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36cdb4a544
Also make the `Decrypt` method private. As far as I can tell, the only motivation for exposing the `SetBytes` and `Reset` methods is to allow `CBoot::SetupWiiMemory` to use the same `SettingsHandler` instance to read settings data and then write it back. It seems cleaner to just use two separate instances, and require a given `SettingsHandler` instance to be used for either writing data to a buffer or reading data from a buffer, but not both. A natural next step is to split the `SettingsHandler` class into two classes, one for writing data and one for reading data. I've deferred that change for a future PR.
129 lines
3.5 KiB
C++
129 lines
3.5 KiB
C++
// Copyright 2012 Dolphin Emulator Project
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// SPDX-License-Identifier: GPL-2.0-or-later
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// Thanks to Treeki for writing the original class - 29/01/2012
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#include "Common/SettingsHandler.h"
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#include <algorithm>
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#include <cstddef>
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#include <ctime>
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#include <iomanip>
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#include <string>
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#include <fmt/chrono.h>
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#include "Common/CommonTypes.h"
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namespace Common
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{
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SettingsHandler::SettingsHandler() : m_buffer{}, m_position{0}, m_key{INITIAL_SEED}, decoded{""}
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{
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}
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SettingsHandler::SettingsHandler(const Buffer& buffer) : SettingsHandler()
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{
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m_buffer = buffer;
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Decrypt();
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}
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const SettingsHandler::Buffer& SettingsHandler::GetBytes() const
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{
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return m_buffer;
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}
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std::string SettingsHandler::GetValue(std::string_view key) const
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{
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constexpr char delim[] = "\n";
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std::string toFind = std::string(delim).append(key).append("=");
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size_t found = decoded.find(toFind);
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if (found != std::string_view::npos)
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{
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size_t delimFound = decoded.find(delim, found + toFind.length());
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if (delimFound == std::string_view::npos)
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delimFound = decoded.length() - 1;
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return decoded.substr(found + toFind.length(), delimFound - (found + toFind.length()));
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}
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else
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{
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toFind = std::string(key).append("=");
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found = decoded.find(toFind);
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if (found == 0)
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{
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size_t delimFound = decoded.find(delim, found + toFind.length());
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if (delimFound == std::string_view::npos)
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delimFound = decoded.length() - 1;
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return decoded.substr(found + toFind.length(), delimFound - (found + toFind.length()));
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}
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}
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return "";
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}
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void SettingsHandler::Decrypt()
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{
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while (m_position < m_buffer.size())
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{
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decoded.push_back((u8)(m_buffer[m_position] ^ m_key));
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m_position++;
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m_key = (m_key >> 31) | (m_key << 1);
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}
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// The decoded data normally uses CRLF line endings, but occasionally
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// (see the comment in WriteLine), lines can be separated by CRLFLF.
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// To handle this, we remove every CR and treat LF as the line ending.
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// (We ignore empty lines.)
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std::erase(decoded, '\x0d');
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}
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void SettingsHandler::AddSetting(std::string_view key, std::string_view value)
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{
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WriteLine(fmt::format("{}={}\r\n", key, value));
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}
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void SettingsHandler::WriteLine(std::string_view str)
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{
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const u32 old_position = m_position;
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const u32 old_key = m_key;
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// Encode and write the line
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for (char c : str)
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WriteByte(c);
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// If the encoded data contains a null byte, Nintendo's decoder will stop at that null byte
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// instead of decoding all the data. To avoid this: If the data we just wrote contains
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// a null byte, add an LF right before the line to prod the values into being different,
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// just like Nintendo does. Due to the chosen key, LF itself never encodes into a null byte.
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const auto begin = m_buffer.cbegin() + old_position;
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const auto end = m_buffer.cbegin() + m_position;
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if (std::find(begin, end, 0) != end)
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{
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m_key = old_key;
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m_position = old_position;
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WriteByte('\n');
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WriteLine(str);
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}
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}
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void SettingsHandler::WriteByte(u8 b)
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{
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if (m_position >= m_buffer.size())
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return;
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m_buffer[m_position] = b ^ m_key;
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m_position++;
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m_key = (m_key >> 31) | (m_key << 1);
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}
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std::string SettingsHandler::GenerateSerialNumber()
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{
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const std::time_t t = std::time(nullptr);
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// Must be 9 characters at most; otherwise the serial number will be rejected by SDK libraries,
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// as there is a check to ensure the string length is strictly lower than 10.
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// 3 for %j, 2 for %H, 2 for %M, 2 for %S.
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return fmt::format("{:%j%H%M%S}", fmt::localtime(t));
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}
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} // namespace Common
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