6 files changed, 115 insertions, 0 deletions
diff --git a/meson.build b/meson.build
index b17ed18..7b751db 100644
--- a/meson.build
+++ b/meson.build
@@ -36,6 +36,8 @@ configure_file(input: 'src/config.h.in',
                configuration : conf_data)
 
 dbus_dep = dependency('sdbus-c++', version: '>= 2.0.0')
+md_dep = dependency('libmd', version: '>= 1.0.0', required: false)
+openssl_dep = dependency('openssl', version: '>= 1.0.0', required: false)
 
 inc = include_directories('src')
 
@@ -203,6 +205,31 @@ base64_dep = declare_dependency(
   link_with: base64_lib,
 )
 
+if md_dep.found()
+  sha1_inner_source = 'src/sha1_md.cc'
+  sha1_inner_dep = md_dep
+elif openssl_dep.found()
+  sha1_inner_source = 'src/sha1_openssl.cc'
+  sha1_inner_dep = openssl_dep
+else
+  error('Need a library with SHA-1, either openssl or libmd')
+endif
+
+sha1_lib = library(
+  'sha1',
+  sources: [
+    'src/sha1.cc',
+    'src/sha1.hh',
+    sha1_inner_source,
+  ],
+  include_directories: inc,
+  dependencies: [sha1_inner_dep],
+)
+sha1_dep = declare_dependency(
+  link_with: sha1_lib,
+  dependencies: [sha1_inner_dep],
+)
+
 bluetooth_jukebox = executable(
   'bluetooth-jukebox',
   sources: [
@@ -355,6 +382,17 @@ test('base64', executable(
   ],
 ))
 
+test('sha1', executable(
+  'test_sha1',
+  sources: ['test/sha1.cc'],
+  include_directories: inc,
+  dependencies : [
+    sha1_dep,
+    base64_dep,
+    test_dependencies,
+  ],
+))
+
 run_clang_tidy = find_program('run-clang-tidy', required: false)
 
 if run_clang_tidy.found()
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
diff --git a/test/sha1.cc b/test/sha1.cc
new file mode 100644
index 0000000..7441f01
--- /dev/null
+++ b/test/sha1.cc
@@ -0,0 +1,17 @@
+#include "sha1.hh"
+
+#include "base64.hh"
+
+#include <gtest/gtest.h>
+
+TEST(Sha1, sanity) {
+  EXPECT_EQ("L9ThxnotKPzthJ7hu3bnORuT6xI=",
+            base64::encode(
+                sha1::hash("The quick brown fox jumps over the lazy dog")));
+
+  EXPECT_EQ("3p8sf9JeGzr60+haC9F9mxANtLM=",
+            base64::encode(
+                sha1::hash("The quick brown fox jumps over the lazy cog")));
+
+  EXPECT_EQ("2jmj7l5rSw0yVb/vlWAYkK/YBwk=", base64::encode(sha1::hash("")));
+}