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-rw-r--r--absl/random/CMakeLists.txt2
-rw-r--r--absl/random/internal/BUILD.bazel2
-rw-r--r--absl/random/internal/nonsecure_base.h107
-rw-r--r--absl/random/internal/nonsecure_base_test.cc66
-rw-r--r--absl/random/internal/salted_seed_seq.h50
5 files changed, 109 insertions, 118 deletions
diff --git a/absl/random/CMakeLists.txt b/absl/random/CMakeLists.txt
index b4ada69b..c3f0b450 100644
--- a/absl/random/CMakeLists.txt
+++ b/absl/random/CMakeLists.txt
@@ -727,7 +727,7 @@ absl_cc_library(
${ABSL_DEFAULT_LINKOPTS}
DEPS
absl::core_headers
- absl::optional
+ absl::inlined_vector
absl::random_internal_pool_urbg
absl::random_internal_salted_seed_seq
absl::random_internal_seed_material
diff --git a/absl/random/internal/BUILD.bazel b/absl/random/internal/BUILD.bazel
index 73535e5b..69f9f80c 100644
--- a/absl/random/internal/BUILD.bazel
+++ b/absl/random/internal/BUILD.bazel
@@ -222,8 +222,8 @@ cc_library(
":salted_seed_seq",
":seed_material",
"//absl/base:core_headers",
+ "//absl/container:inlined_vector",
"//absl/meta:type_traits",
- "//absl/types:optional",
"//absl/types:span",
],
)
diff --git a/absl/random/internal/nonsecure_base.h b/absl/random/internal/nonsecure_base.h
index 730fa2ea..c7d7fa4b 100644
--- a/absl/random/internal/nonsecure_base.h
+++ b/absl/random/internal/nonsecure_base.h
@@ -17,28 +17,82 @@
#include <algorithm>
#include <cstdint>
-#include <iostream>
#include <iterator>
-#include <random>
-#include <string>
#include <type_traits>
+#include <utility>
#include <vector>
#include "absl/base/macros.h"
+#include "absl/container/inlined_vector.h"
#include "absl/meta/type_traits.h"
#include "absl/random/internal/pool_urbg.h"
#include "absl/random/internal/salted_seed_seq.h"
#include "absl/random/internal/seed_material.h"
-#include "absl/types/optional.h"
#include "absl/types/span.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace random_internal {
+// RandenPoolSeedSeq is a custom seed sequence type where generate() fills the
+// provided buffer via the RandenPool entropy source.
+class RandenPoolSeedSeq {
+ private:
+ struct ContiguousTag {};
+ struct BufferTag {};
+
+ // Generate random unsigned values directly into the buffer.
+ template <typename Contiguous>
+ void generate_impl(ContiguousTag, Contiguous begin, Contiguous end) {
+ const size_t n = std::distance(begin, end);
+ auto* a = &(*begin);
+ RandenPool<uint8_t>::Fill(
+ absl::MakeSpan(reinterpret_cast<uint8_t*>(a), sizeof(*a) * n));
+ }
+
+ // Construct a buffer of size n and fill it with values, then copy
+ // those values into the seed iterators.
+ template <typename RandomAccessIterator>
+ void generate_impl(BufferTag, RandomAccessIterator begin,
+ RandomAccessIterator end) {
+ const size_t n = std::distance(begin, end);
+ absl::InlinedVector<uint32_t, 8> data(n, 0);
+ RandenPool<uint32_t>::Fill(absl::MakeSpan(data.begin(), data.end()));
+ std::copy(std::begin(data), std::end(data), begin);
+ }
+
+ public:
+ using result_type = uint32_t;
+
+ size_t size() { return 0; }
+
+ template <typename OutIterator>
+ void param(OutIterator) const {}
+
+ template <typename RandomAccessIterator>
+ void generate(RandomAccessIterator begin, RandomAccessIterator end) {
+ // RandomAccessIterator must be assignable from uint32_t
+ if (begin != end) {
+ using U = typename std::iterator_traits<RandomAccessIterator>::value_type;
+ // ContiguousTag indicates the common case of a known contiguous buffer,
+ // which allows directly filling the buffer. In C++20,
+ // std::contiguous_iterator_tag provides a mechanism for testing this
+ // capability, however until Abseil's support requirements allow us to
+ // assume C++20, limit checks to a few common cases.
+ using TagType = absl::conditional_t<
+ (std::is_pointer<RandomAccessIterator>::value ||
+ std::is_same<RandomAccessIterator,
+ typename std::vector<U>::iterator>::value),
+ ContiguousTag, BufferTag>;
+
+ generate_impl(TagType{}, begin, end);
+ }
+ }
+};
+
// Each instance of NonsecureURBGBase<URBG> will be seeded by variates produced
// by a thread-unique URBG-instance.
-template <typename URBG>
+template <typename URBG, typename Seeder = RandenPoolSeedSeq>
class NonsecureURBGBase {
public:
using result_type = typename URBG::result_type;
@@ -85,49 +139,6 @@ class NonsecureURBGBase {
}
private:
- // Seeder is a custom seed sequence type where generate() fills the provided
- // buffer via the RandenPool entropy source.
- struct Seeder {
- using result_type = uint32_t;
-
- size_t size() { return 0; }
-
- template <typename OutIterator>
- void param(OutIterator) const {}
-
- template <typename RandomAccessIterator>
- void generate(RandomAccessIterator begin, RandomAccessIterator end) {
- if (begin != end) {
- // begin, end must be random access iterators assignable from uint32_t.
- generate_impl(
- std::integral_constant<bool, sizeof(*begin) == sizeof(uint32_t)>{},
- begin, end);
- }
- }
-
- // Commonly, generate is invoked with a pointer to a buffer which
- // can be cast to a uint32_t.
- template <typename RandomAccessIterator>
- void generate_impl(std::integral_constant<bool, true>,
- RandomAccessIterator begin, RandomAccessIterator end) {
- auto buffer = absl::MakeSpan(begin, end);
- auto target = absl::MakeSpan(reinterpret_cast<uint32_t*>(buffer.data()),
- buffer.size());
- RandenPool<uint32_t>::Fill(target);
- }
-
- // The non-uint32_t case should be uncommon, and involves an extra copy,
- // filling the uint32_t buffer and then mixing into the output.
- template <typename RandomAccessIterator>
- void generate_impl(std::integral_constant<bool, false>,
- RandomAccessIterator begin, RandomAccessIterator end) {
- const size_t n = std::distance(begin, end);
- absl::InlinedVector<uint32_t, 8> data(n, 0);
- RandenPool<uint32_t>::Fill(absl::MakeSpan(data.begin(), data.end()));
- std::copy(std::begin(data), std::end(data), begin);
- }
- };
-
static URBG ConstructURBG() {
Seeder seeder;
return URBG(seeder);
diff --git a/absl/random/internal/nonsecure_base_test.cc b/absl/random/internal/nonsecure_base_test.cc
index 698027fc..3502243e 100644
--- a/absl/random/internal/nonsecure_base_test.cc
+++ b/absl/random/internal/nonsecure_base_test.cc
@@ -15,6 +15,7 @@
#include "absl/random/internal/nonsecure_base.h"
#include <algorithm>
+#include <cstdint>
#include <iostream>
#include <memory>
#include <random>
@@ -192,54 +193,35 @@ TEST(NonsecureURBGBase, EqualSeedSequencesYieldEqualVariates) {
}
}
-// This is a PRNG-compatible type specifically designed to test
-// that NonsecureURBGBase::Seeder can correctly handle iterators
-// to arbitrary non-uint32_t size types.
-template <typename T>
-struct SeederTestEngine {
- using result_type = T;
+TEST(RandenPoolSeedSeqTest, SeederWorksForU32) {
+ absl::random_internal::RandenPoolSeedSeq seeder;
- static constexpr result_type(min)() {
- return (std::numeric_limits<result_type>::min)();
- }
- static constexpr result_type(max)() {
- return (std::numeric_limits<result_type>::max)();
- }
-
- template <class SeedSequence,
- typename = typename absl::enable_if_t<
- !std::is_same<SeedSequence, SeederTestEngine>::value>>
- explicit SeederTestEngine(SeedSequence&& seq) {
- seed(seq);
- }
-
- SeederTestEngine(const SeederTestEngine&) = default;
- SeederTestEngine& operator=(const SeederTestEngine&) = default;
- SeederTestEngine(SeederTestEngine&&) = default;
- SeederTestEngine& operator=(SeederTestEngine&&) = default;
+ uint32_t state[2] = {0, 0};
+ seeder.generate(std::begin(state), std::end(state));
+ EXPECT_FALSE(state[0] == 0 && state[1] == 0);
+}
- result_type operator()() { return state[0]; }
+TEST(RandenPoolSeedSeqTest, SeederWorksForU64) {
+ absl::random_internal::RandenPoolSeedSeq seeder;
- template <class SeedSequence>
- void seed(SeedSequence&& seq) {
- std::fill(std::begin(state), std::end(state), T(0));
- seq.generate(std::begin(state), std::end(state));
- }
+ uint64_t state[2] = {0, 0};
+ seeder.generate(std::begin(state), std::end(state));
+ EXPECT_FALSE(state[0] == 0 && state[1] == 0);
+ EXPECT_FALSE((state[0] >> 32) == 0 && (state[1] >> 32) == 0);
+}
- T state[2];
-};
+TEST(RandenPoolSeedSeqTest, SeederWorksForS32) {
+ absl::random_internal::RandenPoolSeedSeq seeder;
-TEST(NonsecureURBGBase, SeederWorksForU32) {
- using U32 =
- absl::random_internal::NonsecureURBGBase<SeederTestEngine<uint32_t>>;
- U32 x;
- EXPECT_NE(0, x());
+ int32_t state[2] = {0, 0};
+ seeder.generate(std::begin(state), std::end(state));
+ EXPECT_FALSE(state[0] == 0 && state[1] == 0);
}
-TEST(NonsecureURBGBase, SeederWorksForU64) {
- using U64 =
- absl::random_internal::NonsecureURBGBase<SeederTestEngine<uint64_t>>;
+TEST(RandenPoolSeedSeqTest, SeederWorksForVector) {
+ absl::random_internal::RandenPoolSeedSeq seeder;
- U64 x;
- EXPECT_NE(0, x());
+ std::vector<uint32_t> state(2);
+ seeder.generate(std::begin(state), std::end(state));
+ EXPECT_FALSE(state[0] == 0 && state[1] == 0);
}
diff --git a/absl/random/internal/salted_seed_seq.h b/absl/random/internal/salted_seed_seq.h
index 5953a090..06291865 100644
--- a/absl/random/internal/salted_seed_seq.h
+++ b/absl/random/internal/salted_seed_seq.h
@@ -22,6 +22,7 @@
#include <memory>
#include <type_traits>
#include <utility>
+#include <vector>
#include "absl/container/inlined_vector.h"
#include "absl/meta/type_traits.h"
@@ -65,15 +66,19 @@ class SaltedSeedSeq {
template <typename RandomAccessIterator>
void generate(RandomAccessIterator begin, RandomAccessIterator end) {
+ using U = typename std::iterator_traits<RandomAccessIterator>::value_type;
+
// The common case is that generate is called with ContiguousIterators
// to uint arrays. Such contiguous memory regions may be optimized,
// which we detect here.
- using tag = absl::conditional_t<
- (std::is_pointer<RandomAccessIterator>::value &&
- std::is_same<absl::decay_t<decltype(*begin)>, uint32_t>::value),
+ using TagType = absl::conditional_t<
+ (std::is_same<U, uint32_t>::value &&
+ (std::is_pointer<RandomAccessIterator>::value ||
+ std::is_same<RandomAccessIterator,
+ typename std::vector<U>::iterator>::value)),
ContiguousAndUint32Tag, DefaultTag>;
if (begin != end) {
- generate_impl(begin, end, tag{});
+ generate_impl(TagType{}, begin, end, std::distance(begin, end));
}
}
@@ -89,8 +94,15 @@ class SaltedSeedSeq {
struct DefaultTag {};
// Generate which requires the iterators are contiguous pointers to uint32_t.
- void generate_impl(uint32_t* begin, uint32_t* end, ContiguousAndUint32Tag) {
- generate_contiguous(absl::MakeSpan(begin, end));
+ // Fills the initial seed buffer the underlying SSeq::generate() call,
+ // then mixes in the salt material.
+ template <typename Contiguous>
+ void generate_impl(ContiguousAndUint32Tag, Contiguous begin, Contiguous end,
+ size_t n) {
+ seq_->generate(begin, end);
+ const uint32_t salt = absl::random_internal::GetSaltMaterial().value_or(0);
+ auto span = absl::Span<uint32_t>(&*begin, n);
+ MixIntoSeedMaterial(absl::MakeConstSpan(&salt, 1), span);
}
// The uncommon case for generate is that it is called with iterators over
@@ -98,27 +110,13 @@ class SaltedSeedSeq {
// case we allocate a temporary 32-bit buffer and then copy-assign back
// to the initial inputs.
template <typename RandomAccessIterator>
- void generate_impl(RandomAccessIterator begin, RandomAccessIterator end,
- DefaultTag) {
- return generate_and_copy(std::distance(begin, end), begin);
- }
-
- // Fills the initial seed buffer the underlying SSeq::generate() call,
- // mixing in the salt material.
- void generate_contiguous(absl::Span<uint32_t> buffer) {
- seq_->generate(buffer.begin(), buffer.end());
- const uint32_t salt = absl::random_internal::GetSaltMaterial().value_or(0);
- MixIntoSeedMaterial(absl::MakeConstSpan(&salt, 1), buffer);
- }
-
- // Allocates a seed buffer of `n` elements, generates the seed, then
- // copies the result into the `out` iterator.
- template <typename Iterator>
- void generate_and_copy(size_t n, Iterator out) {
- // Allocate a temporary buffer, generate, and then copy.
+ void generate_impl(DefaultTag, RandomAccessIterator begin,
+ RandomAccessIterator, size_t n) {
+ // Allocates a seed buffer of `n` elements, generates the seed, then
+ // copies the result into the `out` iterator.
absl::InlinedVector<uint32_t, 8> data(n, 0);
- generate_contiguous(absl::MakeSpan(data.data(), data.size()));
- std::copy(data.begin(), data.end(), out);
+ generate_impl(ContiguousAndUint32Tag{}, data.begin(), data.end(), n);
+ std::copy(data.begin(), data.end(), begin);
}
// Because [rand.req.seedseq] is not required to be copy-constructible,
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-04 00:14:39 +0000