[linux-2.6-block.git] / lib / string_helpers.c

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

/**
 * string_get_size - get the size in the specified units
 * @size:	The size to be converted
 * @units:	units to use (powers of 1000 or 1024)
 * @buf:	buffer to format to
 * @len:	length of buffer
 *
 * This function returns a string formatted to 3 significant figures
 * giving the size in the required units.  Returns 0 on success or
 * error on failure.  @buf is always zero terminated.
 *
 */
int string_get_size(u64 size, const enum string_size_units units,
		    char *buf, int len)
{
	const char *units_10[] = { "B", "kB", "MB", "GB", "TB", "PB",
				   "EB", "ZB", "YB", NULL};
	const char *units_2[] = {"B", "KiB", "MiB", "GiB", "TiB", "PiB",
				 "EiB", "ZiB", "YiB", NULL };
	const char **units_str[] = {
		[STRING_UNITS_10] =  units_10,
		[STRING_UNITS_2] = units_2,
	};
	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);
Commit	Line	Data
3c9f3681 JB	1	/*
	2	* Helpers for formatting and printing strings
	3	*
	4	* Copyright 31 August 2008 James Bottomley
	5	*/
	6	#include <linux/kernel.h>
	7	#include <linux/math64.h>
	8	#include <linux/module.h>
	9	#include <linux/string_helpers.h>
	10
	11	/**
	12	* string_get_size - get the size in the specified units
	13	* @size: The size to be converted
	14	* @units: units to use (powers of 1000 or 1024)
	15	* @buf: buffer to format to
	16	* @len: length of buffer
	17	*
	18	* This function returns a string formatted to 3 significant figures
	19	* giving the size in the required units. Returns 0 on success or
	20	* error on failure. @buf is always zero terminated.
	21	*
	22	*/
	23	int string_get_size(u64 size, const enum string_size_units units,
	24	char *buf, int len)
	25	{
a8659597	26	const char *units_10[] = { "B", "kB", "MB", "GB", "TB", "PB",
3c9f3681 JB	27	"EB", "ZB", "YB", NULL};
	28	const char *units_2[] = {"B", "KiB", "MiB", "GiB", "TiB", "PiB",
	29	"EiB", "ZiB", "YiB", NULL };
	30	const char **units_str[] = {
	31	[STRING_UNITS_10] = units_10,
	32	[STRING_UNITS_2] = units_2,
	33	};
a8659597	34	const unsigned int divisor[] = {
3c9f3681 JB	35	[STRING_UNITS_10] = 1000,
	36	[STRING_UNITS_2] = 1024,
	37	};
	38	int i, j;
	39	u64 remainder = 0, sf_cap;
	40	char tmp[8];
	41
	42	tmp[0] = '\0';
a8659597 PA	43	i = 0;
	44	if (size >= divisor[units]) {
	45	while (size >= divisor[units] && units_str[units][i]) {
	46	remainder = do_div(size, divisor[units]);
	47	i++;
	48	}
3c9f3681	49
a8659597 PA	50	sf_cap = size;
	51	for (j = 0; sf_cap*10 < 1000; j++)
	52	sf_cap *= 10;
3c9f3681	53
a8659597 PA	54	if (j) {
	55	remainder *= 1000;
	56	do_div(remainder, divisor[units]);
	57	snprintf(tmp, sizeof(tmp), ".%03lld",
	58	(unsigned long long)remainder);
	59	tmp[j+1] = '\0';
	60	}
3c9f3681 JB	61	}
3c9f3681 JB	62
a8659597	63	snprintf(buf, len, "%lld%s %s", (unsigned long long)size,
3c9f3681 JB	64	tmp, units_str[units][i]);
	65
	66	return 0;
	67	}
	68	EXPORT_SYMBOL(string_get_size);