5 files changed, 58 insertions, 2 deletions
diff --git a/src/io/stream_writer.cpp b/src/io/stream_writer.cpp
index 26a6a7eb65..f21fdb701c 100644
--- a/src/io/stream_writer.cpp
+++ b/src/io/stream_writer.cpp
@@ -25,9 +25,11 @@ namespace nbt
 namespace io
 {
 
-void stream_writer::write_type(tag_type tt)
+void stream_writer::write_tag(const std::string& key, const tag& t)
 {
-    write_num(static_cast<int8_t>(tt));
+    write_type(t.get_type());
+    write_string(key);
+    write_payload(t);
 }
 
 void stream_writer::write_string(const std::string& str)
diff --git a/src/tag_array.cpp b/src/tag_array.cpp
index f83bce11f7..124c470bd1 100644
--- a/src/tag_array.cpp
+++ b/src/tag_array.cpp
@@ -19,6 +19,7 @@
  */
 #include "tag_array.h"
 #include "io/stream_reader.h"
+#include "io/stream_writer.h"
 #include <istream>
 
 namespace nbt
@@ -102,6 +103,7 @@ template<class T> auto tag_array<T>::cbegin() const -> const_iterator { return d
 template<class T> auto tag_array<T>::cend() const   -> const_iterator { return data.cend(); }
 
 //Slightly different between byte_array and int_array
+//Reading
 template<>
 void tag_array<int8_t>::read_payload(io::stream_reader& reader)
 {
@@ -140,6 +142,26 @@ void tag_array<int32_t>::read_payload(io::stream_reader& reader)
         throw io::input_error("Error reading contents of tag_int_array");
 }
 
+//Writing
+template<>
+void tag_array<int8_t>::write_payload(io::stream_writer& writer) const
+{
+    if(size() > INT32_MAX)
+        throw std::length_error("Byte array is too large for NBT");
+    writer.write_num(static_cast<int32_t>(size()));
+    writer.get_ostr().write(reinterpret_cast<const char*>(data.data()), data.size());
+}
+
+template<>
+void tag_array<int32_t>::write_payload(io::stream_writer& writer) const
+{
+    if(size() > INT32_MAX)
+        throw std::length_error("Int array is too large for NBT");
+    writer.write_num(static_cast<int32_t>(size()));
+    for(int32_t i: data)
+        writer.write_num(i);
+}
+
 template<class T>
 bool operator==(const tag_array<T>& lhs, const tag_array<T>& rhs)
 {
diff --git a/src/tag_compound.cpp b/src/tag_compound.cpp
index 3581dd149b..d0f20512ae 100644
--- a/src/tag_compound.cpp
+++ b/src/tag_compound.cpp
@@ -19,6 +19,7 @@
  */
 #include "tag_compound.h"
 #include "io/stream_reader.h"
+#include "io/stream_writer.h"
 #include <istream>
 #include <sstream>
 
@@ -120,6 +121,13 @@ void tag_compound::read_payload(io::stream_reader& reader)
     }
 }
 
+void tag_compound::write_payload(io::stream_writer& writer) const
+{
+    for(const auto& pair: tags)
+        writer.write_tag(pair.first, pair.second);
+    writer.write_type(tag_type::End);
+}
+
 bool operator==(const tag_compound& lhs, const tag_compound& rhs)
 {
     return lhs.tags == rhs.tags;
diff --git a/src/tag_list.cpp b/src/tag_list.cpp
index f5a5b91758..dbdda2db77 100644
--- a/src/tag_list.cpp
+++ b/src/tag_list.cpp
@@ -20,6 +20,7 @@
 #include "tag_list.h"
 #include "nbt_tags.h"
 #include "io/stream_reader.h"
+#include "io/stream_writer.h"
 #include <istream>
 
 namespace nbt
@@ -158,6 +159,23 @@ void tag_list::read_payload(io::stream_reader& reader)
     }
 }
 
+void tag_list::write_payload(io::stream_writer& writer) const
+{
+    if(size() > INT32_MAX)
+        throw std::length_error("List is too large for NBT");
+    writer.write_type(el_type_ != tag_type::Null
+                      ? el_type_
+                      : tag_type::End);
+    writer.write_num(static_cast<int32_t>(size()));
+    for(const auto& val: tags)
+    {
+        //check if the value is of the correct type
+        if(val.get_type() != el_type_)
+            throw std::bad_cast();
+        writer.write_payload(val);
+    }
+}
+
 bool operator==(const tag_list& lhs, const tag_list& rhs)
 {
     return lhs.el_type_ == rhs.el_type_ && lhs.tags == rhs.tags;
diff --git a/src/tag_string.cpp b/src/tag_string.cpp
index 83cb815c52..1a8f1cd5d2 100644
--- a/src/tag_string.cpp
+++ b/src/tag_string.cpp
@@ -19,6 +19,7 @@
  */
 #include "tag_string.h"
 #include "io/stream_reader.h"
+#include "io/stream_writer.h"
 
 namespace nbt
 {
@@ -90,6 +91,11 @@ void tag_string::read_payload(io::stream_reader& reader)
     }
 }
 
+void tag_string::write_payload(io::stream_writer& writer) const
+{
+    writer.write_string(value);
+}
+
 bool operator==(const tag_string& lhs, const tag_string& rhs)
 {
     return lhs.get() == rhs.get();