Fix compilation and simplify Com_VPrintf

Author: ensiform

src/qcommon/common.c

@@ -198,8 +198,7 @@ to the appropriate place.
 A raw string should NEVER be passed as fmt, because of "%f" type crashers.
 =============
 */
-static qboolean devPrint = qfalse;
-int FORMAT_PRINTF(1, 0) QDECL Com_VPrintf( const char *fmt, va_list argptr ) {
+static int FORMAT_PRINTF(2, 0) QDECL Com_VPrintf( qboolean devPrint, const char *fmt, va_list argptr ) {
 	static qboolean opening_qconsole = qfalse;
 	char		msg[MAXPRINTMSG];
 	int			len;
@@ -291,7 +290,7 @@ void FORMAT_PRINTF(1, 2) QDECL Com_Printf( const char *fmt, ... ) {
 	va_list argptr;
 
 	va_start( argptr, fmt );
-	Com_VPrintf( fmt, argptr );
+	Com_VPrintf( qfalse, fmt, argptr );
 	va_end( argptr );
 }
 
@@ -311,9 +310,7 @@ void FORMAT_PRINTF(1, 2) QDECL Com_DPrintf( const char *fmt, ...) {
 	}
 
 	va_start( argptr, fmt );
-	devPrint = qtrue;
-	Com_VPrintf( fmt, argptr );
-	devPrint = qfalse;
+	Com_VPrintf( qtrue, fmt, argptr );
 	va_end( argptr );
 }
 

src/qcommon/q_shared.c

@@ -1533,18 +1533,51 @@ void Q_strncpyz( char *dest, const char *src, int destsize )
 /*
 =============
 Q_strncpy
+
+allows src and dest to be overlapped for QVM compatibility purposes
 =============
 */
-char *Q_strncpy( char *dest, const char *src, int destsize )
+char *Q_strncpy( char *dest, char *src, int destsize )
 {
-	char *start = dest;
+	char *s = src, *start = dest;
+	int src_len;
 
-	while ( destsize > 0 && (*dest++ = *src++) != '\0' ) {
-		--destsize;
+	while ( *s != '\0' )
+		++s;
+	src_len = (int)(s - src);
+	
+	if ( src_len > destsize ) {
+		src_len = destsize;
 	}
+	destsize -= src_len;
 
-	while ( --destsize > 0 ) {
+	if ( dest > src && dest < src + src_len ) {
+		int i;
+#ifdef _DEBUG
+		Com_Printf( S_COLOR_YELLOW "Q_strncpy: overlapped (dest > src) buffers\n" );
+#endif
+		for ( i = src_len - 1; i >= 0; --i ) {
+			dest[i] = src[i]; // back overlapping
+		}
+		dest += src_len;
+	} else {
+#ifdef _DEBUG
+		if ( src >= dest && src < dest + src_len ) {
+			Com_Printf( S_COLOR_YELLOW "Q_strncpy: overlapped (src >= dst) buffers\n" );
+#ifdef _MSC_VER
+			// __debugbreak();
+#endif 
+		}
+#endif
+		while ( src_len > 0 ) {
+			*dest++ = *src++;
+			--src_len;
+		}
+	}
+
+	while ( destsize > 0 ) {
 		*dest++ = '\0';
+		--destsize;
 	}
 
 	return start;

src/qcommon/qcommon.h

@@ -1097,7 +1097,6 @@ void		Info_Print( const char *s );
 
 void		Com_BeginRedirect (char *buffer, int buffersize, void (*flush)(const char *));
 void		Com_EndRedirect( void );
-int			QDECL Com_VPrintf( const char *fmt, va_list argptr ) FORMAT_PRINTF(1, 0); // conforms to vprintf prototype for print callback passing
 void 		QDECL Com_Printf( const char *fmt, ... ) FORMAT_PRINTF(1, 2);
 void 		QDECL Com_DPrintf( const char *fmt, ... ) FORMAT_PRINTF(1, 2);
 void 		NORETURN QDECL Com_Error( errorParm_t code, const char *fmt, ... ) FORMAT_PRINTF(2, 3);