+#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
-/*
- * Cheesy number->string conversion, complete with carry rounding error.
+#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(unsigned long num, int maxlen, int base, int pow2)
+char *num2str(uint64_t num, int maxlen, int base, int pow2, enum n2s_unit units)
{
- char postfix[] = { ' ', 'K', 'M', 'G', 'P', 'E' };
- unsigned int thousand[] = { 1000, 1024 };
- unsigned int modulo, decimals;
- int post_index;
- char tmp[32], fmt[8];
+ 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[!!pow2];
+ 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 < sizeof(postfix)) {
- sprintf(tmp, "%lu", num);
+ 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];
+ modulo = num % thousand;
+ num /= thousand;
+ carry = modulo >= thousand / 2;
post_index++;
}
+ /*
+ * If no modulo, then we're done.
+ */
if (modulo == -1U) {
done:
- sprintf(buf, "%lu%c", num, postfix[post_index]);
+ 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;
}
- sprintf(tmp, "%lu", num);
- decimals = maxlen - strlen(tmp);
- if (decimals <= 1)
+ /*
+ * 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(fmt, "%%.%uu", decimals - 1);
- sprintf(tmp, fmt, modulo);
- sprintf(buf, "%lu.%s%c", num, tmp, postfix[post_index]);
+ sprintf(buf, "%llu.%s%s%s", (unsigned long long) num, &tmp[2],
+ unitprefix[post_index], unitstr[units]);
return buf;
}