Add base/random module for random utilities.

CMakeLists.txt

@@ -157,6 +157,8 @@ PRIVATE
     base/qthelp_url.h
     base/qt_connection.h
     base/qt_signal_producer.h
+    base/random.cpp
+    base/random.h
     base/required.h
     base/runtime_composer.cpp
     base/runtime_composer.h

base/base_pch.h

@@ -25,4 +25,5 @@
 #include "base/flat_map.h"
 #include "base/flat_set.h"
 #include "base/optional.h"
-#include "base/openssl_help.h"
+#include "base/algorithm.h"
+#include "base/basic_types.h"

base/bytes.cpp

@@ -6,15 +6,13 @@
 //
 #include "base/bytes.h"
 
-#include "base/openssl_help.h"
+#include "base/random.h"
 
 namespace bytes {
 
 void set_random(span destination) {
 	if (!destination.empty()) {
-		RAND_bytes(
-			reinterpret_cast<unsigned char*>(destination.data()),
-			destination.size());
+		base::RandomFill(destination.data(), destination.size());
 	}
 }
 

base/call_delayed.h

@@ -8,7 +8,7 @@
 
 namespace base {
 
-	void call_delayed(crl::time delay, FnMut<void()> &&callable);
+void call_delayed(crl::time delay, FnMut<void()> &&callable);
 
 template <
 	typename Guard,

base/openssl_help.h

@@ -13,7 +13,6 @@
 extern "C" {
 #include <openssl/bn.h>
 #include <openssl/sha.h>
-#include <openssl/rand.h>
 #include <openssl/aes.h>
 #include <openssl/modes.h>
 #include <openssl/crypto.h>
@@ -546,23 +545,6 @@ template <
 		args...);
 }
 
-inline void AddRandomSeed(bytes::const_span data) {
-	RAND_seed(data.data(), data.size());
-}
-
-template <
-	typename T,
-	typename = std::enable_if_t<std::is_trivially_copyable_v<T>>>
-[[nodiscard]] inline T RandomValue() {
-	unsigned char buffer[sizeof(T)];
-	if (!RAND_bytes(buffer, sizeof(T))) {
-		Unexpected("Could not generate random bytes!");
-	}
-	auto result = T();
-	memcpy(&result, buffer, sizeof(T));
-	return result;
-}
-
 inline bytes::vector Pbkdf2Sha512(
 		bytes::const_span password,
 		bytes::const_span salt,

base/random.cpp

@@ -0,0 +1,42 @@
+// This file is part of Desktop App Toolkit,
+// a set of libraries for developing nice desktop applications.
+//
+// For license and copyright information please follow this link:
+// https://github.com/desktop-app/legal/blob/master/LEGAL
+//
+#include "base/random.h"
+
+extern "C" {
+#include <openssl/rand.h>
+} // extern "C"
+
+namespace base {
+
+void RandomFill(bytes::span bytes) {
+	const auto result = RAND_bytes(
+		reinterpret_cast<unsigned char*>(bytes.data()),
+		bytes.size());
+
+	Ensures(result);
+}
+
+int RandomIndex(int count) {
+	Expects(count > 0);
+
+	if (count == 1) {
+		return 0;
+	}
+	const auto max = (std::numeric_limits<uint32>::max() / count) * count;
+	while (true) {
+		const auto random = RandomValue<uint32>();
+		if (random < max) {
+			return int(random % count);
+		}
+	}
+}
+
+void RandomAddSeed(bytes::const_span bytes) {
+	RAND_seed(bytes.data(), bytes.size());
+}
+
+} // namespace base

base/random.h

@@ -0,0 +1,35 @@
+// This file is part of Desktop App Toolkit,
+// a set of libraries for developing nice desktop applications.
+//
+// For license and copyright information please follow this link:
+// https://github.com/desktop-app/legal/blob/master/LEGAL
+//
+#pragma once
+
+#include <cstddef>
+#include <type_traits>
+
+#include "base/bytes.h"
+
+namespace base {
+
+void RandomFill(bytes::span bytes);
+
+inline void RandomFill(void *data, std::size_t length) {
+	RandomFill({ static_cast<bytes::type*>(data), length });
+}
+
+template <
+	typename T,
+	typename = std::enable_if_t<std::is_trivially_copyable_v<T>>>
+[[nodiscard]] inline T RandomValue() {
+	auto result = T();
+	RandomFill({ reinterpret_cast<std::byte*>(&result), sizeof(T) });
+	return result;
+}
+
+[[nodiscard]] int RandomIndex(int count);
+
+void RandomAddSeed(bytes::const_span bytes);
+
+} // namespace base