# SPIFFS (SPI Flash File System)
**V0.3.3**
Copyright (c) 2013-2016 Peter Andersson (pelleplutt1976 at gmail.com)
For legal stuff, see [LICENSE ](https://github.com/pellepl/spiffs/blob/master/LICENSE ). Basically, you may do whatever you want with the source. Use, modify, sell, print it out, roll it and smoke it - as long as I won't be held responsible.
Love to hear feedback though!
## INTRODUCTION
Spiffs is a file system intended for SPI NOR flash devices on embedded targets.
Spiffs is designed with following characteristics in mind:
- Small (embedded) targets, sparse RAM without heap
- Only big areas of data (blocks) can be erased
- An erase will reset all bits in block to ones
- Writing pulls one to zeroes
- Zeroes can only be pulled to ones by erase
- Wear leveling
## FEATURES
What spiffs does:
- Specifically designed for low ram usage
- Uses statically sized ram buffers, independent of number of files
- Posix-like api: open, close, read, write, seek, stat, etc
- It can be run on any NOR flash, not only SPI flash - theoretically also on embedded flash of an microprocessor
- Multiple spiffs configurations can be run on same target - and even on same SPI flash device
- Implements static wear leveling
- Built in file system consistency checks
What spiffs does not:
- Presently, spiffs does not support directories. It produces a flat structure. Creating a file with path *tmp/myfile.txt* will create a file called *tmp/myfile.txt* instead of a *myfile.txt* under directory *tmp* .
- It is not a realtime stack. One write operation might take much longer than another.
- Poor scalability. Spiffs is intended for small memory devices - the normal sizes for SPI flashes. Going beyond ~128MB is probably a bad idea. This is a side effect of the design goal to use as little ram as possible.
- Presently, it does not detect or handle bad blocks.
## MORE INFO
See the [wiki ](https://github.com/pellepl/spiffs/wiki ) for configuring, integrating and using spiffs.
For design, see [docs/TECH_SPEC ](https://github.com/pellepl/spiffs/blob/master/docs/TECH_SPEC ).
For a generic spi flash driver, see [this ](https://github.com/pellepl/spiflash_driver ).
## HISTORY
### 0.3.3
**Might not be compatible with 0.3.2 structures. See issue #40 **
- Possibility to add integer offset to file handles
- Truncate function presumes too few free pages #49
- Bug in truncate function #48 (thanks @PawelDefee )
- Update spiffs_gc.c - remove unnecessary parameter (thanks @PawelDefee )
- Update INTEGRATION docs (thanks @PawelDefee )
- Fix pointer truncation in 64-bit platforms (thanks @igrr )
- Zero-sized files cannot be read #44 (thanks @rojer )
- (More) correct calculation of max_id in obj_lu_find #42 #41 (thanks @lishen2 )
- Check correct error code in obj_lu_find_free #41 (thanks @lishen2 )
- Moar comments for SPIFFS_lseek (thanks @igrr )
- Fixed padding in spiffs_page_object_ix #40 (thanks @jmattsson @lishen2 )
- Fixed gc_quick test (thanks @jmattsson )
- Add SPIFFS_EXCL flag #36
- SPIFFS_close may fail silently if cache is enabled #37
- User data in callbacks #34
- Ignoring SINGLETON build in cache setup (thanks Luca)
- Compilation error fixed #32 (thanks @chotasanjiv )
- Align cand_scores (thanks @hefloryd )
- Fix build warnings when SPIFFS_CACHE is 0 (thanks @ajaybhargav )
New config defines:
- `SPIFFS_FILEHDL_OFFSET`
### 0.3.2
- Limit cache size if too much cache is given (thanks pgeiem)
- New feature - Controlled erase. #23
- SPIFFS_rename leaks file descriptors #28 (thanks benpicco)
- moved dbg print defines in test framework to params_test.h
- lseek should return the resulting offset (thanks hefloryd)
- fixed type on dbg ifdefs
- silence warning about signed/unsigned comparison when spiffs_obj_id is 32 bit (thanks benpicco)
- Possible error in test_spiffs.c #21 (thanks yihcdaso-yeskela)
- Cache might writethrough too often #16
- even moar testrunner updates
- Test framework update and some added tests
- Some thoughts for next gen
- Test sigsevs when having too many sectors #13 (thanks alonewolfx2)
- GC might be suboptimal #11
- Fix eternal readdir when objheader at last block, last entry
New API functions:
- `SPIFFS_gc_quick` - call a nonintrusive gc
- `SPIFFS_gc` - call a full-scale intrusive gc
### 0.3.1
- Removed two return warnings, was too triggerhappy on release
### 0.3.0
- Added existing namecheck when creating files
- Lots of static analysis bugs #6
- Added rename func
- Fix SPIFFS_read length when reading beyond file size
- Added reading beyond file length testcase
- Made build a bit more configurable
- Changed name in spiffs from "errno" to "err_code" due to conflicts compiling in mingw
- Improved GC checks, fixed an append bug, more robust truncate for very special case
- GC checks preempts GC, truncate even less picky
- Struct alignment needed for some targets, define in spiffs config #10
- Spiffs filesystem magic, definable in config
New config defines:
- `SPIFFS_USE_MAGIC` - enable or disable magic check upon mount
- `SPIFFS_ALIGNED_OBJECT_INDEX_TABLES` - alignment for certain targets
New API functions:
- `SPIFFS_rename` - rename files
- `SPIFFS_clearerr` - clears last errno
- `SPIFFS_info` - returns info on used and total bytes in fs
- `SPIFFS_format` - formats the filesystem
- `SPIFFS_mounted` - checks if filesystem is mounted
