Fixed wrong value returned by CIDRToIPv6 function

Author: ip2location-com

com/ip2location/Country.java

@@ -17,7 +17,7 @@
  * <p>
  *
  * @author IP2Location.com
- * @version 8.11.1
+ * @version 8.11.2
  */
 public class Country {
     private final Map<String, Map<String, String>> records = new HashMap<>();

com/ip2location/IP2Location.java

@@ -34,7 +34,7 @@
  * <p>
  *
  * @author IP2Location.com
- * @version 8.11.1
+ * @version 8.11.2
  */
 public class IP2Location {
     private static final Pattern pattern = Pattern.compile("^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$"); // IPv4

com/ip2location/IP2LocationWebService.java

@@ -26,7 +26,7 @@
  * <p>
  *
  * @author IP2Location.com
- * @version 8.11.1
+ * @version 8.11.2
  */
 public class IP2LocationWebService {
     private static final Pattern pattern = Pattern.compile("^[\\dA-Z]{10}$");

com/ip2location/IPResult.java

@@ -7,7 +7,7 @@
  * <p>
  *
  * @author IP2Location.com
- * @version 8.11.1
+ * @version 8.11.2
  */
 public class IPResult {
     static final String NOT_SUPPORTED = "Not_Supported";
@@ -39,7 +39,7 @@ public class IPResult {
     String as;
     String status;
     boolean delay = false;
-    String version = "Version 8.11.1";
+    String version = "Version 8.11.2";
 
     IPResult(String ipstring) {
         ip_address = ipstring;

com/ip2location/IPTools.java

@@ -1,5 +1,7 @@
 package com.ip2location;
 
+import org.apache.commons.lang3.StringUtils;
+
 import java.math.BigInteger;
 import java.net.Inet4Address;
 import java.net.Inet6Address;
@@ -32,7 +34,7 @@
  * <p>
  *
  * @author IP2Location.com
- * @version 8.11.1
+ * @version 8.11.2
  */
 public class IPTools {
     private static final BigInteger MAX_IPV4_RANGE = new BigInteger("4294967295");
@@ -413,8 +415,7 @@ public List<String> IPv6ToCIDR(String IPFrom, String IPTo) throws UnknownHostExc
 
         } while (ipFromBin.compareTo(ipToBin) < 0);
 
-        for (Map.Entry<String, Integer>
-                entry : networks.entrySet()) {
+        for (Map.Entry<String, Integer> entry : networks.entrySet()) {
             result.add(CompressIPv6(BinaryToIP(entry.getKey())) + "/" + entry.getValue());
         }
 
@@ -489,33 +490,26 @@ public String[] CIDRToIPv6(String CIDR) throws UnknownHostException {
         ip = arr[0];
         prefix = Integer.parseInt(arr[1]);
 
-        String hexStartAddress = ExpandIPv6(ip).replaceAll(":", "");
-        String hexEndAddress = hexStartAddress;
+        String[] parts = ExpandIPv6(ip).split("\\:");
 
-        int bits = 128 - prefix;
-        int x;
-        String y;
-        int pos = 31;
-        List<Integer> values;
-        char[] tmp;
-        while (bits > 0) {
-            values = Arrays.asList(4, bits);
-            x = Integer.parseInt(String.valueOf(hexEndAddress.charAt(pos)), 16);
-            y = String.format("%x", (x | (int) (Math.pow(2, Collections.min(values)) - 1))); // single hex char
-
-            // replace char
-            tmp = hexEndAddress.toCharArray();
-            tmp[pos] = y.charAt(0);
-            hexEndAddress = String.valueOf(tmp);
-
-            bits -= 4;
-            pos -= 1;
+        String bitStart = StringUtils.repeat('1', prefix) + StringUtils.repeat('0', 128 - prefix);
+        String bitEnd = StringUtils.repeat('0', prefix) + StringUtils.repeat('1', 128 - prefix);
+
+        int chunkSize = 16;
+
+        String[] floors = bitStart.split("(?<=\\G.{" + chunkSize + "})");
+        String[] ceilings = bitEnd.split("(?<=\\G.{" + chunkSize + "})");
+
+        List<String> startIP = new ArrayList(8);
+        List<String> endIP = new ArrayList(8);
+
+        for (int x = 0; x < 8; x++) {
+            startIP.add(Integer.toHexString(Integer.parseInt(parts[x], 16) & Integer.parseInt(floors[x], 2)));
+            endIP.add(Integer.toHexString(Integer.parseInt(parts[x], 16) | Integer.parseInt(ceilings[x], 2)));
         }
 
-        hexStartAddress = hexStartAddress.replaceAll("(.{4})", "$1:");
-        hexStartAddress = hexStartAddress.substring(0, hexStartAddress.length() - 1);
-        hexEndAddress = hexEndAddress.replaceAll("(.{4})", "$1:");
-        hexEndAddress = hexEndAddress.substring(0, hexEndAddress.length() - 1);
+        String hexStartAddress = ExpandIPv6(StringUtils.join(startIP, ":"));
+        String hexEndAddress = ExpandIPv6(StringUtils.join(endIP, ":"));
 
         return new String[]{hexStartAddress, hexEndAddress};
     }

com/ip2location/Region.java

@@ -1,5 +1,8 @@
 package com.ip2location;
 
+import com.opencsv.*;
+import com.opencsv.exceptions.*;
+
 import java.io.File;
 import java.io.FileReader;
 import java.io.IOException;
@@ -8,17 +11,14 @@
 import java.util.List;
 import java.util.Map;
 
-import com.opencsv.*;
-import com.opencsv.exceptions.*;
-
 /**
  * This class parses region information CSV and returns the region code.
  * <p>
  * Copyright (c) 2002-2023 IP2Location.com
  * <p>
  *
  * @author IP2Location.com
- * @version 8.11.1
+ * @version 8.11.2
  */
 public class Region {
     private final Map<String, List<Map<String, String>>> records = new HashMap<>();
@@ -66,21 +66,19 @@ public String getRegionCode(final String countryCode, final String regionName) t
             throw new IOException("No record available.");
         } else {
             final List<Map<String, String>> items = records.get(countryCode);
-            if (items == null)
-                return null;
+            if (items == null) return null;
 
             final String region = regionName.toUpperCase();
             for (Map<String, String> item : items) {
                 final String regionCode = item.get(region);
-                if (regionCode != null)
-                    return regionCode;
+                if (regionCode != null) return regionCode;
             }
         }
         return null;
     }
 
     /**
-     * @deprecated  Use {{@link #getRegionCode(String, String)} instead.
+     * @deprecated Use {{@link #getRegionCode(String, String)} instead.
      */
     @Deprecated
     public String GetRegionCode(final String countryCode, final String regionName) throws IOException {