Teach uc_hex_decode to skip spaces

src/hex.c

@@ -1,4 +1,5 @@
 #include <stdint.h>
+#include <ctype.h>
 #include <stddef.h>
 #include <string.h>
 #include "ucore/string.h"
@@ -79,14 +80,29 @@ uc_hex_decode(const char *in, size_t maxlen,uint8_t *out)
 {
     size_t i, t;
 
-    for (t = 0,i = 0; i + 1 < maxlen && in[i] && in[i + 1]; i+=2 , ++t) {
+    for (t = 0,i = 0; i + 1 < maxlen ;) {
         int hn, ln;
+        if (!(in[i] && in[i + 1])) {
+            break;
+        }
+
+        if (in[i] == ' '  ||
+            in[i] == '\t' ||
+            in[i] == '\r' ||
+            in[i] == '\n') {
+
+            i++;
+            continue;
+        }
+
         hn = char_to_bin(in[i]);
         ln = char_to_bin(in[i + 1]);
         if (hn == -1 || ln == -1)
             return NULL;
 
         out[t] = (hn << 4 ) | ln;
+        i += 2;
+        t++;
     }
 
     return &out[t];