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There is a newer version: 2.2.0
/*
 * Copyright 2023-2024 wjybxx([email protected])
 *
 * Licensed 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 cn.wjybxx.dson;

import cn.wjybxx.base.io.ConcurrentObjectPool;
import cn.wjybxx.dson.internal.DsonInternals;
import cn.wjybxx.dson.io.DsonIOException;
import cn.wjybxx.dson.io.DsonInput;
import cn.wjybxx.dson.types.*;

import java.util.Objects;

/**
 * @author wjybxx
 * date - 2023/4/22
 */
public final class DsonLiteBinaryReader extends AbstractDsonLiteReader {

    private DsonInput input;
    private final boolean autoClose;

    public DsonLiteBinaryReader(DsonReaderSettings settings, DsonInput input) {
        this(settings, input, settings.autoClose);
    }

    public DsonLiteBinaryReader(DsonReaderSettings settings, DsonInput input, boolean autoClose) {
        super(settings);
        this.input = Objects.requireNonNull(input);
        this.autoClose = autoClose;

        Context context = newContext(null, DsonContextType.TOP_LEVEL, null);
        setContext(context);
    }

    @Override
    protected Context getContext() {
        return (Context) super.getContext();
    }

    @Override
    public void close() {
        Context context = getContext();
        setContext(null);
        while (context != null) {
            Context parent = context.getParent();
            contextPool.release(context);
            context = parent;
        }
        if (input != null) {
            if (autoClose) {
                input.close();
            }
            input = null;
        }
        super.close();
    }

    // region state

    @Override
    public DsonType readDsonType() {
        Context context = this.getContext();
        checkReadDsonTypeState(context);

        final int fullType = input.isAtEnd() ? 0 : Byte.toUnsignedInt(input.readRawByte());
        final int wreTypeBits = Dsons.wireTypeOfFullType(fullType);
        DsonType dsonType = DsonType.forNumber(Dsons.dsonTypeOfFullType(fullType));
        WireType wireType = dsonType.hasWireType() ? WireType.forNumber(wreTypeBits) : WireType.VARINT;
        this.currentDsonType = dsonType;
        this.currentWireType = wireType;
        this.currentWireTypeBits = wreTypeBits;
        this.currentName = INVALID_NAME;

        onReadDsonType(context, dsonType);
        return dsonType;
    }

    @Override
    public DsonType peekDsonType() {
        Context context = this.getContext();
        checkReadDsonTypeState(context);

        final int fullType = input.isAtEnd() ? 0 : Byte.toUnsignedInt(input.getByte(input.getPosition()));
        return DsonType.forNumber(Dsons.dsonTypeOfFullType(fullType));
    }

    @Override
    protected void doReadName() {
        currentName = input.readUint32();
    }

    // endregion

    // region 简单值

    @Override
    protected int doReadInt32() {
        return currentWireType.readInt32(input);
    }

    @Override
    protected long doReadInt64() {
        return currentWireType.readInt64(input);
    }

    @Override
    protected float doReadFloat() {
        return DsonReaderUtils.readFloat(input, currentWireTypeBits);
    }

    @Override
    protected double doReadDouble() {
        return DsonReaderUtils.readDouble(input, currentWireTypeBits);
    }

    @Override
    protected boolean doReadBool() {
        return DsonReaderUtils.readBool(input, currentWireTypeBits);
    }

    @Override
    protected String doReadString() {
        return input.readString();
    }

    @Override
    protected void doReadNull() {

    }

    @Override
    protected Binary doReadBinary() {
        return DsonReaderUtils.readBinary(input);
    }

    @Override
    protected ObjectPtr doReadPtr() {
        return DsonReaderUtils.readPtr(input, currentWireTypeBits);
    }

    @Override
    protected ObjectLitePtr doReadLitePtr() {
        return DsonReaderUtils.readLitePtr(input, currentWireTypeBits);
    }

    @Override
    protected ExtDateTime doReadDateTime() {
        return DsonReaderUtils.readDateTime(input, currentWireTypeBits);
    }

    @Override
    protected Timestamp doReadTimestamp() {
        return DsonReaderUtils.readTimestamp(input);
    }

    // endregion

    // region 容器

    @Override
    protected void doReadStartContainer(DsonContextType contextType, DsonType dsonType) {
        Context newContext = newContext(getContext(), contextType, dsonType);
        int length;
        if (contextType == DsonContextType.HEADER) {
            length = input.readFixed16();
        } else {
            length = input.readFixed32();
        }
        newContext.oldLimit = input.pushLimit(length);
        newContext.name = currentName;

        this.recursionDepth++;
        setContext(newContext);
    }

    @Override
    protected void doReadEndContainer() {
        if (!input.isAtEnd()) {
            throw DsonIOException.bytesRemain(input.getBytesUntilLimit());
        }
        Context context = getContext();
        input.popLimit(context.oldLimit);

        // 恢复上下文
        recoverDsonType(context);
        this.recursionDepth--;
        setContext(context.parent);
        returnContext(context);
    }

    // endregion

    // region 特殊接口

    @Override
    protected void doSkipName() {
        input.readUint32();
    }

    @Override
    protected void doSkipValue() {
        DsonReaderUtils.skipValue(input, getContextType(), currentDsonType, currentWireType, currentWireTypeBits);
    }

    @Override
    protected void doSkipToEndOfObject() {
        DsonReaderUtils.skipToEndOfObject(input);
    }

    @Override
    protected byte[] doReadValueAsBytes() {
        return DsonReaderUtils.readValueAsBytes(input, currentDsonType);
    }

    // endregion

    // region context

    private static final ConcurrentObjectPool contextPool = new ConcurrentObjectPool<>(Context::new, Context::reset,
            DsonInternals.CONTEXT_POOL_SIZE);

    private static Context newContext(Context parent, DsonContextType contextType, DsonType dsonType) {
        Context context = contextPool.acquire();
        context.init(parent, contextType, dsonType);
        return context;
    }

    private static void returnContext(Context context) {
        contextPool.release(context);
    }

    protected static class Context extends AbstractDsonLiteReader.Context {

        int oldLimit = -1;

        public Context() {
        }

        @Override
        public Context getParent() {
            return (Context) parent;
        }

        @Override
        public void reset() {
            super.reset();
            oldLimit = -1;
        }
    }

    // endregion

}