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xt_str2u64_hash(3) Library Functions Manual xt_str2u64_hash(3) NAME xt_str2u64_hash() - Hash a string of up to 8 characters to a 64-bit integer LIBRARY #include <xtend/string.h> -lxtend SYNOPSIS uint64_t xt_str2u64_hash(const char *str) ARGUMENTS str String to convert DESCRIPTION xt_str2u64_hash() is a super-fast hash function that converts a string of 8 or fewer characters to a 64-bit integer. Strings of more than 8 characters may also be hashed, though collisions will occur (same hash value for more than one string) if the first 8 characters are the same. This sort of hashing is useful for storing lists of very short strings, as it eliminates the need to use strdup(), strlcpy(), and strcmp() for pro- cessing. Strings can be compared for equality using a straight integer comparison. Strings of 7 or fewer characters can still be accessed as a string by simply casting to char * for output, then using lexical compari- son with strcmp(), etc. A string of 8 characters will not have a null-ter- minator. The value returned varies depending on endianness. Hence, hash values gen- erated on one architecture will need to be byte swapped before comparison to values generated under a different endianness. RETURN VALUES uint64_t integer containing the characters in str EXAMPLES char *s1 = "hello!", s2 = "Hello!"; uint64_t v1, v2; v1 = xt_str2u64_hash(s1); v2 = xt_str2u64_hash(s2); if ( v1 != v2 ) printf("%s and %s are different.n", (char *)&v1, (char *)&v2); SEE ALSO strdup(3), strcmp(3), strlcpy(3) xt_str2u64_hash(3)
NAME | LIBRARY | SYNOPSIS | ARGUMENTS | DESCRIPTION | RETURN VALUES | EXAMPLES | SEE ALSO
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