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Fix porting of zlib alder32 with large input

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This commit is contained in:
Michaël Larouche 2020-03-31 16:52:16 -04:00 committed by Andrew Kelley
parent e3d12471a2
commit a5af78c376
1 changed files with 30 additions and 9 deletions
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39
lib/std/hash/adler.zig
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@ -42,18 +42,23 @@ pub const Adler32 = struct {
s2 %= base;
} else {
var i: usize = 0;
while (i + nmax <= input.len) : (i += nmax) {
const n = nmax / 16; // note: 16 | nmax
const n = nmax / 16; // note: 16 | nmax
var i: usize = 0;
while (i + nmax <= input.len) {
var rounds: usize = 0;
while (rounds < n) : (rounds += 1) {
comptime var j: usize = 0;
inline while (j < 16) : (j += 1) {
s1 +%= input[i + n * j];
s1 +%= input[i + j];
s2 +%= s1;
}
i += 16;
}
s1 %= base;
s2 %= base;
}
if (i < input.len) {
@ -89,19 +94,35 @@ pub const Adler32 = struct {
};
test "adler32 sanity" {
testing.expect(Adler32.hash("a") == 0x620062);
testing.expect(Adler32.hash("example") == 0xbc002ed);
testing.expectEqual(@as(u32, 0x620062), Adler32.hash("a"));
testing.expectEqual(@as(u32, 0xbc002ed), Adler32.hash("example"));
}
test "adler32 long" {
const long1 = [_]u8{1} ** 1024;
testing.expect(Adler32.hash(long1[0..]) == 0x06780401);
testing.expectEqual(@as(u32, 0x06780401), Adler32.hash(long1[0..]));
const long2 = [_]u8{1} ** 1025;
testing.expect(Adler32.hash(long2[0..]) == 0x0a7a0402);
testing.expectEqual(@as(u32, 0x0a7a0402), Adler32.hash(long2[0..]));
}
test "adler32 very long" {
const long = [_]u8{1} ** 5553;
testing.expect(Adler32.hash(long[0..]) == 0x707f15b2);
testing.expectEqual(@as(u32, 0x707f15b2), Adler32.hash(long[0..]));
}
test "adler32 very long with variation" {
const long = comptime blk: {
@setEvalBranchQuota(7000);
var result: [6000]u8 = undefined;
var i: usize = 0;
while (i < result.len) : (i += 1) {
result[i] = @truncate(u8, i);
}
break :blk result;
};
testing.expectEqual(@as(u32, 0x5af38d6e), std.hash.Adler32.hash(long[0..]));
}