  50         const int k_unit[] = {  [ZFS_NICENUM_1024] = 1024,
  51             [ZFS_NICENUM_BYTES] = 1024,
  52             [ZFS_NICENUM_TIME] = 1000};
  53
  54         double val;
  55
  56         if (format == ZFS_NICENUM_RAW) {
  57                 snprintf(buf, buflen, "%llu", (u_longlong_t)num);
  58                 return;
  59         } else if (format == ZFS_NICENUM_RAWTIME && num > 0) {
  60                 snprintf(buf, buflen, "%llu", (u_longlong_t)num);
  61                 return;
  62         } else if (format == ZFS_NICENUM_RAWTIME && num == 0) {
  63                 snprintf(buf, buflen, "%s", "-");
  64                 return;
  65         }
  66
  67         while (n >= k_unit[format] && index < units_len[format]) {
  68                 n /= k_unit[format];
  69                 index++;
  70         }
  71
  72         u = units[format][index];
  73
  74         /* Don't print zero latencies since they're invalid */
  75         if ((format == ZFS_NICENUM_TIME) && (num == 0)) {
  76                 (void) snprintf(buf, buflen, "-");
  77         } else if ((index == 0) || ((num %
  78             (uint64_t)powl(k_unit[format], index)) == 0)) {
  79                 /*
  80                  * If this is an even multiple of the base, always display
  81                  * without any decimal precision.
  82                  */
  83                 (void) snprintf(buf, buflen, "%llu%s", (u_longlong_t)n, u);
  84
  85         } else {
  86                 /*
  87                  * We want to choose a precision that reflects the best choice
  88                  * for fitting in 5 characters.  This can get rather tricky when
  89                  * we have numbers that are very close to an order of magnitude.
  90                  * For example, when displaying 10239 (which is really 9.999K),
  91                  * we want only a single place of precision for 10.0K.  We could
  92                  * develop some complex heuristics for this, but it's much
  93                  * easier just to try each combination in turn.
  94                  */
  95                 int i;
  96                 for (i = 2; i >= 0; i--) {
  97                         val = (double)num /
  98                             (uint64_t)powl(k_unit[format], index);
  99
 100                         /*
 101                          * Don't print floating point values for time.  Note,
 102                          * we use floor() instead of round() here, since
 103                          * round can result in undesirable results.  For
 104                          * example, if "num" is in the range of
 105                          * 999500-999999, it will print out "1000us".  This
 106                          * doesn't happen if we use floor().
 107                          */
 108                         if (format == ZFS_NICENUM_TIME) {
 109                                 if (snprintf(buf, buflen, "%d%s",
 110                                     (unsigned int) floor(val), u) <= 5)
 111                                         break;
 112
 113                         } else {
 114                                 if (snprintf(buf, buflen, "%.*f%s", i,
 115                                     val, u) <= 5)
 116                                         break;
 117                         }
 118                 }
 119         }
 120 }
 121
 122 /*
 123  * Convert a number to an appropriately human-readable output.
 124  */
 125 void
 126 zfs_nicenum(uint64_t num, char *buf, size_t buflen)
 127 {
 128         zfs_nicenum_format(num, buf, buflen, ZFS_NICENUM_1024);
 129 }
 130
 131 /*
 132  * Convert a time to an appropriately human-readable output.
 133  * @num:        Time in nanoseconds
 134  */
 135 void
 136 zfs_nicetime(uint64_t num, char *buf, size_t buflen)
 137 {
 138         zfs_nicenum_format(num, buf, buflen, ZFS_NICENUM_TIME);
 139 }
 140
 141 /*
 142  * Print out a raw number with correct column spacing
 143  */
 144 void
 145 zfs_niceraw(uint64_t num, char *buf, size_t buflen)
 146 {
 147         zfs_nicenum_format(num, buf, buflen, ZFS_NICENUM_RAW);
 148 }
 149
 150 /*
 151  * Convert a number of bytes to an appropriately human-readable output.
 152  */
 153 void
 154 zfs_nicebytes(uint64_t num, char *buf, size_t buflen)
 155 {
 156         zfs_nicenum_format(num, buf, buflen, ZFS_NICENUM_BYTES);
 157 }