Initial revision

physfs.h

@@ -0,0 +1,597 @@
+/**
+ * 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 can handle byte ordering on alternative processors.
+ *   - 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 very
+ *  familiar to you.
+ *
+ * With the PhysicsFS, you have a single writing directory and multiple
+ *  "search paths" 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 path 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 paths create 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 path to
+ *  "C:\MyGame" and then open "MyConfigFiles/game.cfg". This gives an
+ *  abstraction across all platforms.
+ *
+ * All files opened for writing are opened in relation to the write path,
+ *  which is the root of the writable filesystem. When opening a file for
+ *  reading, PhysicsFS goes through it's internal 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 a 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) 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.
+ *
+ * Files opened through PhysicsFS may NOT contain "." or ".." as path
+ *  elements. Not only are these meaningless on MacOS, 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 and search
+ *  paths. There is no mechanism for creating new symlinks in PhysicsFS.
+ *
+ * The write path is not included in the search path unless you specifically
+ *  add it. While you CAN change the write path as many times as you like,
+ *  you should probably set it once and stick to that path.
+ *
+ * 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 are functions that give you the current
+ *  platform's path separator ("\\" on windows, "/" on Unix, ":" on MacOS),
+ *  which is needed only to set up your search/write paths. There are
+ *  functions to tell you what CD-ROM drives contain accessible discs, and
+ *  functions to recommend good search paths, etc. There are also functions
+ *  to read 16 and 32 bit numbers from files and convert them to the native
+ *  byte order of your processor.
+ *
+ * A recommended order for a search path is the write path, then the base path,
+ *  then the cdrom path, then any archives discovered. Quake 3 does something
+ *  like this, but moves the archives to the start of the search path. There
+ *  is a helper function (PHYSFS_setSanePaths()) that does this for you,
+ *  based on a few parameters. Also see the comments on PHYSFS_getBasePath(),
+ *  and PHYSFS_getUserPath() for info on what those are and how they can help
+ *  you determine an optimal searchpath.
+ *
+ * While you CAN mix stdio/syscall file access with PHYSFS_* calls in a
+ *  program, 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 extention, 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
+
+
+/* functions... */
+
+
+/**
+ * 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 a static buffer
+ *  internal buffer, and this call is not thread safe.
+ *
+ *   @return READ ONLY string of last error message.
+ */
+const char *PHYSFS_getLastError(void);
+
+
+/**
+ * Get a platform-dependent path 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
+ *  paths always use '/' 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 path separator.
+ */
+const char *PHYSFS_getPathSeparator(void);
+
+
+/**
+ * Get an array of paths to available CD-ROM drives. This return value should
+ *  be considered READ ONLY and points to an internal buffer which may change
+ *  with each call to this function. This means that this function is NOT
+ *  thread safe.
+ *
+ * The paths returned are platform-dependent ("D:\" on Win32, "/cdrom" or
+ *  whatnot on Unix). Paths 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 **i;
+ *
+ * // lock thread here, if needed.
+ *
+ * for (i = PHYSFS__getCdRomPaths(); *i != NULL; i++)
+ *     printf("cdrom path [%s] is available.\n", *i);
+ *
+ * // unlock thread here, if needed.
+ *
+ * This call may block while drives spin up. Be forewarned.
+ *
+ *   @return READ ONLY null-term'd array of READ ONLY null-terminated strings.
+ */
+const char **PHYSFS_getCdRomPaths(void);
+
+
+/**
+ * Helper function.
+ *
+ * Get the "base path". This is the directory where the application was run
+ *  from, which is probably the installation directory.
+ *
+ * You should probably use the base path in your search path.
+ *
+ *   @param buffer pointer to buffer to fill with recommended path.
+ *   @param bufsize size of buffer pointed to by (buffer).
+ *  @return a copy of (buffer), for easy use as another function's parameter.
+ */
+char *PHYSFS_getBasePath(char *buffer, int bufferSize);
+
+
+/**
+ * Helper function.
+ *
+ * Get the "user path". 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 users (MacOS, win95), this will
+ *  default to the "base path" returned by PHYSFS_getBasePath().
+ *
+ * You should probably use the user path as the basis for your write path, and
+ *  also put it near the beginning of your search path.
+ *
+ *   @param buffer pointer to buffer to fill with recommended path.
+ *   @param bufsize size of buffer pointed to by (buffer).
+ *  @return a copy of (buffer), for easy use as another function's parameter.
+ */
+char *PHYSFS_getUserPath(char *buffer, int bufferSize);
+
+
+/**
+ * Get the current write path. The default write path is NULL.
+ *
+ *   @param buffer pointer to buffer to fill with recommended path.
+ *   @param bufsize size of buffer pointed to by (buffer).
+ *  @return a copy of (buffer), for easy use as another function's parameter,
+ *           OR NULL IF NO WRITE PATH IS CURRENTLY SET.
+ */
+char *PHYSFS_getWritePath(char *buffer, int bufferSize);
+
+
+/**
+ * Set a new write path. 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 path) if the current path
+ *  still has files open in it.
+ *
+ *   @param newPath The new directory to be the root of the write path,
+ *                   specified in a platform-dependent manner. Setting to NULL
+ *                   disables the write path, 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_setWritePath(const char *newPath);
+
+
+/**
+ * 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 newPath 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, path
+ *                   missing, etc). Specifics of the error can be
+ *                   gleaned from PHYSFS_getLastError().
+ */
+int PHYSFS_addToSearchPath(const char *newPath, int appendToPath);
+
+
+/**
+ * Remove a directory or archive to 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 oldPath 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 *oldPath);
+
+
+/**
+ * Get the current search path. The default search path is an empty list.
+ *
+ * This return value should be considered READ ONLY and points to an internal
+ *  buffer which may change with each call to this function. This means that
+ *  this function is NOT thread safe.
+ *
+ * The returned value is an array of strings, with a NULL entry to signify the
+ *  end of the list:
+ *
+ * char **i;
+ *
+ * // lock thread here, if needed.
+ *
+ * for (i = PHYSFS_getSearchPath(); *i != NULL; i++)
+ *     printf("[%s] is in the search path.\n", *i);
+ *
+ * // unlock thread here, if needed.
+ *
+ *   @return READ ONLY null-term'd array of READ ONLY null-terminated strings.
+ */
+const char **PHYSFS_getSearchPath(void);
+
+
+/**
+ * Helper function.
+ *
+ * Set up sane, default paths. The write path will be set to
+ *  "userpath/.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 Path
+ *    - The Write Path/appName
+ *    - The Base Path (PHYSFS_getBasePath())
+ *    - The Base Path/appName
+ *    - All found CD-ROM paths (optionally)
+ *    - All found CD-ROM paths/appName (optionally)
+ *
+ * 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.
+ *
+ *    @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.
+ *
+ *    @param includeCdRoms Non-zero to include CD-ROMs in the search path, and
+ *                         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.
+ */
+void PHYSFS_setSanePaths(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 path. All missing parent directories are also
+ *  created if they don't exist.
+ *
+ * So if you've got the write path set to "C:\mygame\writepath" and call
+ *  PHYSFS_mkdir("downloads/maps") then the directories
+ *  "C:\mygame\writepath\downloads" and "C:\mygame\writepath\downloads\maps"
+ *  will be created if possible.
+ *
+ *   @param dirname New path 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 path.
+ *
+ * A directory must be empty before this call can delete it. If you need to
+ *  nuke a whole directory tree, use PHYSFS_deltree()...with care.
+ *
+ * So if you've got the write path set to "C:\mygame\writepath" and call
+ *  PHYSFS_delete("downloads/maps/level1.map") then the file
+ *  "C:\mygame\writepath\downloads\maps\level1.map" is removed from the
+ *  physical filesystem, if it exists and the operating system permits the
+ *  deletion.
+ *
+ *   @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);
+
+
+/**
+ * Delete a directory tree. This is specified in platform-independent
+ *  notation in relation to the write path.
+ *
+ * Be CAREFUL with this function; it will take out EVERYTHING under the
+ *  specified directory with extreme prejudice.
+ *
+ * If you specify a filename that is not a directory, PhysicsFS will attempt
+ *  to delete that single file.
+ *
+ * So if you've got the write path set to "C:\mygame\writepath" and call
+ *  PHYSFS_deltree("downloads/maps") then the directory
+ *  "C:\mygame\writepath\downloads\maps" and everything in it (including child
+ *  directories) is removed from the physical filesystem, if it exists and the
+ *  operating system permits the deletion.
+ *
+ *   @param filename root of directory tree to delete.
+ *  @return nonzero on success, zero on error. Specifics of the error can be
+ *          gleaned from PHYSFS_getLastError().
+ */
+int PHYSFS_deltree(const char *filename);
+
+
+/**
+ * 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);
+
+
+/**
+ * Determine if a file exists. Just because it exists does NOT mean that you
+ *  will have access to read or write it.
+ *
+ *   @param filename a file in platform-independent notation.
+ *   @param inWritePath nonzero to check write path, zero to check search path.
+ *  @return nonzero if exists, zero otherwise.
+ */
+int PHYSFS_exists(const char *filename, int inWritePath);
+
+
+/**
+ * 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 buffer will be filled in
+ *  with "C:\mygame\maps\level1.map" and the function returns nonzero.
+ *
+ *     @param buffer pointer to buffer to fill with path.
+ *     @param bufsize size of buffer pointed to by (buffer).
+ *     @param filename file to look for.
+ *    @return nonzero if file was found, zero otherwise. If found, (buffer)
+ *             will be filled in.
+ */
+int PHYSFS_getRealPath(const char *filename, char *buffer, int bufSize);
+
+
+/**
+ * Open a file for writing, in platform-independent notation and in relation
+ *  to the write path 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.
+ *
+ *   @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().
+ */
+void *PHYSFS_openWrite(const char *filename);
+
+
+/**
+ * Open a file for writing, in platform-independent notation and in relation
+ *  to the write path 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.
+ *
+ *   @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().
+ */
+void *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.
+ *
+ *   @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().
+ */
+void *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(void *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).
+ */
+int PHYSFS_read(void *handle, void *buffer, int objSize, 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 read. PHYSFS_getLastError() can shed light on
+ *           the reason this might be < (objCount).
+ */
+int PHYSFS_write(void *handle, void *buffer, int objSize, 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(void *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(void *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(void *handle, int pos);
+
+
+/* Byte-order reading. !!!  Need types (Int16, Int32, etc) for these...
+int PHYSFS_readLE16(void *handle, int *buffer);
+int PHYSFS_readLE32(void *handle, int *buffer);
+int PHYSFS_readBE16(void *handle, int *buffer);
+int PHYSFS_readBE32(void *handle, int *buffer);
+int PHYSFS_writeLE16(void *handle, int buffer);
+int PHYSFS_writeLE32(void *handle, int buffer);
+int PHYSFS_writeBE16(void *handle, int buffer);
+int PHYSFS_writeBE32(void *handle, int buffer);
+*/
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  /* !defined _INCLUDE_PHYSFS_H_ */
+
+/* end of physfs.h ... */
+