YimMenu/src/memory/pattern.cpp

#include "pattern.hpp"

#include "../common.hpp"

namespace memory
{
	std::optional<uint8_t> to_hex(char const c)
	{
		switch (c)
		{
		case '0': return static_cast<uint8_t>(0x0);
		case '1': return static_cast<uint8_t>(0x1);
		case '2': return static_cast<uint8_t>(0x2);
		case '3': return static_cast<uint8_t>(0x3);
		case '4': return static_cast<uint8_t>(0x4);
		case '5': return static_cast<uint8_t>(0x5);
		case '6': return static_cast<uint8_t>(0x6);
		case '7': return static_cast<uint8_t>(0x7);
		case '8': return static_cast<uint8_t>(0x8);
		case '9': return static_cast<uint8_t>(0x9);
		case 'a': return static_cast<uint8_t>(0xa);
		case 'b': return static_cast<uint8_t>(0xb);
		case 'c': return static_cast<uint8_t>(0xc);
		case 'd': return static_cast<uint8_t>(0xd);
		case 'e': return static_cast<uint8_t>(0xe);
		case 'f': return static_cast<uint8_t>(0xf);
		case 'A': return static_cast<uint8_t>(0xA);
		case 'B': return static_cast<uint8_t>(0xB);
		case 'C': return static_cast<uint8_t>(0xC);
		case 'D': return static_cast<uint8_t>(0xD);
		case 'E': return static_cast<uint8_t>(0xE);
		case 'F': return static_cast<uint8_t>(0xF);
		default: return std::nullopt;
		}
	}

	pattern::pattern(std::string_view ida_sig)
	{
		const auto size = ida_sig.size();
		for (std::size_t i{}; i != size; ++i)
		{
			if (ida_sig[i] == ' ')
				continue;
			bool last = (i == ida_sig.size() - 1);
			if (ida_sig[i] != '?')
			{
				if (!last)
				{
					auto c1 = to_hex(ida_sig[i]);
					auto c2 = to_hex(ida_sig[i + 1]);
					if (c1 && c2)
					{
						m_bytes.emplace_back(static_cast<uint8_t>((*c1 * 0x10) + *c2));
					}
				}
			}
			else
			{
				m_bytes.push_back({});

				// add support for double question mark sigs
				if (ida_sig[i + 1] == '?')
				{
					++i;
				}
			}
		}
	}

	pattern::pattern(const void* bytes, std::string_view mask)
	{
		const auto size = mask.size();
		for (std::size_t i{}; i != size; ++i)
		{
			if (mask[i] != '?')
				m_bytes.emplace_back(static_cast<const uint8_t*>(bytes)[i]);
			else
				m_bytes.push_back(std::nullopt);
		}
	}
}