cpp/src/common/container/bit_map.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 COMMON_CONTAINER_BIT_MAP_H
#define COMMON_CONTAINER_BIT_MAP_H

#include <string.h>

#include "utils/errno_define.h"
#include "utils/util_define.h"

namespace common {

class BitMap {
   public:
    BitMap() : bitmap_(nullptr), size_(0), init_as_zero_(true) {}
    ~BitMap();
    int init(uint32_t item_size, bool init_as_zero = true);

    FORCE_INLINE void reset() {
        const char initial_char = init_as_zero_ ? 0x00 : 0xFF;
        memset(bitmap_, initial_char, size_);
    }

    FORCE_INLINE void set(uint32_t index) {
        uint32_t offset = index >> 3;
        ASSERT(offset < size_);

        char *start_addr = bitmap_ + offset;
        uint8_t bit_mask = get_bit_mask(index);
        *start_addr = (*start_addr) | (bit_mask);
    }

    FORCE_INLINE void clear(uint32_t index) {
        uint32_t offset = index >> 3;
        ASSERT(offset < size_);

        char *start_addr = bitmap_ + offset;
        uint8_t bit_mask = get_bit_mask(index);
        *start_addr = (*start_addr) & (~bit_mask);
    }

    FORCE_INLINE bool test(uint32_t index) {
        uint32_t offset = index >> 3;
        ASSERT(offset < size_);

        char *start_addr = bitmap_ + offset;
        uint8_t bit_mask = get_bit_mask(index);
        return (*start_addr & bit_mask);
    }

    FORCE_INLINE uint32_t get_size() { return size_; }

    FORCE_INLINE char *get_bitmap() { return bitmap_; }  // for debug

   private:
    FORCE_INLINE uint8_t get_bit_mask(uint32_t index) {
        return 1 << (index & 7);
    }

   private:
    char *bitmap_;
    uint32_t size_;
    bool init_as_zero_;
};
}  // namespace common

#endif  // COMMON_CONTAINER_BIT_MAP_H