Cleaned up ObjectId generation and made it portable

1 files changed, 16 insertions, 86 deletions

diff --git a/zencore/uid.cpp b/zencore/uid.cpp
index 347333445..b22ac7896 100644
--- a/zencore/uid.cpp
+++ b/zencore/uid.cpp
@@ -2,16 +2,13 @@
 
 #include <zencore/uid.h>
 
+#include <zencore/endian.h>
 #include <zencore/string.h>
 
-#if _WIN32
-#	include <zencore/windows.h>
-#	include <bcrypt.h>
-#	pragma comment(lib, "bcrypt.lib")
-#endif
-
 #include <atomic>
 #include <bit>
+#include <chrono>
+#include <random>
 #include <set>
 #include <unordered_map>
 
@@ -21,59 +18,10 @@ namespace zen {
 
 //////////////////////////////////////////////////////////////////////////
 
-template<typename T>
-T
-EndianSwap(T value)
-{
-	uint8_t dest[sizeof value];
-
-	memcpy(dest, &value, sizeof value);
-
-	for (int i = 0; i < sizeof(value); i++)
-	{
-		uint8_t& other = dest[sizeof(value) - i - 1];
-
-		uint8_t temp = dest[i];
-		dest[i]		 = other;
-		other		 = temp;
-	}
-
-	T ret;
-
-	memcpy(&ret, &value, sizeof value);
-
-	return ret;
-}
-
-#if _WIN32
-__forceinline uint16_t
-EndianSwap(uint16_t value)
-{
-	return _byteswap_ushort(value);
-}
-
-__forceinline uint32_t
-EndianSwap(uint32_t value)
-{
-	return _byteswap_ulong(value);
-}
-
-__forceinline uint64_t
-EndianSwap(uint64_t value)
-{
-	return _byteswap_uint64(value);
-}
-#endif
-
-//////////////////////////////////////////////////////////////////////////
-
 namespace detail {
 	static bool					OidInitialised;
 	static uint32_t				RunId;
 	static std::atomic_uint32_t Serial;
-
-	// Number of 100 nanosecond units from 1/1/1601 to 1/1/1970 - used for Windows impl
-	constexpr int64_t kEpochBias = 116'444'736'000'000'000ull;
 }  // namespace detail
 
 //////////////////////////////////////////////////////////////////////////
@@ -84,48 +32,30 @@ const Oid Oid::Max	= {{~0u, ~0u, ~0u}};
 void
 Oid::Initialize()
 {
-	using namespace detail;
-
-	if (OidInitialised)
-		return;
-
-	OidInitialised = true;
-
-#if _WIN32
-	char rng[8];
-	BCryptGenRandom(NULL, (PUCHAR)rng, sizeof rng, BCRYPT_USE_SYSTEM_PREFERRED_RNG);
+	if (!detail::OidInitialised)
+	{
+		std::random_device Rng;
+		detail::RunId = Rng();
+		detail::Serial = Rng();
 
-	memcpy(&RunId, &rng[0], sizeof(RunId));
-	memcpy((void*)&Serial, &rng[4], sizeof(Serial));
-#else
-#	error Must implement Oid::Initialize
-#endif
+		detail::OidInitialised = true;
+	}
 }
 
 const Oid&
 Oid::Generate()
 {
-	using namespace detail;
-
-	if (!OidInitialised)
+	if (!detail::OidInitialised)
 	{
 		Oid::Initialize();
 	}
 
-#if _WIN32
-	FILETIME filetime;
-
-	GetSystemTimeAsFileTime(&filetime);	 // Time is UTC
-
-	uint64_t filetime64;
-	memcpy(&filetime64, &filetime, sizeof filetime);
+	const uint64_t kOffset = 1'609'459'200;  // Seconds from 1970 -> 2021
+	const uint64_t Time	 = std::chrono::system_clock::to_time_t(std::chrono::system_clock::now()) - kOffset;
 
-	OidBits[0] = EndianSwap(uint32_t((filetime64 - kEpochBias) / 10'000'000l));
-	OidBits[1] = EndianSwap(uint32_t(Serial++));
-	OidBits[2] = RunId;
-#else
-#	error Must implement Oid::Generate
-#endif
+	OidBits[0] = ToNetworkOrder(uint32_t(Time));
+	OidBits[1] = ToNetworkOrder(uint32_t(++detail::Serial));
+	OidBits[2] = detail::RunId;
 
 	return *this;
 }