dim trv_name[64] as char
dim trv_from[20] as int

sub trv_open(s[] as char, trv as int)
    dim x as int
    dim x_points as int
    dim points as int

    'inline TRACE(">trv_open");
    trv_name = s
    open s for read as trv
    if error then
      x = dialog(s, "File not found - Exiting")
      exit program
    endif
    points = -1
    for i=0 to trv_nquestions(trv)-1
        x_points = trv_points(trv, i)
        if x_points > points then
            trv_from[x_points] = i
            points = x_points
        endif
    next
    trv_from[x_points+1] = i-1
    'inline TRACE("<trv_close");
end sub

sub trv_close(trv as int)
    'inline TRACE(">trv_close");
    close trv
    'inline TRACE("<trv_close");
end sub

function trv_nquestions(trv as int) as int
    dim n as int
    get trv,0,n
    'inline TRACE(">trv_nquestions=%d",n);
    trv_nquestions = n
    'inline TRACE("<trv_nquestions");
end function

function trv_points(trv as int, n as int) as long
    dim posn as long
    dim points as long
    'inline TRACE(">trv_points");
    posn = 2+n*12
    get trv,posn,points
    'inline TRACE("n=%d,posn=%ld,points=%ld",n,posn,points);
    trv_points = points
    'inline TRACE("<trv_points");
end function

function trv_usage(trv as int, n as int) as int
    dim posn as long
    dim usage as int
    'inline TRACE(">trv_usage");
    posn = 2+n*12+8
    get trv,posn,usage
    'inline TRACE("n=%d,posn=%ld,usage=%d",n,posn,usage);
    trv_usage = usage
    'inline TRACE("<trv_usage");
end function

sub trv_inc_usage(trv as int, n as int)
    dim posn as long
    dim usage as int
    'inline TRACE(">trv_inc_usage");
    usage = trv_usage(trv, n)
    close trv
    open trv_name for append as trv
    posn = 2+n*12+8
    usage=usage+1
    put trv,posn,usage
    'inline TRACE("n=%d,posn=%ld,usage=%d",n,posn,usage);
    close trv
    open trv_name for read as trv
    'inline TRACE("<trv_inc_usage");
end sub

function trv_find(trv as int, points as long) as int
    dim min_usage as int
    dim x_usage as int
    dim bottom as int
    dim top as int
    dim select as int

    'inline TRACE(">trv_find");

    min_usage = 1000
    trv_find = -1

    bottom=trv_from[points]
    top=trv_from[points+1]-1
    for i=bottom to top
       if trv_usage(trv, i) < min_usage then min_usage = trv_usage(trv, i)
    next
    ''inline TRACE("points=%ld bottom=%d top=%d min_usage=%d", points, bottom, top, min_usage);
    while true
        select = rnd(top-bottom)+bottom
        ''inline TRACE("..select=%d", select);
        if trv_usage(trv, select) <= min_usage then exit while
    wend
    trv_find = select
    'inline TRACE("<trv_find");
end function

function trv_nanswers(trv as int, i as int) as int
    dim posn as long
    dim offset as long
    dim x as char
    dim n as int

    'inline TRACE(">trv_nanswers");

    n=-2

    posn = 2+i*12+4
    get trv,posn,offset
    get trv,offset
    'inline TRACE("i=%d,posn=%ld,offset=%ld",i, posn, offset);
    while(true)
        get trv,,x
        if x=0 then exit while
        inline x = x ^ 0xAA;
        if x=\|\ then n=n+1
    wend
    trv_nanswers = n
    'inline TRACE("<trv_nanswers");
end function

sub trv_getstring(trv as int, s[] as char)
    dim x as char
    dim n as int

    'inline TRACE(">trv_getstring");

    n=0

    while(true)
        get trv,,x
        if x=0 then exit while
        inline x=x^0xAA;
        if x=\|\ then exit while
        s[n] = x
        s[n+1] = 0
        n=n+1
    wend
    'inline TRACE("<trv_getstring");
end sub

function trv_answers(trv as int, i as int, j as int, s[] as char) as int
    dim posn as long
    dim offset as long
    dim x as char
    dim n as int
    dim correct as int

    'inline TRACE(">trv_answers");

    n=-3
    correct = 0

    posn = 2+i*12+4
    get trv,posn,offset
    get trv,offset
    while(true)
        get trv,,x
        if x=0 then exit while
        inline x = x ^ 0xAA;
        if x=\|\ then n=n+1
        if n=j then
            trv_getstring(trv, s)
            if s[0] = \*\ then
                correct=1
                inline strcpy(s, s+1);
            endif
            exit while
        endif
    wend
    trv_answers = correct
    'inline TRACE("<trv_answers");
end function

sub trv_question(trv as int, i as int, s[] as char)
    'inline TRACE(">trv_question");
    trv_answers(trv, i, -1, s)
    'inline TRACE("<trv_question");
end sub

sub trv_category(trv as int, i as int, s[] as char)
    'inline TRACE(">trv_category");
    trv_answers(trv, i, -2, s)
    'inline TRACE("<trv_category");
end sub