[libc] Character converter skeleton class

libc/src/__support/wchar/CMakeLists.txt

@@ -0,0 +1,24 @@
+add_header_library(
+  mbstate
+  HDRS
+    mbstate.h
+  DEPENDS
+    libc.hdr.types.wchar_t    
+)
+
+add_header_library(
+  character_converter
+  HDRS
+    character_converter.h
+  DEPENDS
+    libc.hdr.types.wchar_t
+    .mbstate
+    .utf_ret
+)
+
+add_header_library(
+  utf_ret
+  HDRS
+    utf_ret.h
+  DEPENDS
+)

libc/src/__support/wchar/character_converter.cpp

@@ -0,0 +1 @@
+

libc/src/__support/wchar/character_converter.h

@@ -0,0 +1,20 @@
+
+#include "hdr/types/wchar_t.h"
+#include "src/__support/wchar/mbstate.h"
+#include "src/__support/wchar/utf_ret.h"
+
+class CharacterConverter {
+private:
+  mbstate_t *state;
+
+public:
+  CharacterConverter();
+
+  bool isComplete();
+
+  int push(char utf8_byte);
+  int push(wchar_t utf32);
+
+  utf_ret<char> pop_utf8();
+  utf_ret<wchar_t> pop_utf32();
+};

libc/src/__support/wchar/mbstate.h

@@ -0,0 +1,8 @@
+
+#include "hdr/types/wchar_t.h"
+
+struct mbstate_t {
+  wchar_t partial;
+  unsigned char bits_processed;
+  unsigned char total_bytes;
+};

libc/src/__support/wchar/utf_ret.h

@@ -0,0 +1,5 @@
+
+template <typename T> struct utf_ret {
+  T out;
+  int error;
+};