/* * June 30, 2001 Manuel Novoa III * * All-integer version (hey, not everyone has floating point) of * make_human_readable_str, modified from similar code I had written * for busybox several months ago. * * Notes: * 1) I'm using an unsigned long long to hold the product size * block_size, * as df (which calls this routine) could request a representation of a * partition size in bytes > max of unsigned long. If long longs aren't * available, it would be possible to do what's needed using polynomial * representations (say, powers of 1024) and manipulating coefficients. * The base ten "bytes" output could be handled similarly. * * 2) This routine always outputs a decimal point and a tenths digit when * display_unit != 0. Hence, it isn't uncommon for the returned string * to have a length of 5 or 6. * * It might be nice to add a flag to indicate no decimal digits in * that case. This could be either an additional parameter, or a * special value of display_unit. Such a flag would also be nice for du. * * Some code to omit the decimal point and tenths digit is sketched out * and "#if 0"'d below. */ #include <stdio.h> #include "libbb.h" const char *make_human_readable_str(unsigned long size, unsigned long block_size, unsigned long display_unit) { /* The code will adjust for additional (appended) units. */ static const char zero_and_units[] = { '0', 0, 'k', 'M', 'G', 'T' }; static const char fmt[] = "%Lu"; static const char fmt_tenths[] = "%Lu.%d%c"; static char str[21]; /* Sufficient for 64 bit unsigned integers. */ unsigned long long val; int frac; const char *u; const char *f; u = zero_and_units; f = fmt; frac = 0; val = ((unsigned long long) size) * block_size; if (val == 0) { return u; } if (display_unit) { val += display_unit/2; /* Deal with rounding. */ val /= display_unit; /* Don't combine with the line above!!! */ } else { ++u; while ((val >= KILOBYTE) && (u < zero_and_units + sizeof(zero_and_units) - 1)) { f = fmt_tenths; ++u; frac = ((((int)(val % KILOBYTE)) * 10) + (KILOBYTE/2)) / KILOBYTE; val /= KILOBYTE; } if (frac >= 10) { /* We need to round up here. */ ++val; frac = 0; } #if 0 /* Sample code to omit decimal point and tenths digit. */ if ( /* no_tenths */ 1 ) { if ( frac >= 5 ) { ++val; } f = "%Lu%*c" /* fmt_no_tenths */ ; frac = 1; } #endif } /* If f==fmt then 'frac' and 'u' are ignored. */ snprintf(str, sizeof(str), f, val, frac, *u); return str; }