From 6d11bb4a2d5bc8ab7c1491639f1083532b1b8fd1 Mon Sep 17 00:00:00 2001
From: Bardur Arantsson <bardur@scientician.net>
Date: Sat, 17 Sep 2016 09:58:14 +0200
Subject: Replace RNG with PCG random number generator

---
 src/seed.cc | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 src/seed.cc

(limited to 'src/seed.cc')

diff --git a/src/seed.cc b/src/seed.cc
new file mode 100644
index 00000000..0550c769
--- /dev/null
+++ b/src/seed.cc
@@ -0,0 +1,53 @@
+#include "seed.hpp"
+
+#include <random>
+
+seed_t seed_t::system()
+{
+	seed_t seed;
+	// Use system's random device for seeding.
+	std::random_device random_device;
+	std::uniform_int_distribution<std::uint8_t> distribution;
+	// Extract the number of bytes we need.
+	for (std::size_t i = 0; i < n_bytes; i++)
+	{
+		seed.m_data[i] = distribution(random_device);
+	}
+	// Done
+	return seed;
+}
+
+seed_t seed_t::from_bytes(std::uint8_t bytes[n_bytes])
+{
+	seed_t seed;
+	// Copy
+	for (std::size_t i = 0; i < n_bytes; i++)
+	{
+		seed.m_data[i] = bytes[i];
+	}
+	// Done
+	return seed;
+}
+
+void seed_t::to_bytes(std::uint8_t bytes[n_bytes]) const
+{
+	// Copy
+	for (std::size_t i = 0; i < n_bytes; i++)
+	{
+		bytes[i] = m_data[i];
+	}
+}
+void seed_t::to_uint32(std::uint32_t seed_seq_data[n_uint32]) const
+{
+	for (std::size_t i = 0; i < n_uint32; i++)
+	{
+		// Position in the byte-oriented data.
+		std::size_t p = 4 * i;
+		// Pack m_data[p + 0], ..., m_data[p + 3] into a single uint32_t
+		seed_seq_data[i] = 0;
+		seed_seq_data[i] |= (uint32_t(m_data[p + 0]) << (0 * 8));
+		seed_seq_data[i] |= (uint32_t(m_data[p + 1]) << (1 * 8));
+		seed_seq_data[i] |= (uint32_t(m_data[p + 2]) << (2 * 8));
+		seed_seq_data[i] |= (uint32_t(m_data[p + 3]) << (3 * 8));
+	}
+}
-- 
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