Create nbt_value and further refine tag_compound

2 files changed, 118 insertions, 48 deletions

diff --git a/include/nbt_value.h b/include/nbt_value.h
new file mode 100644
index 0000000000..5af322b4d2
--- /dev/null
+++ b/include/nbt_value.h
@@ -0,0 +1,107 @@
+/*
+ * libnbt++ - A library for the Minecraft Named Binary Tag format.
+ * Copyright (C) 2013, 2015  ljfa-ag
+ *
+ * This file is part of libnbt++.
+ *
+ * libnbt++ is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * libnbt++ is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with libnbt++.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef TAG_REF_PROXY_H_INCLUDED
+#define TAG_REF_PROXY_H_INCLUDED
+
+#include "tag.h"
+#include <memory>
+#include <string>
+
+namespace nbt
+{
+
+//Forward declarations
+class tag_compound;
+class tag_list;
+
+/**
+ * @brief Represents a reference to a tag of fixed type
+ *
+ * This can contain a tag of arbitrary type, but once the tag's type
+ * is set it is immutable.
+ * It can be casted to or assigned values, but if the types do not match it
+ * will throw an exception.
+ * It can also refer to an uninitialized value (e.g. when using tag_compound::operator[]
+ * with a non-existant key).
+ */
+class nbt_value
+{
+public:
+    //Movable but not (implicitly) copyable
+    nbt_value& operator=(nbt_value&&) = default;
+    nbt_value& operator=(const nbt_value&) = delete;
+
+    //nbt_value& operator=(std::unique_ptr<tag>&& ptr);
+
+    //Assignment
+    /**
+     * @brief Assigns the given value to the tag if the type matches
+     * @throw std::bad_cast if the value is not convertible to the tag type
+     * via a widening conversion
+     */
+    nbt_value& operator=(int8_t val);
+    nbt_value& operator=(int16_t val);
+    nbt_value& operator=(int32_t val);
+    nbt_value& operator=(int64_t val);
+    nbt_value& operator=(float val);
+    nbt_value& operator=(double val);
+    nbt_value& operator=(const std::string& str);
+    nbt_value& operator=(tag_compound&& comp);
+    nbt_value& operator=(tag_list&& list);
+
+    //Conversion to tag
+    operator tag&();
+    operator const tag&() const;
+
+    //Conversions to primitives and string
+    /**
+     * @brief Casts the value if the type matches
+     * @throw std::bad_cast if the tag type is not convertible to the desired
+     * type via a widening conversion
+     */
+    explicit operator int8_t() const;
+    explicit operator int16_t() const;
+    explicit operator int32_t() const;
+    explicit operator int64_t() const;
+    explicit operator float() const;
+    explicit operator double() const;
+    explicit operator const std::string&() const;
+
+    /**
+     * @brief In case of a tag_compound, accesses a tag by key
+     * @throw std::bad_cast if the tag type is not tag_compound
+     * @sa tag_compound::operator[]
+     */
+    nbt_value& operator[](const std::string& key);
+    const nbt_value& operator[](const std::string& key) const;
+
+    ///@sa tag::get_type
+    tag_type get_type() const;
+
+    friend bool operator==(const nbt_value& lhs, const nbt_value& rhs);
+    friend bool operator!=(const nbt_value& lhs, const nbt_value& rhs);
+
+private:
+    std::unique_ptr<tag> value;
+};
+
+}
+
+#endif // TAG_REF_PROXY_H_INCLUDED
diff --git a/include/tag_compound.h b/include/tag_compound.h
index 2333713dc5..8fdc2f6617 100644
--- a/include/tag_compound.h
+++ b/include/tag_compound.h
@@ -21,6 +21,7 @@
 #define TAG_COMPOUND_H_INCLUDED
 
 #include "tag.h"
+#include "nbt_value.h"
 #include <map>
 #include <memory>
 #include <string>
@@ -28,10 +29,6 @@
 namespace nbt
 {
 
-//TODO: Create actual proxy class
-typedef tag& tag_ref_proxy;
-typedef const tag& const_tag_ref_proxy;
-
 ///Tag that contains multiple unordered named tags of arbitrary types
 class tag_compound : public tag
 {
@@ -46,61 +43,27 @@ public:
     ///Constructs an empty compound
     tag_compound() {}
 
+    //TODO: Make a separate class similar to and convertible to nbt_value for initializing tag values
+    //tag_compound(std::initializer_list<std::pair<std::string, nbt_value&&>> init);
+
     /**
      * @brief Accesses a tag by key with bounds checking
      *
-     * Returns a reference to the tag with the specified key, or throws an
+     * Returns a nbt_value to the tag with the specified key, or throws an
      * exception if it does not exist.
      * @throw std::out_of_range if given key does not exist
      */
-    tag& at(const std::string& key);
-    const tag& at(const std::string& key) const;
+    nbt_value& at(const std::string& key);
+    const nbt_value& at(const std::string& key) const;
 
     /**
      * @brief Accesses a tag by key
      *
-     * Returns a proxy value that can be converted to @ref tag&.
-     */
-    tag_ref_proxy operator[](const std::string& key);
-    const_tag_ref_proxy operator[](const std::string& key) const;
-
-    /**
-     * @brief Inserts a tag into the compound
-     *
-     * If the given key does not already exist, moves the pointed tag
-     * into the compound.
-     * @return true if the tag was inserted
-     */
-    bool insert(const std::string& key, std::unique_ptr<tag>&& ptr);
-
-    /**
-     * @brief Inserts or assigns a tag
-     *
-     * If the given key already exists, assigns the pointed tag to it.
-     * Otherwise, it is inserted under the given key.
-     * @return true if the key did not exist
-     */
-    bool put(const std::string& key, std::unique_ptr<tag>&& ptr);
-
-    /**
-     * @brief Constructs and inserts a tag into the compound
-     *
-     * If the given key does not exist, constructs a new tag of type @c T
-     * with the given args and inserts it into the compound.
-     * @return true if the tag was inserted
-     */
-    template<class T, class... Args>
-    bool emplace(const std::string& key, Args&&... args);
-
-    /**
-     * @brief Constructs and assigns or inserts a tag into the compound
-     *
-     * Constructs a new tag of type @c T with the given args and inserts
-     * or assigns it to the given key.
-     * @return true if the key did not already exist.
+     * If the key exists, returns a nbt_value to the corresponding tag.
+     * Else, a new uninitalized entry is created under this key.
      */
-    template<class T, class... Args>
-    bool emplace_put(const std::string& key, Args&&... args);
+    nbt_value& operator[](const std::string& key);
+    const nbt_value& operator[](const std::string& key) const;
 
     /**
      * @brief Erases a tag from the compound