I’ve been wondering about making DANSE open-source for a while now (after all if anyone else wants to start using it seriously they will need the source code), but up until recently (well, yesterday) I’ve had a problem: DANSE uses a version of printf written in C# by Richard Prinz which is only available under the Code Project Open License, and this does not allow me to release the code under any other license. I can’t use the CPOL since there is other code also in DANSE released under the GPL.<\/p>\n
I can’t use the built-in printf since I want to target Silverlight as well, and I can’t just use the C# print routines since the students taking the module where this software is used haven’t learned C#, all they know is C.<\/p>\n
So I figured… how hard can it be to write my own version of printf? Perhaps not implementing all the features, but at least being good enough for my purposes here?<\/p>\n
Turns out it’s not that hard, only took a couple of hours. Not very well tested yet, but if anyone else would like to give the following a spin and let me know how they get on, I’d be very interested.<\/p>\n
internal static string sprintf(string format, params Object[] parameters) \/\/ Keep a list of the type-specifiers as I go through... \/\/ The first type specifier will start with a % which is not preceeded by \/\/ Go through the format string, counting how many type specifiers there return sb.ToString(); \/\/ For pointers, characters and strings all that's required is: \/\/ Then if this is an integer, there are some special cases to include the I’ve been wondering about making DANSE open-source for a while now (after all if anyone else wants to start using it seriously they will need the source code), but up until recently (well, yesterday) I’ve had a problem: DANSE uses … Continue reading
\n internal enum eTStype { _int, _float, _exponential, _string, _char, _pointer, _hex, _octal, _gtype, _error }
\n internal class TS
\n {
\n internal int start; internal int end; internal int width; internal int precision; internal eTStype type;
\n internal TS(int A, int B, int C, int D, eTStype what)
\n { start = A; end = B; width = C; precision = D; type = what; }
\n }<\/p>\n
\n {
\n \/\/ Starts from a copy of the string format, then replaces the type specifiers.
\n string result = String.Copy(format);<\/p>\n
\n List
\n \/\/ an escape character '\\', include an option precision field (\".X\")
\n \/\/ and then a length and specifier, both of which are ignored to be
\n \/\/ friendly. The specifier is assumed to end at the first occurrance
\n \/\/ of any one of the following specifiers: i, d, u, o, x, X, f, F, e, E,
\n \/\/ g, G, c, s, or p. (C# knows what these variables are.)<\/p>\n
\n \/\/ are, and making a note of what they are:
\n for (int loop = 0; loop < format.Length; loop++)\n {\n if (format[loop] == '%' && (loop == 0 || format[loop - 1] != '\\\\'))\n {\n \/\/ Found the start of a format string.\n int startTS = loop;\n int precision = 0;\n int width = 0;\n Boolean precisionValid = false;\n eTStype what = eTStype._error;\n\n \/\/ Now I need to find the end of it and work out what it is:\n while (loop < format.Length && what == eTStype._error)\n {\n char c = format[loop];\n if (c == '.') precisionValid = true;\n if (c == '0' || c == '1' || c == '2' || c == '3' || c == '4' || c == '5'\n || c == '6' || c == '7' || c == '8' || c == '9')\n {\n string TryThis = format[loop].ToString();\n int whatIsThis = 0;\n int.TryParse(TryThis, out whatIsThis);\n if (precisionValid == true) precision = precision * 10 + whatIsThis;\n else width = width * 10 + whatIsThis;\n }\n if (c == 'i' || c == 'd' || c == 'u') what = eTStype._int;\n else if (c == 'o') what = eTStype._octal;\n else if (c == 'x' || c == 'X') what = eTStype._hex;\n else if (c == 'f' || c == 'F') what = eTStype._float;\n else if (c == 'e' || c == 'E') what = eTStype._exponential;\n else if (c == 'g' || c == 'G') what = eTStype._gtype;\n else if (c == 'c') what = eTStype._char;\n else if (c == 's') what = eTStype._string;\n else if (c == 'p') what = eTStype._pointer;\n loop++;\n }\n\n if (what != eTStype._error)\n {\n \/\/ Must have found the end of a format string, so add this to the list:\n if (precisionValid == false) precision = -1;\n TS ts = new TS(startTS, loop, width, precision, what);\n myTS.Add(ts);\n }\n }\n }\n\n \/\/ Right - now just go through and make a new string from the \n \/\/ non-type specifier parts of the format string, and the \n \/\/ replacements for the type-specifiers from the parameters list:\n StringBuilder sb = new StringBuilder(format.Length + 20 * myTS.Count);\n int lastFinishes = 0;\n for (int loop = 0; loop < myTS.Count; loop++)\n {\n int includeUpToHere = myTS[loop].start;\n sb.Append(format.Substring(lastFinishes, includeUpToHere - lastFinishes));\n if (parameters.Length > loop) sb.Append(makeString(myTS[loop], parameters[loop]));
\n else sb.Append(\" ERROR - Insufficient Parameters \");
\n lastFinishes = myTS[loop].end;
\n }
\n \/\/ Then add on the bit after all type specifiers:
\n sb.Append(format.Substring(lastFinishes, format.Length - lastFinishes));<\/p>\n
\n }
\n static private string makeString(TS ts, Object parameter)
\n {
\n if (ts.type == eTStype._error) return \"*Error: Unrecognised type specifier*\";<\/p>\n
\n string q = parameter.ToString();<\/p>\n
\n \/\/ precision, and deal with hex and octal numbers:
\n if (ts.type == eTStype._int)
\n {
\n long d;
\n if (long.TryParse(q, out d))
\n {
\n int prec = ts.precision;
\n if (ts.type == eTStype._hex)
\n {
\n q = d.ToString(\"X\" + ((prec < 0) ? \"\" : ts.precision.ToString()));\n }\n else if (ts.type == eTStype._octal)\n {\n \/\/ Precision not implemented for octal yet. Does anyone care?\n string qq = Convert.ToString(d, 8);\n }\n else\n {\n q = d.ToString(\"D\" + ((prec < 0) ? \"\" : ts.precision.ToString()));\n }\n }\n else\n {\n q = \"*Error: Unrecognised type specifier*\";\n }\n }\n\n if (ts.type == eTStype._exponential || ts.type == eTStype._float || ts.type == eTStype._gtype)\n {\n char s = ts.type == eTStype._exponential ? 'e' : ts.type == eTStype._float ? 'f' : 'g';\n double d; int prec = ts.precision;\n if (double.TryParse(q, out d)) q = d.ToString(s + ((prec < 0) ? \"\" : ts.precision.ToString()));\n else q = \"*Error: Unrecognised type specifier*\";\n }\n\n \/\/ Then pad (or truncate) to fit the width required:\n if (ts.width > 0)
\n {
\n while (q.Length < ts.width) q = \" \" + q;\n if (q.Length > ts.width) return q.Substring(0, ts.width);
\n return q;
\n }
\n return q;
\n }
\n }
\n<\/code><\/p>\n","protected":false},"excerpt":{"rendered":"