String.bytesFrom() method.

The method creates a byte string from an array containing octets:
    String.bytesFrom(array).

The method creates a byte string from an encoded string:
    String.bytesFrom(string, encoding)
where encoding are "hex", "base64", "base64url".

This closes #2 issue on Github.

njs/njs_number.c

@@ -215,32 +215,21 @@ njs_number_bin_parse(const u_char **start, const u_char *end)
 uint64_t
 njs_number_hex_parse(const u_char **start, const u_char *end)
 {
-    u_char        c;
     uint64_t      num;
+    nxt_int_t     n;
     const u_char  *p;
 
     p = *start;
 
     num = 0;
 
     while (p < end) {
-        c = (u_char) (*p | 0x20);
-
-        /* Values less than '0' become >= 208. */
-        c = c - '0';
-
-        if (c > 9) {
-            /* Values less than 'a' become >= 159. */
-            c = c - ('a' - '0');
-
-            if (nxt_slow_path(c > 5)) {
-                break;
-            }
-
-            c += 10;
+        n = njs_char_to_hex(*p);
+        if (nxt_slow_path(n < 0)) {
+            break;
         }
 
-        num = num * 16 + c;
+        num = num * 16 + n;
         p++;
     }
 

njs/njs_number.h

@@ -34,6 +34,29 @@ njs_ret_t njs_number_parse_float(njs_vm_t *vm, njs_value_t *args,
 nxt_noinline uint32_t njs_number_to_integer(double num);
 
 
+nxt_inline nxt_int_t
+njs_char_to_hex(u_char c)
+{
+    c |= 0x20;
+
+    /* Values less than '0' become >= 208. */
+    c = c - '0';
+
+    if (c > 9) {
+        /* Values less than 'a' become >= 159. */
+        c = c - ('a' - '0');
+
+        if (nxt_slow_path(c > 5)) {
+            return -1;
+        }
+
+        c += 10;
+    }
+
+    return c;
+}
+
+
 extern const njs_object_init_t  njs_number_constructor_init;
 extern const njs_object_init_t  njs_number_prototype_init;