It's the obvious counterpart to bitwise_zero().
Signed-off-by: Ben Pfaff <[email protected]>
---
lib/util.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
lib/util.h | 2 ++
tests/library.at | 3 ++-
tests/test-util.c | 43 +++++++++++++++++++++++++++++++++++++++++++
4 files changed, 95 insertions(+), 1 deletions(-)
diff --git a/lib/util.c b/lib/util.c
index 810d766..14a97f2 100644
--- a/lib/util.c
+++ b/lib/util.c
@@ -865,6 +865,54 @@ bitwise_zero(void *dst_, unsigned int dst_len, unsigned
dst_ofs,
}
}
+/* Sets to 1 all of the 'n_bits' bits starting from bit 'dst_ofs' in 'dst'.
+ * 'dst' is 'dst_len' bytes long.
+ *
+ * If you consider all of 'dst' to be a single unsigned integer in network byte
+ * order, then bit N is the bit with value 2**N. That is, bit 0 is the bit
+ * with value 1 in dst[dst_len - 1], bit 1 is the bit with value 2, bit 2 is
+ * the bit with value 4, ..., bit 8 is the bit with value 1 in dst[dst_len -
+ * 2], and so on.
+ *
+ * Required invariant:
+ * dst_ofs + n_bits <= dst_len * 8
+ */
+void
+bitwise_one(void *dst_, unsigned int dst_len, unsigned dst_ofs,
+ unsigned int n_bits)
+{
+ uint8_t *dst = dst_;
+
+ if (!n_bits) {
+ return;
+ }
+
+ dst += dst_len - (dst_ofs / 8 + 1);
+ dst_ofs %= 8;
+
+ if (dst_ofs) {
+ unsigned int chunk = MIN(n_bits, 8 - dst_ofs);
+
+ *dst |= ((1 << chunk) - 1) << dst_ofs;
+
+ n_bits -= chunk;
+ if (!n_bits) {
+ return;
+ }
+
+ dst--;
+ }
+
+ while (n_bits >= 8) {
+ *dst-- = 0xff;
+ n_bits -= 8;
+ }
+
+ if (n_bits) {
+ *dst |= (1 << n_bits) - 1;
+ }
+}
+
/* Copies the 'n_bits' low-order bits of 'value' into the 'n_bits' bits
* starting at bit 'dst_ofs' in 'dst', which is 'dst_len' bytes long.
*
diff --git a/lib/util.h b/lib/util.h
index bdad501..63f4a24 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -228,6 +228,8 @@ void bitwise_copy(const void *src, unsigned int src_len,
unsigned int src_ofs,
unsigned int n_bits);
void bitwise_zero(void *dst_, unsigned int dst_len, unsigned dst_ofs,
unsigned int n_bits);
+void bitwise_one(void *dst_, unsigned int dst_len, unsigned dst_ofs,
+ unsigned int n_bits);
void bitwise_put(uint64_t value,
void *dst, unsigned int dst_len, unsigned int dst_ofs,
unsigned int n_bits);
diff --git a/tests/library.at b/tests/library.at
index ca5f29c..dce69de 100644
--- a/tests/library.at
+++ b/tests/library.at
@@ -100,7 +100,8 @@ nibble 0 1 2 3 4 5 6 7 8 9 10 11 12
13 14 15
])
AT_CLEANUP
-AT_SETUP([test log_2_floor])
+AT_SETUP([test utility functions])
+AT_KEYWORDS([util])
AT_CHECK([test-util])
AT_CLEANUP
diff --git a/tests/test-util.c b/tests/test-util.c
index 82d0861..ed98295 100644
--- a/tests/test-util.c
+++ b/tests/test-util.c
@@ -143,6 +143,47 @@ check_bitwise_zero(void)
}
}
+static void
+check_bitwise_one(void)
+{
+ unsigned int n_loops;
+ int dst_ofs;
+ int n_bits;
+
+ n_loops = 0;
+ for (n_bits = 0; n_bits <= 64; n_bits++) {
+ for (dst_ofs = 0; dst_ofs < 64 - n_bits; dst_ofs++) {
+ ovs_be64 dst = htonll(random_uint64());
+ ovs_be64 orig_dst = dst;
+ ovs_be64 expect;
+
+ if (n_bits == 64) {
+ expect = htonll(UINT64_MAX);
+ } else {
+ uint64_t mask = (UINT64_C(1) << n_bits) - 1;
+ expect = orig_dst | htonll(mask << dst_ofs);
+ }
+
+ bitwise_one(&dst, sizeof dst, dst_ofs, n_bits);
+ if (expect != dst) {
+ fprintf(stderr,"bitwise_one(0x%016"PRIx64",8,%d, %d) "
+ "yielded 0x%016"PRIx64" "
+ "instead of the expected 0x%016"PRIx64"\n",
+ ntohll(orig_dst), dst_ofs,
+ n_bits,
+ ntohll(dst), ntohll(expect));
+ abort();
+ }
+
+ n_loops++;
+ }
+ }
+
+ if (n_loops != 64 * (64 + 1) / 2) {
+ abort();
+ }
+}
+
int
main(void)
{
@@ -170,5 +211,7 @@ main(void)
check_bitwise_zero();
+ check_bitwise_one();
+
return 0;
}
--
1.7.2.5
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