Myracle commented on code in PR #27483: URL: https://github.com/apache/flink/pull/27483#discussion_r2929947577
########## flink-table/flink-table-runtime/src/main/java/org/apache/flink/table/runtime/functions/scalar/InetAtonFunction.java: ########## @@ -0,0 +1,159 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.flink.table.runtime.functions.scalar; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.table.data.StringData; +import org.apache.flink.table.functions.BuiltInFunctionDefinitions; +import org.apache.flink.table.functions.SpecializedFunction; + +import javax.annotation.Nullable; + +/** + * Implementation of {@link BuiltInFunctionDefinitions#INET_ATON}. + * + * <p>This function converts an IPv4 address string to its numeric representation. It follows the + * MySQL INET_ATON function behavior, including support for short-form IPv4 addresses. + * + * <p>The conversion formula for a standard IP address A.B.C.D is: A * 256^3 + B * 256^2 + C * 256 + + * D + * + * <p>MySQL-compatible short-form IPv4 addresses are supported: + * + * <ul> + * <li>a.b is interpreted as a.0.0.b + * <li>a.b.c is interpreted as a.b.0.c + * </ul> + * + * <p>Leading zeros in octets are parsed as decimal (consistent with MySQL), not octal. + * + * <p>Note: This function only supports IPv4 addresses. IPv6 addresses are not supported. + * + * <p><b>Implementation Note:</b> This implementation does not use utility classes such as {@code + * com.google.common.net.InetAddresses} or {@code sun.net.util.IPAddressUtil} because: + * + * <ul> + * <li>Guava's {@code InetAddresses.forString()} does not support MySQL-compatible short-form IP + * addresses (e.g., "127.1" interpreted as "127.0.0.1") + * <li>Standard IP parsers may interpret leading zeros as octal (e.g., "010" as 8), while MySQL + * treats them as decimal (e.g., "010" as 10) + * <li>{@code sun.net.util.IPAddressUtil} is a JDK internal API requiring {@code --add-exports}, + * which introduces JDK version compatibility issues + * </ul> + * + * <p>Examples: + * + * <ul> + * <li>INET_ATON('127.0.0.1') returns 2130706433 + * <li>INET_ATON('127.1') returns 2130706433 (short-form: 127.0.0.1) + * <li>INET_ATON('127.0.1') returns 2130706433 (short-form: 127.0.0.1) + * <li>INET_ATON('10.0.0.1') returns 167772161 + * <li>INET_ATON('0.0.0.0') returns 0 + * </ul> + */ +@Internal +public class InetAtonFunction extends BuiltInScalarFunction { + + public InetAtonFunction(SpecializedFunction.SpecializedContext context) { + super(BuiltInFunctionDefinitions.INET_ATON, context); + } + + /** + * Converts an IPv4 address string to its numeric representation. + * + * @param ipAddress the IPv4 address string in dotted-decimal notation (supports short-form) + * @return the numeric representation of the IP address, or null if input is null or invalid + */ + public @Nullable Long eval(@Nullable StringData ipAddress) { + if (ipAddress == null) { + return null; + } + + final String ip = ipAddress.toString(); + if (ip.isEmpty()) { + return null; + } + + return ipToLong(ip); + } + + /** + * Converts an IPv4 address string to a long value. + * + * <p>Supports MySQL-compatible short-form addresses: + * + * <ul> + * <li>a.b -> a.0.0.b + * <li>a.b.c -> a.b.0.c + * <li>a.b.c.d -> standard format + * </ul> + * + * <p>Leading zeros are treated as decimal (not octal), consistent with MySQL behavior. + * + * @param ip the IPv4 address string + * @return the long value, or null if the IP address is invalid + */ + private static @Nullable Long ipToLong(String ip) { + int len = ip.length(); + int octetCount = 0; + int octetStart = 0; + long[] octets = new long[4]; + + for (int i = 0; i <= len; i++) { + if (i == len || ip.charAt(i) == '.') { + if (octetCount >= 4) { + return null; + } + if (octetStart == i) { + return null; + } + + // Parse number manually + long octet = 0; + for (int j = octetStart; j < i; j++) { + char c = ip.charAt(j); + if (c < '0' || c > '9') { + return null; + } + octet = octet * 10 + (c - '0'); + if (octet > 255) { + return null; + } + } + octets[octetCount++] = octet; + octetStart = i + 1; + } + } + + if (octetCount < 2) { + return null; + } Review Comment: > Thanks for pointing this out! > > You're right — I double-checked and MySQL does support single-number addresses. Under the hood, MySQL's `INET_ATON` relies on the C library `inet_aton(3)`, which follows these rules for short-form addresses: > > | Parts | Format | Interpretation | > |-------|--------|---------------| > | 1 | `a` | Direct 32-bit value | > | 2 | `a.b` | `a.0.0.b` | > | 3 | `a.b.c` | `a.b.0.c` | > | 4 | `a.b.c.d` | Standard dotted-decimal | > > So `INET_ATON('1')` returns `1` in MySQL (treating the input as a direct 32-bit address value). My previous implementation rejected single-number inputs with the `if (octetCount < 2)` guard. > > I've made the following changes: > > 1. **Added `case 1` to the switch in `ipToLong()`** — single-number inputs are now accepted as direct 32-bit values (must be in `[0, 0xFFFFFFFF]`). The per-part overflow check in the parsing loop was also raised from `255` to `0xFFFFFFFFL` to accommodate this. > > 2. **Added `inetAtonSingleNumberTestCases()`** — tests `'1'` → `1`, `'0'` → `0`, `'255'` → `255`, `'167772161'` → `167772161` (equivalent to `10.0.0.1`), `'4294967295'` → `4294967295` (max), and `'4294967296'` → `null` (overflow). > > 3. **Moved `'1'` out of invalid input test cases** — it was previously listed as an invalid single-octet input; now it's a valid single-number address. > > Note: MySQL's official docs state that short-form behavior "*may or may not*" return non-NULL (and recommends against relying on it), but in practice MySQL consistently supports it via the C library `inet_aton`. Since our goal is MySQL compatibility, I've implemented the full `inet_aton(3)` behavior. > -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. 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