Question

In an application of mine, I need a large constant (actually static readonly) array of objects. The array is initialized in the type’s static constructor.

The array contains more than a thousand items, and when the type is first used, my program experiences a serious slowdown. I would like to know if there is a way to initialise a large array quickly in C#.

public static class XSampa {
    public class XSampaPair : IComparable<XSampaPair> {
        public XSampaPair GetReverse() {
            return new XSampaPair(Key, Target);
        }
        public string Key { get; private set; }
        public string Target { get; private set; }
        internal XSampaPair(string key, string target) {
            Key = key;
            Target = target;
        }
        public int CompareTo(XSampaPair other) {
            if (other == null)
                throw new ArgumentNullException("other", 
                        "Cannot compare with Null.");
            if (Key == null)
                throw new NullReferenceException("Key is null!");
            if (other.Key == null)
                throw new NullReferenceException("Key is null!");
            if (Key.Length == other.Key.Length)
                return string.Compare(Key, other.Key, 
                        StringComparison.InvariantCulture);
            return other.Key.Length - other.Key;
        }
    }    
    private static readonly XSampaPair[] pairs, reversedPairs;
    public static string ParseXSampaToIpa(this string xsampa) {
        // Parsing code here...
    }
    public static string ParseIpaToXSampa(this string ipa) {
        // reverse code here...
    }
    static XSampa() {
        pairs = new [] {
            new XSampaPair("a", "\u0061"), 
            new XSampaPair("b", "\u0062"),
            new XSampaPair("b_<", "\u0253"), 
            new XSampaPair("c", "\u0063"),
            // And many more pairs initialized here...
        };
        var temp = pairs.Select(x => x.GetReversed());
        reversedPairs = temp.ToArray();
        Array.Sort(pairs);
        Array.Sort(reversedPairs);
    }
}

PS: I use to array to convert X-SAMPA phonetic transcription to a Unicode string with the corresponding IPA characters.

Answer 1

You can serialize a completely initialized onject into a binary file, add that file as a resource, and load it into your array on startup. If your constructors are CPU-intensive, you might get an improvement. Since your code appears to perform some sort of parsing, the chances of getting a decent improvement there are fairly high.