fpc/rtl/unix/timezone.inc
micha 2bd88e3406 read timezone file optimization
git-svn-id: trunk@3907 -
2006-06-21 09:26:17 +00:00

333 lines
6.9 KiB
PHP

{
Support for timezone info in /usr/share/timezone
}
type
ttzhead=packed record
tzh_reserved : array[0..19] of byte;
tzh_ttisgmtcnt,
tzh_ttisstdcnt,
tzh_leapcnt,
tzh_timecnt,
tzh_typecnt,
tzh_charcnt : longint;
end;
pttinfo=^tttinfo;
tttinfo=packed record
offset : longint;
isdst : boolean;
idx : byte;
isstd : byte;
isgmt : byte;
end;
pleap=^tleap;
tleap=record
transition : longint;
change : longint;
end;
var
num_transitions,
num_leaps,
num_types : longint;
transitions : plongint;
type_idxs : pbyte;
types : pttinfo;
zone_names : pchar;
leaps : pleap;
function find_transition(timer:longint):pttinfo;
var
i : longint;
begin
if (num_transitions=0) or (timer<transitions[0]) then
begin
i:=0;
while (i<num_types) and (types[i].isdst) do
inc(i);
if (i=num_types) then
i:=0;
end
else
begin
for i:=1 to num_transitions do
if (timer<transitions[i]) then
break;
i:=type_idxs[i-1];
end;
find_transition:=@types[i];
end;
procedure GetLocalTimezone(timer:longint;var leap_correct,leap_hit:longint);
var
info : pttinfo;
i : longint;
begin
{ reset }
TZDaylight:=false;
TZSeconds:=0;
TZName[false]:=nil;
TZName[true]:=nil;
leap_correct:=0;
leap_hit:=0;
{ get info }
info:=find_transition(timer);
if not assigned(info) then
exit;
TZDaylight:=info^.isdst;
TZSeconds:=info^.offset;
i:=0;
while (i<num_types) do
begin
tzname[types[i].isdst]:=@zone_names[types[i].idx];
inc(i);
end;
tzname[info^.isdst]:=@zone_names[info^.idx];
i:=num_leaps;
repeat
if i=0 then
exit;
dec(i);
until (timer>leaps[i].transition);
leap_correct:=leaps[i].change;
if (timer=leaps[i].transition) and
(((i=0) and (leaps[i].change>0)) or
(leaps[i].change>leaps[i-1].change)) then
begin
leap_hit:=1;
while (i>0) and
(leaps[i].transition=leaps[i-1].transition+1) and
(leaps[i].change=leaps[i-1].change+1) do
begin
inc(leap_hit);
dec(i);
end;
end;
end;
procedure GetLocalTimezone(timer:longint);
var
lc,lh : longint;
begin
GetLocalTimezone(timer,lc,lh);
end;
procedure ReadTimezoneFile(fn:shortstring);
procedure decode(var l:longint);
var
k : longint;
p : pbyte;
begin
p:=pbyte(@l);
if (p[0] and (1 shl 7))<>0 then
k:=not 0
else
k:=0;
k:=(k shl 8) or p[0];
k:=(k shl 8) or p[1];
k:=(k shl 8) or p[2];
k:=(k shl 8) or p[3];
l:=k;
end;
const
bufsize = 2048;
var
buf : array[0..bufsize-1] of byte;
bufptr : pbyte;
f : longint;
procedure readfilebuf;
begin
bufptr := @buf[0];
fpread(f, buf, bufsize);
end;
function readbufbyte: byte;
begin
if bufptr >= @buf[bufsize] then
readfilebuf;
readbufbyte := bufptr^;
inc(bufptr);
end;
function readbuf(var dest; count: integer): integer;
var
numbytes: integer;
begin
readbuf := 0;
repeat
numbytes := @buf[bufsize] - bufptr;
if numbytes > count then
numbytes := count;
if numbytes > 0 then
begin
move(bufptr^, dest, numbytes);
inc(bufptr, numbytes);
dec(count, numbytes);
inc(readbuf, numbytes);
end;
if count > 0 then
readfilebuf
else
break;
until false;
end;
var
tzdir : shortstring;
tzhead : ttzhead;
i : longint;
chars : longint;
begin
if fn='' then
fn:='localtime';
if fn[1]<>'/' then
begin
tzdir:=fpgetenv('TZDIR');
if tzdir='' then
tzdir:='/usr/share/zoneinfo';
if tzdir[length(tzdir)]<>'/' then
tzdir:=tzdir+'/';
fn:=tzdir+fn;
end;
f:=fpopen(fn,Open_RdOnly);
if f<0 then
exit;
bufptr := @buf[bufsize];
i:=readbuf(tzhead,sizeof(tzhead));
if i<>sizeof(tzhead) then
exit;
decode(tzhead.tzh_timecnt);
decode(tzhead.tzh_typecnt);
decode(tzhead.tzh_charcnt);
decode(tzhead.tzh_leapcnt);
decode(tzhead.tzh_ttisstdcnt);
decode(tzhead.tzh_ttisgmtcnt);
num_transitions:=tzhead.tzh_timecnt;
num_types:=tzhead.tzh_typecnt;
chars:=tzhead.tzh_charcnt;
reallocmem(transitions,num_transitions*sizeof(longint));
reallocmem(type_idxs,num_transitions);
reallocmem(types,num_types*sizeof(tttinfo));
reallocmem(zone_names,chars);
reallocmem(leaps,num_leaps*sizeof(tleap));
readbuf(transitions^,num_transitions*4);
readbuf(type_idxs^,num_transitions);
for i:=0 to num_transitions-1 do
decode(transitions[i]);
for i:=0 to num_types-1 do
begin
readbuf(types[i].offset,4);
readbuf(types[i].isdst,1);
readbuf(types[i].idx,1);
decode(types[i].offset);
types[i].isstd:=0;
types[i].isgmt:=0;
end;
readbuf(zone_names^,chars);
for i:=0 to num_leaps-1 do
begin
readbuf(leaps[i].transition,4);
readbuf(leaps[i].change,4);
decode(leaps[i].transition);
decode(leaps[i].change);
end;
for i:=0 to tzhead.tzh_ttisstdcnt-1 do
types[i].isstd:=byte(readbufbyte<>0);
for i:=0 to tzhead.tzh_ttisgmtcnt-1 do
types[i].isgmt:=byte(readbufbyte<>0);
fpclose(f);
end;
Const
// Debian system; contains location of timezone file.
TimeZoneLocationFile = '/etc/timezone';
// SuSE has link in /usr/lib/zoneinfo/localtime to /etc/localtime
// RedHat uses /etc/localtime
TimeZoneFile = '/etc/localtime'; // POSIX
AltTimeZoneFile = '/usr/lib/zoneinfo/localtime'; // Other
{$ifdef BSD}
BSDTimeZonefile = '/usr/share/zoneinfo'; // BSD usually is POSIX
// compliant though
{$ENDIF}
function GetTimezoneFile:shortstring;
var
f,len : longint;
s : shortstring;
info : stat;
begin
GetTimezoneFile:='';
f:=fpopen(TimeZoneLocationFile,Open_RdOnly);
if f>0 then
begin
len:=fpread(f,s[1],high(s));
s[0]:=chr(len);
len:=pos(#10,s);
if len<>0 then
s[0]:=chr(len-1);
fpclose(f);
GetTimezoneFile:=s;
end
// Try SuSE
else if fpstat(TimeZoneFile,{$ifdef oldlinuxstat}baseunix.stat(info){$else}info{$endif})>=0 then
GetTimeZoneFile:=TimeZoneFile
// Try RedHat
else If fpstat(AltTimeZoneFile,{$ifdef oldlinuxstat}baseunix.stat(info){$else}info{$endif})>=0 then
GetTimeZoneFile:=AltTimeZoneFile
{$ifdef BSD}
// else
// If fpstat(BSDTimeZoneFile,{$ifdef oldlinuxstat}baseunix.stat(info){$else}info{$endif})>=0 then
// GetTimeZoneFile:=BSDTimeZoneFile
{$ENDIF}
end;
procedure InitLocalTime;
begin
ReadTimezoneFile(GetTimezoneFile);
GetLocalTimezone(fptime);
end;
procedure DoneLocalTime;
begin
if assigned(transitions) then
freemem(transitions);
if assigned(type_idxs) then
freemem(type_idxs);
if assigned(types) then
freemem(types);
if assigned(zone_names) then
freemem(zone_names);
if assigned(leaps) then
freemem(leaps);
num_transitions:=0;
num_leaps:=0;
num_types:=0;
end;