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Mask checksums to lower 32bits #43

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Merged
nobu merged 1 commit into from
Apr 2, 2022
+11 −3
Merged

Mask checksums to lower 32bits #43

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12 changes: 9 additions & 3 deletions ext/zlib/zlib.c
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Original file line number Diff line number Diff line change
Expand Up @@ -374,18 +374,24 @@ rb_zlib_version(VALUE klass)
return rb_str_new2(zlibVersion());
}

#if SIZEOF_LONG * CHAR_BIT > 32
# define mask32(x) ((x) & 0xffffffff)
#else
# define mask32(x) (x)
#endif

#if SIZEOF_LONG > SIZEOF_INT
static uLong
checksum_long(uLong (*func)(uLong, const Bytef*, uInt), uLong sum, const Bytef *ptr, long len)
{
if (len > UINT_MAX) {
do {
sum = func(sum, ptr, UINT_MAX);
sum = func(mask32(sum), ptr, UINT_MAX);
ptr += UINT_MAX;
len -= UINT_MAX;
} while (len >= UINT_MAX);
}
if (len > 0) sum = func(sum, ptr, (uInt)len);
if (len > 0) sum = func(mask32(sum), ptr, (uInt)len);
return sum;
}
#else
Expand All @@ -411,7 +417,7 @@ do_checksum(int argc, VALUE *argv, uLong (*func)(uLong, const Bytef*, uInt))
}

if (NIL_P(str)) {
sum = func(sum, Z_NULL, 0);
sum = func(mask32(sum), Z_NULL, 0);
}
else if (rb_obj_is_kind_of(str, rb_cIO)) {
VALUE buf;
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2 changes: 2 additions & 0 deletions test/zlib/test_zlib.rb
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Expand Up @@ -1303,6 +1303,7 @@ def test_adler32
assert_equal(0x02820145, Zlib.adler32("foo"))
assert_equal(0x02820145, Zlib.adler32("o", Zlib.adler32("fo")))
assert_equal(0x8a62c964, Zlib.adler32("abc\x01\x02\x03" * 10000))
assert_equal(0x97d1a9f7, Zlib.adler32("p", -305419897))
Tempfile.create("test_zlib_gzip_file_to_io") {|t|
File.binwrite(t.path, "foo")
t.rewind
Expand Down Expand Up @@ -1338,6 +1339,7 @@ def test_crc32
assert_equal(0x8c736521, Zlib.crc32("foo"))
assert_equal(0x8c736521, Zlib.crc32("o", Zlib.crc32("fo")))
assert_equal(0x07f0d68f, Zlib.crc32("abc\x01\x02\x03" * 10000))
assert_equal(0xf136439b, Zlib.crc32("p", -305419897))
Tempfile.create("test_zlib_gzip_file_to_io") {|t|
File.binwrite(t.path, "foo")
t.rewind
Expand Down