cpp/src/encoding/encoder.h

/*
 * 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.
 */

#ifndef ENCODING_ENCODER_H
#define ENCODING_ENCODER_H

#include "common/allocator/byte_stream.h"

namespace storage {

class Encoder {
   public:
    Encoder() {}
    virtual ~Encoder() {}

    virtual void reset() = 0;
    virtual void destroy() = 0;
    // virtual int init(common::TSDataType data_type) = 0;
    virtual int encode(bool value, common::ByteStream& out_stream) = 0;
    virtual int encode(int32_t value, common::ByteStream& out_stream) = 0;
    virtual int encode(int64_t value, common::ByteStream& out_stream) = 0;
    virtual int encode(float value, common::ByteStream& out_stream) = 0;
    virtual int encode(double value, common::ByteStream& out_stream) = 0;
    virtual int encode(common::String value,
                       common::ByteStream& out_stream) = 0;
    virtual int flush(common::ByteStream& out_stream) = 0;

    /**
     * The maximal possible memory size occupied by current Encoder. This
     * statistic value doesn't involve OutputStream.
     *
     * @return the maximal size of possible memory occupied by current encoder
     */
    virtual int get_max_byte_size() = 0;

    /*
     * Batch encoding interfaces.
     * Default implementations fall back to per-value encode().
     * Subclasses may override for better performance.
     */
    virtual int encode_batch(const bool* values, uint32_t count,
                             common::ByteStream& out_stream) {
        int ret = common::E_OK;
        for (uint32_t i = 0; i < count; i++) {
            if (RET_FAIL(encode(values[i], out_stream))) {
                return ret;
            }
        }
        return ret;
    }
    virtual int encode_batch(const int32_t* values, uint32_t count,
                             common::ByteStream& out_stream) {
        int ret = common::E_OK;
        for (uint32_t i = 0; i < count; i++) {
            if (RET_FAIL(encode(values[i], out_stream))) {
                return ret;
            }
        }
        return ret;
    }
    virtual int encode_batch(const int64_t* values, uint32_t count,
                             common::ByteStream& out_stream) {
        int ret = common::E_OK;
        for (uint32_t i = 0; i < count; i++) {
            if (RET_FAIL(encode(values[i], out_stream))) {
                return ret;
            }
        }
        return ret;
    }
    virtual int encode_batch(const float* values, uint32_t count,
                             common::ByteStream& out_stream) {
        int ret = common::E_OK;
        for (uint32_t i = 0; i < count; i++) {
            if (RET_FAIL(encode(values[i], out_stream))) {
                return ret;
            }
        }
        return ret;
    }
    virtual int encode_batch(const double* values, uint32_t count,
                             common::ByteStream& out_stream) {
        int ret = common::E_OK;
        for (uint32_t i = 0; i < count; i++) {
            if (RET_FAIL(encode(values[i], out_stream))) {
                return ret;
            }
        }
        return ret;
    }

    // Batch encode strings from a contiguous buffer with offset array
    // (Arrow-style layout from Tablet::StringColumn).
    // string[i] = buffer + offsets[start_idx + i], length = offsets[start_idx +
    // i + 1] - offsets[start_idx + i].
    virtual int encode_string_batch(const char* buffer, const uint32_t* offsets,
                                    uint32_t start_idx, uint32_t count,
                                    common::ByteStream& out_stream) {
        int ret = common::E_OK;
        for (uint32_t i = 0; i < count; i++) {
            uint32_t idx = start_idx + i;
            uint32_t len = offsets[idx + 1] - offsets[idx];
            common::String val(buffer + offsets[idx], len);
            if (RET_FAIL(encode(val, out_stream))) {
                return ret;
            }
        }
        return ret;
    }
};

}  // end namespace storage
#endif  // ENCODING_ENCODER_H