Hash-based system and method with primary and secondary hash functions for rapidly identifying the existence and location of an item in a file

A system for identifying the existence of an item in a file, comprising:

• primary hash function means, for applying a primary hash function to obtain a primary hash key for a search term;
• hash bucket identification means, coupled to the primary hash function means, for identifying a hash bucket having a primary hash key corresponding to the obtained primary hash key, the hash bucket comprising at least one hash entry, each hash entry comprising a value and a secondary hash key;
• secondary hash function means, for applying a secondary hash function to obtain a secondary hash key for the search term;
• and
• comparing means, coupled to the secondary hash function means and to the hash bucket identification means, for comparing the secondary hash key for the search term with the secondary hash key for at least one hash entry in the identified hash bucket.

A computer-implemented method for rapidly identifying the existence of an item in a file, comprising:

• a) accessing a master file for storing a plurality of items;
• and
• b) accessing a hash table, comprising a plurality of hash buckets, each hash bucket identified by a primary hash key, each hash bucket comprising at least one hash entry, each hash entry comprising:
• a pointer to an item in the master file, for identifying the location of the item;
• and
• a secondary hash key obtained by applying a secondary hash function.

A computer program product comprising a computer-usable medium having computer-readable code embodied therein for rapidly identifying the existence of an item in a file, comprising:

• computer-readable program code devices configured to cause a computer to access a master file for storing a plurality of items;
• and
• computer-readable program code devices configured to cause a computer to access a hash table, comprising a plurality of hash buckets, each hash bucket identified by a primary hash key, each hash bucket comprising at least one hash entry, each hash entry comprising:
• a pointer to an item in the master file, for identifying the location of the item;
• and
• a secondary hash key obtained by applying a secondary hash function.

A computer program product comprising a computer-usable medium having computer-readable code embodied therein for identifying the existence of an item in a file, comprising:

• computer-readable program code devices configured to cause a computer to apply a primary hash function to obtain a primary hash key for a search term;
• computer-readable program code devices configured to cause a computer to identify a hash bucket having a primary hash key corresponding to the obtained primary hash key, the hash bucket comprising at least one hash entry, each hash entry comprising a value and a secondary hash key;
• computer-readable program code devices configured to cause a computer to apply a secondary hash function to obtain a secondary hash key for the search term;
• and
• computer-readable program code devices configured to cause a computer to compare the secondary hash key for the search term with the secondary hash key for at least one hash entry in the identified hash bucket.