tie::substrhash(3pm)
NAME
Tie::SubstrHash - Fixed-table-size, fixed-key-length hashing
SYNOPSIS
require Tie::SubstrHash; tie %myhash, 'Tie::SubstrHash', $key_len, $value_len, $table_size;
DESCRIPTION
The Tie::SubstrHash package provides a hash-table-like interface to an
array of determinate size, with constant key size and record size.
Upon tying a new hash to this package, the developer must specify the
size of the keys that will be used, the size of the value fields that
the keys will index, and the size of the overall table (in terms of
key-value pairs, not size in hard memory). These values will not change
for the duration of the tied hash. The newly-allocated hash table may
now have data stored and retrieved. Efforts to store more than $table_size elements will result in a fatal error, as will efforts to
store a value not exactly $value_len characters in length, or reference
through a key not exactly $key_len characters in length. While these
constraints may seem excessive, the result is a hash table using much
less internal memory than an equivalent freely-allocated hash table.
CAVEATS
Because the current implementation uses the table and key sizes for the
hashing algorithm, there is no means by which to dynamically change the
value of any of the initialization parameters.
- The hash does not support exists().