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518 lines
22 KiB
Plaintext
518 lines
22 KiB
Plaintext
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This file documents the libhfs.a library for accessing HFS volumes.
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Copyright (C) 1996-1998 Robert Leslie
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$Id: libhfs.txt,v 1.11 1998/11/02 22:08:47 rob Exp $
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===============================================================================
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Exported Data
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const char *hfs_error;
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This contains a pointer to a C string describing the last HFS error.
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It is generally only valid after an HFS routine has returned an error
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code (-1 or a NULL pointer).
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This string is encoded using ISO 8859-1.
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In all cases when an error occurs, the global variable `errno' is also
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set to an appropriate value.
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unsigned char hfs_charorder[];
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This array contains the relative sorting order of characters in HFS
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filenames according to the semantics of the Macintosh character set
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and the MacOS string comparison routines as used by HFS. The array can
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be indexed by unsigned character quantities; the resulting value can be
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compared to other array values to determine the relative sorting order
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of the corresponding character indices.
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Public Routines
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----- Volume Routines -----
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hfsvol *hfs_mount(const char *path, int pnum, int flags);
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This routine attempts to open an HFS volume from a source pathname. The
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given `pnum' indicates which ordinal HFS partition is to be mounted,
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or can be 0 to indicate the entire medium should be mounted (ignoring
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any partition structure). If this value is not 0, the requested
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partition must exist.
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The `flags' argument specifies how the volume should be mounted.
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HFS_MODE_RDONLY means the volume should be mounted read-only.
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HFS_MODE_RDWR means the volume must be opened read/write. HFS_MODE_ANY
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means the volume can be mounted either read-only or read/write, with
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preference for the latter.
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The `flags' argument may also specify volume options. HFS_OPT_NOCACHE
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means not to perform any internal block caching, such as would be
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unnecessary for a volume residing in RAM, or if the associated overhead
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is not desired. HFS_OPT_ZERO means that newly-allocated blocks should be
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zero-initialized before use, primarily as a security feature for systems
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on which blocks may otherwise contain random data. Neither of these
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options should normally be necessary, and both may affect performance.
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If an error occurs, this function returns NULL. Otherwise a pointer to a
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volume structure is returned. This pointer is used to access the volume
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and must eventually be passed to hfs_umount() to flush and close the
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volume and free all associated memory.
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int hfs_flush(hfsvol *vol);
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This routine causes all pending changes to be flushed to an HFS volume.
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If a volume is kept open for a long period of time, it would be wise
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to call this periodically to avoid corrupting the volume due to
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unforeseen circumstances (power failure, floppy eject, etc.)
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If an error occurs, this function returns -1. Otherwise it returns 0.
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void hfs_flushall(void);
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This routine is similar to hfs_flush() except that all mounted volumes
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are flushed, and errors are not reported.
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int hfs_umount(hfsvol *vol);
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The specified HFS volume is unmounted; all open files and directories
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on the volume are closed, all pending changes to the volume are
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flushed, and all memory allocated for the volume is freed.
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All volumes opened with hfs_mount() must eventually be closed with
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hfs_umount(), or they will risk corruption.
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If an error occurs, this function returns -1. Otherwise it returns 0.
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In either case, the volume structure pointer will become invalid, as
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will all pointers to open file or directory structures associated with
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the volume.
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void hfs_umountall(void);
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This routine is similar to hfs_umount() except that all mounted volumes
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are closed, and errors are not reported.
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This routine may be useful to call just before a process terminates to
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make sure any remaining open volumes are properly closed.
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hfsvol *hfs_getvol(const char *name);
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This routines searches all mounted volumes for one having the given
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`name', and returns its volume structure pointer. If more than one
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volume have the same name, the most recently mounted one is returned. If
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no volume matches the given name, a NULL pointer is returned.
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The given `name' is assumed to be encoded using MacOS Standard Roman.
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If a NULL pointer is passed to this routine, the current volume is
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returned, if any.
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void hfs_setvol(hfsvol *vol);
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The routine changes the "current" volume. Most HFS routines will accept
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a NULL volume pointer to mean the current volume; by default, the
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current volume is the last one which was mounted.
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int hfs_vstat(hfsvol *vol, hfsvolent *ent);
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This routine fills the volume entity structure `*ent' with information
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about a mounted volume. The fields of the structure are defined in
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the hfs.h header file.
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This routine returns 0 unless a NULL pointer is passed for the volume
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and no volume is current, in which case it returns -1.
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int hfs_vsetattr(hfsvol *vol, hfsvolent *ent);
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This routine allows some attributes of a volume to be changed. The
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attributes which may be changed are: ent->clumpsz, ent->crdate,
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ent->mddate, ent->bkdate, and ent->blessed. Note that the default file
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clump size may only be changed to be a multiple of the volume's
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allocation block size, and the "blessed" folder must either be 0 or a
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valid folder CNID.
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To change the volume's name, use hfs_rename().
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If an error occurs, this function returns -1. Otherwise it returns 0.
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----- Directory Routines -----
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int hfs_chdir(hfsvol *vol, const char *path);
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The "current working directory" for the given volume is changed.
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`path' can be either a relative or absolute HFS path.
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The given `path' is assumed to be encoded using MacOS Standard Roman.
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If an error occurs, this function returns -1. Otherwise it returns 0.
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long hfs_getcwd(hfsvol *vol);
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The internal directory ID of the current working directory for the
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given volume is returned. This value is typically only useful for
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passing to hfs_setcwd() or hfs_dirinfo().
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int hfs_setcwd(hfsvol *vol, long id);
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This routine changes the current working directory for the given
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volume. A directory must exist with the given id.
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If an error occurs, this function returns -1. Otherwise it returns 0.
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int hfs_dirinfo(hfsvol *vol, long *id, char *name);
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This function looks up the given directory ID `*id' and stores in its
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place the directory ID of its parent. If `name' is not NULL, the name
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of the (child) directory is also stored in the buffer pointed to by it,
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which must be at least HFS_MAX_FLEN + 1 (32) bytes long.
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The string `name' will be encoded using MacOS Standard Roman.
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If an error occurs, this function returns -1. Otherwise it returns 0.
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This function can be called repeatedly to construct a full pathname
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to the current working directory. The root directory of a volume
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always has a directory ID of HFS_CNID_ROOTDIR, and a pseudo-parent ID
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of HFS_CNID_ROOTPAR.
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hfsdir *hfs_opendir(hfsvol *vol, const char *path);
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This function prepares to read the contents of a directory. `path'
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must be either an absolute or relative pathname to the desired HFS
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directory. As a special case, if `path' is an empty string, a
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"meta-directory" will be opened containing the root directories from
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all of the currently mounted volumes.
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The string `path' is assumed to be encoded using MacOS Standard Roman.
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This function returns a pointer which must be passed to the other
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directory-related routines to read the directory.
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If an error occurs, this function returns a NULL pointer.
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int hfs_readdir(hfsdir *dir, hfsdirent *ent);
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This routine fills the directory entity structure `*ent' with
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information about the next item in the given open directory. The
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fields of the structure are defined in the hfs.h header file.
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If an error occurs, this function returns -1. Otherwise it returns 0.
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When no more items occur in the directory, this function returns -1
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and sets `errno' to ENOENT.
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int hfs_closedir(hfsdir *dir);
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This function closes an open directory and frees all associated
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memory.
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If an error occurs, this function returns -1. Otherwise it returns 0.
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In either case, the directory structure pointer will no longer be valid.
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----- File Routines -----
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hfsfile *hfs_create(hfsvol *vol, const char *path,
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const char *type, const char *creator);
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This routine creates a new, empty file with the given path, type, and
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creator. The type and creator must be strings of length 4, and have
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particular meaning under MacOS.
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The given `path' is assumed to be encoded using MacOS Standard Roman.
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If the creation is successful, the file is opened and a pointer to a
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file structure is returned, the same as if hfs_open() had been called.
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If an error occurs, this function returns a NULL pointer.
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hfsfile *hfs_open(hfsvol *vol, const char *path);
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This function opens an HFS file in preparation for I/O. Both forks of
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the file may be manipulated once the file is opened; hfs_setfork() is
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used to select the current fork. By default, the data fork is current.
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The given `path' is assumed to be encoded using MacOS Standard Roman.
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A pointer to a file structure is returned. This pointer should be
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passed to other routines to manipulate the file.
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If an error occurs, this function returns a NULL pointer.
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int hfs_setfork(hfsfile *file, int fork);
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This routine selects the current fork in an open file for I/O. HFS
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files have two forks, data and resource. Resource forks normally contain
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structured data, although these HFS routines make no distinction
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between forks when reading or writing. It is up to higher-level
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applications to make sense of the information read or written from
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either fork.
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If 0 is passed to this routine, the data fork is selected. Otherwise
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the resource fork is selected. The seek pointer for the file is
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automatically reset to the beginning of the newly selected fork.
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As a side effect, this routine causes any excess disk blocks allocated
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for the fork which was current before the call to be freed; normally
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extra blocks are allocated during file writes to promote contiguity.
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This routine will return -1 if an error occurs in this process;
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otherwise it will return 0. The current fork will have been changed
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regardless.
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int hfs_getfork(hfsfile *file);
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This routine returns an indication of which fork is currently active
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for I/O operations on the given file. If 0 is returned, the data fork
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is selected. Otherwise the resource fork is selected.
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long hfs_read(hfsfile *file, void *ptr, unsigned long len);
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This routine reads up to `len' bytes from the current fork of an HFS
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file and places them into the buffer pointed to by `ptr' (which must be
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at least `len' bytes long.) The number of bytes actually read is
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returned, and may be less than `len' if the end of the file is reached.
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If this routine returns 0, there is no more data to be read from the
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file. If an error occurs, this routine will return -1.
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It is most efficient to read data in multiples of HFS_BLOCKSZ byte
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blocks at a time.
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long hfs_write(hfsfile *file, const void *ptr, unsigned long len);
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This routine writes up to `len' bytes of data to the current fork of an
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HFS file from the buffer pointed to by `ptr'. The number of bytes
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actually written is returned. If an error occurs, this routine will
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return -1.
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If the end of the file is reached before all bytes have been written,
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the file is automatically extended.
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It is most efficient to write data in multiples of HFS_BLOCKSZ byte
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blocks at a time.
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int hfs_truncate(hfsfile *file, unsigned long len);
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This routine causes the current fork of the specified open file to be
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truncated to at most `len' bytes.
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The disk blocks associated with the freed portion of the file are not
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actually deallocated until either the current fork is changed or the
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file is closed.
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If an error occurs, this function returns -1. Otherwise it returns 0.
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long hfs_seek(hfsfile *file, long offset, int from);
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This routine changes the current seek pointer for the specified open
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file. This pointer determines where the next call to hfs_read() or
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hfs_write() will read or write data within the current fork.
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If `from' is HFS_SEEK_SET, the pointer is set to the absolute position
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given by `offset'.
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If `from' is HFS_SEEK_CUR, the pointer is offset from its current
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position by the amount `offset'. Positive offsets seek forward; negative
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offsets seek backward.
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If `from' is HFS_SEEK_END, the pointer is offset from the end of the
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file by the amount `offset', which ought not be positive.
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It is not presently possible to set the seek pointer beyond the logical
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end of the file.
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The new absolute position of the seek pointer is returned, unless an
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invalid argument was specified, in which case -1 is returned.
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int hfs_close(hfsfile *file);
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This routine causes all pending changes to the specified file to be
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flushed, and all storage associated with the file structure to be
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freed. Any excess disk blocks associated with the file are also
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deallocated at this time.
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If an error occurs, this routine returns -1. Otherwise it returns 0.
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In either case, the file structure pointer will no longer be valid.
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----- Catalog Routines -----
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int hfs_stat(hfsvol *vol, const char *path, hfsdirent *ent);
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This routine fills the directory entity structure `*ent' with
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information about the file or directory specified by `path' on the
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given volume. The fields of the structure are defined in the hfs.h
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header file.
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The given `path' is assumed to be encoded using MacOS Standard Roman.
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If there is no such path, or if another error occurs, this routine
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returns -1. Otherwise it returns 0.
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int hfs_fstat(hfsfile *file, hfsdirent *ent);
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This routine is similar to hfs_stat() except it returns information
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about a file that is already open.
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If an error occurs, this routine returns -1. Otherwise it returns 0.
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int hfs_setattr(hfsvol *vol, const char *path, const hfsdirent *ent);
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This routine changes various attributes of an existing file or
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directory. The attributes which may be changed are: ent->crdate,
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ent->mddate, ent->bkdate, ent->fdflags, ent->fdlocation,
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ent->u.file.type, ent->u.file.creator, and ent->u.dir.rect. Also, the
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locked status of a file may be changed with ent->flags & HFS_ISLOCKED.
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The given `path' is assumed to be encoded using MacOS Standard Roman.
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If an error occurs, this routine returns -1. Otherwise it returns 0.
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int hfs_fsetattr(hfsfile *file, const hfsdirent *ent);
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This routine is similar to hfs_setattr() except it manipulates a file
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that is already open.
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If an error occurs, this routine returns -1. Otherwise it returns 0.
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int hfs_mkdir(hfsvol *vol, const char *path);
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This routine creates a new, empty directory with the given path.
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All parent directories must already exist, but there must not already
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be a file or directory with the complete given path.
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The given `path' is assumed to be encoded using MacOS Standard Roman.
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If an error occurs, this function returns -1. Otherwise it returns 0.
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int hfs_rmdir(hfsvol *vol, const char *path);
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This routine deletes the directory with the given path. The directory
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must be empty.
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The given `path' is assumed to be encoded using MacOS Standard Roman.
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If an error occurs, this function returns -1. Otherwise it returns 0.
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int hfs_delete(hfsvol *vol, const char *path);
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This routine deletes both forks of the file with the given path.
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The given `path' is assumed to be encoded using MacOS Standard Roman.
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If an error occurs, this function returns -1. Otherwise it returns 0.
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int hfs_rename(hfsvol *vol, const char *srcpath, const char *dstpath);
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This routine moves and/or renames the given `srcpath' to `dstpath'.
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The source must exist; the destination must not exist, unless it is a
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directory, in which case an attempt will be made to move the source
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into the destination directory without changing its name.
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If both `srcpath' and `dstpath' refer to root directories, the volume
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specified by `srcpath' will be renamed. Note that volume names may
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only have 1-27 (HFS_MAX_VLEN) characters, while all other names may
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have 1-31 (HFS_MAX_FLEN) characters.
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The given `srcpath' and `dstpath' are assumed to be encoded using MacOS
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Standard Roman.
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If an error occurs, this function returns -1. Otherwise it returns 0.
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----- Media Routines -----
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int hfs_zero(const char *path, unsigned int maxparts,
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unsigned long *blocks);
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This routine initializes a medium with a new, empty driver descriptor
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record and partition map. This is only necessary if it is desired to
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partition the medium; the medium can be used as a whole without
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partitions by specifying 0 to the routines which require a partition
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number.
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The partition map will be empty, with the exception of an entry for the
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partition map itself, plus an entry for the rest of the medium as free
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space. To be useful, one or more HFS partitions should be created with
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hfs_mkpart().
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The partition map will be created just large enough to allow `maxparts'
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individual partitions to be created, not counting the partitions created
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automatically by this routine. This number should be conservative, as
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it may be impossible to create more than this many partitions for the
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lifetime of the medium without re-initializing.
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If `blocks' is not NULL, the total number of blocks available for
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partitioning (after the partition map structures have been created) will
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be stored at this location.
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If an error occurs, this function returns -1. Otherwise it returns 0.
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int hfs_mkpart(const char *path, unsigned long len);
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This routine creates a new HFS partition having `len' blocks on the
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given medium. Space for the partition will be taken from the available
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free space as indicated in the existing partition map.
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It may not be possible to create the requested partition if there are
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not enough free contiguous blocks on the medium, or if there is only
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one slot left in the partition map and the request does not specify
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all the remaining blocks in the free space. (The partition map cannot
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leave any blocks in the medium unaccounted for.)
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If an error occurs, this function returns -1. Otherwise it returns 0.
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int hfs_nparts(const char *path);
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This routine determines the number of HFS partitions present on the
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given medium, if any. If the medium specified by `path' is not
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partitioned, -1 will be returned. Otherwise, a number denoting the total
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number of HFS partitions is returned, including (possibly) 0.
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The number returned by this routine can help determine if a particular
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medium is partitioned, and if so, the allowable range of partition
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numbers which can be passed to the routines which require one. However,
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passing 0 as a partition number always refers to the entire medium,
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ignoring all partitions.
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If an error occurs, this function returns -1.
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int hfs_format(const char *path, int pnum, int mode, const char *vname,
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int nbadblocks, const unsigned long badblocks[]);
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This routine writes a new HFS file system to the specified `path', which
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should be a block device or a writable file. The size of the volume is
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determined either by the maximum size of the device or size of the file,
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or by the size of the indicated partition within the medium.
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If `pnum' is > 0, it selects an ordinal HFS partition in the device
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to receive the file system. The partition must already exist; an error
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will result if it cannot be found. With `pnum' == 0, any partition
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structure on the existing medium will be ignored, and the entire
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device will be used for the new HFS volume.
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Volume options may be specified in the `mode' argument. In addition to
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the options accepted by hfs_mount(), HFS_OPT_2048 may be specified to
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request that the volume allocation blocks be aligned on physical
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2048-byte block boundaries. Such a constraint is necessary to support
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some hybrid CD-ROM file system formats, but is otherwise unnecessary and
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may result in fewer allocation blocks altogether.
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The volume is given the name `vname', which must be between 1 and
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HFS_MAX_VLEN (27) characters in length inclusively, and cannot contain
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any colons (':'). This string is assumed to be encoded using MacOS
|
|
Standard Roman.
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It is possible to map out or "spare" bad blocks on the device such that
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the file system will be made aware of these blocks and will not attempt
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|
to use them to store data. To perform this magic, hfs_format() may be
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passed an array of block numbers to spare. These numbers must
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|
correspond to logical 512-byte blocks on the device and should be
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relative to the beginning of the volume's partition, if any. If no
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|
blocks need to be spared, 0 should be passed for `nbadblocks', and
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`badblocks' may be a NULL pointer. Note that an error can occur if a
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bad block occurs in a critical disk structure, or if there are too
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|
many bad blocks (more than 25%) in the volume.
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If an error occurs, this function returns -1. Otherwise it returns 0.
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===============================================================================
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