Hash Tables

Hash tables allow you to efficiently store large amounts of information which can be quickly referenced and retrieved later on.

A hash table can be created, freed, referenced, or modified using the following commands and identifiers.

/hmake -s <name> <N>

Creates a new hash table with N slots.

A hash table can store an unlimited number of items regardless of the N you choose, however the bigger N is, the faster it will work, depending on the number of items stored.

eg. if you expect that you'll be storing 1000 items in the table, a table of N set to 100 is quite sufficient.

The -s switch makes the command display the result.

/hfree -sw <name>

Frees an existing hash table.

The -w switch indicates that name is a wildcard, all matching tables are freed.

/hadd -smbczuN <name> <item> [data | &binvar]

Adds an item to an existing hash table.

If the item you're adding already exists, the old item is replaced.

The -m switch makes /hadd create the hash table if it doesn't already exist.

The -uN switch unsets the item after N seconds.

The -b indicates that you're adding a &binvar item to the hash table.

The -c switch chops the &binvar up to the first null value and treats it as plain text.

The -z switch decreases hash item once per second until it reaches zero and then unsets it.

The /hinc and /hdec commands use the same parameters as /hadd and increase or decrease the number value of an item.

When used with /hinc or /hdec, the -c switch increases or decreases the value once per second.

/hdel -sw <name> <item>

Deletes an item from a hash table.

The -w switch indicates that item is a wildcard, all matching items are freed.

/hload -sbni <name> <filename> [section]

/hsave -sbniau <name> <filename> [section]

Load or save a table to/from a file.

These load/save plain text to a text file, with item and data on separate lines. $cr and $lf characters are stripped from text when saving as plain text.

The -b switch loads or saves binary files. $cr and $lf are preserved when saving as binary files.

You can use -n to load or save files as data only, with no items. When loading with -n each line of data is assigned an N item value, starting at N = 1.

/hsave also supports -a to append to an existing file instead of overwriting it.

By default /hsave excludes items that are in the /hadd -uN unset list, the -u switch forces it to include the unset items.

The -i switch treats the file as an ini file. You can specify an optional section name after the filename.

Note: /hload does not create the table, it must already have been created by /hmake.

$hget(name/N)

Returns name of a hash table if it exists, or returns the name of the Nth hash table.

Properties: size

$hget(moo).size   returns the N size of table, as specified in /hmake

$hget(name/N, item)

Returns the data associated with an item in the specified hash table.

Properties: unset

The unset property returns the time remaining before an item is unset.

$hget(name/N, item, &binvar)

Assigns the contents of an item to a &binvar.

$hget(name/N, N).item

This allows you to reference the table as an index from 0 to N, in order to look up the Nth item in the table.

If N is zero, returns the total number of items in the table.

You can also reference the Nth data value directly with $hget().data.

Note: This method is provided as a convenience, it is not an efficient way to use the hash table.

$hfind(name/N, text, N, M)

Searches table for the Nth item name which matches text. Returns item name.

Properties: data

If you specify the .data property, searches for a matching data value.

M is optional, and can be:

 n        normal text comparison (default if M isn't specified)

 w        text is wildcard text

 W        hash table item/data is wildcard text

 r        text is regular expression

 R        hash table item/data is regular expression