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Commit | Line | Data |
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9b12e4fe JC |
1 | package units |
2 | ||
3 | import ( | |
4 | "fmt" | |
5 | "regexp" | |
6 | "strconv" | |
7 | "strings" | |
8 | ) | |
9 | ||
10 | // See: http://en.wikipedia.org/wiki/Binary_prefix | |
11 | const ( | |
12 | // Decimal | |
13 | ||
14 | KB = 1000 | |
15 | MB = 1000 * KB | |
16 | GB = 1000 * MB | |
17 | TB = 1000 * GB | |
18 | PB = 1000 * TB | |
19 | ||
20 | // Binary | |
21 | ||
22 | KiB = 1024 | |
23 | MiB = 1024 * KiB | |
24 | GiB = 1024 * MiB | |
25 | TiB = 1024 * GiB | |
26 | PiB = 1024 * TiB | |
27 | ) | |
28 | ||
29 | type unitMap map[string]int64 | |
30 | ||
31 | var ( | |
32 | decimalMap = unitMap{"k": KB, "m": MB, "g": GB, "t": TB, "p": PB} | |
33 | binaryMap = unitMap{"k": KiB, "m": MiB, "g": GiB, "t": TiB, "p": PiB} | |
34 | sizeRegex = regexp.MustCompile(`^(\d+)([kKmMgGtTpP])?[bB]?$`) | |
35 | ) | |
36 | ||
37 | var decimapAbbrs = []string{"B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"} | |
38 | var binaryAbbrs = []string{"B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB"} | |
39 | ||
40 | // CustomSize returns a human-readable approximation of a size | |
41 | // using custom format. | |
42 | func CustomSize(format string, size float64, base float64, _map []string) string { | |
43 | i := 0 | |
44 | for size >= base { | |
45 | size = size / base | |
46 | i++ | |
47 | } | |
48 | return fmt.Sprintf(format, size, _map[i]) | |
49 | } | |
50 | ||
51 | // HumanSize returns a human-readable approximation of a size | |
52 | // capped at 4 valid numbers (eg. "2.746 MB", "796 KB"). | |
53 | func HumanSize(size float64) string { | |
54 | return CustomSize("%.4g %s", size, 1000.0, decimapAbbrs) | |
55 | } | |
56 | ||
57 | // BytesSize returns a human-readable size in bytes, kibibytes, | |
58 | // mebibytes, gibibytes, or tebibytes (eg. "44kiB", "17MiB"). | |
59 | func BytesSize(size float64) string { | |
60 | return CustomSize("%.4g %s", size, 1024.0, binaryAbbrs) | |
61 | } | |
62 | ||
63 | // FromHumanSize returns an integer from a human-readable specification of a | |
64 | // size using SI standard (eg. "44kB", "17MB"). | |
65 | func FromHumanSize(size string) (int64, error) { | |
66 | return parseSize(size, decimalMap) | |
67 | } | |
68 | ||
69 | // RAMInBytes parses a human-readable string representing an amount of RAM | |
70 | // in bytes, kibibytes, mebibytes, gibibytes, or tebibytes and | |
71 | // returns the number of bytes, or -1 if the string is unparseable. | |
72 | // Units are case-insensitive, and the 'b' suffix is optional. | |
73 | func RAMInBytes(size string) (int64, error) { | |
74 | return parseSize(size, binaryMap) | |
75 | } | |
76 | ||
77 | // Parses the human-readable size string into the amount it represents. | |
78 | func parseSize(sizeStr string, uMap unitMap) (int64, error) { | |
79 | matches := sizeRegex.FindStringSubmatch(sizeStr) | |
80 | if len(matches) != 3 { | |
81 | return -1, fmt.Errorf("invalid size: '%s'", sizeStr) | |
82 | } | |
83 | ||
84 | size, err := strconv.ParseInt(matches[1], 10, 0) | |
85 | if err != nil { | |
86 | return -1, err | |
87 | } | |
88 | ||
89 | unitPrefix := strings.ToLower(matches[2]) | |
90 | if mul, ok := uMap[unitPrefix]; ok { | |
91 | size *= mul | |
92 | } | |
93 | ||
94 | return size, nil | |
95 | } |