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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 in- teger 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 processing. Strings can be compared for equality using a straight in- teger comparison. Strings of 7 or fewer characters can still be ac- cessed as a string by simply casting to char * for output, then using lexical comparison with strcmp(), etc. A string of 8 characters will not have a null-terminator. The value returned varies depending on endianness. Hence, hash values generated on one architecture will need to be byte swapped before com- parison 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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