fpc/fcl/linux/osfile.inc

{
    $Id$
    This file is part of the Free Component Library (FCL)
    Copyright (c) 1998 by the Free Pascal development team

    See the file COPYING.FPC, included in this distribution,
    for details about the copyright.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

 **********************************************************************}
{
 This file implements the system-dependent calls needed for the 
 classes unit.
}

{
  oscalls contains a copy of the needed functions from syscalls.inc
  to make things go faster.
}

{$i oscalls.inc}

Function OSCreateFile (Const Filename : string; Mode : Longint) : longint;
{
  Creates a file with name FileName, using mode MODE
  --> Filename : String giving the path to the file.
      Mode     : Mode can be
                 fmCreate    : Create file;
                 fmOpenRead  : open for reading;
                 fmOpenWrite : open for writing;
  <-- File Handle, or -1 on error.
}

var
  regs : SysCallregs;
  NewName : string;

Begin
  // Convert mode. The  meaning of fmcreate isn't 
  // entirely clear..
  if (mode and fmcreate) = fmcreate then
    mode:=OPEN_CREAT or OPEN_RDWR;
  //!! This MUST be changed when using ansistrings !!!
  NewName:=FileName+#0;
  regs.reg2:=longint(@NewName[1]);
  regs.reg3:=Mode;
  regs.reg4:=438;        { 666 octal }
  Do_SysCall(SysCall_nr_open,regs);
  Result:=regs.reg1;
  If Result<0 then Result:=-1;
End;

Function OSReadHandle(Handle : Longint;Var Buffer; Count : Longint): Longint;
{
  Read from a handle
  --> Handle : file,pipe,etc Handle to read from.
      Buffer : Location where to put the read bytes.
      Count  : Number of bytes that should be read
  <-- Number of bytes actually read, or -1 on error.   
}
var sr : syscallregs;

begin
  sr.reg2:=Handle;
  sr.reg3:=Longint(@Buffer);
  sr.reg4:=Count;
  Do_Syscall (syscall_nr_read,sr);
  Result:=sr.reg1;
  If Result<-1 then Result:=-1;  
end;

Function OSWriteHandle(Handle : Longint;var Buffer; Count : longint) : Longint;
{ 
  Write to a handle
  --> Handle : file,pipe,etc Handle to write to.
      Buffer : Location where to get the bytes.
      Count  : Number of bytes that should be written.
  <-- Number of bytes actually written, or -1 on error.   
}
Var sr: syscallregs;

begin
  sr.reg2:=Handle;
  sr.reg3:=Longint(@Buffer);
  sr.reg4:=Count;
  Do_Syscall (syscall_nr_write,sr);
  Result:=sr.reg1;
  If Result<-1 then Result:=-1;  
end;


Function OSSetHandleSize (Handle,Size : Longint) : longint;
{
  Set size of handle (for files only)
  --> Handle : Handle to set size for.
      Size   : Size to be set.
  <-- 0 on succes or -1 on error.
}
Var sr: syscallregs;

begin
  sr.reg2:=Handle;
  sr.reg3:=Size;
  Do_Syscall (SysCall_nr_Ftruncate,sr);
  Result:=sr.reg1;
  If Result<-1 then Result:=-1;
end;

Function OSSeekHandle (Handle,OffSet,Origin : longint) : longint;
{
  Seek Handle position starting from Origin
  --> Handle : Handle of file to do seek on.
      Offset : Position to seek.
      Origin : Where to start seek: 
               soFromBeginning 
               soFromCurrent
               soFromEnd 
  <-- -1 on error, else the new fileposition in bytes from the origin.
}
var sr : syscallregs;

begin
  sr.reg2:=Handle;
  sr.reg3:=Offset;
  sr.reg4:=Origin;
  Do_Syscall(Syscall_nr_lseek,sr);
  Result:=sr.reg1;

  If Result<-1 then Result:=-1;
end;

Function OSCloseHandle (Handle : longint) : longint;
{
  Close file associated with HAndle.
  --> Handle : Handle of file to do seek on.
  <-- 0 on succes, -1 on error.
}
Var sr : syscallregs;

begin
  sr.reg2:=Handle;
  Do_Syscall (syscall_nr_close,sr);
  Result:=sr.reg1;
  If Result<-1 then Result:=-1;
end;