physfs.h
author Ryan C. Gordon <icculus@icculus.org>
Sun, 08 Jul 2001 13:57:28 +0000
changeset 23 bd6ba9c8717c
parent 15 418eacc97ac8
child 28 529214f57d1b
permissions -rw-r--r--
Initial debugging: dropped PhysicsFS routines into the Build engine, replacing Ken's groupfile management. Not finished, but lots of initial debugging is complete. More bugs, likely in OUR groupfile code, are waiting to be fixed, but the KenBuild editor runs without crashing (er...but the palette doesn't seem to be loading... :) ) --ryan.

/**
 * PhysicsFS; a portable, flexible file i/o abstraction.
 *
 * This API gives you access to a system file system in ways superior to the
 *  stdio or system i/o calls. The brief benefits:
 *
 *   - It's portable.
 *   - It's safe. No file access is permitted outside the specified dirs.
 *   - It's flexible. Archives (.ZIP files) can be used transparently as
 *      directory structures.
 *
 * This system is largely inspired by Quake 3's PK3 files and the related
 *  fs_* cvars. If you've ever tinkered with these, then this API will be
 *  familiar to you.
 *
 * With PhysicsFS, you have a single writing directory and multiple
 *  directories (the "search path") for reading. You can think of this as a
 *  filesystem within a filesystem. If (on Windows) you were to set the
 *  writing directory to "C:\MyGame\MyWritingDirectory", then no PHYSFS calls
 *  could touch anything above this directory, including the "C:\MyGame" and
 *  "C:\" directories. This prevents an application's internal scripting
 *  language from piddling over c:\config.sys, for example. If you'd rather
 *  give PHYSFS full access to the system's REAL file system, set the writing
 *  dir to "C:\", but that's generally A Bad Thing for several reasons.
 *
 * Drive letters are hidden in PhysicsFS once you set up your initial paths.
 *  The search path creates a single, hierarchical directory structure.
 *  Not only does this lend itself well to general abstraction with archives,
 *  it also gives better support to operating systems like MacOS and Unix.
 *  Generally speaking, you shouldn't ever hardcode a drive letter; not only
 *  does this hurt portability to non-Microsoft OSes, but it limits your win32
 *  users to a single drive, too. Use the PhysicsFS abstraction functions and
 *  allow user-defined configuration options, too. When opening a file, you
 *  specify it like it was on a Unix filesystem: if you want to write to
 *  "C:\MyGame\MyConfigFiles\game.cfg", then you might set the write dir to
 *  "C:\MyGame" and then open "MyConfigFiles/game.cfg". This gives an
 *  abstraction across all platforms. Specifying a file in this way is termed
 *  "platform-independent notation" in this documentation. Specifying a
 *  a filename in a form such as "C:\mydir\myfile" or
 *  "MacOS hard drive:My Directory:My File" is termed "platform-dependent
 *  notation". The only time you use platform-dependent notation is when
 *  setting up your write directory and search path; after that, all file
 *  access into those directories are done with platform-independent notation.
 *
 * All files opened for writing are opened in relation to the write directory,
 *  which is the root of the writable filesystem. When opening a file for
 *  reading, PhysicsFS goes through the search path. This is NOT the
 *  same thing as the PATH environment variable. An application using
 *  PhysicsFS specifies directories to be searched which may be actual
 *  directories, or archive files that contain files and subdirectories of
 *  their own. See the end of these docs for currently supported archive
 *  formats.
 *
 * Once the search path is defined, you may open files for reading. If you've
 *  got the following search path defined (to use a win32 example again):
 *
 *    C:\mygame
 *    C:\mygame\myuserfiles
 *    D:\mygamescdromdatafiles
 *    C:\mygame\installeddatafiles.zip
 *
 * Then a call to PHYSFS_openRead("textfiles/myfile.txt") (note the directory
 *  separator, lack of drive letter, and lack of dir separator at the start of
 *  the string; this is platform-independent notation) will check for
 *  C:\mygame\textfiles\myfile.txt, then
 *  C:\mygame\myuserfiles\textfiles\myfile.txt, then
 *  D:\mygamescdromdatafiles\textfiles\myfile.txt, then, finally, for
 *  textfiles\myfile.txt inside of C:\mygame\installeddatafiles.zip. Remember
 *  that most archive types and platform filesystems store their filenames in
 *  a case-sensitive manner, so you should be careful to specify it correctly.
 *
 * Files opened through PhysicsFS may NOT contain "." or ".." or ":" as dir
 *  elements. Not only are these meaningless on MacOS and/or Unix, they are a
 *  security hole. Also, symbolic links (which can be found in some archive
 *  types and directly in the filesystem on Unix platforms) are NOT followed
 *  until you call PHYSFS_permitSymbolicLinks(). That's left to your own
 *  discretion, as following a symlink can allow for access outside the write
 *  dir and search paths. There is no mechanism for creating new symlinks in
 *  PhysicsFS.
 *
 * The write dir is not included in the search path unless you specifically
 *  add it. While you CAN change the write dir as many times as you like,
 *  you should probably set it once and stick to it. Remember that your
 *  program will not have permission to write in every directory on Unix and
 *  NT systems.
 *
 * All files are opened in binary mode; there is no endline conversion for
 *  textfiles. Other than that, PhysicsFS has some convenience functions for
 *  platform-independence. There is a function to tell you the current
 *  platform's dir separator ("\\" on windows, "/" on Unix, ":" on MacOS),
 *  which is needed only to set up your search/write paths. There is a
 *  function to tell you what CD-ROM drives contain accessible discs, and a
 *  function to recommend a good search path, etc.
 *
 * A recommended order for the search path is the write dir, then the base dir,
 *  then the cdrom dir, then any archives discovered. Quake 3 does something
 *  like this, but moves the archives to the start of the search path. Build
 *  Engine games, like Duke Nukem 3D and Blood, place the archives last, and
 *  use the base dir for both searching and writing. There is a helper
 *  function (PHYSFS_setSaneConfig()) that puts together a basic configuration
 *  for you, based on a few parameters. Also see the comments on
 *  PHYSFS_getBaseDir(), and PHYSFS_getUserDir() for info on what those
 *  are and how they can help you determine an optimal search path.
 *
 * PhysicsFS is (sort of) NOT thread safe! The error messages returned by
 *  PHYSFS_getLastError are unique by thread, but that's it. Generally
 *  speaking, we'd have to request a mutex at the start of each function,
 *  and release it before returning. Not only is this REALLY slow, it requires
 *  a thread lock portability layer to be written. All that work is only
 *  necessary as a safety if the calling application is poorly written.
 *  Generally speaking, it is safe to call most functions that don't set state
 *  simultaneously; you can read and write and open and close different files
 *  at the same time in different threads, but trying to set the write path in
 *  one thread while opening a file for writing in another will, at best,
 *  cause a polite error, but depending on the race condition results, you may
 *  get a segfault and crash, too. Use your head, and implement you own thread
 *  locks where needed. Also, consider if you REALLY need a multithreaded
 *  solution in the first place.
 *
 * While you CAN use stdio/syscall file access in a program that has PHYSFS_*
 *  calls, doing so is not recommended, and you can not use system
 *  filehandles with PhysicsFS filehandles and vice versa.
 *
 * Note that archives need not be named as such: if you have a ZIP file and
 *  rename it with a .PKG extension, the file will still be recognized as a
 *  ZIP archive by PhysicsFS; the file's contents are used to determine its
 *  type.
 *
 * Currently supported archive types:
 *   - .ZIP (pkZip/WinZip/Info-ZIP compatible)
 *
 * Please see the file LICENSE in the source's root directory.
 *
 *  This file written by Ryan C. Gordon.
 */

#ifndef _INCLUDE_PHYSFS_H_
#define _INCLUDE_PHYSFS_H_

#ifdef __cplusplus
extern "C" {
#endif


typedef struct __PHYSFS_FILE__
{
    void *opaque;
} PHYSFS_file;

typedef struct __PHYSFS_ARCHIVEINFO__
{
    const char *extension;
    const char *description;
} PHYSFS_ArchiveInfo;


/* functions... */

typedef struct __PHYSFS_VERSION__
{
    int major;
    int minor;
    int patch;
} PHYSFS_Version;

#define PHYSFS_VER_MAJOR 0
#define PHYSFS_VER_MINOR 1
#define PHYSFS_VER_PATCH 0

#define PHYSFS_VERSION(x) { \
                            x->major = PHYSFS_VER_MAJOR; \
                            x->minor = PHYSFS_VER_MINOR; \
                            x->patch = PHYSFS_VER_PATCH; \
                          }

/**
 * Get the version of PhysicsFS that is linked against your program. If you
 *  are using a shared library (DLL) version of PhysFS, then it is possible
 *  that it will be different than the version you compiled against.
 *
 * This is a real function; the macro PHYSFS_VERSION tells you what version
 *  of PhysFS you compiled against:
 *
 * PHYSFS_Version compiled;
 * PHYSFS_Version linked;
 *
 * PHYSFS_VERSION(&compiled);
 * PHYSFS_getLinkedVersion(&linked);
 * printf("We compiled against PhysFS version %d.%d.%d ...\n",
 *           compiled.major, compiled.minor, compiled.patch);
 * printf("But we linked against PhysFS version %d.%d.%d.\n",
 *           linked.major, linked.minor, linked.patch);
 *
 * This function may be called safely at any time, even before PHYSFS_init().
 */
void PHYSFS_getLinkedVersion(PHYSFS_Version *ver);


/**
 * Initialize PhysicsFS. This must be called before any other PhysicsFS
 *  function.
 *
 * This should be called prior to any attempts to change your process's
 *  current working directory.
 *
 *   @param argv0 the argv[0] string passed to your program's mainline.
 *  @return nonzero on success, zero on error. Specifics of the error can be
 *          gleaned from PHYSFS_getLastError().
 */
int PHYSFS_init(const char *argv0);


/**
 * Shutdown PhysicsFS. This closes any files opened via PhysicsFS, blanks the
 *  search/write paths, frees memory, and invalidates all of your handles.
 *
 * Note that this call can FAIL if there's a file open for writing that
 *  refuses to close (for example, the underlying operating system was
 *  buffering writes to network filesystem, and the fileserver has crashed,
 *  or a hard drive has failed, etc). It is usually best to close all write
 *  handles yourself before calling this function, so that you can gracefully
 *  handle a specific failure.
 *
 * Once successfully deinitialized, PHYSFS_init() can be called again to
 *  restart the subsystem. All defaults API states are restored at this
 *  point.
 *
 *  @return nonzero on success, zero on error. Specifics of the error can be
 *          gleaned from PHYSFS_getLastError(). If failure, state of PhysFS is
 *          undefined, and probably badly screwed up.
 */
int PHYSFS_deinit(void);


/**
 * Get a list of archive types supported by this implementation of PhysicFS.
 *  These are the file formats usable for search path entries. This is for
 *  informational purposes only. Note that the extension listed is merely
 *  convention: if we list "ZIP", you can open a PkZip-compatible archive
 *  with an extension of "XYZ", if you like.
 *
 * The returned value is an array of pointers to PHYSFS_ArchiveInfo structures,
 *  with a NULL entry to signify the end of the list:
 *
 * PHYSFS_ArchiveInfo **i;
 *
 * for (i = PHYSFS_supportedArchiveTypes(); *i != NULL; i++)
 * {
 *     printf("Supported archive: [%s], which is [%s].\n",
 *              i->extension, i->description);
 * }
 *
 * The return values are pointers to static internal memory, and should
 *  be considered READ ONLY, and never freed.
 *
 *   @return READ ONLY Null-terminated array of READ ONLY structures.
 */
const PHYSFS_ArchiveInfo **PHYSFS_supportedArchiveTypes(void);


/**
 * Certain PhysicsFS functions return lists of information that are
 *  dynamically allocated. Use this function to free those resources.
 *
 *   @param list List of information specified as freeable by this function.
 */
void PHYSFS_freeList(void *list);


/**
 * Get the last PhysicsFS error message as a null-terminated string.
 *  This will be NULL if there's been no error since the last call to this
 *  function. The pointer returned by this call points to an internal buffer.
 *  Each thread has a unique error state associated with it, but each time
 *  a new error message is set, it will overwrite the previous one associated
 *  with that thread. It is safe to call this function at anytime, even
 *  before PHYSFS_init().
 *
 *   @return READ ONLY string of last error message.
 */
const char *PHYSFS_getLastError(void);


/**
 * Get a platform-dependent dir separator. This is "\\" on win32, "/" on Unix,
 *  and ":" on MacOS. It may be more than one character, depending on the
 *  platform, and your code should take that into account. Note that this is
 *  only useful for setting up the search/write paths, since access into those
 *  dirs always use '/' (platform-independent notation) to separate
 *  directories. This is also handy for getting platform-independent access
 *  when using stdio calls.
 *
 *   @return READ ONLY null-terminated string of platform's dir separator.
 */
const char *PHYSFS_getDirSeparator(void);


/**
 * Enable symbolic links. Some physical filesystems and archives contain
 *  files that are just pointers to other files. On the physical filesystem,
 *  opening such a link will (transparently) open the file that is pointed to.
 *
 * By default, PhysicsFS will check if a file is really a symlink during open
 *  calls and fail if it is. Otherwise, the link could take you outside the
 *  write and search paths, and compromise security.
 *
 * If you want to take that risk, call this function with a non-zero parameter.
 *  Note that this is more for sandboxing a program's scripting language, in
 *  case untrusted scripts try to compromise the system. Generally speaking,
 *  a user could very well have a legitimate reason to set up a symlink, so
 *  unless you feel there's a specific danger in allowing them, you should
 *  permit them.
 *
 * Symbolic link permission can be enabled or disabled at any time, and is
 *  disabled by default.
 *
 *   @param allow nonzero to permit symlinks, zero to deny linking.
 */
void PHYSFS_permitSymbolicLinks(int allow);


/**
 * Get an array of dirs to available CD-ROM drives.
 *
 * The dirs returned are platform-dependent ("D:\" on Win32, "/cdrom" or
 *  whatnot on Unix). Dirs are only returned if there is a disc ready and
 *  accessible in the drive. So if you've got two drives (D: and E:), and only
 *  E: has a disc in it, then that's all you get. If the user inserts a disc
 *  in D: and you call this function again, you get both drives. If, on a
 *  Unix box, the user unmounts a disc and remounts it elsewhere, the next
 *  call to this function will reflect that change. Fun.
 *
 * The returned value is an array of strings, with a NULL entry to signify the
 *  end of the list:
 *
 * char **cds = PHYSFS_getCdRomDirs();
 * char **i;
 *
 * for (i = cds; *i != NULL; i++)
 *     printf("cdrom dir [%s] is available.\n", *i);
 *
 * PHYSFS_freeList(cds);
 *
 * This call may block while drives spin up. Be forewarned.
 *
 * When you are done with the returned information, you may dispose of the
 *  resources by calling PHYSFS_freeList() with the returned pointer.
 *
 *   @return Null-terminated array of null-terminated strings.
 */
char **PHYSFS_getCdRomDirs(void);


/**
 * Helper function.
 *
 * Get the "base dir". This is the directory where the application was run
 *  from, which is probably the installation directory, and may or may not
 *  be the process's current working directory.
 *
 * You should probably use the base dir in your search path.
 *
 *  @return READ ONLY string of base dir in platform-dependent notation.
 */
const char *PHYSFS_getBaseDir(void);


/**
 * Helper function.
 *
 * Get the "user dir". This is meant to be a suggestion of where a specific
 *  user of the system can store files. On Unix, this is her home directory.
 *  On systems with no concept of multiple home directories (MacOS, win95),
 *  this will default to something like "C:\mybasedir\users\username"
 *  where "username" will either be the login name, or "default" if the
 *  platform doesn't support multiple users, either.
 *
 * You should probably use the user dir as the basis for your write dir, and
 *  also put it near the beginning of your search path.
 *
 *  @return READ ONLY string of user dir in platform-dependent notation.
 */
const char *PHYSFS_getUserDir(void);


/**
 * Get the current write dir. The default write dir is NULL.
 *
 *  @return READ ONLY string of write dir in platform-dependent notation,
 *           OR NULL IF NO WRITE PATH IS CURRENTLY SET.
 */
const char *PHYSFS_getWriteDir(void);


/**
 * Set a new write dir. This will override the previous setting. If the
 *  directory or a parent directory doesn't exist in the physical filesystem,
 *  PhysicsFS will attempt to create them as needed.
 *
 * This call will fail (and fail to change the write dir) if the current
 *  write dir still has files open in it.
 *
 *   @param newDir The new directory to be the root of the write dir,
 *                   specified in platform-dependent notation. Setting to NULL
 *                   disables the write dir, so no files can be opened for
 *                   writing via PhysicsFS.
 *  @return non-zero on success, zero on failure. All attempts to open a file
 *           for writing via PhysicsFS will fail until this call succeeds.
 *           Specifics of the error can be gleaned from PHYSFS_getLastError().
 *
 */
int PHYSFS_setWriteDir(const char *newDir);


/**
 * Add a directory or archive to the search path. If this is a duplicate, the
 *  entry is not added again, even though the function succeeds.
 *
 *   @param newDir directory or archive to add to the path, in
 *                   platform-dependent notation.
 *   @param appendToPath nonzero to append to search path, zero to prepend.
 *  @return nonzero if added to path, zero on failure (bogus archive, dir
 *                   missing, etc). Specifics of the error can be
 *                   gleaned from PHYSFS_getLastError().
 */
int PHYSFS_addToSearchPath(const char *newDir, int appendToPath);


/**
 * Remove a directory or archive from the search path.
 *
 * This must be a (case-sensitive) match to a dir or archive already in the
 *  search path, specified in platform-dependent notation.
 *
 * This call will fail (and fail to remove from the path) if the element still
 *  has files open in it.
 *
 *    @param oldDir dir/archive to remove.
 *   @return nonzero on success, zero on failure.
 *            Specifics of the error can be gleaned from PHYSFS_getLastError().
 */
int PHYSFS_removeFromSearchPath(const char *oldDir);


/**
 * Get the current search path. The default search path is an empty list.
 *
 * The returned value is an array of strings, with a NULL entry to signify the
 *  end of the list:
 *
 * char **i;
 *
 * for (i = PHYSFS_getSearchPath(); *i != NULL; i++)
 *     printf("[%s] is in the search path.\n", *i);
 *
 * When you are done with the returned information, you may dispose of the
 *  resources by calling PHYSFS_freeList() with the returned pointer.
 *
 *   @return Null-terminated array of null-terminated strings. NULL if there
 *            was a problem (read: OUT OF MEMORY).
 */
char **PHYSFS_getSearchPath(void);


/**
 * Helper function.
 *
 * Set up sane, default paths. The write dir will be set to
 *  "userdir/.appName", which is created if it doesn't exist.
 *
 * The above is sufficient to make sure your program's configuration directory
 *  is separated from other clutter, and platform-independent. The period
 *  before "mygame" even hides the directory on Unix systems.
 *
 *  The search path will be:
 *
 *    - The Write Dir (created if it doesn't exist)
 *    - The Write Dir/appName (created if it doesn't exist)
 *    - The Base Dir (PHYSFS_getBaseDir())
 *    - The Base Dir/appName (if it exists)
 *    - All found CD-ROM dirs (optionally)
 *    - All found CD-ROM dirs/appName (optionally, and if they exist)
 *
 * These directories are then searched for files ending with the extension
 *  (archiveExt), which, if they are valid and supported archives, will also
 *  be added to the search path. If you specified "PKG" for (archiveExt), and
 *  there's a file named data.PKG in the base dir, it'll be checked. Archives
 *  can either be appended or prepended to the search path in alphabetical
 *  order, regardless of which directories they were found in.
 *
 * All of this can be accomplished from the application, but this just does it
 *  all for you. Feel free to add more to the search path manually, too.
 *
 *    @param appName Program-specific name of your program, to separate it
 *                   from other programs using PhysicsFS.
 *
 *    @param archiveExt File extention used by your program to specify an
 *                      archive. For example, Quake 3 uses "pk3", even though
 *                      they are just zipfiles. Specify NULL to not dig out
 *                      archives automatically. Do not specify the '.' char;
 *                      If you want to look for ZIP files, specify "ZIP" and
 *                      not ".ZIP" ... the archive search is case-insensitive.
 *
 *    @param includeCdRoms Non-zero to include CD-ROMs in the search path, and
 *                         (if (archiveExt) != NULL) search them for archives.
 *                         This may cause a significant amount of blocking
 *                         while discs are accessed, and if there are no discs
 *                         in the drive (or even not mounted on Unix systems),
 *                         then they may not be made available anyhow. You may
 *                         want to specify zero and handle the disc setup
 *                         yourself.
 *
 *    @param archivesFirst Non-zero to prepend the archives to the search path.
 *                          Zero to append them. Ignored if !(archiveExt).
 *  @return nonzero on success, zero on error. Specifics of the error can be
 *          gleaned from PHYSFS_getLastError().
 */
int PHYSFS_setSaneConfig(const char *appName, const char *archiveExt,
                          int includeCdRoms, int archivesFirst);


/**
 * Create a directory. This is specified in platform-independent notation in
 *  relation to the write dir. All missing parent directories are also
 *  created if they don't exist.
 *
 * So if you've got the write dir set to "C:\mygame\writedir" and call
 *  PHYSFS_mkdir("downloads/maps") then the directories
 *  "C:\mygame\writedir\downloads" and "C:\mygame\writedir\downloads\maps"
 *  will be created if possible. If the creation of "maps" fails after we
 *  have successfully created "downloads", then the function leaves the
 *  created directory behind and reports failure.
 *
 *   @param dirname New dir to create.
 *  @return nonzero on success, zero on error. Specifics of the error can be
 *          gleaned from PHYSFS_getLastError().
 */
int PHYSFS_mkdir(const char *dirName);


/**
 * Delete a file or directory. This is specified in platform-independent
 *  notation in relation to the write dir.
 *
 * A directory must be empty before this call can delete it.
 *
 * So if you've got the write dir set to "C:\mygame\writedir" and call
 *  PHYSFS_delete("downloads/maps/level1.map") then the file
 *  "C:\mygame\writedir\downloads\maps\level1.map" is removed from the
 *  physical filesystem, if it exists and the operating system permits the
 *  deletion.
 *
 * Note that on Unix systems, deleting a file may be successful, but the
 *  actual file won't be removed until all processes that have an open
 *  filehandle to it (including your program) close their handles.
 *
 *   @param filename Filename to delete.
 *  @return nonzero on success, zero on error. Specifics of the error can be
 *          gleaned from PHYSFS_getLastError().
 */
int PHYSFS_delete(const char *filename);


/**
 * Figure out where in the search path a file resides. The file is specified
 *  in platform-independent notation. The returned filename will be the
 *  element of the search path where the file was found, which may be a
 *  directory, or an archive. Even if there are multiple matches in different
 *  parts of the search path, only the first one found is used, just like
 *  when opening a file.
 *
 * So, if you look for "maps/level1.map", and C:\mygame is in your search
 *  path and C:\mygame\maps\level1.map exists, then "C:\mygame" is returned.
 *
 * If a any part of a match is a symbolic link, and you've not explicitly
 *  permitted symlinks, then it will be ignored, and the search for a match
 *  will continue.
 *
 *     @param filename file to look for.
 *    @return READ ONLY string of element of search path containing the
 *             the file in question. NULL if not found.
 */
const char *PHYSFS_getRealDir(const char *filename);



/**
 * Get a file listing of a search path's directory. Matching directories are
 *  interpolated. That is, if "C:\mydir" is in the search path and contains a
 *  directory "savegames" that contains "x.sav", "y.sav", and "z.sav", and
 *  there is also a "C:\userdir" in the search path that has a "savegames"
 *  subdirectory with "w.sav", then the following code:
 *
 * ------------------------------------------------
 * char **rc = PHYSFS_enumerateFiles("savegames");
 * char **i;
 *
 * for (i = rc; *i != NULL; i++)
 *     printf("We've got [%s].\n", *i);
 *
 * PHYSFS_freeList(rc);
 * ------------------------------------------------
 *
 *  ...will print:
 *
 * ------------------------------------------------
 * We've got [x.sav].
 * We've got [y.sav].
 * We've got [z.sav].
 * We've got [w.sav].
 * ------------------------------------------------
 *
 * Feel free to sort the list however you like. We only promise there will
 *  be no duplicates, but not what order the final list will come back in.
 *
 * Don't forget to call PHYSFS_freeList() with the return value from this
 *  function when you are done with it.
 *
 *    @param dir directory in platform-independent notation to enumerate.
 *   @return Null-terminated array of null-terminated strings.
 */
char **PHYSFS_enumerateFiles(const char *dir);


/**
 * Determine if there is an entry anywhere in the search path by the
 *  name of (fname).
 *
 * Note that entries that are symlinks are ignored if
 *  PHYSFS_permitSymbolicLinks(1) hasn't been called, so you
 *  might end up further down in the search path than expected.
 *
 *    @param fname filename in platform-independent notation.
 *   @return non-zero if filename exists. zero otherwise.
 */
int PHYSFS_exists(const char *fname);


/**
 * Determine if the first occurence of (fname) in the search path is
 *  really a directory entry.
 *
 * Note that entries that are symlinks are ignored if
 *  PHYSFS_permitSymbolicLinks(1) hasn't been called, so you
 *  might end up further down in the search path than expected.
 *
 *    @param fname filename in platform-independent notation.
 *   @return non-zero if filename exists and is a directory.  zero otherwise.
 */
int PHYSFS_isDirectory(const char *fname);


/**
 * Determine if the first occurence of (fname) in the search path is
 *  really a symbolic link.
 *
 * Note that entries that are symlinks are ignored if
 *  PHYSFS_permitSymbolicLinks(1) hasn't been called, and as such,
 *  this function will always return 0 in that case.
 *
 *    @param fname filename in platform-independent notation.
 *   @return non-zero if filename exists and is a symlink.  zero otherwise.
 */
int PHYSFS_isSymbolicLink(const char *fname);


/**
 * Open a file for writing, in platform-independent notation and in relation
 *  to the write dir as the root of the writable filesystem. The specified
 *  file is created if it doesn't exist. If it does exist, it is truncated to
 *  zero bytes, and the writing offset is set to the start.
 *
 * Note that entries that are symlinks are ignored if
 *  PHYSFS_permitSymbolicLinks(1) hasn't been called, and opening a
 *  symlink with this function will fail in such a case.
 *
 *   @param filename File to open.
 *  @return A valid PhysicsFS filehandle on success, NULL on error. Specifics
 *           of the error can be gleaned from PHYSFS_getLastError().
 */
PHYSFS_file *PHYSFS_openWrite(const char *filename);


/**
 * Open a file for writing, in platform-independent notation and in relation
 *  to the write dir as the root of the writable filesystem. The specified
 *  file is created if it doesn't exist. If it does exist, the writing offset
 *  is set to the end of the file, so the first write will be the byte after
 *  the end.
 *
 * Note that entries that are symlinks are ignored if
 *  PHYSFS_permitSymbolicLinks(1) hasn't been called, and opening a
 *  symlink with this function will fail in such a case.
 *
 *   @param filename File to open.
 *  @return A valid PhysicsFS filehandle on success, NULL on error. Specifics
 *           of the error can be gleaned from PHYSFS_getLastError().
 */
PHYSFS_file *PHYSFS_openAppend(const char *filename);


/**
 * Open a file for reading, in platform-independent notation. The search path
 *  is checked one at a time until a matching file is found, in which case an
 *  abstract filehandle is associated with it, and reading may be done.
 *  The reading offset is set to the first byte of the file.
 *
 * Note that entries that are symlinks are ignored if
 *  PHYSFS_permitSymbolicLinks(1) hasn't been called, and opening a
 *  symlink with this function will fail in such a case.
 *
 *   @param filename File to open.
 *  @return A valid PhysicsFS filehandle on success, NULL on error. Specifics
 *           of the error can be gleaned from PHYSFS_getLastError().
 */
PHYSFS_file *PHYSFS_openRead(const char *filename);


/**
 * Close a PhysicsFS filehandle. This call is capable of failing if the
 *  operating system was buffering writes to this file, and (now forced to
 *  write those changes to physical media) can not store the data for any
 *  reason. In such a case, the filehandle stays open. A well-written program
 *  should ALWAYS check the return value from the close call in addition to
 *  every writing call!
 *
 *   @param handle handle returned from PHYSFS_open*().
 *  @return nonzero on success, zero on error. Specifics of the error can be
 *          gleaned from PHYSFS_getLastError().
 */
int PHYSFS_close(PHYSFS_file *handle);


/**
 * Read data from a PhysicsFS filehandle. The file must be opened for reading.
 *
 *   @param handle handle returned from PHYSFS_openRead().
 *   @param buffer buffer to store read data into.
 *   @param objSize size in bytes of objects being read from (handle).
 *   @param objCount number of (objSize) objects to read from (handle).
 *  @return number of objects read. PHYSFS_getLastError() can shed light on
 *           the reason this might be < (objCount), as can PHYSFS_eof().
 *            -1 if complete failure.
 */
int PHYSFS_read(PHYSFS_file *handle, void *buffer,
                unsigned int objSize, unsigned int objCount);


/**
 * Write data to a PhysicsFS filehandle. The file must be opened for writing.
 *
 *   @param handle retval from PHYSFS_openWrite() or PHYSFS_openAppend().
 *   @param buffer buffer to store read data into.
 *   @param objSize size in bytes of objects being read from (handle).
 *   @param objCount number of (objSize) objects to read from (handle).
 *  @return number of objects written. PHYSFS_getLastError() can shed light on
 *           the reason this might be < (objCount). -1 if complete failure.
 */
int PHYSFS_write(PHYSFS_file *handle, void *buffer,
                 unsigned int objSize, unsigned int objCount);


/**
 * Determine if the end of file has been reached in a PhysicsFS filehandle.
 *
 *   @param handle handle returned from PHYSFS_openRead().
 *  @return nonzero if EOF, zero if not.
 */
int PHYSFS_eof(PHYSFS_file *handle);


/**
 * Determine current position within a PhysicsFS filehandle.
 *
 *   @param handle handle returned from PHYSFS_open*().
 *  @return offset in bytes from start of file. -1 if error occurred.
 *           Specifics of the error can be gleaned from PHYSFS_getLastError().
 */
int PHYSFS_tell(PHYSFS_file *handle);


/**
 * Seek to a new position within a PhysicsFS filehandle. The next read or write
 *  will occur at that place. Seeking past the beginning or end of the file is
 *  not allowed.
 *
 *   @param handle handle returned from PHYSFS_open*().
 *   @param pos number of bytes from start of file to seek to.
 *  @return nonzero on success, zero on error. Specifics of the error can be
 *          gleaned from PHYSFS_getLastError().
 */
int PHYSFS_seek(PHYSFS_file *handle, int pos);

#ifdef __cplusplus
}
#endif

#endif  /* !defined _INCLUDE_PHYSFS_H_ */

/* end of physfs.h ... */