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author | Bernd Edlinger <bernd.edlinger@hotmail.de> | 2020-05-25 20:13:47 +0200 |
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committer | Bernd Edlinger <bernd.edlinger@hotmail.de> | 2020-05-29 15:23:33 +0200 |
commit | 082c041b4233b17b80129d4ac6b33a28014442b0 (patch) | |
tree | 50e3c3bbe6b4d3a5d93ecea0c144d457b3323a55 /test/bioprinttest.c | |
parent | f438f53a4e57462216be271c1c965550b6ff9941 (diff) | |
download | openssl-082c041b4233b17b80129d4ac6b33a28014442b0.zip openssl-082c041b4233b17b80129d4ac6b33a28014442b0.tar.gz openssl-082c041b4233b17b80129d4ac6b33a28014442b0.tar.bz2 |
bio printf: Avoid using rounding errors in range check
There is a problem casting ULONG_MAX to double which clang-10 is warning about.
ULONG_MAX typically cannot be exactly represented as a double. ULONG_MAX + 1
can be and this fix uses the latter, however since ULONG_MAX cannot be
represented exactly as a double number we subtract 65535 from this number,
and the result has at most 48 leading one bits, and can therefore be
represented as a double integer without rounding error. By adding
65536.0 to this number we achive the correct result, which should avoid the
warning.
The addresses a symptom of the underlying problem: we print doubles via an
unsigned long integer. Doubles have a far greater range and should be printed
better.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/11955)
Diffstat (limited to 'test/bioprinttest.c')
-rw-r--r-- | test/bioprinttest.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/test/bioprinttest.c b/test/bioprinttest.c index 14f0bfe..3dd5b3e 100644 --- a/test/bioprinttest.c +++ b/test/bioprinttest.c @@ -241,14 +241,48 @@ static int test_fp(int i) return r; } +extern double zero_value; +double zero_value = 0.0; + static int test_big(void) { char buf[80]; + double d, z, inf, nan; /* Test excessively big number. Should fail */ if (!TEST_int_eq(BIO_snprintf(buf, sizeof(buf), "%f\n", 2 * (double)ULONG_MAX), -1)) return 0; + + d = 1.0; + z = zero_value; + inf = d / z; + nan = z / z; + + /* + * Test +/-inf, nan. Should fail. + * Test +/-1.0, +/-0.0. Should work. + */ + if (!TEST_int_eq(BIO_snprintf(buf, sizeof(buf), + "%f", inf), -1) + || !TEST_int_eq(BIO_snprintf(buf, sizeof(buf), + "%f", -inf), -1) + || !TEST_int_eq(BIO_snprintf(buf, sizeof(buf), + "%f", nan), -1) + || !TEST_int_eq(BIO_snprintf(buf, sizeof(buf), + "%f", d), 8) + || !TEST_str_eq(buf, "1.000000") + || !TEST_int_eq(BIO_snprintf(buf, sizeof(buf), + "%f", z), 8) + || !TEST_str_eq(buf, "0.000000") + || !TEST_int_eq(BIO_snprintf(buf, sizeof(buf), + "%f", -d), 9) + || !TEST_str_eq(buf, "-1.000000") + || !TEST_int_eq(BIO_snprintf(buf, sizeof(buf), + "%f", -z), 8) + || !TEST_str_eq(buf, "0.000000")) + return 0; + return 1; } |