43 lines
1.1 KiB
C++
43 lines
1.1 KiB
C++
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// Copyright 2024 The DMBMX2Tools Authors
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// SPDX-License-Identifier: MIT
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#include <base/Types.hpp>
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namespace dmtools::dmbmx {
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/// Z-Axis' variant of the PJW hash algorithm.
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///
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/// # Safety
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/// This function should *not* be given any input other than ASCII.
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constexpr u32 zStringGenerateHash(const char* szString) {
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const char* cursor = szString;
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u32 hashTally {};
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while(*cursor) {
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u32 signExtendedVal = *cursor;
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// If the character is in the ASCII range for lowercase alphabetical letters
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// make it uppercase, by XORing with 0x20 (-= 0x20 works too). If not, don't modify the value.
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if((signExtendedVal - 'a') < 26)
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signExtendedVal ^= 0x20;
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// Do PJW hash
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signExtendedVal += (hashTally << 4);
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hashTally = signExtendedVal & 0xf0000000;
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if(hashTally != 0)
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signExtendedVal ^= (hashTally >> 24);
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hashTally = signExtendedVal & ~hashTally;
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// Advance to the next byte
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cursor++;
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}
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return hashTally;
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}
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static_assert(zStringGenerateHash("Park.zsc") == 0x066e3a33, "zStringGenerateHash is broken");
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} // namespace dmtools::dmbmx
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