- optimization of WideString and FileReader::Printf.

Both now omit the intermediate FString as the target buffer can be directly written to.
WideString was also moved to utf8.cpp/h to uncouple from zstring.

src/common/utility/files.cpp

@@ -34,8 +34,8 @@
 */
 
 #include "files.h"
-	// just for 'clamp'
-#include "zstring.h"
+#include "utf8.h"
+#include "stb_sprintf.h"
 
 
 FILE *myfopen(const char *filename, const char *flags)
@@ -472,13 +472,18 @@ long FileWriter::Seek(long offset, int mode)
 
 size_t FileWriter::Printf(const char *fmt, ...)
 {
-	va_list ap;
-	FString out;
+	char workbuf[STB_SPRINTF_MIN];
+	va_list arglist;
+	va_start(arglist, fmt);
+	auto r = stbsp_vsprintfcb([](const char* cstr, void* data, int len) -> char*
+		{
+			auto fr = (FileWriter*)data;
+			auto writ = fr->Write(cstr, len);
+			return writ == (size_t)len? (char*)cstr : nullptr; // abort if writing caused an error.
+		}, this, workbuf, fmt, arglist);
 
-	va_start(ap, fmt);
-	out.VFormat(fmt, ap);
-	va_end(ap);
-	return Write(out.GetChars(), out.Len());
+	va_end(arglist);
+	return r;
 }
 
 size_t BufferWriter::Write(const void *buffer, size_t len)

src/common/utility/utf8.cpp

@@ -1157,3 +1157,17 @@ bool myisupper(int code)
 	return false;
 }
 
+std::wstring WideString(const char* cin)
+{
+	std::wstring buildbuffer;
+	if (cin)
+	{
+		// This is a bit tricky because we need to support both UTF-8 and legacy content in ISO-8859-1 / Windows 1252
+		// and thanks to user-side string manipulation it can be that a text mixes both.
+		// To convert the string this uses the same function as all text printing in the engine.
+		const uint8_t* in = (const uint8_t*)cin;
+		while (*in) buildbuffer.push_back((wchar_t)GetCharFromString(in));
+	}
+	return buildbuffer;
+}
+

src/common/utility/utf8.h

@@ -18,3 +18,8 @@ int getAlternative(int code);
 extern uint16_t win1252map[];
 extern uint16_t lowerforupper[65536];
 extern uint16_t upperforlower[65536];
+
+// make this only visible on Windows, on other platforms this should not be called.
+#ifdef _WIN32
+std::wstring WideString(const char*);
+#endif

src/common/utility/zstring.cpp

@@ -1326,19 +1326,6 @@ FString &FString::operator=(const wchar_t *copyStr)
 	return *this;
 }
 
-std::wstring WideString(const char *cin)
-{
-	if (!cin) return L"";
-	const uint8_t *in = (const uint8_t*)cin;
-	// This is a bit tricky because we need to support both UTF-8 and legacy content in ISO-8859-1
-	// and thanks to user-side string manipulation it can be that a text mixes both.
-	// To convert the string this uses the same function as all text printing in the engine.
-	TArray<wchar_t> buildbuffer;
-	while (*in) buildbuffer.Push((wchar_t)GetCharFromString(in));
-	buildbuffer.Push(0);
-	return std::wstring(buildbuffer.Data());
-}
-
 static HANDLE StringHeap;
 const SIZE_T STRING_HEAP_SIZE = 64*1024;
 #endif

src/common/utility/zstring.h

@@ -39,6 +39,7 @@
 #include <stddef.h>
 #include <string>
 #include "tarray.h"
+#include "utf8.h"
 
 #ifdef __GNUC__
 #define PRINTFISH(x) __attribute__((format(printf, 2, x)))
@@ -57,10 +58,6 @@
 #define IGNORE_FORMAT_POST
 #endif
 
-#ifdef _WIN32
-std::wstring WideString(const char *);
-#endif
-
 struct FStringData
 {
 	unsigned int Len;		// Length of string, excluding terminating null