1 | /*
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2 | * June 30, 2001 Manuel Novoa III
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3 | *
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4 | * All-integer version (hey, not everyone has floating point) of
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5 | * make_human_readable_str, modified from similar code I had written
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6 | * for busybox several months ago.
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7 | *
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8 | * Notes:
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9 | * 1) I'm using an unsigned long long to hold the product size * block_size,
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10 | * as df (which calls this routine) could request a representation of a
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11 | * partition size in bytes > max of unsigned long. If long longs aren't
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12 | * available, it would be possible to do what's needed using polynomial
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13 | * representations (say, powers of 1024) and manipulating coefficients.
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14 | * The base ten "bytes" output could be handled similarly.
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15 | *
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16 | * 2) This routine always outputs a decimal point and a tenths digit when
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17 | * display_unit != 0. Hence, it isn't uncommon for the returned string
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18 | * to have a length of 5 or 6.
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19 | *
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20 | * It might be nice to add a flag to indicate no decimal digits in
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21 | * that case. This could be either an additional parameter, or a
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22 | * special value of display_unit. Such a flag would also be nice for du.
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23 | *
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24 | * Some code to omit the decimal point and tenths digit is sketched out
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25 | * and "#if 0"'d below.
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26 | */
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27 |
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28 | #include <stdio.h>
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29 | #include "libbb.h"
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30 |
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31 | const char *make_human_readable_str(unsigned long long size,
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32 | unsigned long block_size, unsigned long display_unit)
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33 | {
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34 | /* The code will adjust for additional (appended) units. */
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35 | static const char zero_and_units[] = { '0', 0, 'k', 'M', 'G', 'T' };
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36 | static const char fmt[] = "%llu";
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37 | static const char fmt_tenths[] = "%llu.%d%c";
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38 |
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39 | static char str[21]; /* Sufficient for 64 bit unsigned integers. */
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40 |
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41 | unsigned long long val;
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42 | int frac;
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43 | const char *u;
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44 | const char *f;
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45 |
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46 | u = zero_and_units;
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47 | f = fmt;
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48 | frac = 0;
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49 |
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50 | val = size * block_size;
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51 | if (val == 0) {
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52 | return u;
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53 | }
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54 |
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55 | if (display_unit) {
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56 | val += display_unit/2; /* Deal with rounding. */
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57 | val /= display_unit; /* Don't combine with the line above!!! */
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58 | } else {
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59 | ++u;
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60 | while ((val >= KILOBYTE)
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61 | && (u < zero_and_units + sizeof(zero_and_units) - 1)) {
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62 | f = fmt_tenths;
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63 | ++u;
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64 | frac = ((((int)(val % KILOBYTE)) * 10) + (KILOBYTE/2)) / KILOBYTE;
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65 | val /= KILOBYTE;
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66 | }
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67 | if (frac >= 10) { /* We need to round up here. */
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68 | ++val;
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69 | frac = 0;
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70 | }
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71 | #if 0
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72 | /* Sample code to omit decimal point and tenths digit. */
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73 | if ( /* no_tenths */ 1 ) {
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74 | if ( frac >= 5 ) {
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75 | ++val;
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76 | }
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77 | f = "%llu%*c" /* fmt_no_tenths */ ;
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78 | frac = 1;
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79 | }
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80 | #endif
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81 | }
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82 |
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83 | /* If f==fmt then 'frac' and 'u' are ignored. */
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84 | snprintf(str, sizeof(str), f, val, frac, *u);
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85 |
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86 | return str;
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87 | }
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