Macintosh-Tools/machfs
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Allow catalog file to cross 4+ extents

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This commit is contained in:
Elliot Nunn 2018-10-18 14:05:15 +08:00
parent 67edf73321
commit 7d8a12fb7e
1 changed files with 25 additions and 13 deletions
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38
machfs/main.py
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@ -58,6 +58,25 @@ def _suggest_allocblk_size(volsize, minalign):
return retval
def _get_every_extent(nblocks, firstrecord, cnid, xoflow, fork):
accum = 0
extlist = []
for a, b in btree.unpack_extent_record(firstrecord):
if not b: continue
accum += b
extlist.append((a, b))
while accum < nblocks:
nextrecord = xoflow[cnid, fork, accum]
for a, b in btree.unpack_extent_record(nextrecord):
if not b: continue
accum += b
extlist.append((a, b))
return extlist
class _TempWrapper:
"""Volume uses this to store metadata while serialising"""
def __init__(self, of):
@ -121,11 +140,11 @@ class Volume(directory.AbstractFolder):
self.name = drVN.decode('mac_roman')
block2offset = lambda block: 512*drAlBlSt + drAlBlkSiz*block
extent2bytes = lambda firstblk, blkcnt: from_volume[block2offset(firstblk):block2offset(firstblk+blkcnt)]
extrec2bytes = lambda extrec: b''.join(extent2bytes(a, b) for (a, b) in btree.unpack_extent_record(extrec))
getextents = lambda extents: b''.join(from_volume[block2offset(firstblk):block2offset(firstblk+blkcnt)] for (firstblk, blkcnt) in extents)
getfork = lambda size, extrec1, cnid, fork: getextents(_get_every_extent((size+drAlBlkSiz-1)//drAlBlkSiz, extrec1, cnid, extoflow, fork))[:size]
extoflow = {}
for rec in btree.dump_btree(extrec2bytes(drXTExtRec)):
for rec in btree.dump_btree(getfork(drXTFlSize, drXTExtRec, 3, 'data')):
if rec[0] != 7: continue
xkrFkType, xkrFNum, xkrFABN, extrec = struct.unpack_from('>xBLH12s', rec)
if xkrFkType == 0xFF:
@ -138,7 +157,7 @@ class Volume(directory.AbstractFolder):
childlist = [] # list of (parent_cnid, child_name, child_object) tuples
prev_key = None
for rec in btree.dump_btree(extrec2bytes(drCTExtRec)):
for rec in btree.dump_btree(getfork(drCTFlSize, drCTExtRec, 4, 'data')):
# create a directory tree from the catalog file
rec_len = rec[0]
if rec_len == 0: continue
@ -187,15 +206,8 @@ class Volume(directory.AbstractFolder):
f.crdat, f.mddat, f.bkdat = filCrDat, filMdDat, filBkDat
f.type, f.creator, f.flags, f.x, f.y = struct.unpack_from('>4s4sHHH', filUsrWds)
for fork, length, extrec in [('data', filLgLen, filExtRec), ('rsrc', filRLgLen, filRExtRec)]:
accum = bytearray(extrec2bytes(extrec))
while len(accum) < length:
next_blk = len(accum) // drAlBlkSiz
next_extrec = extoflow[filFlNum, fork, next_blk]
accum.extend(extrec2bytes(next_extrec))
del accum[length:] # logical length can be less than a number of blocks
setattr(f, fork, accum)
f.data = getfork(filLgLen, filExtRec, filFlNum, 'data')
f.rsrc = getfork(filRLgLen, filRExtRec, filFlNum, 'rsrc')
# elif datatype == 3:
# print('dir thread:', rec)