github-mirrors/thirdparty-littlefs
1
0
Fork 0
mirror of https://github.com/eledio-devices/thirdparty-littlefs.git synced 2025-10-31 00:32:38 +01:00
Code Issues Packages Projects Releases Wiki Activity

Edited tag structure to balance size vs id count

Browse Source 
This is a minor tweak that resulted from looking at some other use cases
for the littlefs data-structure on disk. Consider an implementation that
does not need to buffer inline-files in RAM. In this case we should have
as large a tag size field as possible. Unfortunately, we don't have much
space to work with in the 32-bit tag struct, so we have to make some
compromises. These limitations could be removed with a 64-bit tag
struct, at the cost of code size.

32-bit tag structure:
[---       32       ---]
[1|- 9 -|- 9 -|-- 13 --]
 ^   ^     ^      ^- entry length
 |   |     \-------- file id
 |   \-------------- tag type
 \------------------ valid bit
This commit is contained in:
Christopher Haster
2018-09-15 02:40:53 -05:00
parent cafe6ab466
commit d7e4abad0b
4 changed files with 45 additions and 45 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
lfs.h
View File

@@ -49,7 +49,7 @@ typedef uint32_t lfs_block_t;
// to <= 0xfff. Stored in superblock and must be respected by other
// littlefs drivers.
#ifndef LFS_ATTR_MAX
#define LFS_ATTR_MAX 0xffe
#define LFS_ATTR_MAX 0x1ffe
#endif
// Maximum name size in bytes, may be redefined to reduce the size of the
@@ -64,7 +64,7 @@ typedef uint32_t lfs_block_t;
// block. Limited to <= LFS_ATTR_MAX and <= cache_size. Stored in superblock
// and must be respected by other littlefs drivers.
#ifndef LFS_INLINE_MAX
#define LFS_INLINE_MAX 0xffe
#define LFS_INLINE_MAX 0x1ffe
#endif
// Possible error codes, these are negative to allow