be/src/vec/common/format_ip.h

// Licensed to the Apache Software Foundation (ASF) under one
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// 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.
// This file is copied from
// https://github.com/ClickHouse/ClickHouse/blob/master/src/Common/formatIPv6.h
// and modified by Doris

#pragma once

#include <algorithm>
#include <array>
#include <bit>
#include <cstdint>
#include <cstring>
#include <utility>

constexpr size_t IPV4_BINARY_LENGTH = 4;
constexpr size_t IPV4_MAX_TEXT_LENGTH = 15;       /// Does not count tail zero byte.
constexpr size_t IPV4_MIN_NUM_VALUE = 0;          //num value of '0.0.0.0'
constexpr size_t IPV4_MAX_NUM_VALUE = 4294967295; //num value of '255.255.255.255'

namespace doris::vectorized {

extern const std::array<std::pair<const char*, size_t>, 256> one_byte_to_string_lookup_table;

/** Format 4-byte binary sequesnce as IPv4 text: 'aaa.bbb.ccc.ddd',
  * expects in out to be in BE-format, that is 0x7f000001 => "127.0.0.1".
  *
  * Any number of the tail bytes can be masked with given mask string.
  *
  * Assumptions:
  *     src is IPV4_BINARY_LENGTH long,
  *     dst is IPV4_MAX_TEXT_LENGTH long,
  *     mask_tail_octets <= IPV4_BINARY_LENGTH
  *     mask_string is NON-NULL, if mask_tail_octets > 0.
  *
  * Examples:
  *     formatIPv4(&0x7f000001, dst, mask_tail_octets = 0, nullptr);
  *         > dst == "127.0.0.1"
  *     formatIPv4(&0x7f000001, dst, mask_tail_octets = 1, "xxx");
  *         > dst == "127.0.0.xxx"
  *     formatIPv4(&0x7f000001, dst, mask_tail_octets = 1, "0");
  *         > dst == "127.0.0.0"
  */
inline void formatIPv4(const unsigned char* src, size_t src_size, char*& dst,
                       uint8_t mask_tail_octets = 0, const char* mask_string = "xxx") {
    const size_t mask_length = mask_string ? strlen(mask_string) : 0;
    const size_t limit = std::min(IPV4_BINARY_LENGTH, IPV4_BINARY_LENGTH - mask_tail_octets);
    const size_t padding = std::min(4 - src_size, limit);
    for (size_t octet = 0; octet < padding; ++octet) {
        *dst++ = '0';
        *dst++ = '.';
    }

    for (size_t octet = 4 - src_size; octet < limit; ++octet) {
        uint8_t value = 0;
        if constexpr (std::endian::native == std::endian::little)
            value = static_cast<uint8_t>(src[IPV4_BINARY_LENGTH - octet - 1]);
        else
            value = static_cast<uint8_t>(src[octet]);
        const uint8_t len = one_byte_to_string_lookup_table[value].second;
        const char* str = one_byte_to_string_lookup_table[value].first;

        memcpy(dst, str, len);
        dst += len;

        *dst++ = '.';
    }

    for (size_t mask = 0; mask < mask_tail_octets; ++mask) {
        memcpy(dst, mask_string, mask_length);
        dst += mask_length;

        *dst++ = '.';
    }

    dst--;
}

inline void formatIPv4(const unsigned char* src, char*& dst, uint8_t mask_tail_octets = 0,
                       const char* mask_string = "xxx") {
    formatIPv4(src, 4, dst, mask_tail_octets, mask_string);
}

} // namespace doris::vectorized