forked from Imagelibrary/littlefs
d308ec8322
Mainly to make room for some future planned stuff:
- Moved the mroot's redund bits from LFSR_TAG_GEOMETRY to
LFSR_TAG_MAGIC:
LFSR_TAG_MAGIC 0x003r v--- ---- --11 --rr
This has the benefit of living in a fixed location (off=0x5), which
may make mounting/debugging easier. It also makes LFSR_TAG_GEOMETRY
less of a special case (LFSR_TAG_MAGIC is already a _very_ special
case).
Unfortunately, this does get in the way of our previous magic=0x3
encoding. To compensate (and to avoid conflicts with LFSR_TAG_NULL),
I've added the 0x3_ prefix. This has the funny side-effect of
rendering redunds 0-3 as ascii 0-3 (0x30-0x33), which is a complete
accident but may actually be useful when debugging.
Currently all config tags fit in the 0x3_ prefix, which is nice for
debugging but not a hard requirement.
- Flipped LFSR_TAG_FILELIMIT/NAMELIMIT:
LFSR_TAG_FILELIMIT 0x0039 v--- ---- --11 1--1
LFSR_TAG_NAMELIMIT 0x003a v--- ---- --11 1-1-
The file limit is a _bit_ more fundamental. It's effectively the
required integer size for the filesystem.
These may also be followed by LFSR_TAG_ATTRLIMIT based on how future
attr revisits go.
- Rearranged struct tags so that LFSR_TAG_BRANCH = 0x300:
LFSR_TAG_BRANCH 0x030r v--- --11 ---- --rr
LFSR_TAG_DATA 0x0304 v--- --11 ---- -1--
LFSR_TAG_BLOCK 0x0308 v--- --11 ---- 1err
LFSR_TAG_DDKEY* 0x0310 v--- --11 ---1 ----
LFSR_TAG_DID 0x0314 v--- --11 ---1 -1--
LFSR_TAG_BSHRUB 0x0318 v--- --11 ---1 1---
LFSR_TAG_BTREE 0x031c v--- --11 ---1 11rr
LFSR_TAG_MROOT 0x032r v--- --11 --1- --rr
LFSR_TAG_MDIR 0x0324 v--- --11 --1- -1rr
LFSR_TAG_MTREE 0x032c v--- --11 --1- 11rr
*Planned
LFSR_TAG_BRANCH is a very special tag when it comes to bshrub/btree
traversal, so I think it deserves the subtype=0 slot.
This also just makes everything fit together better, and makes room
for the future planned ddkey tag.
Code changes minimal:
code stack ctx
before: 35728 2440 640
after: 35732 (+0.0%) 2440 (+0.0%) 640 (+0.0%)
343 lines
12 KiB
Python
Executable File
343 lines
12 KiB
Python
Executable File
#!/usr/bin/env python3
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# prevent local imports
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if __name__ == "__main__":
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__import__('sys').path.pop(0)
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import io
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import math as mt
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import os
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import struct
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import sys
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TAG_NULL = 0x0000 ## 0x0000 v--- ---- ---- ----
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TAG_CONFIG = 0x0000 ## 0x00tt v--- ---- -ttt tttt
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TAG_MAGIC = 0x0031 # 0x003r v--- ---- --11 --rr
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TAG_VERSION = 0x0034 # 0x0034 v--- ---- --11 -1--
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TAG_RCOMPAT = 0x0035 # 0x0035 v--- ---- --11 -1-1
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TAG_WCOMPAT = 0x0036 # 0x0036 v--- ---- --11 -11-
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TAG_OCOMPAT = 0x0037 # 0x0037 v--- ---- --11 -111
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TAG_GEOMETRY = 0x0038 # 0x0038 v--- ---- --11 1---
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TAG_FILELIMIT = 0x0039 # 0x0039 v--- ---- --11 1--1
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TAG_NAMELIMIT = 0x003a # 0x003a v--- ---- --11 1-1-
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TAG_GDELTA = 0x0100 ## 0x01tt v--- ---1 -ttt ttrr
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TAG_GRMDELTA = 0x0100 # 0x0100 v--- ---1 ---- ----
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TAG_NAME = 0x0200 ## 0x02tt v--- --1- -ttt tttt
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TAG_REG = 0x0201 # 0x0201 v--- --1- ---- ---1
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TAG_DIR = 0x0202 # 0x0202 v--- --1- ---- --1-
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TAG_STICKYNOTE = 0x0203 # 0x0203 v--- --1- ---- --11
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TAG_BOOKMARK = 0x0204 # 0x0204 v--- --1- ---- -1--
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TAG_STRUCT = 0x0300 ## 0x03tt v--- --11 -ttt ttrr
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TAG_BRANCH = 0x0300 # 0x030r v--- --11 ---- --rr
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TAG_DATA = 0x0304 # 0x0304 v--- --11 ---- -1--
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TAG_BLOCK = 0x0308 # 0x0308 v--- --11 ---- 1err
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TAG_DID = 0x0314 # 0x0314 v--- --11 ---1 -1--
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TAG_BSHRUB = 0x0318 # 0x0318 v--- --11 ---1 1---
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TAG_BTREE = 0x031c # 0x031c v--- --11 ---1 11rr
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TAG_MROOT = 0x0321 # 0x032r v--- --11 --1- --rr
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TAG_MDIR = 0x0325 # 0x0324 v--- --11 --1- -1rr
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TAG_MTREE = 0x032c # 0x032c v--- --11 --1- 11rr
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TAG_ATTR = 0x0400 ## 0x04aa v--- -1-a -aaa aaaa
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TAG_UATTR = 0x0400 # 0x04aa v--- -1-- -aaa aaaa
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TAG_SATTR = 0x0500 # 0x05aa v--- -1-1 -aaa aaaa
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TAG_SHRUB = 0x1000 ## 0x1kkk v--1 kkkk -kkk kkkk
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TAG_ALT = 0x4000 ## 0x4kkk v1cd kkkk -kkk kkkk
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TAG_B = 0x0000
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TAG_R = 0x2000
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TAG_LE = 0x0000
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TAG_GT = 0x1000
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TAG_CKSUM = 0x3000 ## 0x300p v-11 ---- ---- ---p
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TAG_P = 0x0001
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TAG_NOTE = 0x3100 ## 0x3100 v-11 ---1 ---- ----
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TAG_ECKSUM = 0x3200 ## 0x3200 v-11 --1- ---- ----
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TAG_GCKSUMDELTA = 0x3300 ## 0x3300 v-11 --11 ---- ----
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# open with '-' for stdin/stdout
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def openio(path, mode='r', buffering=-1):
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import os
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if path == '-':
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if 'r' in mode:
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return os.fdopen(os.dup(sys.stdin.fileno()), mode, buffering)
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else:
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return os.fdopen(os.dup(sys.stdout.fileno()), mode, buffering)
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else:
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return open(path, mode, buffering)
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def fromleb128(data, j=0):
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word = 0
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d = 0
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while j+d < len(data):
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b = data[j+d]
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word |= (b & 0x7f) << 7*d
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word &= 0xffffffff
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if not b & 0x80:
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return word, d+1
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d += 1
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return word, d
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def fromtag(data, j=0):
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d = 0
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tag = struct.unpack('>H', data[j:j+2].ljust(2, b'\0'))[0]; d += 2
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weight, d_ = fromleb128(data, j+d); d += d_
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size, d_ = fromleb128(data, j+d); d += d_
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return tag>>15, tag&0x7fff, weight, size, d
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# human readable tag repr
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def tagrepr(tag, weight=None, size=None, *,
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global_=False,
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toff=None):
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# null tags
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if (tag & 0x6fff) == TAG_NULL:
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return '%snull%s%s' % (
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'shrub' if tag & TAG_SHRUB else '',
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' w%d' % weight if weight else '',
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' %d' % size if size else '')
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# config tags
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elif (tag & 0x6f00) == TAG_CONFIG:
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return '%s%s%s%s' % (
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'shrub' if tag & TAG_SHRUB else '',
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'magic' if (tag & 0xfff) == TAG_MAGIC
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else 'version' if (tag & 0xfff) == TAG_VERSION
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else 'rcompat' if (tag & 0xfff) == TAG_RCOMPAT
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else 'wcompat' if (tag & 0xfff) == TAG_WCOMPAT
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else 'ocompat' if (tag & 0xfff) == TAG_OCOMPAT
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else 'geometry' if (tag & 0xfff) == TAG_GEOMETRY
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else 'filelimit' if (tag & 0xfff) == TAG_FILELIMIT
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else 'namelimit' if (tag & 0xfff) == TAG_NAMELIMIT
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else 'config 0x%02x' % (tag & 0xff),
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' w%d' % weight if weight else '',
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' %s' % size if size is not None else '')
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# global-state delta tags
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elif (tag & 0x6f00) == TAG_GDELTA:
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if global_:
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return '%s%s%s%s' % (
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'shrub' if tag & TAG_SHRUB else '',
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'grm' if (tag & 0xfff) == TAG_GRMDELTA
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else 'gstate 0x%02x' % (tag & 0xff),
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' w%d' % weight if weight else '',
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' %s' % size if size is not None else '')
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else:
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return '%s%s%s%s' % (
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'shrub' if tag & TAG_SHRUB else '',
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'grmdelta' if (tag & 0xfff) == TAG_GRMDELTA
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else 'gdelta 0x%02x' % (tag & 0xff),
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' w%d' % weight if weight else '',
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' %s' % size if size is not None else '')
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# name tags, includes file types
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elif (tag & 0x6f00) == TAG_NAME:
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return '%s%s%s%s' % (
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'shrub' if tag & TAG_SHRUB else '',
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'name' if (tag & 0xfff) == TAG_NAME
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else 'reg' if (tag & 0xfff) == TAG_REG
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else 'dir' if (tag & 0xfff) == TAG_DIR
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else 'stickynote' if (tag & 0xfff) == TAG_STICKYNOTE
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else 'bookmark' if (tag & 0xfff) == TAG_BOOKMARK
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else 'name 0x%02x' % (tag & 0xff),
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' w%d' % weight if weight else '',
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' %s' % size if size is not None else '')
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# structure tags
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elif (tag & 0x6f00) == TAG_STRUCT:
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return '%s%s%s%s' % (
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'shrub' if tag & TAG_SHRUB else '',
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'branch' if (tag & 0xfff) == TAG_BRANCH
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else 'data' if (tag & 0xfff) == TAG_DATA
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else 'block' if (tag & 0xfff) == TAG_BLOCK
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else 'did' if (tag & 0xfff) == TAG_DID
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else 'bshrub' if (tag & 0xfff) == TAG_BSHRUB
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else 'btree' if (tag & 0xfff) == TAG_BTREE
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else 'mroot' if (tag & 0xfff) == TAG_MROOT
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else 'mdir' if (tag & 0xfff) == TAG_MDIR
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else 'mtree' if (tag & 0xfff) == TAG_MTREE
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else 'struct 0x%02x' % (tag & 0xff),
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' w%d' % weight if weight else '',
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' %s' % size if size is not None else '')
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# custom attributes
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elif (tag & 0x6e00) == TAG_ATTR:
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return '%s%sattr 0x%02x%s%s' % (
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'shrub' if tag & TAG_SHRUB else '',
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's' if tag & 0x100 else 'u',
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((tag & 0x100) >> 1) ^ (tag & 0xff),
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' w%d' % weight if weight else '',
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' %s' % size if size is not None else '')
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# alt pointers
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elif tag & TAG_ALT:
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return 'alt%s%s 0x%03x%s%s' % (
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'r' if tag & TAG_R else 'b',
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'gt' if tag & TAG_GT else 'le',
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tag & 0x0fff,
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' w%d' % weight if weight is not None else '',
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' 0x%x' % (0xffffffff & (toff-size))
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if size and toff is not None
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else ' -%d' % size if size
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else '')
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# checksum tags
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elif (tag & 0x7f00) == TAG_CKSUM:
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return 'cksum%s%s%s%s' % (
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'p' if not tag & 0xfe and tag & TAG_P else '',
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' 0x%02x' % (tag & 0xff) if tag & 0xfe else '',
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' w%d' % weight if weight else '',
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' %s' % size if size is not None else '')
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# note tags
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elif (tag & 0x7f00) == TAG_NOTE:
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return 'note%s%s%s' % (
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' 0x%02x' % (tag & 0xff) if tag & 0xff else '',
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' w%d' % weight if weight else '',
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' %s' % size if size is not None else '')
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# erased-state checksum tags
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elif (tag & 0x7f00) == TAG_ECKSUM:
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return 'ecksum%s%s%s' % (
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' 0x%02x' % (tag & 0xff) if tag & 0xff else '',
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' w%d' % weight if weight else '',
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' %s' % size if size is not None else '')
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# global-checksum delta tags
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elif (tag & 0x7f00) == TAG_GCKSUMDELTA:
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if global_:
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return 'gcksum%s%s%s' % (
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' 0x%02x' % (tag & 0xff) if tag & 0xff else '',
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' w%d' % weight if weight else '',
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' %s' % size if size is not None else '')
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else:
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return 'gcksumdelta%s%s%s' % (
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' 0x%02x' % (tag & 0xff) if tag & 0xff else '',
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' w%d' % weight if weight else '',
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' %s' % size if size is not None else '')
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# unknown tags
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else:
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return '0x%04x%s%s' % (
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tag,
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' w%d' % weight if weight is not None else '',
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' %d' % size if size is not None else '')
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def list_tags():
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# here be magic, parse our script's source to get to the tag comments
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import inspect
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import re
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tags = []
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tag_pattern = re.compile(
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'^(?P<name>TAG_[^ ]*) *= *(?P<tag>[^ #]+) *#+ *(?P<comment>.*)$')
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for line in inspect.getsourcelines(
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inspect.getmodule(inspect.currentframe()))[0]:
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m = tag_pattern.match(line)
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if m:
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tags.append(m.groups())
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# find widths for alignment
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w = [0]
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for n, t, c in tags:
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w[0] = max(w[0], len('LFSR_'+n))
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# print
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for n, t, c in tags:
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print('%-*s %s' % (
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w[0], 'LFSR_'+n,
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c))
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def dbg_tags(data, *,
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word_bits=32):
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# figure out tag size in bytes
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if word_bits != 0:
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n = 2 + 2*mt.ceil(word_bits / 7)
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lines = []
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# interpret as ints?
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if not isinstance(data, bytes):
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for tag in data:
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lines.append((
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' '.join('%02x' % b for b in struct.pack('>H', tag)),
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tagrepr(tag)))
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# interpret as bytes?
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else:
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j = 0
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while j < len(data):
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# bounded tags?
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if word_bits != 0:
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v, tag, w, size, d = fromtag(data[j:j+n])
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# unbounded?
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else:
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v, tag, w, size, d = fromtag(data, j)
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lines.append((
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' '.join('%02x' % b for b in data[j:j+d]),
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tagrepr(tag, w, size)))
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j += d
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# skip attached data if there is any
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if not tag & TAG_ALT:
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j += size
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# figure out widths
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w = [0]
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for l in lines:
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w[0] = max(w[0], len(l[0]))
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# then print results
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for l in lines:
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print('%-*s %s' % (
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w[0], l[0],
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l[1]))
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def main(tags, *,
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list=False,
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hex=False,
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input=None,
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word_bits=32):
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list_ = list; del list
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hex_ = hex; del hex
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# list all known tags
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if list_:
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list_tags()
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# interpret as a sequence of hex bytes
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elif hex_:
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bytes_ = [b for tag in tags for b in tag.split()]
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dbg_tags(bytes(int(b, 16) for b in bytes_),
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word_bits=word_bits)
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# parse tags in a file
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elif input:
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with openio(input, 'rb') as f:
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dbg_tags(f.read(),
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word_bits=word_bits)
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# default to interpreting as ints
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else:
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dbg_tags((int(tag, 0) for tag in tags),
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word_bits=word_bits)
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if __name__ == "__main__":
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import argparse
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import sys
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parser = argparse.ArgumentParser(
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description="Decode littlefs tags.",
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allow_abbrev=False)
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parser.add_argument(
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'tags',
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nargs='*',
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help="Tags to decode.")
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parser.add_argument(
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'-l', '--list',
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action='store_true',
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help="List all known tags.")
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parser.add_argument(
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'-x', '--hex',
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action='store_true',
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help="Interpret as a sequence of hex bytes.")
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parser.add_argument(
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'-i', '--input',
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help="Read tags from this file. Can use - for stdin.")
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parser.add_argument(
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'-w', '--word-bits',
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nargs='?',
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type=lambda x: int(x, 0),
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const=0,
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help="Word size in bits. 0 is unbounded. Defaults to 32.")
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sys.exit(main(**{k: v
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for k, v in vars(parser.parse_intermixed_args()).items()
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if v is not None}))
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