Ichthyostega
9c74466778
This is something I wanted to clean-up since a very long time indeed, but always postponed it, since it requires a lot of nasty clean-up and disentangling.... Several parts had been stashed away into `src/lib/test`, which are not really related: * the testrunner and testsuite builder * generic helper utilities * specialised test-support facilities, e.g. the EventLog This changeset introduces a new top-level test folder and a namespace `::test` Code from this folder is linked into a shared library `libtestsupport.so`, which resides in the linkage hierarchy between »Vessel« and »Vault«, yet is no longer part of the Lumiera application and only linked into the test-suite.
111 lines
2.5 KiB
C++
111 lines
2.5 KiB
C++
/*
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random.cpp - storage and implementation for random number framework
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Copyright (C)
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2024, Hermann Vosseler <Ichthyostega@web.de>
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**Lumiera** is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2 of the License, or (at your
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option) any later version. See the file COPYING for further details.
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* *****************************************************************/
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/** @file random.cpp
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** Implementation details and common storage for random number generation.
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** @todo 3/2024 work out how some executions or performances are configured reproducibly.
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*/
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#include "lib/random.hpp"
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#include <string>
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using std::string;
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namespace lib {
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namespace {
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const string ENTROPY_SOURCE_SPEC{"/dev/random"};
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class EntropyNucleus
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: public SeedNucleus
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{
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std::random_device entropySource_;
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uint64_t
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getSeed() override
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{
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return entropySource_();
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}
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public:
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EntropyNucleus(string const& SPEC)
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: entropySource_{SPEC}
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{ }
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};
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class EternalNucleus
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: public SeedNucleus
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{
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uint64_t
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getSeed() override
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{
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return LIFE_AND_UNIVERSE_4EVER;
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}
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};
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/** static global entropy source instance */
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EntropyNucleus entropyNucleus{ENTROPY_SOURCE_SPEC};
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/// @todo this one should somehow be configurable
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EternalNucleus eternalNucleus;
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Random::Seed defaultNucleus{defaultGen};
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}
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Random defaultGen{eternalNucleus};
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Random entropyGen{entropyNucleus};
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SeedNucleus&
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seedFromDefaultGen()
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{
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return defaultNucleus;
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}
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SeedNucleus::~SeedNucleus() { }
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void
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randomiseRandomness()
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{
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entropyGen.reseed(entropyNucleus);
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defaultGen.reseed(entropyNucleus);
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}
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/**
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* @remark this is a general-purpose util mostly used in unit-tests
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* to generate a short string item that looks readable; probabilities
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* of individual letters were chosen non-uniformely to improve readability.
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*/
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string
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randStr (size_t len)
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{
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static const string alpha{"aaaabbccdddeeeeeffgghiiiiiijjkkllmmnnnoooopqqrrssttuuuuvwwxxxxxxxxxyyyyzz0123456789"};
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static const size_t MAXCH{alpha.size()};
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string garbage(len,'\0');
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size_t p = len;
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while (p)
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garbage[--p] = alpha[rani (MAXCH)];
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return garbage;
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}
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} // namespace lib
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