Docs added (NAPTR type), code style fixes

Author: sergey-lukin

README.markdown

@@ -28,6 +28,7 @@ Table of Contents
     * [TYPE_TXT](#type_txt)
     * [TYPE_AAAA](#type_aaaa)
     * [TYPE_SRV](#type_srv)
+    * [TYPE_NAPTR](#type_naptr)
     * [TYPE_SPF](#type_spf)
     * [CLASS_IN](#class_in)
     * [SECTION_AN](#section_an)
@@ -373,6 +374,16 @@ See RFC 2782 for details.
 
 [Back to TOC](#table-of-contents)
 
+TYPE_NAPTR
+----------
+`syntax: typ = r.TYPE_NAPTR`
+
+The `NAPTR` resource record type, equal to the decimal number `35`.
+
+See RFC 2915 for details.
+
+[Back to TOC](#table-of-contents)
+
 TYPE_SPF
 ---------
 `syntax: typ = r.TYPE_SPF`

lib/resty/dns/resolver.lua

@@ -211,17 +211,22 @@ local function _encode_name(s)
     return char(#s) .. s
 end
 
+
 local function _decode_string(buf, pos)
     local slen = byte(buf, pos)
+
     if slen == 0 then
         return "", pos + 1
     end
+
     if pos + 1 + slen >= #buf then
         return nil, 'truncated'
     end
+
     return sub(buf, pos + 1, pos + slen), pos + slen + 1
 end
 
+
 local function _decode_name(buf, pos)
     local labels = {}
     local nptrs = 0
@@ -501,34 +506,43 @@ local function parse_section(answers, section, buf, start_pos, size,
                 return nil, "bad NAPTR record value length: " .. len
             end
 
-            local hi = byte(buf, pos)
-            local lo = byte(buf, pos + 1)
-            ans.order = lshift(hi, 8) + lo
+            local order_hi = byte(buf, pos)
+            local order_lo = byte(buf, pos + 1)
+            ans.order = lshift(order_hi, 8) + order_lo
 
-            hi = byte(buf, pos + 2)
-            lo = byte(buf, pos + 3)
-            ans.preference = lshift(hi, 8) + lo
+            local preference_hi = byte(buf, pos + 2)
+            local preference_lo = byte(buf, pos + 3)
+            ans.preference = lshift(preference_hi, 8) + preference_lo
 
-            local str, p = _decode_string(buf, pos + 4)
-            if not str then return nil, pos end
-            ans.flags = str
+            local flags_str, p = _decode_string(buf, pos + 4)
+            if not flags_str then
+                return nil, pos
+            end
+            ans.flags = flags_str
 
-            str, p = _decode_string(buf, p)
-            if not str then return nil, pos end
-            ans.services = str
+            local services_str, p = _decode_string(buf, p)
+            if not services_str then
+                return nil, pos
+            end
+            ans.services = services_str
 
-            str, p = _decode_string(buf, p)
-            if not str then return nil, pos end
-            ans.regexp = str
+            local regexp_str, p = _decode_string(buf, p)
+            if not regexp_str then
+                return nil, pos
+            end
+            ans.regexp = regexp_str
 
             if p - pos < len then
-                str,p = _decode_name(buf, p)
-                if not str then return nil, pos end
-                ans.replacements = str
+                local replacements_str,p = _decode_name(buf, p)
+                if not replacements_str
+                    then return nil, pos
+                end
+                ans.replacements = replacements_str
             end
 
             if p - pos ~= len then
-                return nil, format("bad NAPTR record length: %d ~= %d", p - pos, len)
+                return nil, format("bad NAPTR record length: %d ~= %d",
+                                   p - pos, len)
             end
 
             pos = p