Replace Boost.UUID with a simple UUID4 generator

Author: tstenner

CMakeLists.txt

@@ -92,6 +92,7 @@ add_library(lslobj OBJECT
 	src/util/cast.cpp
 	src/util/inireader.hpp
 	src/util/inireader.cpp
+	src/util/uuid.hpp
 	thirdparty/loguru/loguru.cpp
 	$<$<BOOL:${LSL_LEGACY_CPP_ABI}>:src/legacy/legacy_abi.cpp src/legacy/legacy_abi.h>
 	# headers

src/stream_info_impl.cpp

@@ -1,9 +1,8 @@
 #include "stream_info_impl.h"
 #include "api_config.h"
 #include "util/cast.hpp"
+#include "util/uuid.hpp"
 #include <algorithm>
-#include <boost/uuid/random_generator.hpp>
-#include <boost/uuid/uuid_io.hpp>
 #include <loguru.hpp>
 #include <sstream>
 #include <utility>
@@ -258,7 +257,7 @@ void stream_info_impl::uid(const std::string &v) {
 
 const std::string& stream_info_impl::reset_uid()
 {
-	uid(lslboost::uuids::to_string(lslboost::uuids::random_generator()()));
+	uid(UUID::random().to_string());
 	return uid_;
 }
 

src/util/uuid.hpp

@@ -0,0 +1,56 @@
+#pragma once
+
+#include <random>
+#include <string>
+
+struct UUID {
+	uint8_t data[16]{0};
+
+	void set_version(uint8_t version = 4) {
+		data[6] = (data[6] & 0x0f) | static_cast<uint8_t>(version << 4);
+	}
+
+	void set_variant2() { data[8] = (data[8] & 0x3f) | 0x80; }
+
+	/// return the UUID formatted as RFC 4122 UUID
+	std::string to_string() const {
+		std::string out(36, '0');
+		auto pos = out.begin();
+		const uint8_t *curbyte = data;
+
+		/// helper: write `n` hex-formatted bytes as hex to a string, incrementing the positions
+		const auto copybytesashex = [&pos, &curbyte](int n) {
+			const char tbl[] = "0123456789abcdef";
+			for (int i = 0; i < n; ++i) {
+				*pos++ = tbl[*curbyte / 16];
+				*pos++ = tbl[*curbyte++ & 0x0f];
+			}
+		};
+
+		copybytesashex(2);
+
+		// 4x "abcd-"
+		for (int i = 0; i < 4; ++i) {
+			copybytesashex(2);
+			*pos++ = '-';
+		}
+		copybytesashex(6);
+		return out;
+	}
+
+	/// generate a random UUID4
+	static UUID random() {
+		UUID uuid;
+
+		// cast data to an array of the RNGs native type, write random bytes directly to it
+		std::random_device rng;
+		using rand_t = std::random_device::result_type;
+		constexpr int rand_elems = sizeof(UUID::data) / sizeof(rand_t);
+		rand_t *data_view = reinterpret_cast<rand_t*>(uuid.data);
+		for (int i = 0; i < rand_elems; ++i) data_view[i] = rng();
+
+		uuid.set_version(4);
+		uuid.set_variant2();
+		return uuid;
+	}
+};

testing/test_int_streaminfo.cpp

@@ -15,6 +15,7 @@ bool contains(const T(&valid)[N], const T target) {
 TEST_CASE("uid", "[basic][streaminfo]") {
 	lsl::stream_info_impl info;
 	const std::string uid = info.reset_uid();
+	INFO(uid)
 	REQUIRE(uid.length() == 36);
 	for(auto i=0u; i<uid.size(); ++i)
 		if(i==8||i==13||i==18||i==23) REQUIRE(uid[i] == '-');