Method DoUnboundedNext

library/cpp/blockcodecs/core/stream.cpp:163–212

TDecodedInput::~TDecodedInput() = default;

size_t TDecodedInput::DoUnboundedNext(const void** ptr) {
    if (!S_) {
        return 0;
    }

    TCodecID codecId;
    TBlockLen blockLen;

    {
        const size_t payload = sizeof(TCodecID) + sizeof(TBlockLen);
        char buf[32];

        S_->LoadOrFail(buf, payload);

        TMemoryInput in(buf, payload);

        ::Load(&in, codecId);
        ::Load(&in, blockLen);
    }

    if (!blockLen) {
        S_ = nullptr;

        return 0;
    }

    if (Y_UNLIKELY(blockLen > 1024 * 1024 * 1024)) {
        ythrow yexception() << "block size exceeds 1 GiB";
    }

    TBuffer block;
    block.Resize(blockLen);

    S_->LoadOrFail(block.Data(), blockLen);

    auto codec = CodecByID(codecId);

    if (C_) {
        Y_ENSURE(C_->Name() == codec->Name(), TStringBuf("incorrect stream codec"));
    }

    if (codec->DecompressedLength(block) > MAX_BUF_LEN) {
        ythrow yexception() << "broken stream";
    }

    codec->Decode(block, D_);
    *ptr = D_.Data();

    return D_.Size();
}