dbase: Database system functions

Here are the low level functions for handling the database.

Future development

There is room for improvements to the speed of some of this functions. In the final version of the language some checks could be thrown out. But meanwhile it is better to check everything twice so errors can be dealt with.

Known bugs

Handling of longer indexes

Indexes that get too long don't behave right. It a record is edited there is one record overwritten and the old record is left. It looks like the routine to fetch the next record is not correct for the new leafs in the index tree.

Global dbstate	[Read Add Edit Update]

Routine	showidxs	Show then contence of the indexes to a table
table	number	Table to use

Routine	ptrinfo	Get the contence of a pointer in readable form
ptr	pointer	The pointer to read
returns:	string	A string with the contence

Routine	getrec	Get the recordnumber part of a pointer
ptr	pointer	The pointer
index	number
returns:	number

Routine	tablelen	get the length of a table
table	number	the table
returns:	number	the length or 0 if no table found

Routine	maxbranch
index	number
returns:	number

Routine	maxleaf
branch	number
index	number
returns:	number

Global log	stream

Routine	initdb	initiate the database
tables	number	the current number of tables
indexes	number	the current number of indexes

Routine	addrecord	adds a record to a table
table	number	the table to use
returns:	pointer	a field-pointer to the new record

Routine	cpyrecord	adds a record to a table
ptr	pointer	pointer to the current record
table	number	the table to alter
returns:	pointer	a pointer to the new record

Routine	deleterecord	deletes the contents of a record
record	number	the record to delete
table	number	the table to use

Routine	changeindex	change the value in an index
ptr	pointer
rec	number
index	number

Routine	searchindex	calculate new search position
current	number	position where was searched last
level	byte	level of the search from 1 till last=current
check	byte	is the current value higher or lower or the same
max	number	number of elements in the index
returns:	number	new position to search from or null when end

Routine	getrecptr	get a pointer to a record number
rec	number
table	number
returns:	pointer	the created pointer

Routine	getpointer	get a pointer value
branch	number
leaf	number
index	number
returns:	pointer	the created pointer

Routine	getbranch
ptr	pointer
returns:	number

Routine	ptrmin1
ptr	pointer
index	number
returns:	pointer

Routine	recalcptr
ptr	pointer
index	number
returns:	pointer

Routine	ptrplus1
ptr	pointer
index	number
returns:	pointer

Routine	subptr
val	number
index	number
branch	number
diff	number

Routine	addptr
val	number
index	number
branch	number
leaf	number
old	number

Routine	addindex	add record to an index
ptr	pointer	pointer to the new position in the index
rec	number	record number to add
index	number	the index to add to

Routine	mergeleft
ptr	pointer	pointer to the old position in the index
index	number	the index to delet from

Routine	mergeright
ptr	pointer	pointer to the old position in the index
index	number	the index to delet from

Routine	deleteindex	add record to an index
ptr	pointer	pointer to the old position in the index
index	number	the index to delet from