-- File: MSegmentOnNSSegmentImpl.mesa  Edited by
-- Breisacher.es	31-Jan-86 15:32:39
-- MEW			11-Apr-86  7:45:38

-- Copyright (C) 1985, 1986 by Xerox Corporation. All rights reserved.

DIRECTORY
  Environment,
  Heap,
  File,
  MFile,
  MFileOnNSFileOps,
  MSegment,
  NSSegment,
  Space;

MSegmentOnNSSegmentImpl: PROGRAM
  IMPORTS Heap, MFile, MFileOnNSFileOps, NSSegment, Space
  EXPORTS MSegment = 
  BEGIN OPEN MSegment;

  Handle: TYPE = LONG POINTER TO Object;
  Object: PUBLIC TYPE = RECORD [
    mfh: MFile.Handle,
    fileBase: File.PageNumber,
    interval: Space.Interval];
    
  zone: UNCOUNTED ZONE ¬ Heap.Create [initial: 1];
  
  NotImplemented: ERROR = CODE;
  
  << MSegment EXPORTS >>
  
  Error: PUBLIC ERROR [segment: Handle, code: ErrorCode] = CODE;

  Activate: PUBLIC PROCEDURE [segment: Handle] = {ERROR NotImplemented};
  Address: PUBLIC PROCEDURE [segment: Handle] RETURNS [LONG POINTER] = {
    RETURN [segment.interval.pointer]};
  AddresstoSegment: PUBLIC PROCEDURE [pointer: LONG POINTER] RETURNS [Handle] = {ERROR NotImplemented};
  Base: PUBLIC PROCEDURE [segment: Handle] RETURNS [Environment.PageNumber] = {ERROR NotImplemented};
  BasetoSegment: PUBLIC PROCEDURE [page: Environment.PageNumber] RETURNS [Handle] = {ERROR NotImplemented};
  CopyIn: PUBLIC PROCEDURE [
    segment: Handle, file: MFile.Handle, 
    fileBase: File.PageNumber, count: Environment.PageCount] = {
    [] ¬ NSSegment.CopyIn [pointer: segment.interval.pointer,
      origin: [
          file: MFileOnNSFileOps.NSHandleFromMFHandle [file],
	  base: fileBase, count: count]];
    };
  CopyOut: PUBLIC PROCEDURE [
    segment: Handle, file: MFile.Handle, fileBase: File.PageNumber, 
    count: Environment.PageCount] = {ERROR NotImplemented};
  CopySegment: PUBLIC PROCEDURE [segment: Handle] RETURNS [newSegment: Handle] = {ERROR NotImplemented};

  Create: PUBLIC PROCEDURE [
    file: MFile.Handle ¬ NIL, release: ReleaseData,
    fileBase: File.PageNumber ¬ 0,
    pages: Environment.PageCount ¬ defaultPages, 
    swapInfo: SwapUnitOption ¬ defaultSwapUnitOption,
    usage: Space.Usage ¬ Space.unknownUsage]
    RETURNS [segment: Handle] = {
    segment ¬ zone.NEW [Object ¬ [mfh: file, fileBase: fileBase, interval: Space.nullInterval]];
    CreateInternal [segment, file, release, fileBase, pages, swapInfo, usage];
    };
    
  CreateInternal: PROCEDURE [
    segment: Handle, 
    file: MFile.Handle ¬ NIL, release: ReleaseData,
    fileBase: File.PageNumber ¬ 0,
    pages: Environment.PageCount ¬ defaultPages, 
    swapInfo: SwapUnitOption ¬ defaultSwapUnitOption,
    usage: Space.Usage ¬ Space.unknownUsage] = {
    segment.interval ¬ IF file = NIL THEN
      [Space.ScratchMap [pages, usage], pages]
    ELSE
      NSSegment.Map [
        origin: [
          file: MFileOnNSFileOps.NSHandleFromMFHandle [file],
	  base: fileBase, count: pages],
	usage: usage, swapUnits: swapInfo];
    };
    
  Deactivate: PUBLIC PROCEDURE [segment: Handle] = {ERROR NotImplemented};
  Delete: PUBLIC PROCEDURE [segment: Handle] = {
    [] ¬ Space.Unmap [segment.interval.pointer];
    IF segment.mfh # NIL THEN MFile.Release[segment.mfh];
    zone.FREE [@segment];
    };
  EquivalentSegments: PUBLIC PROCEDURE [seg1, seg2: Handle] RETURNS [BOOLEAN] = {ERROR NotImplemented};
  ForceOut: PUBLIC PROCEDURE [segment: Handle] = {Space.ForceOut [segment.interval]};
  GetFile: PUBLIC PROCEDURE [segment: Handle] RETURNS [MFile.Handle] = {RETURN [segment.mfh]};
  GetFileBase: PUBLIC PROCEDURE [segment: Handle] RETURNS [File.PageNumber] = {RETURN [segment.fileBase]};
  GetFilePages: PUBLIC PROCEDURE [segment: Handle] 
    RETURNS [File.PageCount] = {
    RETURN [NSSegment.GetSizeInPages [
      MFileOnNSFileOps.NSHandleFromMFHandle [segment.mfh]]];
    };
  GetReleaseData: PUBLIC PROCEDURE [segment: Handle] RETURNS [ReleaseData] = {ERROR NotImplemented};
  Kill: PUBLIC PROCEDURE [segment: Handle] = {ERROR NotImplemented};
  MakeReadOnly: PUBLIC PROCEDURE [segment: Handle] = {ERROR NotImplemented};
  MakeWritable: PUBLIC PROCEDURE [segment: Handle] = {ERROR NotImplemented};
  Pages: PUBLIC PROCEDURE [segment: Handle] RETURNS [Environment.PageCount] = {RETURN [segment.interval.count]};
  
  Reset: PUBLIC PROCEDURE [
    segment: Handle, file: MFile.Handle ¬ dontChangeFile, 
    release: ReleaseData ¬ dontChangeReleaseData, 
    fileBase: File.PageNumber ¬ dontChangeFileBase, 
    pages: Environment.PageCount ¬ dontChangePages, 
    swapInfo: SwapUnitOption ¬ defaultSwapUnitOption,
    usage: Space.Usage ¬ dontChangeUsage] = {
    IF file = dontChangeFile THEN file ¬ segment.mfh;
    IF fileBase = dontChangeFileBase THEN fileBase ¬ segment.fileBase;
    IF pages = dontChangePages THEN pages ¬ segment.interval.count;
    « Kludgy impl, I guess, but it's easy.  Just delete the old one and create a new one basically. »
    [] ¬ Space.Unmap [segment.interval.pointer];
    segment.mfh ¬ file;
    segment.fileBase ¬ fileBase;
    CreateInternal [segment, file, release, fileBase, pages, swapInfo, usage];
    };
    
  SetReleaseData: PUBLIC PROCEDURE [segment: Handle, release: ReleaseData] = {};


  GetPages: PUBLIC PROCEDURE [npages: CARDINAL] RETURNS [base: LONG POINTER] = {ERROR NotImplemented};
  GetWords: PUBLIC PROCEDURE [nwords: CARDINAL] RETURNS [base: LONG POINTER] = {ERROR NotImplemented};
  FreePages, FreeWords: PUBLIC PROCEDURE [base: LONG POINTER] = {ERROR NotImplemented};


  END.

MSegment
  To Definitely Impl:
    Address, Create, CopyIn, Delete, GetFilePages    
    
  To Maybe Impl: