C# app to count #ifdef usage
Here's a little tool I wrote to count #ifdef usage in a project. It provides a summary of the #define name and frequency; plus a detailed XML file of each location that the #define occurred at.
For example, when applied to this sample file (in directory c:\temp\1):
1: void Foo() 2: { 3: #ifdef ABC 4: A1(); 5: #ifndef ABC || defined(DEF) 6: A2(); 7: #elif XYZ 8: A3(); 9: #endif 10:}
Run it:
Counter.exe c:\temp\1 c:\temp\t.xml
This scans through all files in the directory and all subdirectories. It prints the summary below. This includes each #define usage sorted by increasing frequency (highlighted in red). It also includes the preprocessor directives because the parser I use is very simple; and the directives are actually interesting to have.
Counter Usage: counter <directory> <xml output file> Summary: frequence | name 1 DEF 1 elif 1 XYZ 1 defined 1 ifdef 1 ifndef 2 ABC Done!
It also produces this more detailed xml file that shows where each usage occurs:
<?xml version="1.0" encoding="Windows-1252"?> <report> <item name="DEF" frequency="1"> <location>c:\temp\1\q.cpp:5</location> </item> <item name="elif" frequency="1"> <location>c:\temp\1\q.cpp:7</location> </item> <item name="XYZ" frequency="1"> <location>c:\temp\1\q.cpp:7</location> </item> <item name="defined" frequency="1"> <location>c:\temp\1\q.cpp:5</location> </item> <item name="ifdef" frequency="1"> <location>c:\temp\1\q.cpp:3</location> </item> <item name="ifndef" frequency="1"> <location>c:\temp\1\q.cpp:5</location> </item> <item name="ABC" frequency="2"> <location>c:\temp\1\q.cpp:3</location> <location>c:\temp\1\q.cpp:5</location> </item> </report>
Why is this useful?
The sample file above is simple and contrived; this would be more interesting when applied to larger projects that use #ifdef a lot for features. It can serve as a useful metric to recognize high #ifdef usages and try to drive them down via better componentization models. For example, rather than toggling a feature via #ifdef, consider toggling it via better class or file partitioning.
Here's the source:
It compiles with .NET 2.0:
// Program to count #ifdef labels. // https://blogs.msdn.com/jmstall using System; using System.Collections.Generic; using System.Text; using System.Text.RegularExpressions; using System.IO; using System.Xml; namespace Counter { // stats for a given directory and its subdirectories. class DirStats : BaseStats { // Parse all #ifdefs in this directory and subdirs. public DirStats(string directory) { ParseDirectory(directory); } // Track all #defines within this directory and all subdirectories. void ParseDirectory(string directory) { // Do all files foreach (string filename in Directory.GetFiles(directory)) { ParseFile(filename); } // Do all subdirectories foreach (string subdirectory in Directory.GetDirectories(directory)) { ParseDirectory(subdirectory); } } // Track all #defines within the filename. void ParseFile(string filename) { m_total++; int lineNumber = 1; // Read all lines. TextReader tr = new StreamReader(filename); // Parse all lines string line; while ((line = tr.ReadLine()) != null) { ParseLine(line, filename, lineNumber); lineNumber++; } } int m_total; } // Track stats in an arbitrary quanta class BaseStats { // Single copy of RegEx static Regex m_regex; // Update the stats with #defines from a single line. // line - input line to search for #defines. // filename - filename that line is in. Used for context. // lineNumber - line number where the line occurs within the filename. Used for context. protected void ParseLine(string line, string filename, int lineNumber) { if (line == null) return; line = line.Trim(); // Only care about lines like #ifdef, #if defined, #endif, #elif // Most lines should fail here. if (!line.StartsWith("#if") && !line.StartsWith("#elif")) return; int idx = 0; // Regex expressions are NOT cached by default in .NET 2.0. // Use static to ensure caching. // See : https://blogs.msdn.com/bclteam/archive/2006/10/19/regex-class-caching-changes-between-net-framework-1-1-and-net-framework-2-0-josh-free.aspx if (m_regex == null) { // This just captures identifiers on the line. // It's a sufficient approximation of the C preprocessor for #ifdef usage. m_regex = new Regex(@"(\w+|\/)"); } // Loop to allow multiple defines in a single line. Eg: // #if defined(ABC) && !defined(DEF_FOO) // some comment // should collect both ABC and DEF_FOO, but not anything after '//' since that's a comment. // This also includes preprocessor directives like ifdef, ifndef, define, etc. // But those can be easily filtered out by the end-user. while (true) { Match m = m_regex.Match(line, idx); if (!m.Success) { break; } string val = m.Groups[1].Value; if (val == "/") // hit a comment. break; Increment(val, filename + ":" + lineNumber); // Groups.Index is from offset 0, not from idx. int i = m.Groups[1].Index; System.Diagnostics.Debug.Assert(i >= idx); int len = m.Groups[1].Length; idx = (i + len); } } // Increment the stat for the given #define. // define - the #define name to increment // context - a string describing the location of the #define (eg, "c:\myfile.txt:8") void Increment(string define, string context) { List<string> list; if (!m_frequency.TryGetValue(define, out list)) { list = new List<string>(); m_frequency[define] = list; } list.Add(context); } // frequency of each #ifdef in the file. // Key = the name of a #define. // Value = List of locations that #define occurs. // The m_frequency[name].Count == # of times 'name' occurs. // Using <string, List<string>> gives lets us store where exactly each #define usage occurs. // If we just cared about frequency, we could use <string, int> (where the int = List<string>.Count) protected Dictionary<string, List<string>> m_frequency = new Dictionary<string, List<string>>(); // Produces 2 reports. // Prints a summary to twSummary, which is just (name, frequency) sorted by frequency. // Prints a detailed report to twDetails listing all usages. public void PrintReport(TextWriter twSummary, XmlWriter xmlDetails) { // Lets us avoid null checks everywhere. if (twSummary == null) { twSummary = TextWriter.Null; } twSummary.WriteLine("Summary:"); twSummary.WriteLine("frequence | name"); xmlDetails.WriteStartElement("report"); int len = m_frequency.Values.Count; int[] vals = new int[len]; int idx = 0; foreach(List<string> l in m_frequency.Values) { vals[idx] = l.Count; idx++; } string[] keys = new String[m_frequency.Keys.Count]; m_frequency.Keys.CopyTo(keys, 0); // sort by increasing order of frequency Array.Sort(vals, keys); for(idx = 0; idx< len; idx++) { string name = keys[idx]; int frequency = vals[idx]; twSummary.WriteLine("{0} {1}", frequency, name); // Write to detailed report, including location of each occurence. xmlDetails.WriteStartElement("item"); xmlDetails.WriteAttributeString("name", name); xmlDetails.WriteAttributeString("frequency", frequency.ToString()); // Print each occurence foreach(string context in m_frequency[name]) { xmlDetails.WriteElementString("location", context); } xmlDetails.WriteEndElement(); // item } xmlDetails.WriteEndElement(); // report. } } // Entry point class Program { static void Main(string[] args) { Console.WriteLine("Counter"); Console.WriteLine(" Usage: counter <directory> <xml output file>"); string directory = args[0]; // input directory to search string outputPath = args[1]; // XML file to write out details XmlWriter x = new XmlTextWriter(outputPath, Encoding.Default); BaseStats f = new DirStats(directory); x.WriteStartDocument(); f.PrintReport(Console.Out, x); x.Close(); Console.WriteLine("Done!"); } } } // end Counter namespace