hex: Simplify hex_encode

The documentation for hex_encode indicates that it returns simply true or
false. The old implementation was returning the written length on success,
cast to boolean. This will elicit a warning under MSVC.

On further examination, there is no need to check/modify the length inside
the loop, since we can check it once before starting. As a result the code
can be simplified a bit.

A side affect of this change is that nothing will be written at all if the
length is incorrect, vs the previous code writing characters until the length
available is exhausted. I prefer the new semantics but YMMV.

Signed-off-by: Jon Griffiths <jon_p_griffiths@yahoo.com>

diff --git a/ccan/str/hex/hex.c b/ccan/str/hex/hex.c
index fd4074f3d6a4f484e33674fa80b126b0fb1416db..6e031779fe87b325670040606fafefdef562c1f4 100644 (file)
--- a/ccan/str/hex/hex.c
+++ b/ccan/str/hex/hex.c
@@ -50,21 +50,17 @@ static char hexchar(unsigned int val)
 
 bool hex_encode(const void *buf, size_t bufsize, char *dest, size_t destsize)
 {
-       size_t used = 0;
+       size_t i;
 
-       if (destsize < 1)
+       if (destsize < hex_str_size(bufsize))
                return false;
 
-       while (used < bufsize) {
-               unsigned int c = ((const unsigned char *)buf)[used];
-               if (destsize < 3)
-                       return false;
+       for (i = 0; i < bufsize; i++) {
+               unsigned int c = ((const unsigned char *)buf)[i];
                *(dest++) = hexchar(c >> 4);
                *(dest++) = hexchar(c & 0xF);
-               used++;
-               destsize -= 2;
        }
        *dest = '\0';
 
-       return used + 1;
+       return true;
 }