Utils: added function to get radix 10 string length of signed integer.

src/util.c

@@ -251,6 +251,18 @@ uint32_t digits10(uint64_t v) {
     return 12 + digits10(v / 1000000000000UL);
 }
 
+/* Like digits10() but for signed values. */
+uint32_t sdigits10(int64_t v) {
+    if (v < 0) {
+        /* Abs value of LLONG_MIN requires special handling. */
+        uint64_t uv = (v != LLONG_MIN) ?
+                      -v : ((uint64_t) LLONG_MAX)+1;
+        return digits10(uv)+1; /* +1 for the minus. */
+    } else {
+        return digits10(v);
+    }
+}
+
 /* Convert a long long into a string. Returns the number of
  * characters needed to represent the number.
  * If the buffer is not big enough to store the string, 0 is returned.

src/util.h

@@ -35,6 +35,8 @@
 int stringmatchlen(const char *p, int plen, const char *s, int slen, int nocase);
 int stringmatch(const char *p, const char *s, int nocase);
 long long memtoll(const char *p, int *err);
+uint32_t digits10(uint64_t v);
+uint32_t sdigits10(int64_t v);
 int ll2string(char *s, size_t len, long long value);
 int string2ll(const char *s, size_t slen, long long *value);
 int string2l(const char *s, size_t slen, long *value);