Comment by mikewarot

Long, long ago I came up with a text search algorithm while working on PCxRef to help technical sales support at IBM. My first approach using a naive string search took about 30 seconds on a PC. My algorithm got it down to the speed of disk access.

Basically I precomputed a table of masks and used the XLAT instruction in a very tight loop to fly though all the product descriptions for everything IBM offered back around 1983. I could accommodate case insensitivity and single character wildcards.

The test search was always "dos tech ref" to find the IBM DOS Technical reference manual.