4 files changed, 60 insertions, 0 deletions
diff --git a/src/sha1.cc b/src/sha1.cc
new file mode 100644
index 0000000..5d20ca9
--- /dev/null
+++ b/src/sha1.cc
@@ -0,0 +1,16 @@
+#include "sha1.hh"
+
+namespace sha1 {
+
+std::array<uint8_t, 20> hash(std::span<char const> input) {
+  // std::string and std::string_view -> std::span includes null terminating
+  // byte.
+  if (!input.empty() && input.back() == '\0') {
+    return hash(std::span{reinterpret_cast<uint8_t const*>(input.data()),
+                          input.size() - 1});
+  }
+  return hash(
+      std::span{reinterpret_cast<uint8_t const*>(input.data()), input.size()});
+}
+
+}  // namespace sha1
diff --git a/src/sha1.hh b/src/sha1.hh
new file mode 100644
index 0000000..a885a09
--- /dev/null
+++ b/src/sha1.hh
@@ -0,0 +1,15 @@
+#ifndef SHA1_HH
+#define SHA1_HH
+
+#include <array>    // IWYU pragma: export
+#include <cstdint>  // IWYU pragma: export
+#include <span>     // IWYU pragma: export
+
+namespace sha1 {
+
+std::array<uint8_t, 20> hash(std::span<uint8_t const> input);
+std::array<uint8_t, 20> hash(std::span<char const> input);
+
+}  // namespace sha1
+
+#endif  // SHA1_HH
diff --git a/src/sha1_md.cc b/src/sha1_md.cc
new file mode 100644
index 0000000..274eb60
--- /dev/null
+++ b/src/sha1_md.cc
@@ -0,0 +1,16 @@
+#include "sha1.hh"
+
+#include <sha1.h>
+
+namespace sha1 {
+
+std::array<uint8_t, 20> hash(std::span<uint8_t const> input) {
+  std::array<uint8_t, 20> ret;
+  SHA1_CTX ctx;
+  SHA1Init(&ctx);
+  SHA1Update(&ctx, input.data(), input.size());
+  SHA1Final(ret.data(), &ctx);
+  return ret;
+}
+
+}  // namespace sha1
diff --git a/src/sha1_openssl.cc b/src/sha1_openssl.cc
new file mode 100644
index 0000000..9e6d77e
--- /dev/null
+++ b/src/sha1_openssl.cc
@@ -0,0 +1,13 @@
+#include "sha1.hh"
+
+#include <openssl/sha.h>
+
+namespace sha1 {
+
+std::array<uint8_t, 20> hash(std::span<uint8_t const> input) {
+  std::array<uint8_t, 20> ret;
+  SHA1(input.data(), input.size(), ret.data());
+  return ret;
+}
+
+}  // namespace sha1