common: New function string_to_u64.

* common/stringhelp.c (string_to_u64): New.
* dirmngr/http.c (longcounter_t): Remove.
(struct cookie_s): Change content_length to uint64_t.
(parse_response): Use string_to_u64.
--

Meanwhile we allow some C99 features including stdint.h.  Thus we can
simplify things now.

Signed-off-by: Werner Koch <wk@gnupg.org>

common/stringhelp.c

@@ -58,6 +58,7 @@
 
 #define tohex_lower(n) ((n) < 10 ? ((n) + '0') : (((n) - 10) + 'a'))
 
+
 /* Sometimes we want to avoid mixing slashes and backslashes on W32
    and prefer backslashes.  There is usual no problem with mixing
    them, however a very few W32 API calls can't grok plain slashes.
@@ -660,6 +661,25 @@ compare_filenames (const char *a, const char *b)
 }
 
 
+/* Convert a base-10 number in STRING into a 64 bit unsigned int
+ * value.  Leading white spaces are skipped but no error checking is
+ * done.  Thus it is similar to atoi(). */
+uint64_t
+string_to_u64 (const char *string)
+{
+  uint64_t val = 0;
+
+  while (spacep (string))
+    string++;
+  for (; digitp (string); string++)
+    {
+      val *= 10;
+      val += *string - '0';
+    }
+  return val;
+}
+
+
 /* Convert 2 hex characters at S to a byte value.  Return this value
    or -1 if there is an error. */
 int