The Boyer–Moore string search algorithm is a particularly efficient string searching algorithm, an it has been the standard benchmark for the practical string search literature. It was developed by Bob Boyer and J Strother Moore in 1977. The algorithm preprocesses the target string (key) that is being searched for, but not the string being searched (unlike some algorithms which preprocess the string to be searched, and can then amortize the expense of the preprocessing by searching repeatedly). The execution time of the Boyer-Moore algorithm can actually be sub-linear: it doesn't need to actually check every character of the string to be searched but rather skips over some of them. Generally the algorithm gets faster as the key being searched for becomes longer. Its efficiency derives from the fact that, with each unsuccessful attempt to find a match between the search string and the text it's searching in, it uses the information gained from that attempt to rule out as many positions of the text as possible where the string could not match.