 ! Copyright (C) 2005, 2009 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: kernel sequences arrays generic assocs io math
-namespaces parser prettyprint strings io.styles words
-system sorting splitting grouping math.parser classes memory
-combinators fry vm specialized-arrays accessors continuations
-classes.struct generalizations ;
+USING: accessors arrays assocs classes classes.struct
+combinators combinators.smart continuations fry generalizations
+generic grouping io io.styles kernel make math math.parser
+math.statistics memory namespaces parser prettyprint sequences
+sorting specialized-arrays splitting strings system vm words ;
 SPECIALIZED-ARRAY: gc-event
 IN: tools.memory
 
 <PRIVATE
 
 : commas ( n -- str )
-    number>string
-    reverse 3 group "," join reverse ;
+    dup 0 < [ neg commas "-" prepend ] [
+        number>string
+        reverse 3 group "," join reverse
+    ] if ;
 
 : kilobytes ( n -- str )
     1024 /i commas " KB" append ;
 
 : micros>string ( n -- str )
-    commas " microseconds" append ;
+    commas " µs" append ;
 
 : fancy-table. ( obj alist -- )
     [ [ nip first ] [ second call( obj -- str ) ] 2bi 2array ] with map

        { "Total time:" [ total-time>> micros>string ] }
        { "Space reclaimed:" [ space-reclaimed kilobytes ] }
    } fancy-table. ;

    enable-gc-events [ ] [ disable-gc-events drop ] cleanup
    disable-gc-events byte-array>gc-event-array ; inline

<PRIVATE

: gc-op-string ( op -- string )
    {
        { collect-nursery-op      [ "Copying from nursery" ] }
        { collect-aging-op        [ "Copying from aging"   ] }
        { collect-to-tenured-op   [ "Copying to tenured"   ] }
        { collect-full-op         [ "Mark and sweep"       ] }
        { collect-compact-op      [ "Mark and compact"     ] }
        { collect-growing-heap-op [ "Grow heap"            ] }
    } case ;

: (space-occupied) ( data-heap-room code-heap-room -- n )
    [
        [ [ nursery>> ] [ aging>> ] [ tenured>> ] tri [ occupied>> ] tri@ ]
        [ occupied>> ]
        bi*
    ] sum-outputs ;

: space-occupied-before ( event -- bytes )
    [ data-heap-before>> ] [ code-heap-before>> ] bi (space-occupied) ;

: space-occupied-after ( event -- bytes )
    [ data-heap-after>> ] [ code-heap-after>> ] bi (space-occupied) ;

: space-reclaimed ( event -- bytes )
    [ space-occupied-before ] [ space-occupied-after ] bi - ;

TUPLE: gc-stats collections times ;

: <gc-stats> ( -- stats )
    gc-stats new
        0 >>collections
        V{ } clone >>times ; inline

: compute-gc-stats ( events -- stats )
    V{ } clone [
        '[
            dup op>> _ [ drop <gc-stats> ] cache
            [ 1 + ] change-collections
            [ total-time>> ] dip times>> push
        ] each
    ] keep sort-keys ;

: gc-stats-table-row ( pair -- row )
    [
        [ first gc-op-string ] [
            second
            [ collections>> ]
            [
                times>> {
                    [ sum micros>string ]
                    [ mean >integer micros>string ]
                    [ median >integer micros>string ]
                    [ infimum micros>string ]
                    [ supremum micros>string ]
                } cleave
            ] bi
        ] bi
    ] output>array ;

: gc-stats-table ( stats -- table )
    [ gc-stats-table-row ] map
    { "" "Number" "Total" "Mean" "Median" "Min" "Max" } prefix ;

: heap-sizes ( events -- seq )
    [
        [
            [ [ start-time>> ] [ space-occupied-before ] bi 2array , ]
            [ [ [ start-time>> ] [ total-time>> ] bi + ] [ space-occupied-after ] bi 2array , ]
            bi
        ] each
    ] { } make ;

: aggregate-stats-table ( stats -- table )
    [ { "Total collections:" "Total GC time:" } ] dip
    values
    [ [ collections>> ] sigma ]
    [ [ times>> sum ] sigma micros>string ]
    bi 2array zip ;

PRIVATE>

: gc-event. ( event -- )
    {
