highperfocused/bitcoin
1
0
Fork 0
mirror of https://github.com/bitcoin/bitcoin.git synced 2026-01-19 23:03:45 +01:00
Code Issues Packages Projects Releases Wiki Activity

random: refactor: move rand* utilities to RandomMixin

Browse Source 
Rather than make all the useful types of randomness be exclusive to
FastRandomContext, move it to a separate RandomMixin class where it can be reused by
other RNGs.

A Curiously Recurring Template Pattern (CRTP) is used for this, to provide the ability
for individual RNG classes to override one or more randomness functions, without
needing the runtime-cost of virtual classes.

Specifically, RNGs are expected to only provide fillrand and rand64, while all others
are derived from those:
- randbits
- randrange
- randbytes
- rand32
- rand256
- randbool
- rand_uniform_delay
- rand_uniform_duration
- min(), max(), operator()(), to comply with C++ URBG concept.
This commit is contained in:
Pieter Wuille
2024-03-10 08:58:56 -04:00
parent 40dd86fc3b
commit 9b14d3d2da
2 changed files with 148 additions and 92 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
src/random.cpp
View File

@@ -665,7 +665,7 @@ void FastRandomContext::fillrand(Span<std::byte> output) noexcept
rng.Keystream(output);
}
FastRandomContext::FastRandomContext(const uint256& seed) noexcept : requires_seed(false), rng(MakeByteSpan(seed)), bitbuf_size(0) {}
FastRandomContext::FastRandomContext(const uint256& seed) noexcept : requires_seed(false), rng(MakeByteSpan(seed)) {}
bool Random_SanityCheck()
{
@@ -715,7 +715,7 @@ bool Random_SanityCheck()
static constexpr std::array<std::byte, ChaCha20::KEYLEN> ZERO_KEY{};
FastRandomContext::FastRandomContext(bool fDeterministic) noexcept : requires_seed(!fDeterministic), rng(ZERO_KEY), bitbuf_size(0)
FastRandomContext::FastRandomContext(bool fDeterministic) noexcept : requires_seed(!fDeterministic), rng(ZERO_KEY)
{
// Note that despite always initializing with ZERO_KEY, requires_seed is set to true if not
// fDeterministic. That means the rng will be reinitialized with a secure random key upon first
@@ -726,10 +726,8 @@ FastRandomContext& FastRandomContext::operator=(FastRandomContext&& from) noexce
{
requires_seed = from.requires_seed;
rng = from.rng;
bitbuf = from.bitbuf;
bitbuf_size = from.bitbuf_size;
from.requires_seed = true;
from.bitbuf_size = 0;
static_cast<RandomMixin<FastRandomContext>&>(*this) = std::move(from);
return *this;
}