SPIFFS_write() function

the file system struct

the filehandle

the data to write

how much to write

Returns last error of last file operation.

Clears last error.

Initializes the file system dynamic parameters and mounts the filesystem. If SPIFFS_USE_MAGIC is enabled the mounting may fail with SPIFFS_ERR_NOT_A_FS if the flash does not contain a recognizable file system. In this case, SPIFFS_format must be called prior to remounting.

Closes a filehandle. If there are pending write operations, these are finalized before closing.

Truncates a file at given size

Gets file status by path

Gets file status by filehandle

Unmounts the file system. All file handles will be flushed of any cached writes and closed.

Opens/creates a file.

Returns nonzero if spiffs is mounted, or zero if unmounted.

Opens a directory stream corresponding to the given name. The stream is positioned at the first entry in the directory. On hydrogen builds the name argument is ignored as hydrogen builds always correspond to a flat file structure - no directories.

Formats the entire file system. All data will be lost. The filesystem must not be mounted when calling this. NB: formatting is awkward. Due to backwards compatibility, SPIFFS_mount MUST be called prior to formatting in order to configure the filesystem. If SPIFFS_mount succeeds, SPIFFS_unmount must be called before calling SPIFFS_format. If SPIFFS_mount fails, SPIFFS_format can be called directly without calling SPIFFS_unmount first.

Reads from given filehandle.

Moves the read/write file offset. Resulting offset is returned or negative if error. lseek(fs, fd, 0, SPIFFS_SEEK_CUR) will thus return current offset.

Removes a file by path

Will try to make room for given amount of bytes in the filesystem by moving pages and erasing blocks. If it is physically impossible, err_no will be set to SPIFFS_ERR_FULL. If there already is this amount (or more) of free space, SPIFFS_gc will silently return. It is recommended to call SPIFFS_info before invoking this method in order to determine what amount of bytes to give. NB: the garbage collector is automatically called when spiffs needs free pages. The reason for this function is to give possibility to do background tidying when user knows the system is idle. Use with care.

Flushes all pending write operations from cache for given file

Renames a file

Updates file's metadata

Updates file's metadata

Runs a consistency check on given filesystem.

Returns number of total bytes available and number of used bytes. This is an estimation, and depends on if there a many files with little data or few files with much data. NB: If used number of bytes exceeds total bytes, a SPIFFS_check should run. This indicates a power loss in midst of things. In worst case (repeated powerlosses in mending or gc) you might have to delete some files.

Opens a file by given dir entry. Optimization purposes, when traversing a file system with SPIFFS_readdir a normal SPIFFS_open would need to traverse the filesystem again to find the file, whilst SPIFFS_open_by_dirent already knows where the file resides.

Opens a file by given page index. Optimization purposes, opens a file by directly pointing to the page index in the spi flash. If the page index does not point to a file header SPIFFS_ERR_NOT_A_FILE is returned.

Removes a file by filehandle

Creates a new file.

Tries to find a block where most or all pages are deleted, and erase that block if found. Does not care for wear levelling. Will not move pages around. If parameter max_free_pages are set to 0, only blocks with only deleted pages will be selected. NB: the garbage collector is automatically called when spiffs needs free pages. The reason for this function is to give possibility to do background tidying when user knows the system is idle. Use with care. Setting max_free_pages to anything larger than zero will eventually wear flash more as a block containing free pages can be erased. Will set err_no to SPIFFS_OK if a block was found and erased, SPIFFS_ERR_NO_DELETED_BLOCK if no matching block was found, or other error.

Check if EOF reached.

Get position in file.

Registers a callback function that keeps track on operations on file headers. Do note, that this callback is called from within internal spiffs mechanisms. Any operations on the actual file system being callbacked from in this callback will mess things up for sure - do not do this. This can be used to track where files are and move around during garbage collection, which in turn can be used to build location tables in ram. Used in conjuction with SPIFFS_open_by_page this may improve performance when opening a lot of files. Must be invoked after mount.

Maps the first level index lookup to a given memory map. This will make reading big files faster, as the memory map will be used for looking up data pages instead of searching for the indices on the physical medium. When mapping, all affected indicies are found and the information is copied to the array. Whole file or only parts of it may be mapped. The index map will cover file contents from argument offset until and including arguments (offset+len). It is valid to map a longer range than the current file size. The map will then be populated when the file grows. On garbage collections and file data page movements, the map array will be automatically updated. Do not tamper with the map array, as this contains the references to the data pages. Modifying it from outside will corrupt any future readings using this file descriptor. The map will no longer be used when the file descriptor closed or the file is unmapped. This can be useful to get faster and more deterministic timing when reading large files, or when seeking and reading a lot within a file.

Unmaps the index lookup from this filehandle. All future readings will proceed as normal, requiring reading of the first level indices from physical media. The map and map buffer given in function SPIFFS_ix_map will no longer be referenced by spiffs. It is not strictly necessary to unmap a file before closing it, as closing a file will automatically unmap it.

Moves the offset for the index map given in function SPIFFS_ix_map. Parts or all of the map buffer will repopulated.

Utility function to get number of spiffs_page_ix entries a map buffer must contain on order to map given amount of file data in bytes. See function SPIFFS_ix_map and SPIFFS_ix_map_entries_to_bytes.

Utility function to amount of file data bytes that can be mapped when mapping a file with buffer having given number of spiffs_page_ix entries. See function SPIFFS_ix_map and SPIFFS_bytes_to_ix_map_entries.