unit systemunit;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, Math;

function cpuUtilization: extended;
function numCpus: int64;
function momentanFreieCpus: int64;
function belegterSpeicher: int64;
function minCache: int64;
function shellSubst(s: string): string;
function mkTemp(s: string): string;

implementation

uses
  process, lowlevelunit;

var _cpuLastUsed,_cpuLastIdle: int64;

function cpuUtilization: extended;
var
  procstat:  textfile;
  s:         string;
  used,idle: int64;
  i:         integer;
begin
  result:=0;
  s:='';
  assignfile(procstat,'/proc/stat');
  reset(procstat);
  while not eof(procstat) do begin
    readln(procstat,s);
    if pos('cpu ',s)=1 then break;
  end;
  closefile(procstat);
  if pos('cpu ',s)<>1 then exit;
  delete(s,1,pos(' ',s));
  s:=trim(s);
  used:=0;
  idle:=0;
  for i:=0 to 3 do begin
    used:=used+idle;
    idle:=strtoint(copy(s,1,pos(' ',s)-1));
    delete(s,1,pos(' ',s));
    s:=trim(s);
  end;
  result:=(used-_cpuLastUsed)/max(1,used-_cpuLastUsed + idle-_cpuLastIdle);
  _cpuLastUsed:=used;
  _cpuLastIdle:=idle;
end;

function numCpus: int64;
var
  procstat:  textfile;
  s:         string;
begin
  result:=0;
  s:='';
  assignfile(procstat,'/proc/stat');
  reset(procstat);
  while not eof(procstat) do begin
    readln(procstat,s);
    if (pos('cpu',s)=1) and
       (pos('cpu ',s)<>1) then
      inc(result);
  end;
  closefile(procstat);
end;

function momentanFreieCpus: int64;
begin
  result:=floor(numCpus*(1-cpuUtilization));
end;

function belegterSpeicher: int64;
var
  f:    textFile;
  s:    string;
begin
 s:='/proc/'+inttostr(getProcessId)+'/smaps';
 result:=0;
 if not fileexists(s) then exit;
 assignfile(f,s);
 reset(f);
 while not eof(f) do begin
   readln(f,s);
   if (leftStr(s,4)='Rss:') and (rightStr(s,3)=' kB') then
     result:=result+strtoint(trim(copy(s,5,length(s)-4-3)));
 end;
 closefile(f);
end;

function minCache: int64;
var
  f:    textFile;
  s:    string;
begin
 s:='/proc/cpuinfo';
 result:=0;
 if not fileexists(s) then exit;
 assignfile(f,s);
 reset(f);
 while not eof(f) do begin
   readln(f,s);
   if (leftStr(s,10)='cache size') and (rightStr(s,3)=' kB') then begin
     delete(s,1,pos(':',s));
     delete(s,length(s)-2,3);
     s:=trim(s);
     if result=0 then result:=strtoint(s)
     else result:=min(result,strtoint(s));
   end;
 end;
 closefile(f);
end;

function shellSubst(s: string): string;
var
  name: string;
begin
  result:=s;
  while pos('${',result)>0 do begin
    s:=leftStr(result,pos('${',result)-1);
    delete(result,1,pos('${',result)-1+length('${'));
    name:=leftStr(result,pos('}',result)-1);
    delete(result,1,length(name+'}'));
    result:=s+GetEnvironmentVariable(name)+result;
  end;
end;

function mkTemp(s: string): string;
var
  args: array of string;
begin
  setlength(args,0);
  while s<>'' do begin
    setlength(args,length(args)+1);
    args[length(args)-1]:=erstesArgument(s);
  end;
  result:='';
  if not runCommand('/usr/bin/mktemp',args,result) then
    raise exception.create('Fehler beim Ausführen von ''/usr/bin/mktemp '+s+'''!');
  result:=trim(result);
end;

begin
  _cpuLastUsed:=0;
  _cpuLastIdle:=0;
  cpuUtilization;
end.