PREDICATE_IS_ASCII

Author: wenshao

core/src/main/java/com/alibaba/fastjson2/JSONReader.java

@@ -3240,13 +3240,8 @@ protected final String toString(Map object) {
     }
 
     public static JSONReader of(byte[] utf8Bytes) {
-        boolean ascii = false;
-        if (PREDICATE_IS_ASCII != null) {
-            ascii = PREDICATE_IS_ASCII.test(utf8Bytes);
-        }
-
         Context context = createReadContext();
-        if (ascii) {
+        if (PREDICATE_IS_ASCII.test(utf8Bytes)) {
             return new JSONReaderASCII(context, null, utf8Bytes, 0, utf8Bytes.length);
         }
 
@@ -3255,25 +3250,15 @@ public static JSONReader of(byte[] utf8Bytes) {
 
     @Deprecated
     public static JSONReader of(Context context, byte[] utf8Bytes) {
-        boolean ascii = false;
-        if (PREDICATE_IS_ASCII != null) {
-            ascii = PREDICATE_IS_ASCII.test(utf8Bytes);
-        }
-
-        if (ascii) {
+        if (PREDICATE_IS_ASCII.test(utf8Bytes)) {
             return new JSONReaderASCII(context, null, utf8Bytes, 0, utf8Bytes.length);
         }
 
         return new JSONReaderUTF8(context, null, utf8Bytes, 0, utf8Bytes.length);
     }
 
     public static JSONReader of(byte[] utf8Bytes, Context context) {
-        boolean ascii = false;
-        if (PREDICATE_IS_ASCII != null) {
-            ascii = PREDICATE_IS_ASCII.test(utf8Bytes);
-        }
-
-        if (ascii) {
+        if (PREDICATE_IS_ASCII.test(utf8Bytes)) {
             return new JSONReaderASCII(context, null, utf8Bytes, 0, utf8Bytes.length);
         }
 
@@ -3510,7 +3495,7 @@ public static JSONReader of(String str) {
         }
 
         Context context = JSONFactory.createReadContext();
-        if (STRING_VALUE != null && STRING_CODER != null && PREDICATE_IS_ASCII != null) {
+        if (STRING_VALUE != null && STRING_CODER != null) {
             try {
                 final int LATIN1 = 0;
                 int coder = STRING_CODER.applyAsInt(str);

core/src/main/java/com/alibaba/fastjson2/util/JDKUtils.java

@@ -316,6 +316,9 @@ public class JDKUtils {
                     initErrorLast = e;
                 }
             }
+            if (isAscii == null) {
+                isAscii = JDKUtils::isASCII;
+            }
 
             PREDICATE_IS_ASCII = isAscii;
         }
@@ -506,4 +509,21 @@ public static String latin1StringJDK8(byte[] bytes, int offset, int strlen) {
         }
         return STRING_CREATOR_JDK8.apply(chars, Boolean.TRUE);
     }
+
+    public static boolean isASCII(byte[] chars) {
+        int i = 0;
+        int strlen = chars.length;
+        for (int upperBound = (strlen & ~7); i < upperBound; i += 8) {
+            if ((UNSAFE.getLong(chars, ARRAY_BYTE_BASE_OFFSET + i) & 0x8080808080808080L) != 0) {
+                return false;
+            }
+        }
+
+        for (; i < strlen; ++i) {
+            if (UNSAFE.getByte(chars, ARRAY_BYTE_BASE_OFFSET + i) < 0) {
+                return false;
+            }
+        }
+        return true;
+    }
 }