Add Hash_Engine

src/cli/perf_hash_engine.cpp

@@ -0,0 +1,76 @@
+/*
+* (C) 2026 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include "perf.h"
+
+#if defined(BOTAN_HAS_HASH_ENGINES)
+
+   #include <botan/exceptn.h>
+   #include <botan/hash.h>
+   #include <botan/rng.h>
+   #include <botan/internal/fmt.h>
+   #include <botan/internal/hash_engine.h>
+
+namespace Botan_CLI {
+
+namespace {
+
+class PerfTest_HashEngine final : public PerfTest {
+   public:
+      void go(const PerfConfig& config) override {
+         const std::vector<std::string> hashes = {"SHA-256", "SHA-512", "SHAKE-256(256)"};
+
+         const std::vector<size_t> msg_sizes = {64, 256, 1024, 16384};
+         const std::vector<size_t> counts = {16, 32, 128};
+
+         for(const auto& hash_fn : hashes) {
+            std::unique_ptr<Botan::Hash_Engine> engine;
+
+            try {
+               engine = Botan::Hash_Engine::create_or_throw(hash_fn);
+            } catch(Botan::Not_Implemented&) {
+               continue;
+            }
+
+            const size_t out_len = engine->output_length();
+
+            for(size_t msg_size : msg_sizes) {
+               for(size_t count : counts) {
+                  std::vector<uint8_t> input_buf(count * msg_size);
+                  std::vector<uint8_t> output_buf(count * out_len);
+
+                  config.rng().randomize(input_buf);
+
+                  std::vector<std::span<const uint8_t>> input_spans(count);
+                  std::vector<std::span<uint8_t>> output_spans(count);
+
+                  for(size_t i = 0; i < count; ++i) {
+                     input_spans[i] = std::span<const uint8_t>(input_buf.data() + i * msg_size, msg_size);
+                     output_spans[i] = std::span<uint8_t>(output_buf.data() + i * out_len, out_len);
+                  }
+
+                  const std::string name =
+                     Botan::fmt("Hash_Engine({}) n={}", hash_fn, count);
+
+                  const uint64_t total_bytes = static_cast<uint64_t>(count) * msg_size;
+                  auto timer = config.make_timer(name, total_bytes, "batch_hash", engine->provider(), msg_size);
+
+                  timer->run_until_elapsed(config.runtime(), [&]() { engine->batch_hash(output_spans, input_spans); });
+
+                  config.record_result(*timer);
+               }
+            }
+         }
+      }
+};
+
+}  // namespace
+
+BOTAN_REGISTER_PERF_TEST("hash_engine", PerfTest_HashEngine);
+
+}  // namespace Botan_CLI
+
+#endif

src/lib/hash_engine/hash_engine.cpp

@@ -0,0 +1,155 @@
+/*
+* (C) 2026 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/internal/hash_engine.h>
+
+#include <botan/assert.h>
+#include <botan/hash.h>
+
+#if defined(BOTAN_HAS_THREAD_UTILS)
+   #include <botan/internal/thread_pool.h>
+#endif
+
+namespace Botan {
+
+namespace {
+
+class Base_Hash_Engine final : public Hash_Engine {
+   public:
+      explicit Base_Hash_Engine(std::unique_ptr<HashFunction> hash) : m_hash(std::move(hash)) {}
+
+      std::string name() const override { return m_hash->name(); }
+
+      std::string provider() const override { return "base"; }
+
+      size_t output_length() const override { return m_hash->output_length(); }
+
+      size_t parallelism() const override { return 1; }
+
+      void batch_hash(std::span<std::span<uint8_t>> outputs, std::span<std::span<const uint8_t>> inputs) override {
+         BOTAN_ARG_CHECK(outputs.size() == inputs.size(),
+                         "Hash_Engine::batch_hash requires same number of inputs and outputs");
+
+         for(size_t i = 0; i != inputs.size(); ++i) {
+            BOTAN_ARG_CHECK(outputs[i].size() >= output_length(), "Hash_Engine::batch_hash output buffer too small");
+            m_hash->update(inputs[i]);
+            m_hash->final(outputs[i].first(output_length()));
+         }
+      }
+
+   private:
+      std::unique_ptr<HashFunction> m_hash;
+};
+
+#if defined(BOTAN_HAS_THREAD_UTILS)
+
+class Threaded_Hash_Engine final : public Hash_Engine {
+   public:
+      Threaded_Hash_Engine(std::unique_ptr<HashFunction> hash, Thread_Pool& threadpool) :
+            m_threadpool(threadpool),
+            m_name(hash->name()),
+            m_output_length(hash->output_length()),
+            m_thread_count(m_threadpool.worker_count()) {
+         BOTAN_ASSERT_NOMSG(m_thread_count > 0);
+         m_hashes.reserve(m_thread_count);
+         for(size_t i = 0; i != m_thread_count; ++i) {
+            m_hashes.push_back(hash->new_object());
+         }
+      }
+
+      std::string name() const override { return m_name; }
+
+      std::string provider() const override { return "threads"; }
+
+      size_t output_length() const override { return m_output_length; }
+
+      size_t parallelism() const override { return m_thread_count; }
+
+      void batch_hash(std::span<std::span<uint8_t>> outputs, std::span<std::span<const uint8_t>> inputs) override {
+         BOTAN_ARG_CHECK(outputs.size() == inputs.size(),
+                         "Hash_Engine::batch_hash requires same number of inputs and outputs");
+
+         const size_t count = inputs.size();
+         const size_t threads = usable_threads(count);
+
+         if(threads <= 1) {
+            hash_chunk(*m_hashes[0], m_output_length, outputs, inputs, 0, count);
+            return;
+         }
+
+         dispatch(threads, count, [&](size_t t, size_t offset, size_t n) {
+            hash_chunk(*m_hashes[t], m_output_length, outputs, inputs, offset, n);
+         });
+      }
+
+   private:
+      size_t usable_threads(size_t count) const {
+         // Chunk work to not spread too thinly since just queuing the work
+         // in the pool has nonzero overhead.
+         constexpr size_t MIN_HASHES_PER_THREAD = 64;
+
+         const size_t max_useful_threads = count / MIN_HASHES_PER_THREAD;
+         return std::min(m_thread_count, std::max<size_t>(max_useful_threads, 1));
+      }
+
+      template <typename F>
+      void dispatch(size_t threads, size_t count, F work_fn) {
+         const size_t per_thread = count / threads;
+         const size_t remainder = count % threads;
+
+         std::vector<std::future<void>> futures;
+         futures.reserve(threads);
+
+         size_t offset = 0;
+         for(size_t t = 0; t != threads; ++t) {
+            // First remainder threads get 1 extra hash over the main batch
+            const size_t n = per_thread + (t < remainder ? 1 : 0);
+            futures.push_back(m_threadpool.run(work_fn, t, offset, n));
+            offset += n;
+         }
+
+         for(auto& f : futures) {
+            f.get();
+         }
+      }
+
+      static void hash_chunk(HashFunction& hash,
+                             size_t output_length,
+                             std::span<std::span<uint8_t>> outputs,
+                             std::span<std::span<const uint8_t>> inputs,
+                             size_t offset,
+                             size_t count) {
+         for(size_t i = offset; i != offset + count; ++i) {
+            hash.update(inputs[i]);
+            hash.final(outputs[i].first(output_length));
+         }
+      }
+
+      Thread_Pool& m_threadpool;
+      std::string m_name;
+      size_t m_output_length;
+      size_t m_thread_count;
+      std::vector<std::unique_ptr<HashFunction>> m_hashes;
+};
+
+#endif
+
+}  // namespace
+
+std::unique_ptr<Hash_Engine> Hash_Engine::create_or_throw(std::string_view hash_fn) {
+   auto hash = HashFunction::create_or_throw(hash_fn);
+
+#if defined(BOTAN_HAS_THREAD_UTILS)
+   auto& threadpool = Thread_Pool::global_instance();
+   if(threadpool.worker_count() > 0) {
+      return std::make_unique<Threaded_Hash_Engine>(std::move(hash), threadpool);
+   }
+#endif
+
+   return std::make_unique<Base_Hash_Engine>(std::move(hash));
+}
+
+}  // namespace Botan

src/lib/hash_engine/hash_engine.h

@@ -0,0 +1,65 @@
+/*
+* (C) 2026 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#ifndef BOTAN_HASH_ENGINE_H_
+#define BOTAN_HASH_ENGINE_H_
+
+#include <botan/types.h>
+#include <memory>
+#include <span>
+#include <string>
+
+namespace Botan {
+
+class BOTAN_TEST_API Hash_Engine {
+   public:
+      /**
+      * @return name of the hash
+      */
+      virtual std::string name() const = 0;
+
+      /**
+      * @return provider of the engine (eg "base", "avx2", "avx512")
+      */
+      virtual std::string provider() const = 0;
+
+      /**
+      * @return output length of the hash function
+      */
+      virtual size_t output_length() const = 0;
+
+      /**
+      * @return native parallelism of this implementation
+      */
+      virtual size_t parallelism() const = 0;
+
+      /**
+      * Hash many inputs
+      *
+      * Each message must be exactly identical length
+      */
+      virtual void batch_hash(std::span<std::span<uint8_t>> outputs, std::span<std::span<const uint8_t>> inputs) = 0;
+
+      /**
+      * Create a new Hash_Engine or throw Not_Implemented
+      */
+      static std::unique_ptr<Hash_Engine> create_or_throw(std::string_view hash_fn);
+
+      Hash_Engine(const Hash_Engine& other) = delete;
+      Hash_Engine(Hash_Engine&& other) = delete;
+
+      Hash_Engine& operator=(const Hash_Engine& other) = delete;
+      Hash_Engine& operator=(Hash_Engine&& other) = delete;
+
+      virtual ~Hash_Engine() = default;
+
+   protected:
+      Hash_Engine() = default;
+};
+
+}  // namespace Botan
+
+#endif

src/lib/hash_engine/info.txt

@@ -0,0 +1,16 @@
+<internal_defines>
+HASH_ENGINES -> 20260222
+</internal_defines>
+
+<module_info>
+name -> "Hash Engine"
+</module_info>
+
+<requires>
+hash
+</requires>
+
+<header:internal>
+hash_engine.h
+</header:internal>
+