mirror of
https://github.com/eledio-devices/thirdparty-littlefs.git
synced 2025-10-31 16:14:16 +01:00
d7e4abad0b
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
107 lines
2.8 KiB
Python
Executable File
107 lines
2.8 KiB
Python
Executable File
#!/usr/bin/env python2
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import struct
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import binascii
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TYPES = {
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(0x1ff, 0x002): 'reg',
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(0x1ff, 0x003): 'dir',
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(0x1ff, 0x001): 'superblock',
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(0x1ff, 0x020): 'delete',
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(0x1f0, 0x0e0): 'globals',
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(0x1ff, 0x080): 'tail soft',
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(0x1ff, 0x081): 'tail hard',
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(0x1f0, 0x0a0): 'crc',
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(0x1ff, 0x040): 'struct dir',
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(0x1ff, 0x041): 'struct inline',
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(0x1ff, 0x042): 'struct ctz',
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(0x100, 0x100): 'attr',
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}
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def typeof(type):
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for prefix in range(9):
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mask = 0x1ff & ~((1 << prefix)-1)
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if (mask, type & mask) in TYPES:
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return TYPES[mask, type & mask] + (
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' [%0*x]' % (prefix/4, type & ((1 << prefix)-1))
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if prefix else '')
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else:
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return '[%02x]' % type
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def main(*blocks):
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# find most recent block
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file = None
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rev = None
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crc = None
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versions = []
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for block in blocks:
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try:
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nfile = open(block, 'rb')
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ndata = nfile.read(4)
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ncrc = binascii.crc32(ndata)
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nrev, = struct.unpack('<I', ndata)
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assert rev != nrev
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if not file or ((rev - nrev) & 0x80000000):
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file = nfile
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rev = nrev
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crc = ncrc
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versions.append((nrev, '%s (rev %d)' % (block, nrev)))
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except (IOError, struct.error):
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pass
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if not file:
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print 'Bad metadata pair {%s}' % ', '.join(blocks)
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return 1
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print "--- %s ---" % ', '.join(v for _,v in sorted(versions, reverse=True))
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# go through each tag, print useful information
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print "%-4s %-8s %-14s %3s %3s %s" % (
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'off', 'tag', 'type', 'id', 'len', 'dump')
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tag = 0xffffffff
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off = 4
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while True:
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try:
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data = file.read(4)
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crc = binascii.crc32(data, crc)
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ntag, = struct.unpack('<I', data)
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except struct.error:
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break
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tag ^= ntag
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off += 4
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type = (tag & 0x7fc00000) >> 22
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id = (tag & 0x003fe000) >> 13
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size = (tag & 0x00001fff) >> 0
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iscrc = (type & 0x1f0) == 0x0f0
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data = file.read(size if size != 0x1fff else 0)
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if iscrc:
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crc = binascii.crc32(data[:4], crc)
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else:
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crc = binascii.crc32(data, crc)
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print '%04x: %08x %-14s %3s %3s %-23s %-8s' % (
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off, tag,
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typeof(type) + (' bad!' if iscrc and ~crc else ''),
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id if id != 0x1ff else '.',
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size if size != 0x1fff else 'x',
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' '.join('%02x' % ord(c) for c in data[:8]),
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''.join(c if c >= ' ' and c <= '~' else '.' for c in data[:8]))
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off += size if size != 0x1fff else 0
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if iscrc:
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crc = 0
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tag ^= (type & 1) << 31
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return 0
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if __name__ == "__main__":
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import sys
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sys.exit(main(*sys.argv[1:]))
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