+#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
/**
* 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)
+ * @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_* macros defined in num2str.h
+ * @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, int 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;
- const char *unitstr[] = { "", "/s", "B", "bit", "B/s", "bit/s" };
- const unsigned int thousand[] = { 1000, 1024 };
- unsigned int modulo, decimals;
- int unit_index = 0, post_index, carry = 0;
- char tmp[32];
+ 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)
unitprefix = sistr;
for (post_index = 0; base > 1; post_index++)
- base /= thousand[!!pow2];
+ base /= thousand;
switch (units) {
+ case N2S_NONE:
+ break;
case N2S_PERSEC:
- unit_index = 1;
break;
case N2S_BYTE:
- unit_index = 2;
break;
case N2S_BIT:
- unit_index = 3;
num *= 8;
break;
case N2S_BYTEPERSEC:
- unit_index = 4;
break;
case N2S_BITPERSEC:
- unit_index = 5;
num *= 8;
break;
}
+ /*
+ * Divide by K/Ki until string length of num <= maxlen.
+ */
modulo = -1U;
- while (post_index < sizeof(sistr)) {
+ while (post_index < ARRAY_SIZE(sistr)) {
sprintf(tmp, "%llu", (unsigned long long) num);
if (strlen(tmp) <= maxlen)
break;
- modulo = num % thousand[!!pow2];
- num /= thousand[!!pow2];
- carry = modulo >= thousand[!!pow2] / 2;
+ 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[unit_index]);
+ unitprefix[post_index], unitstr[units]);
return buf;
}
+ /*
+ * If no room for decimals, then we're done.
+ */
sprintf(tmp, "%llu", (unsigned long long) num);
- decimals = maxlen - strlen(tmp);
- if (decimals <= 1) {
+ if ((int)(maxlen - strlen(tmp)) <= 1) {
if (carry)
num++;
goto done;
}
- do {
- sprintf(tmp, "%u", modulo);
- if (strlen(tmp) <= decimals - 1)
- break;
-
- modulo = (modulo + 9) / 10;
- } while (1);
+ /*
+ * 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.%u%s%s", (unsigned long long) num, modulo,
- unitprefix[post_index], unitstr[unit_index]);
+ sprintf(buf, "%llu.%s%s%s", (unsigned long long) num, &tmp[2],
+ unitprefix[post_index], unitstr[units]);
return buf;
}