Add Buf class.

3 files changed, 54 insertions, 40 deletions

diff --git a/c/util.h b/c/util.h
index 1d8d222..698ce10 100644
--- a/c/util.h
+++ b/c/util.h
@@ -4,42 +4,51 @@
 #include <algorithm>
 #include <cstring>
 #include <memory>
+#include <string>
 #include <SWI-Prolog.h>
 #include <windows.h>
 
-#define CAT(a, b) a##b
-#define APPLY(a, ...) a(__VA_ARGS__)
-#define UNUSED APPLY(CAT, unused_, __COUNTER__)
+/* Buf is a span-like structure of a buffer and its size. */
+template <typename T>
+struct Buf
+{
+	T* data;
+	size_t size;
+	Buf(T* data, size_t size) : data(data), size(size) {}
+	Buf(std::basic_string<T>& s) : data(s.data()), size(s.capacity()) {}
+	template <size_t N> Buf(T (&data)[N]) : data(data), size(N) {}
+	operator T*() { return data; }
+	T& operator *() { return *data; }
+	T& operator [](size_t i) { return data[i]; }
+};
 
-/* Format static wide string. */
-template<size_t N, typename... T>
-inline int Swprintf(wchar_t (&buf)[N], const wchar_t* const fmt, T... xs)
+/* Format wide string. */
+template<typename... T>
+inline int Swprintf(Buf<wchar_t> buf, const wchar_t* const fmt, T... xs)
 {
-	return _snwprintf_s(buf, N, _TRUNCATE, fmt, xs...);
+	return _snwprintf_s(buf, buf.size, _TRUNCATE, fmt, xs...);
 }
 
 /* Format static narrow string. */
-template<size_t N, typename... T>
-inline int Sprintf(char (&buf)[N], const char* const fmt, T... xs)
+template<typename... T>
+inline int Sprintf(Buf<char> buf, const char* const fmt, T... xs)
 {
-	return _snprintf_s(buf, N, _TRUNCATE, fmt, xs...);
+	return _snprintf_s(buf, buf.size, _TRUNCATE, fmt, xs...);
 }
 
 /* Copy to static wide string buffer. */
-template <size_t N>
-inline wchar_t* Wcscpy(wchar_t (&dst)[N], const wchar_t* const src)
+inline wchar_t* Wcscpy(Buf<wchar_t> dst, const wchar_t* const src)
 {
-	const size_t len = std::min(N, wcslen(src)+1);
+	const size_t len = std::min(dst.size, wcslen(src)+1);
 	memcpy(dst, src, len*sizeof(wchar_t));
 	dst[len-1] = 0;
 	return dst;
 }
 
 /* Copy to static narrow string buffer. */
-template <size_t N>
-inline char* Strcpy(char (&dst)[N], const char* const src)
+inline char* Strcpy(Buf<char> dst, const char* const src)
 {
-	const size_t len = std::min(N, strlen(src)+1);
+	const size_t len = std::min(dst.size, strlen(src)+1);
 	memcpy(dst, src, len);
 	dst[len-1] = 0;
 	return dst;
@@ -52,4 +61,8 @@ inline int Cmp(const int a, const int b)
 	return -1;
 }
 
+#define CAT(a, b) a##b
+#define APPLY(a, ...) a(__VA_ARGS__)
+#define UNUSED APPLY(CAT, unused_, __COUNTER__)
+
 #endif
diff --git a/c/win.cpp b/c/win.cpp
index ea47fb0..c7ce7ec 100644
--- a/c/win.cpp
+++ b/c/win.cpp
@@ -1,4 +1,5 @@
 #include <utility>
+#include <string>
 #include <SWI-Prolog.h>
 #include <windows.h>
 
@@ -7,28 +8,6 @@
 #include "win.h"
 #include "wcharptr.h"
 
-void ShowException(const wchar_t* const fmt, const wchar_t* const title, const UINT uType) noexcept
-{
-	const wchar_t* what = L"an exception";
-	WcharPtr why;
-
-	try {
-		std::rethrow_exception(std::current_exception());
-        } catch (const term_t& t) {
-		what = L"a Prolog exception";
-		try { why = PlString(t); } catch (...) {}
-	} catch (const Win32Error& e) {
-		what = L"a Windows error";
-		try { why = WcharPtr::Copy(e.What()); } catch (...) {}
-	} catch (const std::exception& e) {
-		try { why = WcharPtr::FromNarrow(e.what()); } catch (...) {}
-	} catch (...) {}
-
-	wchar_t msg[512];
-	Swprintf(msg, fmt, what, static_cast<wchar_t*>(why));
-	EBMessageBox(msg, title, uType);
-}
-
 void WithNextWindow(void (*proc)(HWND))
 {
 	/* WithNextWindow uses a CBT hook to call an arbitrary
@@ -103,6 +82,28 @@ int EBMessageBox(const std::wstring_view text, const std::wstring_view caption,
 	return MessageBox(g_hWnd, text.data(), caption.data(), uType);
 }
 
+void ShowException(const wchar_t* const fmt, const wchar_t* const title, const UINT uType) noexcept
+{
+	const wchar_t* what = L"an exception";
+	WcharPtr why;
+
+	try {
+		std::rethrow_exception(std::current_exception());
+        } catch (const term_t& t) {
+		what = L"a Prolog exception";
+		try { why = PlString(t); } catch (...) {}
+	} catch (const Win32Error& e) {
+		what = L"a Windows error";
+		try { why = WcharPtr::Copy(e.What()); } catch (...) {}
+	} catch (const std::exception& e) {
+		try { why = WcharPtr::FromNarrow(e.what()); } catch (...) {}
+	} catch (...) {}
+
+	std::wstring msg(wcslen(fmt)+wcslen(what)+wcslen(why), 0);
+	Swprintf(msg, fmt, what, static_cast<wchar_t*>(why));
+	EBMessageBox(msg, title, uType);
+}
+
 int GetRelativeCursorPos(const HWND hWnd, POINT* const pt) noexcept
 {
 	RECT rc;
diff --git a/c/win.h b/c/win.h
index 3bb0d6e..ab5cf05 100644
--- a/c/win.h
+++ b/c/win.h
@@ -5,12 +5,12 @@
 #include <string_view>
 #include <windows.h>
 
-/* Show message box for current exception. */
-void ShowException(const wchar_t* fmt, const wchar_t* title, UINT uType = MB_ICONWARNING) noexcept;
 /* Run given procedure at creation of next window. */
 void WithNextWindow(void (*proc)(HWND));
 /* Display message box centered in main window. */
 int EBMessageBox(std::wstring_view text, std::wstring_view data, UINT uType);
+/* Show message box for current exception. */
+void ShowException(const wchar_t* fmt, const wchar_t* title, UINT uType = MB_ICONWARNING) noexcept;
 /* Retrieve mouse position relative to given window's client area. */
 int GetRelativeCursorPos(HWND hWnd, POINT* pt) noexcept;
 /* Cached values from GetSystemMetrics. */