update api & utility

Author: i3water

src/Blinker/BlinkerApi.h

@@ -102,9 +102,9 @@ class BlinkerApi
         bool button(const String & _bName)
         {
             int8_t num = checkNum(_bName, _Button, _bCount);
-            String state = STRING_find_string_value(static_cast<Proto*>(this)->dataParse(), _bName);
+            String state;
 
-            if (state != "") {
+            if (STRING_find_string_value(static_cast<Proto*>(this)->dataParse(), state, _bName)) {
                 _fresh = true;
             }
 
@@ -306,9 +306,9 @@ class BlinkerApi
         bool buttonParse(const String & _bName)
         {
             int8_t num = checkNum(_bName, _Button, _bCount);
-            String state = STRING_find_string_value(static_cast<Proto*>(this)->dataParse(), _bName);
+            String state;
 
-            if (state != "") {
+            if (STRING_find_string_value(static_cast<Proto*>(this)->dataParse(), state, _bName)) {
                 _fresh = true;
             }
 

src/utility/BlinkerUtility.h

@@ -94,18 +94,19 @@ bool STRING_contais_string(const String & src, const String & key)
     return key == src.substring(addr_start, addr_start + keyLen);
 }
 
-String STRING_find_string_value(const String & src, const String & key)
+bool STRING_find_string_value(const String & src,String & dst, const String & key)
 {
     int addr_start = src.indexOf(key);
     uint8_t keyLen = key.length();
 
     int addr_end = src.indexOf(STRING_VALUE_END, addr_start + keyLen + STRING_VALUE_SKIP);
 
     if (addr_start == -1 || addr_end == -1) {
-        return "";
+        return false;
     }
     else {
-        return src.substring(addr_start + keyLen + STRING_VALUE_SKIP, addr_end);
+        dst = src.substring(addr_start + keyLen + STRING_VALUE_SKIP, addr_end);
+        return true;
     }
 }