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BFile

BFile is the OS’s native interface to the filesystem. It has quite a bit of legacy, so it’s not very easy to use. Please note that BFile cannot be used from within gint, so do a gint_world_switch() (<gint/gint.h>) to call BFile functions; otherwise the add-in is likely to crash.

There are two different filesystems:

  • An older, in-house one made by CASIO and informally called CASIOWIN (which is the name of the OS itself), which is incomplete, hard to use, and very limiting, but also very fast.
  • A newer one, designed by Kyoto Software Research and called Fugue, which is mostly complete and behaves as a regular filesystem, though very slow.

You can detect which one is used by querying gint[HWFS] (<gint/hardware.h>):

  • HWFS_FUGUE is the newer one; it is found in:
  • The fx-CG series (in France: Prizm and Graph 90+E)
  • The fx G-III series (in France: Graph 35+E II)
  • HWFS_CASIOWIN is the older one; it is found in all older black-and-white model that have a storage memory.

Wherever Fugue is used, gint supports the Unix file API (open, read, write, etc) and the C99 standard file API (fopen, fread, fwrite, etc), so there is no need to call into BFile directly (you should still do a world switch before using these functions).

You should only have to use BFile if you’re dealing with the CASIOWIN filesystem. With Fugue, not only are the Unix/C99 APIs easier to use, but the meanings of arguments and return values in BFile calls also change compared to the CASIOWIN filesystem, so there’s little to gain anyway.

If you’re here for the CASIOWIN filesystem, be aware of its limitations. In general reading files will work fine; expect no issues with that. Modifying files is where things get difficult. Keep the following in mind:

  • Non-standard meanings of arguments and return values (eg. BFile_Read() returns the number of readable bytes between the new position and EOF).
  • Files must be created with a fixed size indicated in BFile_Create() and are initialized with 0xff.
  • A write to a file can only replace 1’s with 0’s, meaning in practice a file can only be written to once. (That’s why it’s created with 0xff.)
  • All writes must be of even size; writing an odd number of bytes can mess up the file and confuse the filesystem.
  • Only one level of folders is supported; attempting to create second-level subfolders results in weird recursive directories (don’t do that).

File paths in the OS use the non-standard FONTCHARACTER encoding, which is a 16-bit fixed-width encoding. Most users don’t care about special characters; in GCC, you can get a 16-bit literal string with the u"" prefix, eg. u”\\fls0\data.bin” which is what you usually supply as the [uint16_t const *path] argument.

All functions return nonnegative values on success. If no return value is described then a successful call returns 0. Unless specified otherwise, all functions can also return a negative error code as documented near the end of this header.

Macros

Section titled “Macros”
#define GINT_BFILE

Source

Section titled “Source”