Fix display of Unicode text.

Turns out that SWI-Prolog's wide string functions, which I started
using in 03fe361, do not convert between narrow Prolog atoms and wide
C strings, as I mistakenly thought. Instead, they work with wide
Prolog atoms. In hindsight, it is not surprising.

6 files changed, 52 insertions, 20 deletions

diff --git a/README b/README
index ebe22ef..c8b3f5c 100644
--- a/README
+++ b/README
@@ -69,12 +69,13 @@ Following is a summary of some coding conventions used in the project.
  - w	= WORD, WPARAM
  - dw	= DWORD
  - lvi	= LVITEM
- - sz	= unmangaged, zero-terminated string (char *)
- - wsz	= ... wide string (wchar_t *)
- - tsz	= ... tstring (TCHAR *)
- - str	= ... managed string (std::string)
+ - sz	= unmanaged, zero-terminated narrow string (char*)
+ - wsz	= ... wide string (wchar_t*)
+ - tsz	= ... tstring (TCHAR*)
+ - str	= managed narrow string (std::string)
  - wstr	= ... (std::wstring)
  - tstr	= ... (std::basic_string<TCHAR>)
+ - bstr	= ... (std::basic_string<T> of any type T)
 
 The list above is non-exhaustive. Variables whose type is unknown (in
 templates) do not need prefixes. Some very common self-explanatory
diff --git a/c/common.cpp b/c/common.cpp
index 4ce95a0..155c099 100644
--- a/c/common.cpp
+++ b/c/common.cpp
@@ -57,6 +57,24 @@ Library::~Library()
 	FreeLibrary(m_hModule);
 }
 
+/* Convert narrow unmanaged string to narrow/wide basic string. */
+template <>
+std::basic_string<char> BstrFromSz(const char* sz, int)
+{
+	return std::string(sz);
+}
+
+template <>
+std::basic_string<wchar_t> BstrFromSz(const char* sz, int iCp)
+{
+	int cbMultiByte = strlen(sz)+1;
+	int cchWideChar = MultiByteToWideChar(iCp, 0, sz, cbMultiByte, NULL, 0);
+	std::wstring wstr(cchWideChar, 0);
+	if (!MultiByteToWideChar(iCp, 0, sz, cbMultiByte, wstr.data(), cchWideChar))
+		throw Win32Error(GetLastError());
+	return wstr;
+}
+
 /* Move message box to center of main window. */
 static LRESULT CALLBACK CBTProc(const int nCode, const WPARAM wParam, const LPARAM lParam) noexcept
 {
diff --git a/c/common.h b/c/common.h
index 5fe6d62..fb21e6f 100644
--- a/c/common.h
+++ b/c/common.h
@@ -11,6 +11,7 @@
 #define WA "A"
 #endif
 
+template <typename T> std::basic_string<T> BstrFromSz(const char* sz, int iCp = CP_UTF8);
 int EBMessageBox(const TCHAR* tszText, const TCHAR* tszCaption, unsigned uType);
 
 struct Win32Error : public std::exception
diff --git a/c/datalistview.cpp b/c/datalistview.cpp
index b728fa8..1ceeb3b 100644
--- a/c/datalistview.cpp
+++ b/c/datalistview.cpp
@@ -57,21 +57,21 @@ void DataListView::ShowEpisode(const int iEpisode)
 	    PL_predicate("episode_datum", 3, "episode_data"), t);
 
 	for (int i = 0; PL_next_solution(q); i++) {
-		TCHAR* tszKey;
-		TCHAR* tszValue;
+		std::basic_string<TCHAR> tstrKey;
+		std::basic_string<TCHAR> tstrValue;
 
-		if (!(PlGet(t+1, &tszKey) && PlGet(t+2, &tszValue)))
+		if (!(PlGet(t+1, &tstrKey) && PlGet(t+2, &tstrValue)))
 			continue;
 
 		lviKey.mask = LVIF_TEXT;
 		lviKey.iItem = i;
 		lviKey.iSubItem = 0;
-		lviKey.pszText = tszKey;
+		lviKey.pszText = tstrKey.data();
 		ListView_InsertItem(hWnd, &lviKey);
 
 		lviValue.iItem = i;
 		lviValue.iSubItem = 1;
-		lviValue.pszText = tszValue;
+		lviValue.pszText = tstrValue.data();
 		ListView_SetItem(hWnd, &lviValue);
 	}
 
diff --git a/c/episodelistview.cpp b/c/episodelistview.cpp
index cdb3dc7..bc01ce9 100644
--- a/c/episodelistview.cpp
+++ b/c/episodelistview.cpp
@@ -414,17 +414,16 @@ void EpisodeListView::Update()
 /* Update episode name and rating. */
 void EpisodeListView::UpdateItem(const LVITEM* const pLvi)
 {
-	Mark m;
-	TCHAR* tszName;
+	std::basic_string<TCHAR> tstrName;
 	int iRating;
 	static TCHAR tszRating[3];
 
-	if (!Pl("episode_data","episode_title",pLvi->lParam,&tszName)) {
+	if (!Pl("episode_data","episode_title",pLvi->lParam,&tstrName)) {
 		if (!Pl("episode_data","update_episode_data")) goto r;
-		if (!Pl("episode_data","episode_title",pLvi->lParam,&tszName))
+		if (!Pl("episode_data","episode_title",pLvi->lParam,&tstrName))
 			goto r;
 	}
-	ListView_SetItemText(hWnd, pLvi->iItem, ELVSITITLE, tszName);
+	ListView_SetItemText(hWnd, pLvi->iItem, ELVSITITLE, tstrName.data());
 
 r:	if (!Pl("episode_data","episode_rating",pLvi->lParam,&iRating)) {
 		ListView_SetItemText(hWnd, pLvi->iItem, ELVSIRATING, (TCHAR*)TEXT(""));
diff --git a/c/pl.h b/c/pl.h
index 8325c86..44b8a5e 100644
--- a/c/pl.h
+++ b/c/pl.h
@@ -1,9 +1,12 @@
 #ifndef PL_H
 #define PL_H
 
+#include <string>
 #include <windows.h>
 #include <SWI-Prolog.h>
 
+#include "common.h"
+
 int PL_get_tchars(term_t t, TCHAR** pTsz, int iFlags);
 
 struct Frame
@@ -43,14 +46,13 @@ inline int PlPut(term_t t, long long x) { return PL_put_int64(t, x); }
 inline int PlPut(term_t t, atom_t x) { return PL_put_atom(t, x); }
 inline int PlPut(term_t t, char* x) { return PL_put_atom_chars(t, x); }
 inline int PlPut(term_t t, const char* x) { return PL_put_atom_chars(t, x); }
-inline int PlPut(term_t t, wchar_t* x) { return PL_unify_wchars(t, PL_ATOM, -1, x); }
-inline int PlPut(term_t t, const wchar_t* x) { return PL_unify_wchars(t, PL_ATOM, -1, x); }
 inline int PlPut(term_t, int*) { return -1; }
 inline int PlPut(term_t, long*) { return -1; }
 inline int PlPut(term_t, long long*) { return -1; }
 inline int PlPut(term_t, atom_t*) { return -1; }
 inline int PlPut(term_t, char**) { return -1; }
-inline int PlPut(term_t, wchar_t**) { return -1; }
+inline int PlPut(term_t, std::string*) { return -1; }
+inline int PlPut(term_t, std::wstring*) { return -1; }
 
 inline int PlGet(term_t, int) { return -1; }
 inline int PlGet(term_t, long) { return -1; }
@@ -58,14 +60,25 @@ inline int PlGet(term_t, long long) { return -1; }
 inline int PlGet(term_t, atom_t) { return -1; }
 inline int PlGet(term_t, char*) { return -1; }
 inline int PlGet(term_t, const char*) { return -1; }
-inline int PlGet(term_t, wchar_t*) { return -1; }
-inline int PlGet(term_t, const wchar_t*) { return -1; }
 inline int PlGet(term_t t, int* x) { return PL_get_integer(t, x); }
 inline int PlGet(term_t t, long* x) { return PL_get_long(t, x); }
 inline int PlGet(term_t t, long long* x) { return PL_get_int64(t, x); }
 inline int PlGet(term_t t, atom_t* x) { return PL_get_atom(t, x); }
 inline int PlGet(term_t t, char** x) { return PL_get_atom_chars(t, x); }
-inline int PlGet(term_t t, wchar_t** x) { size_t len; return PL_get_wchars(t, &len, x, CVT_ATOM); }
+inline int PlGet(term_t t, std::string* x) { 
+	Mark m;
+	char* sz;
+	if (!PlGet(t, &sz)) return 0;
+	*x = sz;
+	return 1;
+}
+inline int PlGet(term_t t, std::wstring* x) { 
+	Mark m;
+	char* sz;
+	if (!PlGet(t, &sz)) return 0;
+	*x = BstrFromSz<wchar_t>(sz);
+	return 1; /* or catch potential exception from BstrFromSz? */
+}
 
 /* Put in or get from a term reference an arbitrary number of values,
  * returning false if any value could not be put/got. */