[fio.git] / lib / num2str.c

#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "../compiler/compiler.h"
#include "../oslib/asprintf.h"
#include "num2str.h"

#define ARRAY_SIZE(x)    (sizeof((x)) / (sizeof((x)[0])))

/**
 * num2str() - Cheesy number->string conversion, complete with carry rounding error.
 * @num: quantity (e.g., number of blocks, bytes or bits)
 * @maxlen: max number of digits in the output string (not counting prefix and units, but counting .)
 * @base: multiplier for num (e.g., if num represents Ki, use 1024)
 * @pow2: select unit prefix - 0=power-of-10 decimal SI, nonzero=power-of-2 binary IEC
 * @units: select units - N2S_* constants defined in num2str.h
 * @returns a malloc'd buffer containing "number[<unit prefix>][<units>]"
 */
char *num2str(uint64_t num, int maxlen, int base, int pow2, enum n2s_unit units)
{
	const char *sistr[] = { "", "k", "M", "G", "T", "P", "E" };
	const char *iecstr[] = { "", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei" };
	const char **unitprefix;
	static const char *const unitstr[] = {
		[N2S_NONE]	= "",
		[N2S_PERSEC]	= "/s",
		[N2S_BYTE]	= "B",
		[N2S_BIT]	= "bit",
		[N2S_BYTEPERSEC]= "B/s",
		[N2S_BITPERSEC]	= "bit/s"
	};
	const unsigned int thousand = pow2 ? 1024 : 1000;
	unsigned int modulo;
	int post_index, carry = 0;
	char tmp[32];
	char *buf;

	compiletime_assert(sizeof(sistr) == sizeof(iecstr), "unit prefix arrays must be identical sizes");
	assert(units < ARRAY_SIZE(unitstr));

	if (pow2)
		unitprefix = iecstr;
	else
		unitprefix = sistr;

	for (post_index = 0; base > 1; post_index++)
		base /= thousand;

	switch (units) {
	case N2S_NONE:
		break;
	case N2S_PERSEC:
		break;
	case N2S_BYTE:
		break;
	case N2S_BIT:
		num *= 8;
		break;
	case N2S_BYTEPERSEC:
		break;
	case N2S_BITPERSEC:
		num *= 8;
		break;
	}

	/*
	 * Divide by K/Ki until string length of num <= maxlen.
	 */
	modulo = -1U;
	while (post_index < ARRAY_SIZE(sistr)) {
		sprintf(tmp, "%llu", (unsigned long long) num);
		if (strlen(tmp) <= maxlen)
			break;

		modulo = num % thousand;
		num /= thousand;
		carry = modulo >= thousand / 2;
		post_index++;
	}

	if (post_index >= ARRAY_SIZE(sistr))
		post_index = 0;

	/*
	 * If no modulo, then we're done.
	 */
	if (modulo == -1U) {
done:
		if (asprintf(&buf, "%llu%s%s", (unsigned long long) num,
			     unitprefix[post_index], unitstr[units]) < 0)
			buf = NULL;
		return buf;
	}

	/*
	 * If no room for decimals, then we're done.
	 */
	sprintf(tmp, "%llu", (unsigned long long) num);
	if ((int)(maxlen - strlen(tmp)) <= 1) {
		if (carry)
			num++;
		goto done;
	}

	/*
	 * Fill in everything and return the result.
	 */
	assert(maxlen - strlen(tmp) - 1 > 0);
	assert(modulo < thousand);
	sprintf(tmp, "%.*f", (int)(maxlen - strlen(tmp) - 1),
		(double)modulo / (double)thousand);

	if (asprintf(&buf, "%llu.%s%s%s", (unsigned long long) num, &tmp[2],
		     unitprefix[post_index], unitstr[units]) < 0)
		buf = NULL;
	return buf;
}
Commit	Line	Data
	1	#include <assert.h>
	2	#include <stdlib.h>
	3	#include <stdio.h>
	4	#include <string.h>
	5
	6	#include "../compiler/compiler.h"
	7	#include "../oslib/asprintf.h"
	8	#include "num2str.h"
	9
	10	#define ARRAY_SIZE(x) (sizeof((x)) / (sizeof((x)[0])))
	11
	12	/**
	13	* num2str() - Cheesy number->string conversion, complete with carry rounding error.
	14	* @num: quantity (e.g., number of blocks, bytes or bits)
	15	* @maxlen: max number of digits in the output string (not counting prefix and units, but counting .)
	16	* @base: multiplier for num (e.g., if num represents Ki, use 1024)
	17	* @pow2: select unit prefix - 0=power-of-10 decimal SI, nonzero=power-of-2 binary IEC
	18	* @units: select units - N2S_* constants defined in num2str.h
	19	* @returns a malloc'd buffer containing "number[<unit prefix>][<units>]"
	20	*/
	21	char *num2str(uint64_t num, int maxlen, int base, int pow2, enum n2s_unit units)
	22	{
	23	const char *sistr[] = { "", "k", "M", "G", "T", "P", "E" };
	24	const char *iecstr[] = { "", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei" };
	25	const char **unitprefix;
	26	static const char *const unitstr[] = {
	27	[N2S_NONE] = "",
	28	[N2S_PERSEC] = "/s",
	29	[N2S_BYTE] = "B",
	30	[N2S_BIT] = "bit",
	31	[N2S_BYTEPERSEC]= "B/s",
	32	[N2S_BITPERSEC] = "bit/s"
	33	};
	34	const unsigned int thousand = pow2 ? 1024 : 1000;
	35	unsigned int modulo;
	36	int post_index, carry = 0;
	37	char tmp[32];
	38	char *buf;
	39
	40	compiletime_assert(sizeof(sistr) == sizeof(iecstr), "unit prefix arrays must be identical sizes");
	41	assert(units < ARRAY_SIZE(unitstr));
	42
	43	if (pow2)
	44	unitprefix = iecstr;
	45	else
	46	unitprefix = sistr;
	47
	48	for (post_index = 0; base > 1; post_index++)
	49	base /= thousand;
	50
	51	switch (units) {
	52	case N2S_NONE:
	53	break;
	54	case N2S_PERSEC:
	55	break;
	56	case N2S_BYTE:
	57	break;
	58	case N2S_BIT:
	59	num *= 8;
	60	break;
	61	case N2S_BYTEPERSEC:
	62	break;
	63	case N2S_BITPERSEC:
	64	num *= 8;
	65	break;
	66	}
	67
	68	/*
	69	* Divide by K/Ki until string length of num <= maxlen.
	70	*/
	71	modulo = -1U;
	72	while (post_index < ARRAY_SIZE(sistr)) {
	73	sprintf(tmp, "%llu", (unsigned long long) num);
	74	if (strlen(tmp) <= maxlen)
	75	break;
	76
	77	modulo = num % thousand;
	78	num /= thousand;
	79	carry = modulo >= thousand / 2;
	80	post_index++;
	81	}
	82
	83	if (post_index >= ARRAY_SIZE(sistr))
	84	post_index = 0;
	85
	86	/*
	87	* If no modulo, then we're done.
	88	*/
	89	if (modulo == -1U) {
	90	done:
	91	if (asprintf(&buf, "%llu%s%s", (unsigned long long) num,
	92	unitprefix[post_index], unitstr[units]) < 0)
	93	buf = NULL;
	94	return buf;
	95	}
	96
	97	/*
	98	* If no room for decimals, then we're done.
	99	*/
	100	sprintf(tmp, "%llu", (unsigned long long) num);
	101	if ((int)(maxlen - strlen(tmp)) <= 1) {
	102	if (carry)
	103	num++;
	104	goto done;
	105	}
	106
	107	/*
	108	* Fill in everything and return the result.
	109	*/
	110	assert(maxlen - strlen(tmp) - 1 > 0);
	111	assert(modulo < thousand);
	112	sprintf(tmp, "%.*f", (int)(maxlen - strlen(tmp) - 1),
	113	(double)modulo / (double)thousand);
	114
	115	if (asprintf(&buf, "%llu.%s%s%s", (unsigned long long) num, &tmp[2],
	116	unitprefix[post_index], unitstr[units]) < 0)
	117	buf = NULL;
	118	return buf;
	119	}