Implementation of substring in C# and which algorithm does it use?

Question

I have a question, i'm doing some research on some programming languages. The research is about the efficiency of the substring functions in C# and Java.

Questions like is C# using a brute force kind of way, or do they implement Boyer-Moore's algorithm like a good boy. I need the source code for this, I already found it for Java ( Who use a brute force implementation in the indexOf()method for those who wonder ).

Does anyone have an idea how i can retrieve the source code for methods like these in C#. I have visual studios installed on my laptop but i can't find any source code...

Your help will much obliged!

Frank · Accepted Answer · 2015-01-07 15:57:01Z

6

Microsoft has published the complete framework source code, including comments. You will find the actual implementation over here on referencesource. For SubString, it comes down to some unmanaged code:

    [System.Security.SecurityCritical]  // auto-generated
    unsafe string InternalSubString(int startIndex, int length) {
        Contract.Assert( startIndex >= 0 && startIndex <= this.Length, "StartIndex is out of range!");
        Contract.Assert( length >= 0 && startIndex <= this.Length - length, "length is out of range!");            

        String result = FastAllocateString(length);

        fixed(char* dest = &result.m_firstChar)
            fixed(char* src = &this.m_firstChar) {
                wstrcpy(dest, src + startIndex, length);
            }

        return result;

As you can see, they are using wstrcpy which probably is as fast as it gets.

answered Jan 7, 2015 at 15:57

Frank

4,50116 silver badges29 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Markvds Over a year ago

Thanks you so much! No idea they released it cause it always was closed source.

ajb Over a year ago

@user1758777 Making .NET open source is a very recent development--in the last two months. See blogs.msdn.com/b/dotnet/archive/2014/11/12/….

Collectives™ on Stack Overflow

Implementation of substring in C# and which algorithm does it use?

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related