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/*

 * jmemmac.c

 *

 * Copyright (C) 1992-1997, Thomas G. Lane.

 * This file is part of the Independent JPEG Group's software.

 * For conditions of distribution and use, see the accompanying README file.

 *

 * jmemmac.c provides an Apple Macintosh implementation of the system-

 * dependent portion of the JPEG memory manager.

 *

 * If you use jmemmac.c, then you must define USE_MAC_MEMMGR in the

 * JPEG_INTERNALS part of jconfig.h.

 *

 * jmemmac.c uses the Macintosh toolbox routines NewPtr and DisposePtr

 * instead of malloc and free.  It accurately determines the amount of

 * memory available by using CompactMem.  Notice that if left to its

 * own devices, this code can chew up all available space in the

 * application's zone, with the exception of the rather small "slop"

 * factor computed in jpeg_mem_available().  The application can ensure

 * that more space is left over by reducing max_memory_to_use.

 *

 * Large images are swapped to disk using temporary files and System 7.0+'s

 * temporary folder functionality.

 *

 * Note that jmemmac.c depends on two features of MacOS that were first

 * introduced in System 7: FindFolder and the FSSpec-based calls.

 * If your application uses jmemmac.c and is run under System 6 or earlier,

 * and the jpeg library decides it needs a temporary file, it will abort,

 * printing error messages about requiring System 7.  (If no temporary files

 * are created, it will run fine.)

 *

 * If you want to use jmemmac.c in an application that might be used with

 * System 6 or earlier, then you should remove dependencies on FindFolder

 * and the FSSpec calls.  You will need to replace FindFolder with some

 * other mechanism for finding a place to put temporary files, and you

 * should replace the FSSpec calls with their HFS equivalents:

 *

 *     FSpDelete     ->  HDelete

 *     FSpGetFInfo   ->  HGetFInfo

 *     FSpCreate     ->  HCreate

 *     FSpOpenDF     ->  HOpen      *** Note: not HOpenDF ***

 *     FSMakeFSSpec  ->  (fill in spec by hand.)

 *

 * (Use HOpen instead of HOpenDF.  HOpen is just a glue-interface to PBHOpen,

 * which is on all HFS macs.  HOpenDF is a System 7 addition which avoids the

 * ages-old problem of names starting with a period.)

 *

 * Contributed by Sam Bushell (jsam@iagu.on.net) and

 * Dan Gildor (gyld@in-touch.com).

 */

#define JPEG_INTERNALS

#include "jinclude.h"

#include "jpeglib.h"

#include "jmemsys.h"    /* import the system-dependent declarations */

#ifndef USE_MAC_MEMMGR  /* make sure user got configuration right */

  You forgot to define USE_MAC_MEMMGR in jconfig.h. /* deliberate syntax error */

#endif

#include <Memory.h>     /* we use the MacOS memory manager */

#include <Files.h>      /* we use the MacOS File stuff */

#include <Folders.h>    /* we use the MacOS HFS stuff */

#include <Script.h>     /* for smSystemScript */

#include <Gestalt.h>    /* we use Gestalt to test for specific functionality */

#ifndef TEMP_FILE_NAME          /* can override from jconfig.h or Makefile */

#define TEMP_FILE_NAME  "JPG%03d.TMP"

#endif

static int next_file_num;       /* to distinguish among several temp files */

/*

 * Memory allocation and freeing are controlled by the MacOS library

 * routines NewPtr() and DisposePtr(), which allocate fixed-address

 * storage.  Unfortunately, the IJG library isn't smart enough to cope

 * with relocatable storage.

 */

GLOBAL(void *)

jpeg_get_small (j_common_ptr cinfo, size_t sizeofobject)

{

  return (void *) NewPtr(sizeofobject);

}

GLOBAL(void)

jpeg_free_small (j_common_ptr cinfo, void * object, size_t sizeofobject)

{

  DisposePtr((Ptr) object);

}

/*

 * "Large" objects are treated the same as "small" ones.

 * NB: we include FAR keywords in the routine declarations simply for

 * consistency with the rest of the IJG code; FAR should expand to empty

 * on rational architectures like the Mac.

 */

GLOBAL(void FAR *)

jpeg_get_large (j_common_ptr cinfo, size_t sizeofobject)

{

  return (void FAR *) NewPtr(sizeofobject);

}

GLOBAL(void)

jpeg_free_large (j_common_ptr cinfo, void FAR * object, size_t sizeofobject)

{

  DisposePtr((Ptr) object);

}

/*

 * This routine computes the total memory space available for allocation.

 */

GLOBAL(long)

jpeg_mem_available (j_common_ptr cinfo, long min_bytes_needed,

                    long max_bytes_needed, long already_allocated)

{

  long limit = cinfo->mem->max_memory_to_use - already_allocated;

  long slop, mem;

  /* Don't ask for more than what application has told us we may use */

  if (max_bytes_needed > limit && limit > 0)

    max_bytes_needed = limit;

  /* Find whether there's a big enough free block in the heap.

   * CompactMem tries to create a contiguous block of the requested size,

   * and then returns the size of the largest free block (which could be

   * much more or much less than we asked for).

   * We add some slop to ensure we don't use up all available memory.

   */

  slop = max_bytes_needed / 16 + 32768L;

  mem = CompactMem(max_bytes_needed + slop) - slop;

  if (mem < 0)

    mem = 0;                     /* sigh, couldn't even get the slop */

  /* Don't take more than the application says we can have */

  if (mem > limit && limit > 0)

    mem = limit;

  return mem;

}

/*

 * Backing store (temporary file) management.

 * Backing store objects are only used when the value returned by

 * jpeg_mem_available is less than the total space needed.  You can dispense

 * with these routines if you have plenty of virtual memory; see jmemnobs.c.

 */

METHODDEF(void)

read_backing_store (j_common_ptr cinfo, backing_store_ptr info,

                    void FAR * buffer_address,

                    long file_offset, long byte_count)

{

  long bytes = byte_count;

  long retVal;

  if ( SetFPos ( info->temp_file, fsFromStart, file_offset ) != noErr )

    ERREXIT(cinfo, JERR_TFILE_SEEK);

  retVal = FSRead ( info->temp_file, &bytes,

                    (unsigned char *) buffer_address );

  if ( retVal != noErr || bytes != byte_count )

    ERREXIT(cinfo, JERR_TFILE_READ);

}

METHODDEF(void)

write_backing_store (j_common_ptr cinfo, backing_store_ptr info,

                     void FAR * buffer_address,

                     long file_offset, long byte_count)

{

  long bytes = byte_count;

  long retVal;

  if ( SetFPos ( info->temp_file, fsFromStart, file_offset ) != noErr )

    ERREXIT(cinfo, JERR_TFILE_SEEK);

  retVal = FSWrite ( info->temp_file, &bytes,

                     (unsigned char *) buffer_address );

  if ( retVal != noErr || bytes != byte_count )

    ERREXIT(cinfo, JERR_TFILE_WRITE);

}

METHODDEF(void)

close_backing_store (j_common_ptr cinfo, backing_store_ptr info)

{

  FSClose ( info->temp_file );

  FSpDelete ( &(info->tempSpec) );

}

/*

 * Initial opening of a backing-store object.

 *

 * This version uses FindFolder to find the Temporary Items folder,

 * and puts the temporary file in there.

 */

GLOBAL(void)

jpeg_open_backing_store (j_common_ptr cinfo, backing_store_ptr info,

                         long total_bytes_needed)

{

  short         tmpRef, vRefNum;

  long          dirID;

  FInfo         finderInfo;

  FSSpec        theSpec;

  Str255        fName;

  OSErr         osErr;

  long          gestaltResponse = 0;

  /* Check that FSSpec calls are available. */

  osErr = Gestalt( gestaltFSAttr, &gestaltResponse );

  if ( ( osErr != noErr )

       || !( gestaltResponse & (1<<gestaltHasFSSpecCalls) ) )

    ERREXITS(cinfo, JERR_TFILE_CREATE, "- System 7.0 or later required");

  /* TO DO: add a proper error message to jerror.h. */

  /* Check that FindFolder is available. */

  osErr = Gestalt( gestaltFindFolderAttr, &gestaltResponse );

  if ( ( osErr != noErr )

       || !( gestaltResponse & (1<<gestaltFindFolderPresent) ) )

    ERREXITS(cinfo, JERR_TFILE_CREATE, "- System 7.0 or later required.");

  /* TO DO: add a proper error message to jerror.h. */

  osErr = FindFolder ( kOnSystemDisk, kTemporaryFolderType, kCreateFolder,

                       &vRefNum, &dirID );

  if ( osErr != noErr )

    ERREXITS(cinfo, JERR_TFILE_CREATE, "- temporary items folder unavailable");

  /* TO DO: Try putting the temp files somewhere else. */

  /* Keep generating file names till we find one that's not in use */

  for (;;) {

    next_file_num++;            /* advance counter */

    sprintf(info->temp_name, TEMP_FILE_NAME, next_file_num);

    strcpy ( (Ptr)fName+1, info->temp_name );

    *fName = strlen (info->temp_name);

    osErr = FSMakeFSSpec ( vRefNum, dirID, fName, &theSpec );

    if ( (osErr = FSpGetFInfo ( &theSpec, &finderInfo ) ) != noErr )

      break;

  }

  osErr = FSpCreate ( &theSpec, '????', '????', smSystemScript );

  if ( osErr != noErr )

    ERREXITS(cinfo, JERR_TFILE_CREATE, info->temp_name);

  osErr = FSpOpenDF ( &theSpec, fsRdWrPerm, &(info->temp_file) );

  if ( osErr != noErr )

    ERREXITS(cinfo, JERR_TFILE_CREATE, info->temp_name);

  info->tempSpec = theSpec;

  info->read_backing_store = read_backing_store;

  info->write_backing_store = write_backing_store;

  info->close_backing_store = close_backing_store;

  TRACEMSS(cinfo, 1, JTRC_TFILE_OPEN, info->temp_name);

}

/*

 * These routines take care of any system-dependent initialization and

 * cleanup required.

 */

GLOBAL(long)

jpeg_mem_init (j_common_ptr cinfo)

{

  next_file_num = 0;

  /* max_memory_to_use will be initialized to FreeMem()'s result;

   * the calling application might later reduce it, for example

   * to leave room to invoke multiple JPEG objects.

   * Note that FreeMem returns the total number of free bytes;

   * it may not be possible to allocate a single block of this size.

   */

  return FreeMem();

}

GLOBAL(void)

jpeg_mem_term (j_common_ptr cinfo)

{

  /* no work */

}