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This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * Copyright 2016 The Netty Project
 *
 * The Netty Project 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 io.netty.handler.codec.smtp;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.DecoderException;
import io.netty.handler.codec.LineBasedFrameDecoder;
import io.netty.util.CharsetUtil;
import io.netty.util.internal.UnstableApi;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * Decoder for SMTP responses.
 */
@UnstableApi
public final class SmtpResponseDecoder extends LineBasedFrameDecoder {

    private List details;

    /**
     * Creates a new instance that enforces the given {@code maxLineLength}.
     */
    public SmtpResponseDecoder(int maxLineLength) {
        super(maxLineLength);
    }

    @Override
    protected SmtpResponse decode(ChannelHandlerContext ctx, ByteBuf buffer) throws Exception {
        ByteBuf frame = (ByteBuf) super.decode(ctx, buffer);
        if (frame == null) {
            // No full line received yet.
            return null;
        }
        try {
            final int readable = frame.readableBytes();
            final int readerIndex = frame.readerIndex();
            if (readable < 3) {
                throw newDecoderException(buffer, readerIndex, readable);
            }
            final int code = parseCode(frame);
            final int separator = frame.readByte();
            final CharSequence detail = frame.isReadable() ? frame.toString(CharsetUtil.US_ASCII) : null;

            List details = this.details;

            switch (separator) {
            case ' ':
                // Marks the end of a response.
                this.details = null;
                if (details != null) {
                    if (detail != null) {
                        details.add(detail);
                    }
                } else {
                    if (detail == null) {
                        details = Collections.emptyList();
                    } else {
                        details = Collections.singletonList(detail);
                    }
                }
                return new DefaultSmtpResponse(code, details);
            case '-':
                // Multi-line response.
                if (detail != null) {
                    if (details == null) {
                        // Using initial capacity as it is very unlikely that we will receive a multi-line response
                        // with more then 3 lines.
                        this.details = details = new ArrayList(4);
                    }
                    details.add(detail);
                }
                break;
            default:
                throw newDecoderException(buffer, readerIndex, readable);
            }
        } finally {
            frame.release();
        }
        return null;
    }

    private static DecoderException newDecoderException(ByteBuf buffer, int readerIndex, int readable) {
        return new DecoderException(
                "Received invalid line: '" + buffer.toString(readerIndex, readable, CharsetUtil.US_ASCII) + '\'');
    }

    /**
     * Parses the io.netty.handler.codec.smtp code without any allocation, which is three digits.
     */
    private static int parseCode(ByteBuf buffer) {
        final int first = parseNumber(buffer.readByte()) * 100;
        final int second = parseNumber(buffer.readByte()) * 10;
        final int third = parseNumber(buffer.readByte());
        return first + second + third;
    }

    private static int parseNumber(byte b) {
        return Character.digit((char) b, 10);
    }
}