Reworking byte order utility functions for Windows platforms.
Functions htonll and ntohll are only available when
NTDDI_VERSION>=NTDDI_WIN8 or INCL_EXTRA_HTON_FUNCTIONS is defined,
instead of assuming this to be true, this CL replaces them with
_byteswap_uint64 [1].
On top of that, the following functions were assuming host to be
little endian on Windows and NaCl:
- htobe16(v)
- htobe32(v)
- be16toh(v)
- be32toh(v)
- htobe64(v)
- be64toh(v)
But it is the application's responsibility to check the host
endianness before calling ntohs, ntohl (and probably also htons and
htonl). See [2], especially: "The ntohs function returns the value
in host byte order. If the netshort parameter is already in host byte
order, then this function will reverse it. It is up to the application
to determine if the byte order must be reversed.".
After this CL, WebRTC should do the right thing based on the value
of WEBRTC_ARCH_{BIG,LITTLE}_ENDIAN.
[1] - https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/byteswap-uint64-byteswap-ulong-byteswap-ushort
[2] - https://docs.microsoft.com/en-us/windows/desktop/api/winsock/nf-winsock-ntohs
Bug: None
Change-Id: I61ca882ad81dd090fd164b0fdfeec64cd088a71d
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/129901
Reviewed-by: Tommi <tommi@webrtc.org>
Reviewed-by: Noah Richards <noahric@chromium.org>
Reviewed-by: Yves Gerey <yvesg@google.com>
Reviewed-by: Yves Gerey <yvesg@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27371}diff --git a/rtc_base/byte_order.h b/rtc_base/byte_order.h
index 2b50f0d..ae1c634 100644
--- a/rtc_base/byte_order.h
+++ b/rtc_base/byte_order.h
@@ -35,6 +35,7 @@
#define le16toh(v) OSSwapLittleToHostInt16(v)
#define le32toh(v) OSSwapLittleToHostInt32(v)
#define le64toh(v) OSSwapLittleToHostInt64(v)
+
#elif defined(WEBRTC_WIN) || defined(__native_client__)
#if defined(WEBRTC_WIN)
@@ -42,45 +43,56 @@
#include <winsock2.h>
#else
#include <netinet/in.h>
-#endif
+#endif // defined(WEBRTC_WIN)
+#if defined(WEBRTC_ARCH_LITTLE_ENDIAN)
#define htobe16(v) htons(v)
#define htobe32(v) htonl(v)
#define be16toh(v) ntohs(v)
#define be32toh(v) ntohl(v)
-#if defined(WEBRTC_WIN)
-#define htobe64(v) htonll(v)
-#define be64toh(v) ntohll(v)
-#endif
-
-#if defined(WEBRTC_ARCH_LITTLE_ENDIAN)
#define htole16(v) (v)
#define htole32(v) (v)
#define htole64(v) (v)
#define le16toh(v) (v)
#define le32toh(v) (v)
#define le64toh(v) (v)
+#if defined(WEBRTC_WIN)
+#define htobe64(v) _byteswap_uint64(v)
+#define be64toh(v) _byteswap_uint64(v)
+#endif // defined(WEBRTC_WIN)
#if defined(__native_client__)
#define htobe64(v) __builtin_bswap64(v)
#define be64toh(v) __builtin_bswap64(v)
-#endif
+#endif // defined(__native_client__)
+
#elif defined(WEBRTC_ARCH_BIG_ENDIAN)
+#define htobe16(v) (v)
+#define htobe32(v) (v)
+#define be16toh(v) (v)
+#define be32toh(v) (v)
#define htole16(v) __builtin_bswap16(v)
#define htole32(v) __builtin_bswap32(v)
#define htole64(v) __builtin_bswap64(v)
#define le16toh(v) __builtin_bswap16(v)
#define le32toh(v) __builtin_bswap32(v)
#define le64toh(v) __builtin_bswap64(v)
+#if defined(WEBRTC_WIN)
+#define htobe64(v) (v)
+#define be64toh(v) (v)
+#endif // defined(WEBRTC_WIN)
#if defined(__native_client__)
#define htobe64(v) (v)
#define be64toh(v) (v)
-#endif
+#endif // defined(__native_client__)
#else
#error WEBRTC_ARCH_BIG_ENDIAN or WEBRTC_ARCH_LITTLE_ENDIAN must be defined.
#endif // defined(WEBRTC_ARCH_LITTLE_ENDIAN)
+
#elif defined(WEBRTC_POSIX)
#include <endian.h>
-#endif
+#else
+#error "Missing byte order functions for this arch."
+#endif // defined(WEBRTC_MAC)
namespace rtc {
