release/src/router/busybox/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
  26 #include "libbb.h"
  27
  28 const char* FAST_FUNC make_human_readable_str(unsigned long long val,
  29         unsigned long block_size, unsigned long display_unit)
  30 {
  31         static const char unit_chars[] ALIGN1 = {
  32                 '\0', 'K', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'
  33         };
  34
  35         unsigned frac; /* 0..9 - the fractional digit */
  36         const char *u;
  37         const char *fmt;
  38
  39         if (val == 0)
  40                 return "0";
  41
  42         fmt = "%llu";
  43         if (block_size > 1)
  44                 val *= block_size;
  45         frac = 0;
  46         u = unit_chars;
  47
  48         if (display_unit) {
  49                 val += display_unit/2;  /* Deal with rounding */
  50                 val /= display_unit;    /* Don't combine with the line above! */
  51                 /* will just print it as ulonglong (below) */
  52         } else {
  53                 while ((val >= 1024)
  54                  /* && (u < unit_chars + sizeof(unit_chars) - 1) - always true */
  55                 ) {
  56                         fmt = "%llu.%u%c";
  57                         u++;
  58                         frac = (((unsigned)val % 1024) * 10 + 1024/2) / 1024;
  59                         val /= 1024;
  60                 }
  61                 if (frac >= 10) { /* we need to round up here */
  62                         ++val;
  63                         frac = 0;
  64                 }
  65 #if 1
  66                 /* If block_size is 0, dont print fractional part */
  67                 if (block_size == 0) {
  68                         if (frac >= 5) {
  69                                 ++val;
  70                         }
  71                         fmt = "%llu%*c";
  72                         frac = 1;
  73                 }
  74 #endif
  75         }
  76
  77         return auto_string(xasprintf(fmt, val, frac, *u));
  78 }
  79
  80
  81 /* vda's implementations of the similar idea */
  82
  83 /* Convert unsigned long long value into compact 5-char representation.
  84  * String is not terminated (buf[5] is untouched) */
  85 char* FAST_FUNC smart_ulltoa5(unsigned long long ul, char buf[5], const char *scale)
  86 {
  87         const char *fmt;
  88         char c;
  89         unsigned v, u, idx = 0;
  90
  91         if (ul > 99999) { // do not scale if 99999 or less
  92                 ul *= 10;
  93                 do {
  94                         ul /= 1024;
  95                         idx++;
  96                 } while (ul >= 100000);
  97         }
  98         v = ul; // ullong divisions are expensive, avoid them
  99
 100         fmt = " 123456789";
 101         u = v / 10;
 102         v = v % 10;
 103         if (!idx) {
 104                 // 99999 or less: use "12345" format
 105                 // u is value/10, v is last digit
 106                 c = buf[0] = " 123456789"[u/1000];
 107                 if (c != ' ') fmt = "0123456789";
 108                 c = buf[1] = fmt[u/100%10];
 109                 if (c != ' ') fmt = "0123456789";
 110                 c = buf[2] = fmt[u/10%10];
 111                 if (c != ' ') fmt = "0123456789";
 112                 buf[3] = fmt[u%10];
 113                 buf[4] = "0123456789"[v];
 114         } else {
 115                 // value has been scaled into 0..9999.9 range
 116                 // u is value, v is 1/10ths (allows for 92.1M format)
 117                 if (u >= 100) {
 118                         // value is >= 100: use "1234M', " 123M" formats
 119                         c = buf[0] = " 123456789"[u/1000];
 120                         if (c != ' ') fmt = "0123456789";
 121                         c = buf[1] = fmt[u/100%10];
 122                         if (c != ' ') fmt = "0123456789";
 123                         v = u % 10;
 124                         u = u / 10;
 125                         buf[2] = fmt[u%10];
 126                 } else {
 127                         // value is < 100: use "92.1M" format
 128                         c = buf[0] = " 123456789"[u/10];
 129                         if (c != ' ') fmt = "0123456789";
 130                         buf[1] = fmt[u%10];
 131                         buf[2] = '.';
 132                 }
 133                 buf[3] = "0123456789"[v];
 134                 buf[4] = scale[idx]; /* typically scale = " kmgt..." */
 135         }
 136         return buf + 5;
 137 }
 138
 139 /* Convert unsigned long long value into compact 4-char
 140  * representation. Examples: "1234", "1.2k", " 27M", "123T"
 141  * String is not terminated (buf[4] is untouched) */
 142 char* FAST_FUNC smart_ulltoa4(unsigned long long ul, char buf[4], const char *scale)
 143 {
 144         const char *fmt;
 145         char c;
 146         unsigned v, u, idx = 0;
 147
 148         if (ul > 9999) { // do not scale if 9999 or less
 149                 ul *= 10;
 150                 do {
 151                         ul /= 1024;
 152                         idx++;
 153                 } while (ul >= 10000);
 154         }
 155         v = ul; // ullong divisions are expensive, avoid them
 156
 157         fmt = " 123456789";
 158         u = v / 10;
 159         v = v % 10;
 160         if (!idx) {
 161                 // 9999 or less: use "1234" format
 162                 // u is value/10, v is last digit
 163                 c = buf[0] = " 123456789"[u/100];
 164                 if (c != ' ') fmt = "0123456789";
 165                 c = buf[1] = fmt[u/10%10];
 166                 if (c != ' ') fmt = "0123456789";
 167                 buf[2] = fmt[u%10];
 168                 buf[3] = "0123456789"[v];
 169         } else {
 170                 // u is value, v is 1/10ths (allows for 9.2M format)
 171                 if (u >= 10) {
 172                         // value is >= 10: use "123M', " 12M" formats
 173                         c = buf[0] = " 123456789"[u/100];
 174                         if (c != ' ') fmt = "0123456789";
 175                         v = u % 10;
 176                         u = u / 10;
 177                         buf[1] = fmt[u%10];
 178                 } else {
 179                         // value is < 10: use "9.2M" format
 180                         buf[0] = "0123456789"[u];
 181                         buf[1] = '.';
 182                 }
 183                 buf[2] = "0123456789"[v];
 184                 buf[3] = scale[idx]; /* typically scale = " kmgt..." */
 185         }
 186         return buf + 4;
 187 }