[fio.git] / lib / num2str.c

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

#include "../compiler/compiler.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" };
	const char *iecstr[] = { "", "Ki", "Mi", "Gi", "Ti", "Pi" };
	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], fmt[32];
	char *buf;

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

	buf = malloc(128);
	if (!buf)
		return NULL;

	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 no modulo, then we're done.
	 */
	if (modulo == -1U) {
done:
		if (post_index >= ARRAY_SIZE(sistr))
			post_index = 0;

		sprintf(buf, "%llu%s%s", (unsigned long long) num,
			unitprefix[post_index], unitstr[units]);
		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(fmt, "%%.%df", (int)(maxlen - strlen(tmp) - 1));
	sprintf(tmp, fmt, (double)modulo / (double)thousand);

	sprintf(buf, "%llu.%s%s%s", (unsigned long long) num, &tmp[2],
			unitprefix[post_index], unitstr[units]);
	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 "num2str.h"
	8
	9	#define ARRAY_SIZE(x) (sizeof((x)) / (sizeof((x)[0])))
	10
	11	/**
	12	* num2str() - Cheesy number->string conversion, complete with carry rounding error.
	13	* @num: quantity (e.g., number of blocks, bytes or bits)
	14	* @maxlen: max number of digits in the output string (not counting prefix and units, but counting .)
	15	* @base: multiplier for num (e.g., if num represents Ki, use 1024)
	16	* @pow2: select unit prefix - 0=power-of-10 decimal SI, nonzero=power-of-2 binary IEC
	17	* @units: select units - N2S_* constants defined in num2str.h
	18	* @returns a malloc'd buffer containing "number[<unit prefix>][<units>]"
	19	*/
	20	char *num2str(uint64_t num, int maxlen, int base, int pow2, enum n2s_unit units)
	21	{
	22	const char *sistr[] = { "", "k", "M", "G", "T", "P" };
	23	const char *iecstr[] = { "", "Ki", "Mi", "Gi", "Ti", "Pi" };
	24	const char **unitprefix;
	25	static const char *const unitstr[] = {
	26	[N2S_NONE] = "",
	27	[N2S_PERSEC] = "/s",
	28	[N2S_BYTE] = "B",
	29	[N2S_BIT] = "bit",
	30	[N2S_BYTEPERSEC]= "B/s",
	31	[N2S_BITPERSEC] = "bit/s"
	32	};
	33	const unsigned int thousand = pow2 ? 1024 : 1000;
	34	unsigned int modulo;
	35	int post_index, carry = 0;
	36	char tmp[32], fmt[32];
	37	char *buf;
	38
	39	compiletime_assert(sizeof(sistr) == sizeof(iecstr), "unit prefix arrays must be identical sizes");
	40	assert(units < ARRAY_SIZE(unitstr));
	41
	42	buf = malloc(128);
	43	if (!buf)
	44	return NULL;
	45
	46	if (pow2)
	47	unitprefix = iecstr;
	48	else
	49	unitprefix = sistr;
	50
	51	for (post_index = 0; base > 1; post_index++)
	52	base /= thousand;
	53
	54	switch (units) {
	55	case N2S_NONE:
	56	break;
	57	case N2S_PERSEC:
	58	break;
	59	case N2S_BYTE:
	60	break;
	61	case N2S_BIT:
	62	num *= 8;
	63	break;
	64	case N2S_BYTEPERSEC:
	65	break;
	66	case N2S_BITPERSEC:
	67	num *= 8;
	68	break;
	69	}
	70
	71	/*
	72	* Divide by K/Ki until string length of num <= maxlen.
	73	*/
	74	modulo = -1U;
	75	while (post_index < ARRAY_SIZE(sistr)) {
	76	sprintf(tmp, "%llu", (unsigned long long) num);
	77	if (strlen(tmp) <= maxlen)
	78	break;
	79
	80	modulo = num % thousand;
	81	num /= thousand;
	82	carry = modulo >= thousand / 2;
	83	post_index++;
	84	}
	85
	86	/*
	87	* If no modulo, then we're done.
	88	*/
	89	if (modulo == -1U) {
	90	done:
	91	if (post_index >= ARRAY_SIZE(sistr))
	92	post_index = 0;
	93
	94	sprintf(buf, "%llu%s%s", (unsigned long long) num,
	95	unitprefix[post_index], unitstr[units]);
	96	return buf;
	97	}
	98
	99	/*
	100	* If no room for decimals, then we're done.
	101	*/
	102	sprintf(tmp, "%llu", (unsigned long long) num);
	103	if ((int)(maxlen - strlen(tmp)) <= 1) {
	104	if (carry)
	105	num++;
	106	goto done;
	107	}
	108
	109	/*
	110	* Fill in everything and return the result.
	111	*/
	112	assert(maxlen - strlen(tmp) - 1 > 0);
	113	assert(modulo < thousand);
	114	sprintf(fmt, "%%.%df", (int)(maxlen - strlen(tmp) - 1));
	115	sprintf(tmp, fmt, (double)modulo / (double)thousand);
	116
	117	sprintf(buf, "%llu.%s%s%s", (unsigned long long) num, &tmp[2],
	118	unitprefix[post_index], unitstr[units]);
	119	return buf;
	120	}