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wyhash: keep tail bytes on iterative update

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Update calls with input longer then one block must ensure that
last sixteen bytes are available when final is called.

Fixes #16695
This commit is contained in:
none 2023-08-05 12:45:33 +03:00 committed by Andrew Kelley
parent 90fde14c5f
commit f3fbdf2b44
1 changed files with 20 additions and 0 deletions
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20
lib/std/hash/wyhash.zig
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@ -57,6 +57,10 @@ pub const Wyhash = struct {
} }
const remaining_bytes = input[i..]; const remaining_bytes = input[i..];
if (remaining_bytes.len < 16 and i >= 48) {
const rem = 16 - remaining_bytes.len;
@memcpy(self.buf[self.buf.len - rem ..], input[i - rem .. i]);
}
@memcpy(self.buf[0..remaining_bytes.len], remaining_bytes); @memcpy(self.buf[0..remaining_bytes.len], remaining_bytes);
self.buf_len = remaining_bytes.len; self.buf_len = remaining_bytes.len;
} }
@ -271,3 +275,19 @@ test "iterative non-divisible update" {
try std.testing.expectEqual(iterative_hash, non_iterative_hash); try std.testing.expectEqual(iterative_hash, non_iterative_hash);
} }
} }
test "iterative maintains last sixteen" {
const input = "Z" ** 48 ++ "01234567890abcdefg";
const seed = 0;
for (0..17) |i| {
const payload = input[0 .. input.len - i];
const non_iterative_hash = Wyhash.hash(seed, payload);
var wh = Wyhash.init(seed);
wh.update(payload);
const iterative_hash = wh.final();
try expectEqual(non_iterative_hash, iterative_hash);
}
}