string_helpers.c

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/*
 * Helpers for formatting and printing strings
 *
 * Copyright 31 August 2008 James Bottomley
 */
#include <linux/kernel.h>
#include <linux/math64.h>
#include <linux/export.h>
#include <linux/string_helpers.h>

int string_get_size(u64 size, const enum string_size_units units,
            char *buf, int len)
{
    static const char *units_10[] = { "B", "kB", "MB", "GB", "TB", "PB",
                   "EB", "ZB", "YB", NULL};
    static const char *units_2[] = {"B", "KiB", "MiB", "GiB", "TiB", "PiB",
                 "EiB", "ZiB", "YiB", NULL };
    static const char **units_str[] = {
        [STRING_UNITS_10] =  units_10,
        [STRING_UNITS_2] = units_2,
    };
    static const unsigned int divisor[] = {
        [STRING_UNITS_10] = 1000,
        [STRING_UNITS_2] = 1024,
    };
    int i, j;
    u64 remainder = 0, sf_cap;
    char tmp[8];

    tmp[0] = '\0';
    i = 0;
    if (size >= divisor[units]) {
        while (size >= divisor[units] && units_str[units][i]) {
            remainder = do_div(size, divisor[units]);
            i++;
        }

        sf_cap = size;
        for (j = 0; sf_cap*10 < 1000; j++)
            sf_cap *= 10;

        if (j) {
            remainder *= 1000;
            do_div(remainder, divisor[units]);
            snprintf(tmp, sizeof(tmp), ".%03lld",
                 (unsigned long long)remainder);
            tmp[j+1] = '\0';
        }
    }

    snprintf(buf, len, "%lld%s %s", (unsigned long long)size,
         tmp, units_str[units][i]);

    return 0;
}
EXPORT_SYMBOL(string_get_size);