Contents of /tags/mkinitrd-6_1_5/busybox/libbb/human_readable.c
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Wed Aug 5 17:52:52 2009 UTC (15 years, 1 month ago) by niro
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Wed Aug 5 17:52:52 2009 UTC (15 years, 1 month ago) by niro
File MIME type: text/plain
File size: 2781 byte(s)
tagged 'mkinitrd-6_1_5'
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 | |
31 | const char* FAST_FUNC 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 unit_chars[] ALIGN1 = { |
36 | '\0', 'K', 'M', 'G', 'T', 'P', 'E' |
37 | }; |
38 | static const char fmt[] ALIGN1 = "%llu"; |
39 | static const char fmt_tenths[] ALIGN1 = "%llu.%d%c"; |
40 | |
41 | static char str[21] ALIGN1; /* Sufficient for 64 bit unsigned integers */ |
42 | |
43 | unsigned long long val; |
44 | int frac; |
45 | const char *u; |
46 | const char *f; |
47 | smallint no_tenths; |
48 | |
49 | if (size == 0) |
50 | return "0"; |
51 | |
52 | /* If block_size is 0 then do not print tenths */ |
53 | no_tenths = 0; |
54 | if (block_size == 0) { |
55 | no_tenths = 1; |
56 | block_size = 1; |
57 | } |
58 | |
59 | u = unit_chars; |
60 | val = size * block_size; |
61 | f = fmt; |
62 | frac = 0; |
63 | |
64 | if (display_unit) { |
65 | val += display_unit/2; /* Deal with rounding */ |
66 | val /= display_unit; /* Don't combine with the line above!!! */ |
67 | /* will just print it as ulonglong (below) */ |
68 | } else { |
69 | while ((val >= 1024) |
70 | && (u < unit_chars + sizeof(unit_chars) - 1) |
71 | ) { |
72 | f = fmt_tenths; |
73 | u++; |
74 | frac = (((int)(val % 1024)) * 10 + 1024/2) / 1024; |
75 | val /= 1024; |
76 | } |
77 | if (frac >= 10) { /* We need to round up here. */ |
78 | ++val; |
79 | frac = 0; |
80 | } |
81 | #if 1 |
82 | /* Sample code to omit decimal point and tenths digit. */ |
83 | if (no_tenths) { |
84 | if (frac >= 5) { |
85 | ++val; |
86 | } |
87 | f = "%llu%*c" /* fmt_no_tenths */; |
88 | frac = 1; |
89 | } |
90 | #endif |
91 | } |
92 | |
93 | /* If f==fmt then 'frac' and 'u' are ignored. */ |
94 | snprintf(str, sizeof(str), f, val, frac, *u); |
95 | |
96 | return str; |
97 | } |