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 always 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 * It might be nice to add a flag to indicate no decimal digits in 22 * that case. This could be either an additional parameter, or a 23 * special value of display_unit. Such a flag would also be nice for du. 24 * 25 * Some code to omit the decimal point and tenths digit is sketched out 26 * and "#if 0"'d below. 27 */ 28 29#include "libbb.h" 30 31const char *make_human_readable_str(unsigned long long size, 32 unsigned long block_size, unsigned long display_unit) 33{ 34 /* The code will adjust for additional (appended) units */ 35 static const char zero_and_units[] ALIGN1 = { '0', 0, 'k', 'M', 'G', 'T' }; 36 static const char fmt[] ALIGN1 = "%llu"; 37 static const char fmt_tenths[] ALIGN1 = "%llu.%d%c"; 38 39 static char str[21] ALIGN1; /* Sufficient for 64 bit unsigned integers */ 40 41 unsigned long long val; 42 int frac; 43 const char *u; 44 const char *f; 45 46 u = zero_and_units; 47 f = fmt; 48 frac = 0; 49 50 val = size * block_size; 51 if (val == 0) { 52 return u; 53 } 54 55 if (display_unit) { 56 val += display_unit/2; /* Deal with rounding */ 57 val /= display_unit; /* Don't combine with the line above!!! */ 58 } else { 59 ++u; 60 while ((val >= 1024) 61 && (u < zero_and_units + sizeof(zero_and_units) - 1) 62 ) { 63 f = fmt_tenths; 64 ++u; 65 frac = (((int)(val % 1024)) * 10 + 1024/2) / 1024; 66 val /= 1024; 67 } 68 if (frac >= 10) { /* We need to round up here. */ 69 ++val; 70 frac = 0; 71 } 72 } 73 74 /* If f==fmt then 'frac' and 'u' are ignored. */ 75 snprintf(str, sizeof(str), f, val, frac, *u); 76 77 return str; 78} 79