Find location of a short sequence of bytes in byte array

Question

How can I efficiently find the location of the first instance of a four byte sequence within a byte array? Is there something more efficient than looping through the whole array, or a built-in method?

I'm searching through a byte array for a pair of CrLF. I can't convert it to string for an InStr first because I need the position of it in the original byte array.

I am trying to figure out the location of this, as it delimits between a string portion and a binary portion, similar (well, exactly like for this part of it) to an HTTP header. There is a string portion, and two CrLf before the content begins.

You'll need to convert some examples to vb (or just use them in a referenced C# project), but some good alternatives are here: stackoverflow.com/questions/283456/byte-array-pattern-search. — rsenna
– rsenna, Commented Jan 15, 2011 at 22:19

Community · Accepted Answer · 2020-06-20 09:12:55Z

1

You may use Boyer-Moore's algorithm, which is better than linear in the average.

HTH!

edited Jun 20, 2020 at 9:12

CommunityBot

11 silver badge

answered Jan 15, 2011 at 22:20

Dr. belisarius

61.2k15 gold badges121 silver badges198 bronze badges

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

Comments

helloworld922 · Accepted Answer · 2011-01-15 22:05:40Z

1

Assuming nothing about the data set (sorted/special ordering) the best you can do is an O(n) algorithm, which means looking through the whole array once.

answered Jan 15, 2011 at 22:05

helloworld922

11k7 gold badges53 silver badges91 bronze badges

1 Comment

Brad Over a year ago

Ok, that answers my question. Thank you!

Collectives™ on Stack Overflow

Find location of a short sequence of bytes in byte array

2 Answers 2

Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related