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package jdk.internal.net.http.qpack.readers;

import jdk.internal.net.http.qpack.DecodingCallback;
import jdk.internal.net.http.qpack.DynamicTable;
import jdk.internal.net.http.qpack.FieldSectionPrefix;
import jdk.internal.net.http.qpack.HeaderField;
import jdk.internal.net.http.qpack.QPACK;

import java.nio.ByteBuffer;
import java.util.concurrent.atomic.AtomicLong;

import static java.lang.String.format;
import static jdk.internal.net.http.http3.Http3Error.QPACK_DECOMPRESSION_FAILED;
import static jdk.internal.net.http.qpack.QPACK.Logger.Level.NORMAL;

final class FieldLineIndexedPostBaseReader extends FieldLineReader {
    private final IntegerReader integerReader;
    private final QPACK.Logger logger;

    public FieldLineIndexedPostBaseReader(DynamicTable dynamicTable, long maxSectionSize,
                                          AtomicLong sectionSizeTracker, QPACK.Logger logger) {
        super(dynamicTable, maxSectionSize, sectionSizeTracker);
        this.integerReader = new IntegerReader(
                new ReaderError(QPACK_DECOMPRESSION_FAILED, false));
        this.logger = logger;
    }

    public void configure(int b) {
        integerReader.configure(4);
    }

    //    0   1   2   3   4   5   6   7
    //  +---+---+---+---+---+---+---+---+
    //  | 0 | 0 | 0 | 1 |  Index (4+)   |
    //  +---+---+---+---+---------------+
    //
    public boolean read(ByteBuffer input, FieldSectionPrefix prefix,
                        DecodingCallback action) {
        if (!integerReader.read(input)) {
            return false;
        }
        long relativeIndex = integerReader.get();
        long absoluteIndex = prefix.base() + relativeIndex;
        if (logger.isLoggable(NORMAL)) {
            logger.log(NORMAL, () -> format("Post-Base Indexed Field Line: base=%s index=%s[%s]",
                    prefix.base(), relativeIndex, absoluteIndex));
        }
        checkEntryIndex(absoluteIndex, prefix);
        HeaderField f = entryAtIndex(absoluteIndex);
        checkSectionSize(DynamicTable.headerSize(f));
        action.onIndexed(absoluteIndex, f.name(), f.value());
        reset();
        return true;
    }

    public void reset() {
        integerReader.reset();
    }
}