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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