Turn floating point comparison into memcmp() to silence compiler (#3849)

In numerical methods, it is indeed a bad idea to compare
floating point numbers for equality, but this just tests
that fr_dbuff_in() and fr_dbuff_out(), barring lack of space
breaking fr_dbuff_in(), are inverses for float and double.
No floating point arithmetic involved, so it's reasonable to
compare the raw bits. We'll use memcmp() to (1) emphasize that
and (2) keep the compiler from warning about comparing floating
point values for equality.

diff --git a/src/lib/util/dbuff_tests.c b/src/lib/util/dbuff_tests.c
index 77510f47242d42b6f04effaee514fb6af7442c1b..70fe95a5bc1131e74c2f8bc6040ce8f7d0a4d1f3 100644 (file)
--- a/src/lib/util/dbuff_tests.c
+++ b/src/lib/util/dbuff_tests.c
@@ -108,8 +108,10 @@ static void test_dbuff_net_encode(void)
        int16_t         i16val = 0x1234;
        int32_t         i32val = 0xd34d;
        int64_t         i64val = 0x123456789abcdef0;
-       float           fval = 0;
-       double          dval = 0;
+       float           float_in = 1.0f + FLT_EPSILON;
+       float           float_out = 0;
+       double          double_in = 1.0 + DBL_EPSILON;
+       double          double_out = 0;
 
        TEST_CASE("Generate wire format unsigned 16-bit value");
        memset(buff, 0, sizeof(buff));
@@ -254,18 +256,18 @@ static void test_dbuff_net_encode(void)
        TEST_CASE("Generate wire-format float");
        memset(buff, 0, sizeof(buff));
        fr_dbuff_init(&dbuff, buff, sizeof(buff));
-       TEST_CHECK(fr_dbuff_in(&dbuff, 1.0f + FLT_EPSILON) == 4);
+       TEST_CHECK(fr_dbuff_in(&dbuff, float_in) == 4);
        fr_dbuff_set_to_start(&dbuff);
-       TEST_CHECK(fr_dbuff_out(&fval, &dbuff) == 4);
-       TEST_CHECK(fval == 1.0f + FLT_EPSILON);
+       TEST_CHECK(fr_dbuff_out(&float_out, &dbuff) == 4);
+       TEST_CHECK(memcmp(&float_out, &float_in, sizeof(float)) == 0);
 
        TEST_CASE("Generate wire-format double");
        memset(buff, 0, sizeof(buff));
        fr_dbuff_init(&dbuff, buff, sizeof(buff));
-       TEST_CHECK(fr_dbuff_in(&dbuff, 1.0 + DBL_EPSILON) == 8);
+       TEST_CHECK(fr_dbuff_in(&dbuff, double_in) == 8);
        fr_dbuff_set_to_start(&dbuff);
-       TEST_CHECK(fr_dbuff_out(&dval, &dbuff) == 8);
-       TEST_CHECK(dval == 1.0 + DBL_EPSILON);
+       TEST_CHECK(fr_dbuff_out(&double_out, &dbuff) == 8);
+       TEST_CHECK(memcmp(&double_out, &double_in, sizeof(double)) == 0);
 
        TEST_CASE("Refuse to write to too-small space");
        fr_dbuff_init(&dbuff, buff, sizeof(uint32_t));