On Tue, Jul 31, 2012 at 10:40:13AM -0700, Ethan Jackson wrote:
> Oh one more thing:
>
> This seems like the kind of thing that's both easy to get wrong, and
> easy to unit test. Does it make sense to add one?
Yes, I folded this in, thanks:
diff --git a/tests/library.at b/tests/library.at
index 70660a2..0765c3f 100644
--- a/tests/library.at
+++ b/tests/library.at
@@ -103,12 +103,14 @@ AT_CLEANUP
m4_foreach(
[testname],
[[ctz],
+ [popcount],
[log_2_floor],
[bitwise_copy],
[bitwise_zero],
[bitwise_one],
[bitwise_is_all_zeros]],
[AT_SETUP([testname[()] function])
+ AT_KEYWORDS([testname])
AT_CHECK([test-util testname], [0], [], [])
AT_CLEANUP])
diff --git a/tests/test-util.c b/tests/test-util.c
index 71a7f21..b98fc79 100644
--- a/tests/test-util.c
+++ b/tests/test-util.c
@@ -26,6 +26,9 @@
#include "random.h"
#include "util.h"
+#undef NDEBUG
+#include <assert.h>
+
static void
check_log_2_floor(uint32_t x, int n)
{
@@ -85,6 +88,59 @@ test_ctz(int argc OVS_UNUSED, char *argv[] OVS_UNUSED)
check_ctz(0, 32);
}
+static void
+shuffle(unsigned int *p, size_t n)
+{
+ for (; n > 1; n--, p++) {
+ unsigned int *q = &p[rand() % n];
+ unsigned int tmp = *p;
+ *p = *q;
+ *q = tmp;
+ }
+}
+
+static void
+check_popcount(uint32_t x, int n)
+{
+ if (popcount(x) != n) {
+ fprintf(stderr, "popcount(%#"PRIx32") is %d but should be %d\n",
+ x, popcount(x), n);
+ abort();
+ }
+}
+
+static void
+test_popcount(int argc OVS_UNUSED, char *argv[] OVS_UNUSED)
+{
+ unsigned int bits[32];
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(bits); i++) {
+ bits[i] = 1u << i;
+ }
+
+ check_popcount(0, 0);
+
+ for (i = 0; i < 1000; i++) {
+ uint32_t x = 0;
+ int j;
+
+ shuffle(bits, ARRAY_SIZE(bits));
+ for (j = 0; j < 32; j++) {
+ x |= bits[j];
+ check_popcount(x, j + 1);
+ }
+ assert(x == UINT32_MAX);
+
+ shuffle(bits, ARRAY_SIZE(bits));
+ for (j = 31; j >= 0; j--) {
+ x &= ~bits[j];
+ check_popcount(x, j);
+ }
+ assert(x == 0);
+ }
+}
+
/* Returns the sum of the squares of the first 'n' positive integers. */
static unsigned int
sum_of_squares(int n)
@@ -282,6 +338,7 @@ test_follow_symlinks(int argc, char *argv[])
static const struct command commands[] = {
{"ctz", 0, 0, test_ctz},
+ {"popcount", 0, 0, test_popcount},
{"log_2_floor", 0, 0, test_log_2_floor},
{"bitwise_copy", 0, 0, test_bitwise_copy},
{"bitwise_zero", 0, 0, test_bitwise_zero},
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