diff --git a/src/main/java/com/reandroid/arsc/decoder/ColorUtil.java b/src/main/java/com/reandroid/arsc/decoder/ColorUtil.java
index 311fd7d..a4ca742 100644
--- a/src/main/java/com/reandroid/arsc/decoder/ColorUtil.java
+++ b/src/main/java/com/reandroid/arsc/decoder/ColorUtil.java
@@ -18,9 +18,6 @@ package com.reandroid.arsc.decoder;
 import com.reandroid.arsc.util.HexUtil;
 import com.reandroid.arsc.value.ValueType;
 
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-
 public class ColorUtil {
 
     public static String decode(ValueType valueType, int data){
@@ -48,68 +45,84 @@ public class ColorUtil {
         return "#" + hex.substring(index);
     }
     public static ValueDecoder.EncodeResult encode(String hexColor){
-        if(hexColor == null){
+        int[] values = hexToIntegers(hexColor);
+        if(values == null){
             return null;
         }
-        hexColor = hexColor.toUpperCase();
-        Matcher matcher = PATTERN_COLOR.matcher(hexColor);
-        if(!matcher.matches()){
-            return null;
-        }
-        char[] s = hexColor.toCharArray();
-        int len = s.length;
         ValueType valueType;
         int color = 0;
 
+        int len = values.length;
         if (len == 4) {
             valueType = ValueType.INT_COLOR_RGB4;
-            color |= 0xFF0000;
-            color |= get_hex(s[1]) << 20;
-            color |= get_hex(s[1]) << 16;
-            color |= get_hex(s[2]) << 12;
-            color |= get_hex(s[2]) << 8;
-            color |= get_hex(s[3]) << 4;
-            color |= get_hex(s[3]);
+            color |= 0xFF000000;
+            color |= values[1] << 20;
+            color |= values[1] << 16;
+            color |= values[2] << 12;
+            color |= values[2] << 8;
+            color |= values[3] << 4;
+            color |= values[3];
         } else if (len == 5) {
             valueType = ValueType.INT_COLOR_ARGB4;
-            color |= 0xFFFF0000;
-            color |= get_hex(s[1]) << 28;
-            color |= get_hex(s[1]) << 24;
-            color |= get_hex(s[2]) << 20;
-            color |= get_hex(s[2]) << 16;
-            color |= get_hex(s[3]) << 12;
-            color |= get_hex(s[3]) << 8;
-            color |= get_hex(s[4]) << 4;
-            color |= get_hex(s[4]);
+            color |= values[1] << 28;
+            color |= values[1] << 24;
+            color |= values[2] << 20;
+            color |= values[2] << 16;
+            color |= values[3] << 12;
+            color |= values[3] << 8;
+            color |= values[4] << 4;
+            color |= values[4];
         } else if (len == 7) {
             valueType = ValueType.INT_COLOR_RGB8;
             color |= 0xFF000000;
-            color |= get_hex(s[1]) << 20;
-            color |= get_hex(s[2]) << 16;
-            color |= get_hex(s[3]) << 12;
-            color |= get_hex(s[4]) << 8;
-            color |= get_hex(s[5]) << 4;
-            color |= get_hex(s[6]);
+            color |= values[1] << 20;
+            color |= values[2] << 16;
+            color |= values[3] << 12;
+            color |= values[4] << 8;
+            color |= values[5] << 4;
+            color |= values[6];
         } else if (len == 9) {
             valueType = ValueType.INT_COLOR_ARGB8;
-            color |= get_hex(s[1]) << 28;
-            color |= get_hex(s[2]) << 24;
-            color |= get_hex(s[3]) << 20;
-            color |= get_hex(s[4]) << 16;
-            color |= get_hex(s[5]) << 12;
-            color |= get_hex(s[6]) << 8;
-            color |= get_hex(s[7]) << 4;
-            color |= get_hex(s[8]);
+            color |= values[1] << 28;
+            color |= values[2] << 24;
+            color |= values[3] << 20;
+            color |= values[4] << 16;
+            color |= values[5] << 12;
+            color |= values[6] << 8;
+            color |= values[7] << 4;
+            color |= values[8];
         }else {
             return null;
         }
         return new ValueDecoder.EncodeResult(valueType, color);
     }
-    private static int get_hex(char ch){
-        if(ch <= '9'){
-            return ch - '0';
+    private static int[] hexToIntegers(String hexColor){
+        if(hexColor == null){
+            return null;
         }
-        return 10 + (ch - 'A');
+        int length = hexColor.length();
+        if(length < 4 || length > 9){
+            return null;
+        }
+        hexColor = hexColor.toUpperCase();
+        char[] chars = hexColor.toCharArray();
+        if(chars[0] != '#'){
+            return null;
+        }
+        length = chars.length;
+        int[] result = new int[length];
+        for(int i = 1; i < length; i++){
+            int ch = chars[i];
+            int value;
+            if(ch >= '0' && ch <= '9'){
+                value = ch - '0';
+            }else if(ch >= 'A' && ch <= 'F'){
+                value = 10 + (ch - 'A');
+            }else {
+                return null;
+            }
+            result[i] = value;
+        }
+        return result;
     }
-    public static final Pattern PATTERN_COLOR = Pattern.compile("^#([0-9a-fA-F]{3,8})$");
 }