/** * SDBM hashing algorithm: * * this algorithm was created for sdbm (a public-domain reimplementation of * ndbm) database library. it was found to do well in scrambling bits, * causing better distribution of the keys and fewer splits. it also happens * to be a good general hashing function with good distribution. the actual * function is hash(i) = hash(i - 1) * 65599 + str[i]; what is included below * is the faster version used in gawk. [there is even a faster, duff-device * version] the magic constant 65599 was picked out of thin air while * experimenting with different constants, and turns out to be a prime. this * is one of the algorithms used in berkeley db (see sleepycat) and elsewhere. */unsignedlongsdbm(constunsignedchar*str){unsignedlonghash=0;intc;while((c=tolower(*str++)))hash=c+(hash<<6)+(hash<<16)-hash;returnhash;}// vim: set ts=4 sw=4: