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MagneticCardReader: Simplify checksum logic.

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This commit is contained in:
Jordan Woyak
2026-03-18 22:39:12 -05:00
parent 7fbe96d42e
commit 816e3a654a
1 changed files with 3 additions and 12 deletions
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Source/Core/Core/HW/MagCard/MagneticCardReader.cpp
+3 -12
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@@ -676,18 +676,9 @@ bool MagneticCardReader::ReceivePacket(std::span<const u8> packet)
return false;
}
// Checksum is XOR of the previous bytes.
// This includes the count byte that we already chopped off.
const u8 read_checksum = packet.back();
// TODO C++23:
// std::ranges::fold_left(packet.first(packet.size() - 1), u8(packet.size()), std::bit_xor{});
const auto range_to_checksum = packet.first(packet.size() - 1);
const auto proper_checksum = std::accumulate(range_to_checksum.begin(), range_to_checksum.end(),
u8(packet.size()), std::bit_xor{});
// Verify checksum. Skip packet if invalid.
if (read_checksum != proper_checksum)
// The final byte is an XOR checksum of all previous bytes,
// including the count byte that we already chopped off.
if (std::accumulate(packet.begin(), packet.end(), u8(packet.size()), std::bit_xor{}) != 0)
{
WARN_LOG_FMT(SERIALINTERFACE_CARD, "ReceivePacket: Bad checksum!");
return false;