basic: add unaligned macros for little endian

Also add test code for that.

2 files changed, 120 insertions, 1 deletions

diff --git a/src/basic/unaligned.h b/src/basic/unaligned.h
index d6181dd9a9..a8115eaa1f 100644
--- a/src/basic/unaligned.h
+++ b/src/basic/unaligned.h
@@ -21,8 +21,11 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
+#include <endian.h>
 #include <stdint.h>
 
+/* BE */
+
 static inline uint16_t unaligned_read_be16(const void *_u) {
         const uint8_t *u = _u;
 
@@ -64,3 +67,47 @@ static inline void unaligned_write_be64(void *_u, uint64_t a) {
         unaligned_write_be32(u, (uint32_t) (a >> 32));
         unaligned_write_be32(u + 4, (uint32_t) a);
 }
+
+/* LE */
+
+static inline uint16_t unaligned_read_le16(const void *_u) {
+        const uint8_t *u = _u;
+
+        return (((uint16_t) u[1]) << 8) |
+                ((uint16_t) u[0]);
+}
+
+static inline uint32_t unaligned_read_le32(const void *_u) {
+        const uint8_t *u = _u;
+
+        return (((uint32_t) unaligned_read_le16(u + 2)) << 16) |
+                ((uint32_t) unaligned_read_le16(u));
+}
+
+static inline uint64_t unaligned_read_le64(const void *_u) {
+        const uint8_t *u = _u;
+
+        return (((uint64_t) unaligned_read_le32(u + 4)) << 32) |
+                ((uint64_t) unaligned_read_le32(u));
+}
+
+static inline void unaligned_write_le16(void *_u, uint16_t a) {
+        uint8_t *u = _u;
+
+        u[0] = (uint8_t) a;
+        u[1] = (uint8_t) (a >> 8);
+}
+
+static inline void unaligned_write_le32(void *_u, uint32_t a) {
+        uint8_t *u = _u;
+
+        unaligned_write_le16(u, (uint16_t) a);
+        unaligned_write_le16(u + 2, (uint16_t) (a >> 16));
+}
+
+static inline void unaligned_write_le64(void *_u, uint64_t a) {
+        uint8_t *u = _u;
+
+        unaligned_write_le32(u, (uint32_t) a);
+        unaligned_write_le32(u + 4, (uint32_t) (a >> 32));
+}
diff --git a/src/test/test-unaligned.c b/src/test/test-unaligned.c
index 1754d06b2d..ec52db262c 100644
--- a/src/test/test-unaligned.c
+++ b/src/test/test-unaligned.c
@@ -26,7 +26,7 @@ static uint8_t data[] = {
         0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
 };
 
-int main(int argc, const char *argv[]) {
+static void test_be(void) {
         uint8_t scratch[16];
 
         assert_se(unaligned_read_be16(&data[0]) == 0x0001);
@@ -91,3 +91,75 @@ int main(int argc, const char *argv[]) {
         unaligned_write_be64(&scratch[7], 0x0708090a0b0c0d0e);
         assert_se(memcmp(&scratch[7], &data[7], sizeof(uint64_t)) == 0);
 }
+
+static void test_le(void) {
+        uint8_t scratch[16];
+
+        assert_se(unaligned_read_le16(&data[0]) == 0x0100);
+        assert_se(unaligned_read_le16(&data[1]) == 0x0201);
+
+        assert_se(unaligned_read_le32(&data[0]) == 0x03020100);
+        assert_se(unaligned_read_le32(&data[1]) == 0x04030201);
+        assert_se(unaligned_read_le32(&data[2]) == 0x05040302);
+        assert_se(unaligned_read_le32(&data[3]) == 0x06050403);
+
+        assert_se(unaligned_read_le64(&data[0]) == 0x0706050403020100);
+        assert_se(unaligned_read_le64(&data[1]) == 0x0807060504030201);
+        assert_se(unaligned_read_le64(&data[2]) == 0x0908070605040302);
+        assert_se(unaligned_read_le64(&data[3]) == 0x0a09080706050403);
+        assert_se(unaligned_read_le64(&data[4]) == 0x0b0a090807060504);
+        assert_se(unaligned_read_le64(&data[5]) == 0x0c0b0a0908070605);
+        assert_se(unaligned_read_le64(&data[6]) == 0x0d0c0b0a09080706);
+        assert_se(unaligned_read_le64(&data[7]) == 0x0e0d0c0b0a090807);
+
+        zero(scratch);
+        unaligned_write_le16(&scratch[0], 0x0100);
+        assert_se(memcmp(&scratch[0], &data[0], sizeof(uint16_t)) == 0);
+        zero(scratch);
+        unaligned_write_le16(&scratch[1], 0x0201);
+        assert_se(memcmp(&scratch[1], &data[1], sizeof(uint16_t)) == 0);
+
+        zero(scratch);
+        unaligned_write_le32(&scratch[0], 0x03020100);
+
+        assert_se(memcmp(&scratch[0], &data[0], sizeof(uint32_t)) == 0);
+        zero(scratch);
+        unaligned_write_le32(&scratch[1], 0x04030201);
+        assert_se(memcmp(&scratch[1], &data[1], sizeof(uint32_t)) == 0);
+        zero(scratch);
+        unaligned_write_le32(&scratch[2], 0x05040302);
+        assert_se(memcmp(&scratch[2], &data[2], sizeof(uint32_t)) == 0);
+        zero(scratch);
+        unaligned_write_le32(&scratch[3], 0x06050403);
+        assert_se(memcmp(&scratch[3], &data[3], sizeof(uint32_t)) == 0);
+
+        zero(scratch);
+        unaligned_write_le64(&scratch[0], 0x0706050403020100);
+        assert_se(memcmp(&scratch[0], &data[0], sizeof(uint64_t)) == 0);
+        zero(scratch);
+        unaligned_write_le64(&scratch[1], 0x0807060504030201);
+        assert_se(memcmp(&scratch[1], &data[1], sizeof(uint64_t)) == 0);
+        zero(scratch);
+        unaligned_write_le64(&scratch[2], 0x0908070605040302);
+        assert_se(memcmp(&scratch[2], &data[2], sizeof(uint64_t)) == 0);
+        zero(scratch);
+        unaligned_write_le64(&scratch[3], 0x0a09080706050403);
+        assert_se(memcmp(&scratch[3], &data[3], sizeof(uint64_t)) == 0);
+        zero(scratch);
+        unaligned_write_le64(&scratch[4], 0x0B0A090807060504);
+        assert_se(memcmp(&scratch[4], &data[4], sizeof(uint64_t)) == 0);
+        zero(scratch);
+        unaligned_write_le64(&scratch[5], 0x0c0b0a0908070605);
+        assert_se(memcmp(&scratch[5], &data[5], sizeof(uint64_t)) == 0);
+        zero(scratch);
+        unaligned_write_le64(&scratch[6], 0x0d0c0b0a09080706);
+        assert_se(memcmp(&scratch[6], &data[6], sizeof(uint64_t)) == 0);
+        zero(scratch);
+        unaligned_write_le64(&scratch[7], 0x0e0d0c0b0a090807);
+        assert_se(memcmp(&scratch[7], &data[7], sizeof(uint64_t)) == 0);
+}
+
+int main(int argc, const char *argv[]) {
+        test_be();
+        test_le();
+}