Searchengine

General

Items in blue are planned but not implemented yet.

Search Expression Language

FILTER is an special AND only allowed at the end...
-traverse result, put all indexes with 1 in an array. select random items from indexarray till time limit reached or all items selected, put in new clean boolean array.return as result to and with...-
-what about selecting modes? random, first, last.. ? first and last are trivial to implement..
Autorating is (playcount-playcountmin)*10/(playcountmax-playcountmin)

In EBNF:

NUMARG := number | numberid
STRARG := string | stringid

NUMOP : = '>' | '>=' | '<' | '<=' | '!=' | '=='
STROP : = CONTAINS | EQUALS | STARTSWITH | ENDSWITH

COMPARE : = NUMARG NUMOP NUMARG | STRARG STROP STRARG

EXPR := COMPARE | NOT EXPR | LPAREN MEXPR RPAREN

LEXPR := EXPR (AND EXPR)*

MEXPR := LEXPR (OR LEXPR)*

QUERY := MEXPR (SHUFFLE)? (PLAYTIMELIMIT)? EOF

numberid := year | rating | playcount | autorating
stringid := title | genre | artist | album | filename

Tokenfile description

Token Types

Token type	ID	Description
EOF	0	End of file / search
NOT	1	invert expression operator
AND	2	and expression operator
OR	3	or expression operator
GT	4	GreaterThan? ( > ) number operator
GTE	5	GreaterThanorEqual? ( >= ) number operator
LT	6	LessThan? ( < ) number operator
LTE	7	LessThanorEqual? ( <= ) number operator
EQ	8	Equal ( == ) number operator
NE	9	NotEqual? ( = ) number operator
CONTAINS	10	contains string operator
EQUALS	11	equals string operator
STARTSWITH	12	startswith string operator
ENDSWITH	13	startswith string operator
LPAREN	14	'(' open new multiple-expression
RPAREN	15	')' close previously opened multiple-expression
NUM	16	Number, value stored in intvalue
NUMID	17	Number property of a song, intvalue holds numberid (see NumberID? intvalues)
STRING	18	String, stored in spelling
STRINGID	19	String property of a song, intvalue holds stringid (see StringID? intvalues)
SHUFFLE	20	Shuffle results
PLAYTIMELIMIT	21	Limit playtime to # minutes (in intvalue)

Token Entry

Field	Size	Description
kind	1	Token type (see Token Types)
spelling	255	Text of a TOKEN_STRING
intvalue	4	Intvalue of this token

Token file

# Token Entries
1 EOF Token entry.
EOF

Todo

1) optimize album / artist names.
2) dynamic caching for targets with less ram (i have no idea how to do this (HCl))

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CategoryPlugin: Database Searchengine [Player, Recorder, Ondio, iRiver]