Fix num2str() output when modulo != -1U

[fio.git] / lib / num2str.c

diff --git a/lib/num2str.c b/lib/num2str.c
index e114cdf8ebea83db1d79725403475f977b7d7cc9..8d0884132fe4ce5a3f2aace08fe26ef9eb5b28bf 100644 (file)
--- a/lib/num2str.c
+++ b/lib/num2str.c
@@ -2,47 +2,113 @@
 #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_* macros 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, int 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;
+       const char *unitstr[] = { "", "/s", "B", "bit", "B/s", "bit/s" };
+       const unsigned int thousand[] = { 1000, 1024 };
+       unsigned int modulo;
+       int unit_index = 0, post_index, carry = 0;
+       char tmp[32], fmt[32];
        char *buf;
 
+       compiletime_assert(sizeof(sistr) == sizeof(iecstr), "unit prefix arrays must be identical sizes");
+
        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];
 
+       switch (units) {
+       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(postfix)) {
-               sprintf(tmp, "%lu", num);
+       while (post_index < sizeof(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;
                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[unit_index]);
                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[!!pow2]);
+       sprintf(fmt, "%%.%df", (int)(maxlen - strlen(tmp) - 1));
+       sprintf(tmp, fmt, (double)modulo / (double)thousand[!!pow2]);
 
-       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[unit_index]);
        return buf;
 }