Compactification: Obtain hash string length from hasher.

4 files changed, 25 insertions, 0 deletions

diff --git a/src/buildtool/crypto/hash_impl_sha1.cpp b/src/buildtool/crypto/hash_impl_sha1.cpp
index 97ff5464..d188f9cf 100644
--- a/src/buildtool/crypto/hash_impl_sha1.cpp
+++ b/src/buildtool/crypto/hash_impl_sha1.cpp
@@ -51,6 +51,10 @@ class HashImplSha1 final : public Hasher::IHashImpl {
         return {};
     }
 
+    [[nodiscard]] auto GetHashLength() const noexcept -> size_t final {
+        return SHA_DIGEST_LENGTH * kCharsPerNumber;
+    }
+
   private:
     SHA_CTX ctx_{};
     bool initialized_{};
diff --git a/src/buildtool/crypto/hash_impl_sha256.cpp b/src/buildtool/crypto/hash_impl_sha256.cpp
index ea96a3ba..a677807b 100644
--- a/src/buildtool/crypto/hash_impl_sha256.cpp
+++ b/src/buildtool/crypto/hash_impl_sha256.cpp
@@ -51,6 +51,10 @@ class HashImplSha256 final : public Hasher::IHashImpl {
         return {};
     }
 
+    [[nodiscard]] auto GetHashLength() const noexcept -> size_t final {
+        return SHA256_DIGEST_LENGTH * kCharsPerNumber;
+    }
+
   private:
     SHA256_CTX ctx_{};
     bool initialized_{};
diff --git a/src/buildtool/crypto/hash_impl_sha512.cpp b/src/buildtool/crypto/hash_impl_sha512.cpp
index 4b96e470..41ca792b 100644
--- a/src/buildtool/crypto/hash_impl_sha512.cpp
+++ b/src/buildtool/crypto/hash_impl_sha512.cpp
@@ -51,6 +51,10 @@ class HashImplSha512 final : public Hasher::IHashImpl {
         return {};
     }
 
+    [[nodiscard]] auto GetHashLength() const noexcept -> size_t final {
+        return SHA512_DIGEST_LENGTH * kCharsPerNumber;
+    }
+
   private:
     SHA512_CTX ctx_{};
     bool initialized_{};
diff --git a/src/buildtool/crypto/hasher.hpp b/src/buildtool/crypto/hasher.hpp
index 4bbcc7b7..a926fab1 100644
--- a/src/buildtool/crypto/hasher.hpp
+++ b/src/buildtool/crypto/hasher.hpp
@@ -17,6 +17,7 @@
 
 #include <cstddef>
 #include <cstdint>
+#include <limits>
 #include <memory>
 #include <optional>
 #include <string>
@@ -69,6 +70,10 @@ class Hasher {
     /// \brief Interface for hash implementations
     class IHashImpl {
       public:
+        static constexpr size_t kCharsPerNumber =
+            std::numeric_limits<std::uint8_t>::max() /
+            std::numeric_limits<signed char>::max();
+
         IHashImpl() noexcept = default;
         IHashImpl(IHashImpl const&) = delete;
         IHashImpl(IHashImpl&&) = default;
@@ -89,6 +94,9 @@ class Hasher {
         [[nodiscard]] virtual auto Compute(std::string const& data) && noexcept
             -> std::string = 0;
 
+        /// \brief Obtain length of the resulting hash string.
+        [[nodiscard]] virtual auto GetHashLength() const noexcept -> size_t = 0;
+
         static auto FatalError() noexcept -> void {
             Logger::Log(LogLevel::Error, "Failed to compute hash.");
             std::terminate();
@@ -111,6 +119,11 @@ class Hasher {
         return HashDigest{{}};
     }
 
+    /// \brief Obtain length of the resulting hash string.
+    [[nodiscard]] auto GetHashLength() const noexcept -> size_t {
+        return impl_->GetHashLength();
+    }
+
   private:
     std::unique_ptr<IHashImpl> impl_;