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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 */
+}
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