contrib/tar/lib/human.c

   1 /* human.c -- print human readable file size
   2    Copyright (C) 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Originally contributed by lm@sgi.com;
  19    --si, output block size selection, and large file support
  20    added by eggert@twinsun.com.  */
  21
  22 #if HAVE_CONFIG_H
  23 # include <config.h>
  24 #endif
  25
  26 #include <sys/types.h>
  27 #include <stdio.h>
  28
  29 #if HAVE_LIMITS_H
  30 # include <limits.h>
  31 #endif
  32
  33 #if HAVE_STRING_H
  34 # include <string.h>
  35 #else
  36 # include <strings.h>
  37 #endif
  38
  39 #ifndef CHAR_BIT
  40 # define CHAR_BIT 8
  41 #endif
  42 #if HAVE_STDLIB_H
  43 # include <stdlib.h>
  44 #endif
  45
  46 #ifndef HAVE_DECL_GETENV
  47 "this configure-time declaration test was not run"
  48 #endif
  49 #if !HAVE_DECL_GETENV
  50 char *getenv ();
  51 #endif
  52
  53 #if ENABLE_NLS
  54 # include <libintl.h>
  55 # define _(Text) gettext (Text)
  56 #else
  57 # define _(Text) Text
  58 #endif
  59
  60 #include <argmatch.h>
  61 #include <error.h>
  62 #include <xstrtol.h>
  63
  64 #include "human.h"
  65
  66 static const char suffixes[] =
  67 {
  68   0,    /* not used */
  69   'k',  /* kilo */
  70   'M',  /* Mega */
  71   'G',  /* Giga */
  72   'T',  /* Tera */
  73   'P',  /* Peta */
  74   'E',  /* Exa */
  75   'Z',  /* Zetta */
  76   'Y'   /* Yotta */
  77 };
  78
  79 /* If INEXACT_STYLE is not human_round_to_even, and if easily
  80    possible, adjust VALUE according to the style.  */
  81 static double
  82 adjust_value (enum human_inexact_style inexact_style, double value)
  83 {
  84   /* Do not use the floor or ceil functions, as that would mean
  85      linking with the standard math library, which is a porting pain.
  86      So leave the value alone if it is too large to easily round.  */
  87   if (inexact_style != human_round_to_even && value < (uintmax_t) -1)
  88     {
  89       uintmax_t u = value;
  90       value = u + (inexact_style == human_ceiling && u != value);
  91     }
  92
  93   return value;
  94 }
  95
  96 /* Like human_readable_inexact, except always round to even.  */
  97 char *
  98 human_readable (uintmax_t n, char *buf,
  99                 int from_block_size, int output_block_size)
 100 {
 101   return human_readable_inexact (n, buf, from_block_size, output_block_size,
 102                                  human_round_to_even);
 103 }
 104
 105 /* Convert N to a human readable format in BUF.
 106
 107    N is expressed in units of FROM_BLOCK_SIZE.  FROM_BLOCK_SIZE must
 108    be nonnegative.
 109
 110    OUTPUT_BLOCK_SIZE must be nonzero.  If it is positive, use units of
 111    OUTPUT_BLOCK_SIZE in the output number.
 112
 113    Use INEXACT_STYLE to determine whether to take the ceiling or floor
 114    of any result that cannot be expressed exactly.
 115
 116    If OUTPUT_BLOCK_SIZE is negative, use a format like "127k" if
 117    possible, using powers of -OUTPUT_BLOCK_SIZE; otherwise, use
 118    ordinary decimal format.  Normally -OUTPUT_BLOCK_SIZE is either
 119    1000 or 1024; it must be at least 2.  Most people visually process
 120    strings of 3-4 digits effectively, but longer strings of digits are
 121    more prone to misinterpretation.  Hence, converting to an
 122    abbreviated form usually improves readability.  Use a suffix
 123    indicating which power is being used.  For example, assuming
 124    -OUTPUT_BLOCK_SIZE is 1024, 8500 would be converted to 8.3k,
 125    133456345 to 127M, 56990456345 to 53G, and so on.  Numbers smaller
 126    than -OUTPUT_BLOCK_SIZE aren't modified.  */
 127
 128 char *
 129 human_readable_inexact (uintmax_t n, char *buf,
 130                         int from_block_size, int output_block_size,
 131                         enum human_inexact_style inexact_style)
 132 {
 133   uintmax_t amt;
 134   int base;
 135   int to_block_size;
 136   int tenths = 0;
 137   int power;
 138   char *p;
 139
 140   /* 0 means adjusted N == AMT.TENTHS;
 141      1 means AMT.TENTHS < adjusted N < AMT.TENTHS + 0.05;
 142      2 means adjusted N == AMT.TENTHS + 0.05;
 143      3 means AMT.TENTHS + 0.05 < adjusted N < AMT.TENTHS + 0.1.  */
 144   int rounding = 0;
 145
 146   if (output_block_size < 0)
 147     {
 148       base = -output_block_size;
 149       to_block_size = 1;
 150     }
 151   else
 152     {
 153       base = 0;
 154       to_block_size = output_block_size;
 155     }
 156
 157   p = buf + LONGEST_HUMAN_READABLE;
 158   *p = '\0';
 159
 160 #ifdef lint
 161   /* Suppress `used before initialized' warning.  */
 162   power = 0;
 163 #endif
 164
 165   /* Adjust AMT out of FROM_BLOCK_SIZE units and into TO_BLOCK_SIZE units.  */
 166
 167   {
 168     int multiplier;
 169     int divisor;
 170     int r2;
 171     int r10;
 172     if (to_block_size <= from_block_size
 173         ? (from_block_size % to_block_size != 0
 174            || (multiplier = from_block_size / to_block_size,
 175                (amt = n * multiplier) / multiplier != n))
 176         : (from_block_size == 0
 177            || to_block_size % from_block_size != 0
 178            || (divisor = to_block_size / from_block_size,
 179                r10 = (n % divisor) * 10,
 180                r2 = (r10 % divisor) * 2,
 181                amt = n / divisor,
 182                tenths = r10 / divisor,
 183                rounding = r2 < divisor ? 0 < r2 : 2 + (divisor < r2),
 184                0)))
 185       {
 186         /* Either the result cannot be computed easily using uintmax_t,
 187            or from_block_size is zero.  Fall back on floating point.
 188            FIXME: This can yield answers that are slightly off.  */
 189
 190         double damt = n * (from_block_size / (double) to_block_size);
 191
 192         if (! base)
 193           sprintf (buf, "%.0f", adjust_value (inexact_style, damt));
 194         else
 195           {
 196             double e = 1;
 197             power = 0;
 198
 199             do
 200               {
 201                 e *= base;
 202                 power++;
 203               }
 204             while (e * base <= damt && power < sizeof suffixes - 1);
 205
 206             damt /= e;
 207
 208             sprintf (buf, "%.1f%c", adjust_value (inexact_style, damt),
 209                      suffixes[power]);
 210             if (4 < strlen (buf))
 211               sprintf (buf, "%.0f%c",
 212                        adjust_value (inexact_style, damt * 10) / 10,
 213                        suffixes[power]);
 214           }
 215
 216         return buf;
 217       }
 218   }
 219
 220   /* Use power of BASE notation if adjusted AMT is large enough.  */
 221
 222   if (base && base <= amt)
 223     {
 224       power = 0;
 225
 226       do
 227         {
 228           int r10 = (amt % base) * 10 + tenths;
 229           int r2 = (r10 % base) * 2 + (rounding >> 1);
 230           amt /= base;
 231           tenths = r10 / base;
 232           rounding = (r2 < base
 233                       ? 0 < r2 + rounding
 234                       : 2 + (base < r2 + rounding));
 235           power++;
 236         }
 237       while (base <= amt && power < sizeof suffixes - 1);
 238
 239       *--p = suffixes[power];
 240
 241       if (amt < 10)
 242         {
 243           if (2 * (1 - (int) inexact_style)
 244               < rounding + (tenths & (inexact_style == human_round_to_even)))
 245             {
 246               tenths++;
 247               rounding = 0;
 248
 249               if (tenths == 10)
 250                 {
 251                   amt++;
 252                   tenths = 0;
 253                 }
 254             }
 255
 256           if (amt < 10)
 257             {
 258               *--p = '0' + tenths;
 259               *--p = '.';
 260               tenths = rounding = 0;
 261             }
 262         }
 263     }
 264
 265   if (inexact_style == human_ceiling
 266       ? 0 < tenths + rounding
 267       : inexact_style == human_round_to_even
 268       ? 5 < tenths + (2 < rounding + (amt & 1))
 269       : /* inexact_style == human_floor */ 0)
 270     {
 271       amt++;
 272
 273       if (amt == base && power < sizeof suffixes - 1)
 274         {
 275           *p = suffixes[power + 1];
 276           *--p = '0';
 277           *--p = '.';
 278           amt = 1;
 279         }
 280     }
 281
 282   do
 283     *--p = '0' + (int) (amt % 10);
 284   while ((amt /= 10) != 0);
 285
 286   return p;
 287 }
 288
 289
 290 /* The default block size used for output.  This number may change in
 291    the future as disks get larger.  */
 292 #ifndef DEFAULT_BLOCK_SIZE
 293 # define DEFAULT_BLOCK_SIZE 1024
 294 #endif
 295
 296 static char const *const block_size_args[] = { "human-readable", "si", 0 };
 297 static int const block_size_types[] = { -1024, -1000 };
 298
 299 static int
 300 default_block_size (void)
 301 {
 302   return getenv ("POSIXLY_CORRECT") ? 512 : DEFAULT_BLOCK_SIZE;
 303 }
 304
 305 static strtol_error
 306 humblock (char const *spec, int *block_size)
 307 {
 308   int i;
 309
 310   if (! spec && ! (spec = getenv ("BLOCK_SIZE")))
 311     *block_size = default_block_size ();
 312   else if (0 <= (i = ARGMATCH (spec, block_size_args, block_size_types)))
 313     *block_size = block_size_types[i];
 314   else
 315     {
 316       char *ptr;
 317       unsigned long val;
 318       strtol_error e = xstrtoul (spec, &ptr, 0, &val, "eEgGkKmMpPtTyYzZ0");
 319       if (e != LONGINT_OK)
 320         return e;
 321       if (*ptr)
 322         return LONGINT_INVALID_SUFFIX_CHAR;
 323       if ((int) val < 0 || val != (int) val)
 324         return LONGINT_OVERFLOW;
 325       *block_size = (int) val;
 326     }
 327
 328   return LONGINT_OK;
 329 }
 330
 331 void
 332 human_block_size (char const *spec, int report_errors, int *block_size)
 333 {
 334   strtol_error e = humblock (spec, block_size);
 335   if (*block_size == 0)
 336     {
 337       *block_size = default_block_size ();
 338       e = LONGINT_INVALID;
 339     }
 340   if (e != LONGINT_OK && report_errors)
 341     STRTOL_FATAL_ERROR (spec, _("block size"), e);
 342 }