// Copyright 2024 The DMBMX2Tools Authors
// SPDX-License-Identifier: MIT

#include <base/Types.hpp>

namespace dmtools::dmbmx {

	/// Z-Axis' variant of the PJW hash algorithm.
	///
	/// # Safety
	/// This function should *not* be given any input other than ASCII.
	constexpr u32 zStringGenerateHash(const char* szString) {
		const char* cursor = szString;
		u32 hashTally {};

		while(*cursor) {
			u32 signExtendedVal = *cursor;

			// If the character is in the ASCII range for lowercase alphabetical letters
			// make it uppercase, by XORing with 0x20 (-= 0x20 works too). If not, don't modify the value.
			if((signExtendedVal - 'a') < 26)
				signExtendedVal ^= 0x20;

			// Do PJW hash
			signExtendedVal += (hashTally << 4);
			hashTally = signExtendedVal & 0xf0000000;

			if(hashTally != 0)
				signExtendedVal ^= (hashTally >> 24);

			hashTally = signExtendedVal & ~hashTally;

			// Advance to the next byte
			cursor++;
		}

		return hashTally;
	}

	static_assert(zStringGenerateHash("Park.zsc") == 0x066e3a33, "zStringGenerateHash is broken");

} // namespace dmtools::dmbmx