From 625e870b4fb7ff4caf4d8a4614e9bda7c174b291 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Tue, 13 May 2014 19:47:58 +0200 Subject: shared: add ALIGN_POWER2 macro Sounds easy, turns out to be horrible to implement: ALIGN_POWER2 returns the next higher power of 2. clz(0) is undefined, same is true for left-shift-overflows, yey, C rocks! --- src/test/test-util.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'src/test/test-util.c') diff --git a/src/test/test-util.c b/src/test/test-util.c index 93929cd9fc..caf8d2b12b 100644 --- a/src/test/test-util.c +++ b/src/test/test-util.c @@ -37,6 +37,36 @@ static void test_streq_ptr(void) { assert_se(!streq_ptr("abc", "cdef")); } +static void test_align_power2(void) { + unsigned long i, p2; + + assert_se(ALIGN_POWER2(0) == 0); + assert_se(ALIGN_POWER2(1) == 1); + assert_se(ALIGN_POWER2(2) == 2); + assert_se(ALIGN_POWER2(3) == 4); + assert_se(ALIGN_POWER2(12) == 16); + + assert_se(ALIGN_POWER2(ULONG_MAX) == 0); + assert_se(ALIGN_POWER2(ULONG_MAX - 1) == 0); + assert_se(ALIGN_POWER2(ULONG_MAX - 1024) == 0); + assert_se(ALIGN_POWER2(ULONG_MAX / 2) == ULONG_MAX / 2 + 1); + assert_se(ALIGN_POWER2(ULONG_MAX + 1) == 0); + + for (i = 1; i < 131071; ++i) { + for (p2 = 1; p2 < i; p2 <<= 1) + /* empty */ ; + + assert_se(ALIGN_POWER2(i) == p2); + } + + for (i = ULONG_MAX - 1024; i < ULONG_MAX; ++i) { + for (p2 = 1; p2 && p2 < i; p2 <<= 1) + /* empty */ ; + + assert_se(ALIGN_POWER2(i) == p2); + } +} + static void test_first_word(void) { assert_se(first_word("Hello", "")); assert_se(first_word("Hello", "Hello")); @@ -680,6 +710,7 @@ int main(int argc, char *argv[]) { log_open(); test_streq_ptr(); + test_align_power2(); test_first_word(); test_close_many(); test_parse_boolean(); -- cgit v1.2.1