| 1 | |
| 2 | * Helpers for formatting and printing strings
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| 3 | *
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| 4 | * Copyright 31 August 2008 James Bottomley
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| 5 |
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| 6 | #include <linux/kernel.h>
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| 7 | #include <linux/math64.h>
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| 8 | #include <linux/export.h>
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| 9 | #include <linux/string_helpers.h>
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| 10 |
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| 11 | |
| 12 | * string_get_size - get the size in the specified units
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| 13 | * @size: The size to be converted
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| 14 | * @units: units to use (powers of 1000 or 1024)
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| 15 | * @buf: buffer to format to
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| 16 | * @len: length of buffer
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| 17 | *
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| 18 | * This function returns a string formatted to 3 significant figures
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| 19 | * giving the size in the required units. Returns 0 on success or
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| 20 | * error on failure. @buf is always zero terminated.
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| 21 | *
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| 22 |
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| 23 | int string_get_size(u64 size, const enum string_size_units units,
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| 24 | char *buf, int len)
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| 25 | {
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| 26 | static const char *units_10[] = { "B", "kB", "MB", "GB", "TB", "PB",
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| 27 | "EB", "ZB", "YB", NULL};
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| 28 | static const char *units_2[] = {"B", "KiB", "MiB", "GiB", "TiB", "PiB",
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| 29 | "EiB", "ZiB", "YiB", NULL };
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| 30 | static const char **units_str[] = {
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| 31 | [STRING_UNITS_10] = units_10,
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| 32 | [STRING_UNITS_2] = units_2,
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| 33 | };
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| 34 | static const unsigned int divisor[] = {
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| 35 | [STRING_UNITS_10] = 1000,
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| 36 | [STRING_UNITS_2] = 1024,
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| 37 | };
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| 38 | int i, j;
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| 39 | u64 remainder = 0, sf_cap;
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| 40 | char tmp[8];
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| 41 |
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| 42 | tmp[0] = '\0';
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| 43 | i = 0;
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| 44 | if (size >= divisor[units]) {
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| 45 | while (size >= divisor[units] && units_str[units][i]) {
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| 46 | remainder = do_div(size, divisor[units]);
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| 47 | i++;
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| 48 | }
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| 49 |
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| 50 | sf_cap = size;
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| 51 | for (j = 0; sf_cap*10 < 1000; j++)
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| 52 | sf_cap *= 10;
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| 53 |
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| 54 | if (j) {
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| 55 | remainder *= 1000;
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| 56 | do_div(remainder, divisor[units]);
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| 57 | snprintf(tmp, sizeof(tmp), ".%03lld",
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| 58 | (unsigned long long)remainder);
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| 59 | tmp[j+1] = '\0';
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| 60 | }
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| 61 | }
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| 62 |
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| 63 | snprintf(buf, len, "%lld%s %s", (unsigned long long)size,
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| 64 | tmp, units_str[units][i]);
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| 65 |
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| 66 | return 0;
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| 67 | }
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| 68 | EXPORT_SYMBOL(string_get_size);
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