--- a/FXAnalyse.c	Fri Dec 13 17:03:36 2013 +0100
+++ b/FXAnalyse.c	Fri Dec 13 17:04:28 2013 +0100
@@ -159,20 +159,25 @@
 static int LoggingPanel;
 
 
-// format and add thousands separator */
-char * thousands(char *buffer, int len, char *fmt, double val)
+char * thousands(char *buffer, int size, char *fmt, double val)
 {
-	int c = snprintf(buffer, len, fmt, val);
-	char *p  = strchr(buffer, '.');
-	int n = buffer + c - p;
-	while (p > (buffer + 3)) {
-		// shift by 3 digits
-		p -= 3;
-		n += 4;
-		// make space for separator
-		memmove(p + 1, p, n);
-		// insert thousand separator
-		*p = ' ';
+	// compute how many separators we need
+	int nsep = (int)(log10(fabs(val)+1.0))/3;
+	// format value
+	int len = snprintf(buffer, size, fmt, val);
+	char *src = buffer + len + 1;
+	char *dst = src + nsep;
+	// copy till decimal separator
+	while (*src != '.')
+		*dst-- = *src--;
+	// copy till the beginning inserting separators
+	int n = -1;
+	while (1) {
+		*dst-- = *src--;
+		if (isdigit(*src) && (++n) && ((n % 3) == 0))
+			*dst-- = ' ';
+		if (src == buffer)
+			break;
 	}
 	return buffer;
 }