![openfish hex fiend openfish hex fiend](https://ae01.alicdn.com/kf/H9740a042b8734593b58762189706c1a7Q/LILYGO-TTGO-T-Solar-433-868-915MHz-Solar-Power-Development-Board-STM8L152-CPU-SX1262-Lora-With.jpg)
Ultimate Unix Geek chuckles into his xterms.
![openfish hex fiend openfish hex fiend](https://s3.manualzz.com/store/data/023085434_1-32f231d9c4f45b6851f8ffded1f4157c.png)
So I confidently ran my benchmark, for a 1 gigabyte file. It may not be faster than grep, but it should be at least as fast, because this is the fastest algorithm known. " There," I sigh, finishing and sitting back. So we look at the character in haystack and if it's not what we're looking for, we jump ahead by the right distance for that character, which is in jump_table. If (last_char_in_needle != haystack_char) So the first part of my Boyer-Moore string searching algorithm looked like this:Ĭhar haystack_char = haystack A single mismatch allowed us to skip 100 characters!įor performance, the number of characters you can skip on a mismatch is usually stored in an array indexed by the character value. If it's an 'x', well, 'x' doesn't appear anywhere in needle, so you can skip ahead all of needle and look at the 200th character in haystack. If haystack's mismatch isn't in needle at all, then you can skip ahead a whole needle's length.įor example, if you're searching for a string of 100 'a's ( needle), you look at the 100th character in haystack. If your needle character doesn't match the character you're looking at in haystack, you can move needle forwards in haystack until haystack's mismatched character lines up with the same character in needle. Instead of starting the search at the beginning of needle, you start at the end. The best known is Boyer-Moore (I won't insult your intelligence with a Wikipedia link, but the article there gives a good overview).īoyer-Moore works like this: you have some string you're looking for, which we'll call the needle, and some string you want to find it in, which we'll call the haystack. So I am resigned to the linear algorithms. Since my program is supposed to work on dozens of gigabytes, preflighting is impossible - there's no place to put all the data that preflighting generates, and nobody wants to sit around while I generate it. Now, everyone knows that without some sort of preflighting, the fastest string search you can do still takes linear time. Having exhausted all my trash-talking avenues, it's time to get to work. The aphorism at the top, like the ex girlfriend who first told it to me, is dim in my recollection. I look straight into the back of his head, covered by a snarl of greasy locks, and reply with a snarl of my own: You're mine. Discarded crushed Mountain Dew cans litter the floor. I imagine the author of grep, Ultimate Unix Geek, squinting at vi the glow of a dozen xterms is the only light to fall on his ample frame covered by overalls, cheese doodles, and a tangle of beard. The first step in any potentially impossible project is, of course, to announce that you are on the verge of succeeding. So I set out to search faster than grep by thirty percent. And, as everyone knows, the best way to get amazing results is to set arbitrary goals without any basis for believing they can be reached. But Hex Fiend is supposed to be fast, and I want blazingly quick search that leaves the bewildered competition coughing in trails of dust. See, I was working on Hex Fiend, and searching was dog slow. And my girlfriend too, who's contractually obligated to pay attention to everything I say. "I'm going to beat grep by thirty percent!" I confidently crow to anyone who would listen, those foolish enough to enter my office. See the API reference for details.Old age and treachery will beat youth and skill every time.
#Openfish hex fiend license
Its permissive BSD-style license won’t burden you.