libbb/human_readable.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * June 30, 2001                 Manuel Novoa III
   4  *
   5  * All-integer version (hey, not everyone has floating point) of
   6  * make_human_readable_str, modified from similar code I had written
   7  * for busybox several months ago.
   8  *
   9  * Notes:
  10  *   1) I'm using an unsigned long long to hold the product size * block_size,
  11  *      as df (which calls this routine) could request a representation of a
  12  *      partition size in bytes > max of unsigned long.  If long longs aren't
  13  *      available, it would be possible to do what's needed using polynomial
  14  *      representations (say, powers of 1024) and manipulating coefficients.
  15  *      The base ten "bytes" output could be handled similarly.
  16  *
  17  *   2) This routine outputs a decimal point and a tenths digit when
  18  *      display_unit == 0.  Hence, it isn't uncommon for the returned string
  19  *      to have a length of 5 or 6.
  20  *
  21  *      If block_size is also 0, no decimal digits are printed.
  22  *
  23  * Licensed under GPLv2, see file LICENSE in this source tree.
  24  */
  25 #include "libbb.h"
  26
  27 const char* FAST_FUNC make_human_readable_str(unsigned long long val,
  28         unsigned long block_size, unsigned long display_unit)
  29 {
  30         static const char unit_chars[] ALIGN1 = {
  31                 '\0', 'K', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'
  32         };
  33
  34         unsigned frac; /* 0..9 - the fractional digit */
  35         const char *u;
  36         const char *fmt;
  37
  38         if (val == 0)
  39                 return "0";
  40
  41         fmt = "%llu";
  42         if (block_size > 1)
  43                 val *= block_size;
  44         frac = 0;
  45         u = unit_chars;
  46
  47         if (display_unit) {
  48                 val += display_unit/2;  /* Deal with rounding */
  49                 val /= display_unit;    /* Don't combine with the line above! */
  50                 /* will just print it as ulonglong (below) */
  51         } else {
  52                 while ((val >= 1024)
  53                  /* && (u < unit_chars + sizeof(unit_chars) - 1) - always true */
  54                 ) {
  55                         fmt = "%llu.%u%c";
  56                         u++;
  57                         frac = (((unsigned)val % 1024) * 10 + 1024/2) / 1024;
  58                         val /= 1024;
  59                 }
  60                 if (frac >= 10) { /* we need to round up here */
  61                         ++val;
  62                         frac = 0;
  63                 }
  64 #if 1
  65                 /* If block_size is 0, dont print fractional part */
  66                 if (block_size == 0) {
  67                         if (frac >= 5) {
  68                                 ++val;
  69                         }
  70                         fmt = "%llu%*c";
  71                         frac = 1;
  72                 }
  73 #endif
  74         }
  75
  76         return auto_string(xasprintf(fmt, val, frac, *u));
  77 }
  78
  79
  80 /* vda's implementations of the similar idea */
  81
  82 /* Convert unsigned long long value into compact 5-char representation.
  83  * String is not terminated (buf[5] is untouched) */
  84 char* FAST_FUNC smart_ulltoa5(unsigned long long ul, char buf[5], const char *scale)
  85 {
  86         const char *fmt;
  87         char c;
  88         unsigned v, u, idx = 0;
  89
  90         if (ul > 99999) { // do not scale if 99999 or less
  91                 ul *= 10;
  92                 do {
  93                         ul /= 1024;
  94                         idx++;
  95                 } while (ul >= 100000);
  96         }
  97         v = ul; // ullong divisions are expensive, avoid them
  98
  99         fmt = " 123456789";
 100         u = v / 10;
 101         v = v % 10;
 102         if (!idx) {
 103                 // 99999 or less: use "12345" format
 104                 // u is value/10, v is last digit
 105                 c = buf[0] = " 123456789"[u/1000];
 106                 if (c != ' ') fmt = "0123456789";
 107                 c = buf[1] = fmt[u/100%10];
 108                 if (c != ' ') fmt = "0123456789";
 109                 c = buf[2] = fmt[u/10%10];
 110                 if (c != ' ') fmt = "0123456789";
 111                 buf[3] = fmt[u%10];
 112                 buf[4] = "0123456789"[v];
 113         } else {
 114                 // value has been scaled into 0..9999.9 range
 115                 // u is value, v is 1/10ths (allows for 92.1M format)
 116                 if (u >= 100) {
 117                         // value is >= 100: use "1234M', " 123M" formats
 118                         c = buf[0] = " 123456789"[u/1000];
 119                         if (c != ' ') fmt = "0123456789";
 120                         c = buf[1] = fmt[u/100%10];
 121                         if (c != ' ') fmt = "0123456789";
 122                         v = u % 10;
 123                         u = u / 10;
 124                         buf[2] = fmt[u%10];
 125                 } else {
 126                         // value is < 100: use "92.1M" format
 127                         c = buf[0] = " 123456789"[u/10];
 128                         if (c != ' ') fmt = "0123456789";
 129                         buf[1] = fmt[u%10];
 130                         buf[2] = '.';
 131                 }
 132                 buf[3] = "0123456789"[v];
 133                 buf[4] = scale[idx]; /* typically scale = " kmgt..." */
 134         }
 135         return buf + 5;
 136 }
 137
 138 /* Convert unsigned long long value into compact 4-char
 139  * representation. Examples: "1234", "1.2k", " 27M", "123T"
 140  * String is not terminated (buf[4] is untouched) */
 141 char* FAST_FUNC smart_ulltoa4(unsigned long long ul, char buf[4], const char *scale)
 142 {
 143         const char *fmt;
 144         char c;
 145         unsigned v, u, idx = 0;
 146
 147         if (ul > 9999) { // do not scale if 9999 or less
 148                 ul *= 10;
 149                 do {
 150                         ul /= 1024;
 151                         idx++;
 152                 } while (ul >= 10000);
 153         }
 154         v = ul; // ullong divisions are expensive, avoid them
 155
 156         fmt = " 123456789";
 157         u = v / 10;
 158         v = v % 10;
 159         if (!idx) {
 160                 // 9999 or less: use "1234" format
 161                 // u is value/10, v is last digit
 162                 c = buf[0] = " 123456789"[u/100];
 163                 if (c != ' ') fmt = "0123456789";
 164                 c = buf[1] = fmt[u/10%10];
 165                 if (c != ' ') fmt = "0123456789";
 166                 buf[2] = fmt[u%10];
 167                 buf[3] = "0123456789"[v];
 168         } else {
 169                 // u is value, v is 1/10ths (allows for 9.2M format)
 170                 if (u >= 10) {
 171                         // value is >= 10: use "123M', " 12M" formats
 172                         c = buf[0] = " 123456789"[u/100];
 173                         if (c != ' ') fmt = "0123456789";
 174                         v = u % 10;
 175                         u = u / 10;
 176                         buf[1] = fmt[u%10];
 177                 } else {
 178                         // value is < 10: use "9.2M" format
 179                         buf[0] = "0123456789"[u];
 180                         buf[1] = '.';
 181                 }
 182                 buf[2] = "0123456789"[v];
 183                 buf[3] = scale[idx]; /* typically scale = " kmgt..." */
 184         }
 185         return buf + 4;
 186 }