/**
* 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
const char **unitprefix;
const char *unitstr[] = { "", "/s", "B", "bit", "B/s", "bit/s" };
const unsigned int thousand[] = { 1000, 1024 };
- unsigned int modulo, decimals;
+ unsigned int modulo;
int unit_index = 0, post_index, carry = 0;
- char tmp[32];
+ char tmp[32], fmt[32];
char *buf;
compiletime_assert(sizeof(sistr) == sizeof(iecstr), "unit prefix arrays must be identical sizes");
break;
}
+ /*
+ * Divide by K/Ki until string length of num <= maxlen.
+ */
modulo = -1U;
while (post_index < sizeof(sistr)) {
sprintf(tmp, "%llu", (unsigned long long) num);
post_index++;
}
+ /*
+ * If no modulo, then we're done.
+ */
if (modulo == -1U) {
done:
if (post_index >= ARRAY_SIZE(sistr))
return buf;
}
+ /*
+ * If no room for decimals, then we're done.
+ */
sprintf(tmp, "%llu", (unsigned long long) num);
- decimals = maxlen - strlen(tmp);
- if ((int)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[!!pow2]);
+ sprintf(fmt, "%%.%df", (int)(maxlen - strlen(tmp) - 1));
+ sprintf(tmp, fmt, (double)modulo / (double)thousand[!!pow2]);
- sprintf(buf, "%llu.%u%s%s", (unsigned long long) num, modulo,
+ sprintf(buf, "%llu.%s%s%s", (unsigned long long) num, &tmp[2],
unitprefix[post_index], unitstr[unit_index]);
return buf;
}