win32: add registry wrapper

Makefile.am

@@ -270,7 +270,9 @@ if PLATFORM_WIN32
 UTIL_FILES += 			\
     backtrace_null.cpp		\
     io_win32.cpp		\
-    time_win32.cpp
+    time_win32.cpp		\
+    win32/registry.hpp		\
+    win32/registry.cpp
 endif
 
 ###############################################################################

win32/registry.cpp

@@ -0,0 +1,102 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Copyright 2015 Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "registry.hpp"
+
+#include "../debug.hpp"
+#include "../except.hpp"
+
+#include <string>
+#include <cstdint>
+
+using util::win32::key;
+
+
+///////////////////////////////////////////////////////////////////////////////
+typedef uint64_t QWORD;
+
+//-----------------------------------------------------------------------------
+template <typename T> constexpr DWORD type_to_id (void);
+
+template <> constexpr DWORD type_to_id<DWORD> (void) { return REG_DWORD; }
+template <> constexpr DWORD type_to_id<QWORD> (void) { return REG_QWORD; }
+template <> constexpr DWORD type_to_id<void>  (void) { return REG_NONE;  }
+template <> constexpr DWORD type_to_id<std::string> (void) { return REG_SZ; }
+
+
+//-----------------------------------------------------------------------------
+template <typename T> constexpr DWORD restrict_to_id (void);
+
+template <> constexpr DWORD restrict_to_id<DWORD> (void) { return RRF_RT_DWORD; }
+template <> constexpr DWORD restrict_to_id<QWORD> (void) { return RRF_RT_QWORD; }
+template <> constexpr DWORD restrict_to_id<void>  (void) { return RRF_RT_REG_NONE; }
+template <> constexpr DWORD restrict_to_id<std::string> (void) { return RRF_RT_REG_SZ; }
+
+
+///////////////////////////////////////////////////////////////////////////////
+key::key (HKEY root, const char *child, REGSAM rights)
+{
+    auto err = RegOpenKeyEx (root, child, 0, rights, &m_handle);
+    win32_error::try_code (err);
+}
+
+
+//-----------------------------------------------------------------------------
+key::~key ()
+{
+    auto err = RegCloseKey (m_handle);
+    win32_error::try_code (err);
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+template <typename T>
+T
+key::data (const char *name) const
+{
+    T     value;
+    DWORD type;
+    DWORD size = sizeof (value);
+
+    auto err = RegGetValue (m_handle, name, &value, restrict_to_id<T> (), nullptr, &value, &size);
+    win32_error::try_code (err);
+
+    return value;
+}
+
+
+//-----------------------------------------------------------------------------
+std::set<std::string>
+key::values (void) const
+{
+    std::set<std::string> all;
+
+    for (DWORD i = 0; ; ++i) {
+        std::string name (255, '\0');
+        DWORD size = name.size ();
+
+        auto err = RegEnumValue (m_handle, i, &name[0], &size, nullptr, nullptr, nullptr, nullptr);
+        if (ERROR_NO_MORE_ITEMS == err)
+            return all;
+        if (ERROR_SUCCESS != err)
+            win32_error::throw_code (err);
+
+        CHECK_GT (size, 0);
+        name.resize (size - 1);
+
+        all.insert (std::move (name));
+    }
+}

win32/registry.hpp

@@ -0,0 +1,42 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Copyright 2015 Danny Robson <danny@nerdcruft.net>
+ */
+
+#ifndef __UTIL_WIN32_REGISTRY_HPP
+#define __UTIL_WIN32_REGISTRY_HPP
+
+#include <windows.h>
+
+#include <set>
+#include <string>
+
+namespace util { namespace win32 {
+    class key {
+    public:
+        key (HKEY root, const char *child, REGSAM rights = KEY_READ);
+        ~key ();
+
+        template <typename T>
+        T data (const char *name = nullptr) const;
+
+        std::set<std::string>
+        values (void) const;
+
+    private:
+        HKEY m_handle;
+    };
+} }
+
+#endif