[Libguestfs] [libnbd PATCH 3/6] common: include: Define bswap_16, bswap_32 and bswap_64 [finish port]
From: "Richard W.M. Jones" <rjones(a)redhat.com>
Complete porting nbdkit commit 2bc1f3383e00 ("common: include: Define
bswap_16, bswap_32 and bswap_64.", 2020-05-30). Libnbd commit def468c2a9e5
("common/include/byte-swapping.h: Synchronize with nbdkit.", 2020-10-27)
had ported nbdkit commit 2bc1f3383e00 earlier, but it contains the
following omissions / mistakes:
- In the header file, it starts using the WORDS_BIGENDIAN macro, but it
does not port the AC_C_BIGENDIAN stanza from nbdkit's "configure.ac".
- It does not port the test case extension.
Fill those gaps now.
Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
(cherry picked from nbdkit commit 2bc1f3383e00bd5bbe2e1bb911ab56e1e42c4db3)
---
configure.ac | 3 +++
common/include/test-byte-swapping.c | 18 ++++++++++++++++++
2 files changed, 21 insertions(+)
diff --git a/configure.ac b/configure.ac
index d967277ea308..6919b2782d0a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -43,6 +43,9 @@ AM_PROG_CC_C_O
AX_PTHREAD
+dnl Defines WORDS_BIGENDIAN on big endian platforms.
+AC_C_BIGENDIAN
+
dnl Check for C++ (optional, we just use this to test the header
dnl can be included from C++ code).
AC_PROG_CXX
diff --git a/common/include/test-byte-swapping.c b/common/include/test-byte-swapping.c
index fcb83c574bfc..741b3d11517e 100644
--- a/common/include/test-byte-swapping.c
+++ b/common/include/test-byte-swapping.c
@@ -85,5 +85,23 @@ main (void)
i64 = htobe64 (0x123456789abcdef0);
assert (memcmp (&i64, be64, 8) == 0);
+ memcpy (&i16, le16, 2);
+ i16 = bswap_16 (i16);
+ assert (memcmp (&i16, be16, 2) == 0);
+ i16 = bswap_16 (i16);
+ assert (memcmp (&i16, le16, 2) == 0);
+
+ memcpy (&i32, le32, 4);
+ i32 = bswap_32 (i32);
+ assert (memcmp (&i32, be32, 4) == 0);
+ i32 = bswap_32 (i32);
+ assert (memcmp (&i32, le32, 4) == 0);
+
+ memcpy (&i64, le64, 8);
+ i64 = bswap_64 (i64);
+ assert (memcmp (&i64, be64, 8) == 0);
+ i64 = bswap_64 (i64);
+ assert (memcmp (&i64, le64, 8) == 0);
+
exit (EXIT_SUCCESS);
}