How does memchr() work under the hood?

Question

Background: I\'m trying to create a pure D language implementation of functionality that\'s roughly equivalent to C\'s memchr but uses arrays and indices i

Answer 1

memchr like memset and memcpy generally reduce to fairly small amount of machine code. You are unlikely to be able to reproduce that kind of speed without inlining similar assembly code. One major issue to consider in an implementation is data alignment.

One generic technique you may be able to use is to insert a sentinel at the end of the string being searched, which guarantees that you will find it. It allows you to move the test for end of string from inside the loop, to after the loop.