Rico Mariani's Performance Tidbits

Performance Quiz #6 -- Chinese/English Dictionary reader

Raymond Chen is running a series of articles about how to build and optimize the startup time of a Chinese/English dictionary.

• Developing a Chinese/English dictionary: Introduction
• Loading the dictionary, part 1: Starting point and then my analysis
• Loading the dictionary, part 2: Character conversion and then my analysis
• Loading the dictionary, part 3: Breaking the text into lines and then my analysis
• Loading the dictionary, part 4: Character conversion redux and then my analysis
• Analyzing the managed code
• Loading the dictionary, part 5: Avoiding string copying and then my analysis
• Optimizing the managed version
• Loading the dictionary, part 6: Taking advantage of our memory allocation pattern and then my analysis
• Performance Quiz #6 -- Conclusion, Studying the Space

Actually truth be told I got a look at his article quite some time ago as he was kind enough to ask me for comments well in advance.  At the time I couldn't resist doing a managed version of the same program to see how it would do.  So I encourage you to watch as Raymond works through various steps optimizing his program and see how it comes along. 

This managed code is a line for line conversion in the dumbest possible way of his initial program with no attempt whatsoever to optimize anything.

And then, the question of the hour:  How does Raymond's program fare vs. the equivalent managed code below?

Feel free to comment on the code, the problem, or just the unfairness of it all but please don't accuse me of concluding too much from the result of just this one benchmark :) :)

using System;
using System.IO;
using System.Text;
using System.Collections;

namespace NS
{
   class Test
    {
        [System.Runtime.InteropServices.DllImport("Kernel32.dll")]
        private static extern bool QueryPerformanceCounter(out long lpPerformanceCount);

        [System.Runtime.InteropServices.DllImport("Kernel32.dll")]
        private static extern bool QueryPerformanceFrequency(out long lpFrequency);

        static void Main(string[] args)
        {
            long startTime, endTime, freq;

            QueryPerformanceFrequency(out freq);
            QueryPerformanceCounter(out startTime);

            Dictionary dict = new Dictionary();        

            QueryPerformanceCounter(out endTime);

            Console.WriteLine("Length: {0}", dict.Length());
            Console.WriteLine("frequency: {0:n0}", freq);
            Console.WriteLine("time: {0:n5}s", (endTime - startTime)/(double)freq);
        }

        class DictionaryEntry
        {
            private string trad;
            private string pinyin;
            private string english;

            static public DictionaryEntry Parse(string line)
            {
                DictionaryEntry de = new DictionaryEntry();
               
                int start = 0;
                int end = line.IndexOf(' ', start);
               
                if (end == -1) return null;
                de.trad = line.Substring(start, end - start);
               
                start = line.IndexOf('[', end);
                if (start == -1) return null;
               
                end = line.IndexOf(']', ++start);
               
                if (end == -1) return null;
               
                de.pinyin = line.Substring(start, end - start);

                start = line.IndexOf('/', end);
               
                if (start == -1) return null;
                start++;
               
                end = line.LastIndexOf('/');
                if (end == -1) return null;
                if (end <= start) return null;
               
                de.english = line.Substring(start, end-start);

                return de;
            }
        };

        class Dictionary
        {
            ArrayList dict;
           
            public Dictionary()
            {
                StreamReader src = new StreamReader(
                    "cedict.b5", 
                    System.Text.Encoding.GetEncoding(950));
                string s;
                DictionaryEntry de;
                dict = new ArrayList();

                while ((s = src.ReadLine()) != null)
                {
                    if (s.Length > 0 && s[0] != '#') {
                        if (null != (de = DictionaryEntry.Parse(s))) {
                            dict.Add(de);
                        }
                    }
                }
            }

            public int Length() { return dict.Count; }      
        };        
    }
}