175 lines
3.5 KiB
C++
175 lines
3.5 KiB
C++
///////////////////////////////////////////////////////////////////////////////
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// Copyright (c) Lewis Baker
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// Licenced under MIT license. See LICENSE.txt for details.
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///////////////////////////////////////////////////////////////////////////////
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#include <cppcoro/net/ipv4_address.hpp>
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namespace
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{
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namespace local
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{
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constexpr bool is_digit(char c)
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{
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return c >= '0' && c <= '9';
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}
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constexpr std::uint8_t digit_value(char c)
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{
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return static_cast<std::uint8_t>(c - '0');
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}
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}
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}
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std::optional<cppcoro::net::ipv4_address>
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cppcoro::net::ipv4_address::from_string(std::string_view string) noexcept
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{
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if (string.empty()) return std::nullopt;
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if (!local::is_digit(string[0]))
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{
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return std::nullopt;
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}
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const auto length = string.length();
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std::uint8_t partValues[4];
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if (string[0] == '0' && length > 1)
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{
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if (local::is_digit(string[1]))
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{
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// Octal format (not supported)
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return std::nullopt;
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}
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else if (string[1] == 'x')
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{
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// Hexadecimal format (not supported)
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return std::nullopt;
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}
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}
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// Parse the first integer.
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// Could be a single 32-bit integer or first integer in a dotted decimal string.
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std::size_t pos = 0;
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{
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constexpr std::uint32_t maxValue = 0xFFFFFFFFu / 10;
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constexpr std::uint32_t maxDigit = 0xFFFFFFFFu % 10;
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std::uint32_t partValue = local::digit_value(string[pos]);
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++pos;
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while (pos < length && local::is_digit(string[pos]))
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{
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const auto digitValue = local::digit_value(string[pos]);
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++pos;
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// Check if this digit would overflow the 32-bit integer
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if (partValue > maxValue || (partValue == maxValue && digitValue > maxDigit))
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{
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return std::nullopt;
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}
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partValue = (partValue * 10) + digitValue;
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}
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if (pos == length)
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{
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// A single-integer string
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return ipv4_address{ partValue };
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}
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else if (partValue > 255)
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{
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// Not a valid first component of dotted decimal
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return std::nullopt;
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}
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partValues[0] = static_cast<std::uint8_t>(partValue);
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}
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for (int part = 1; part < 4; ++part)
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{
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if ((pos + 1) >= length || string[pos] != '.' || !local::is_digit(string[pos + 1]))
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{
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return std::nullopt;
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}
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// Skip the '.'
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++pos;
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// Check for an octal format (not yet supported)
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const bool isPartOctal =
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(pos + 1) < length &&
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string[pos] == '0' &&
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local::is_digit(string[pos + 1]);
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if (isPartOctal)
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{
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return std::nullopt;
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}
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std::uint32_t partValue = local::digit_value(string[pos]);
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++pos;
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if (pos < length && local::is_digit(string[pos]))
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{
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partValue = (partValue * 10) + local::digit_value(string[pos]);
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++pos;
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if (pos < length && local::is_digit(string[pos]))
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{
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partValue = (partValue * 10) + local::digit_value(string[pos]);
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if (partValue > 255)
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{
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return std::nullopt;
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}
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++pos;
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}
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}
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partValues[part] = static_cast<std::uint8_t>(partValue);
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}
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if (pos < length)
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{
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// Extra chars after end of a valid IPv4 string
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return std::nullopt;
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}
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return ipv4_address{ partValues };
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}
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std::string cppcoro::net::ipv4_address::to_string() const
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{
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// Buffer is large enough to hold larges ip address
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// "xxx.xxx.xxx.xxx"
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char buffer[15];
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char* c = &buffer[0];
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for (int i = 0; i < 4; ++i)
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{
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if (i > 0)
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{
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*c++ = '.';
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}
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if (m_bytes[i] >= 100)
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{
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*c++ = '0' + (m_bytes[i] / 100);
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*c++ = '0' + (m_bytes[i] % 100) / 10;
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*c++ = '0' + (m_bytes[i] % 10);
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}
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else if (m_bytes[i] >= 10)
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{
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*c++ = '0' + (m_bytes[i] / 10);
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*c++ = '0' + (m_bytes[i] % 10);
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}
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else
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{
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*c++ = '0' + m_bytes[i];
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}
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}
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return std::string{ &buffer[0], c };
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}
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