num2str(): Use asprintf() instead of malloc()

This patch reduces the size of the buffer allocated by num2str().

Signed-off-by: Bart Van Assche <bvanassche@acm.org>

diff --git a/lib/num2str.c b/lib/num2str.c
index 1abe22f33794c0ccf6b724e74aef7a1f62271166..ce17727598d16e51ddb25576ef5718d3d223abe0 100644 (file)
--- a/lib/num2str.c
+++ b/lib/num2str.c
@@ -4,6 +4,7 @@
 #include <string.h>
 
 #include "../compiler/compiler.h"
+#include "../oslib/asprintf.h"
 #include "num2str.h"
 
 #define ARRAY_SIZE(x)    (sizeof((x)) / (sizeof((x)[0])))
@@ -39,10 +40,6 @@ char *num2str(uint64_t num, int maxlen, int base, int pow2, enum n2s_unit units)
        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
@@ -91,8 +88,9 @@ done:
                if (post_index >= ARRAY_SIZE(sistr))
                        post_index = 0;
 
-               sprintf(buf, "%llu%s%s", (unsigned long long) num,
-                       unitprefix[post_index], unitstr[units]);
+               if (asprintf(&buf, "%llu%s%s", (unsigned long long) num,
+                            unitprefix[post_index], unitstr[units]) < 0)
+                       buf = NULL;
                return buf;
        }
 
@@ -114,7 +112,8 @@ done:
        sprintf(fmt, "%%.%df", (int)(maxlen - strlen(tmp) - 1));
        sprintf(tmp, fmt, (double)modulo / (double)thousand);
 
-       sprintf(buf, "%llu.%s%s%s", (unsigned long long) num, &tmp[2],
-                       unitprefix[post_index], unitstr[units]);
+       if (asprintf(&buf, "%llu.%s%s%s", (unsigned long long) num, &tmp[2],
+                    unitprefix[post_index], unitstr[units]) < 0)
+               buf = NULL;
        return buf;
 }