Improve IEC binary and SI decimal prefix handling

[fio.git] / lib / num2str.c

diff --git a/lib/num2str.c b/lib/num2str.c
index 12d6f39aa5dbca892e9d03af9150aa28a3a47861..940d4a5e289133a03c89569dc3cca01a5e604b4c 100644 (file)
--- a/lib/num2str.c
+++ b/lib/num2str.c
@@ -4,37 +4,66 @@
 
 #include "../fio.h"
 
-/*
- * Cheesy number->string conversion, complete with carry rounding error.
+#define ARRAY_LENGTH(arr)      sizeof(arr) / sizeof((arr)[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)
+ * @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 fio.h
+ * @returns a malloc'd buffer containing "number[<unit prefix>][<units>]"
  */
-char *num2str(unsigned long num, int maxlen, int base, int pow2, int unit_base)
+char *num2str(uint64_t num, int maxlen, int base, int pow2, int units)
 {
-       const char *postfix[] = { "", "K", "M", "G", "P", "E" };
-       const char *byte_postfix[] = { "", "B", "bit" };
+       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 byte_post_index = 0, post_index, carry = 0;
+       int unit_index = 0, post_index, carry = 0;
        char tmp[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 (unit_base) {
-       case 1:
-               byte_post_index = 2;
+       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 8:
-               byte_post_index = 1;
+       case N2S_BYTEPERSEC:
+               unit_index = 4;
+               break;
+       case N2S_BITPERSEC:
+               unit_index = 5;
+               num *= 8;
                break;
        }
 
        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;
 
@@ -46,12 +75,15 @@ char *num2str(unsigned long num, int maxlen, int base, int pow2, int unit_base)
 
        if (modulo == -1U) {
 done:
-               sprintf(buf, "%lu%s%s", num, postfix[post_index],
-                       byte_postfix[byte_post_index]);
+               if (post_index >= ARRAY_LENGTH(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);
+       sprintf(tmp, "%llu", (unsigned long long) num);
        decimals = maxlen - strlen(tmp);
        if (decimals <= 1) {
                if (carry)
@@ -67,7 +99,7 @@ done:
                modulo = (modulo + 9) / 10;
        } while (1);
 
-       sprintf(buf, "%lu.%u%s%s", num, modulo, postfix[post_index],
-               byte_postfix[byte_post_index]);
+       sprintf(buf, "%llu.%u%s%s", (unsigned long long) num, modulo,
+                       unitprefix[post_index], unitstr[unit_index]);
        return buf;
 }