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https://github.com/iKarith/cppo-ng.git
synced 2024-06-07 00:29:29 +00:00
Use struct.{un,}pack_into instead of int methods
The methods int.to_bytes() and int.from_bytes() are ... both messy and ugly, contrary to the Zen of Python. Right now, we're just writing out single ints and words, but eventually we'll be reading and writing whole structures, so it makes sense to begin moving the codebase in that direction. I've written only the functions I either use or see a use for immediately, save for pack_u32be() which I wrote for date conversions, and then immediately realized we don't want to use for that purpose yet. We can remove it if we don't ultimately need it.
This commit is contained in:
T. Joseph Carter
parent
e2d5e63a75
commit
23392b77de
64
cppo
64
cppo
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@ -36,6 +36,7 @@ import uuid # for temp directory
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import subprocess
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#import tempfile # not used, but should be for temp directory?
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import logging
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import struct
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from binascii import a2b_hex, b2a_hex
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class Globals:
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@ -78,6 +79,22 @@ g.dos33 = False # (DOS 3.3 image source, selected automatically
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# functions
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def pack_u24be(buf: bytes, offset: int, val: int):
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lo16 = val & 0xffff
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hi8 = (val >> 16) & 0xff
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struct.pack_into('>BH', buf, offset, hi8, lo16)
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def pack_u32be(buf: bytes, offset: int, val: int):
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# Currently unused, will be needed for resource fork dates later
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struct.pack_into('>L', buf, offset, val)
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def unpack_u16le(buf: bytes, offset: int = 0) -> int:
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return struct.unpack_from('<H', buf, offset)[0]
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def unpack_u24le(buf: bytes, offset: int = 0) -> int:
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lo16, hi8 = struct.unpack_from('<HB', buf, offset)
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return lo16 | (hi8 << 16)
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def date_prodos_to_unix(prodos_date: bytes) -> int:
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"""Returns a UNIX timestamp given a raw ProDOS date"""
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"""The ProDOS date consists of two 16-bit words stored little-
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@ -179,7 +196,7 @@ def getFileName(arg1, arg2):
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def getCaseMask(arg1, arg2):
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start = getStartPos(arg1, arg2)
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caseMaskDec = int.from_bytes(g.image_data[sli(start+28,2)], 'little')
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caseMaskDec = unpack_u16le(g.image_data, start + 28)
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if caseMaskDec < 32768:
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return None
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else:
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@ -223,17 +240,14 @@ def getAuxType(arg1, arg2):
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else: # TXT (T) or other
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return '0000'
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else: # ProDOS
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return (
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b2a_hex(g.image_data[sli(start+32,1)])
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+ b2a_hex(g.image_data[sli(start+31,1)])
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).decode()
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return format(unpack_u16le(g.image_data, start + 31), '04x')
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def getKeyPointer(arg1, arg2):
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start = getStartPos(arg1, arg2)
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if g.dos33:
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return list(g.image_data[sli(start,2)])
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else: # ProDOS
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return int.from_bytes(g.image_data[sli(start+17,2)], 'little')
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return unpack_u16le(g.image_data, start + 17)
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def getFileLength(arg1, arg2):
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start = getStartPos(arg1, arg2)
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@ -243,19 +257,15 @@ def getFileLength(arg1, arg2):
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fileStart = list(g.image_data[sli(ts(fileTSlist)+12,2)])
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if fileType == '06': # BIN (B)
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# file length is in second two bytes of file data
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return (int.from_bytes(g.image_data[
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sli(ts(fileStart)+2, 2)
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], 'little') + 4)
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file_size = unpack_u16le(g.image_data, ts(fileStart) + 2) + 4
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elif fileType == 'FC' or fileType == 'FA': # BAS (A) or INT (I)
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# file length is in first two bytes of file data
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return (int.from_bytes(g.image_data[
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sli(ts(fileStart), 2)
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], 'little') + 2)
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file_size = unpack_u16le(g.image_data, ts(fileStart)) + 2
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else: # TXT (T) or other
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# sadly, we have to walk the whole file
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# length is determined by sectors in TSlist, minus wherever
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# anything after the first zero in the last sector
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fileSize = 0
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file_size = 0
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lastTSpair = None
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prevTSpair = [0,0]
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nextTSlistSector = fileTSlist
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@ -265,7 +275,7 @@ def getFileLength(arg1, arg2):
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for tsPos in range(12, 256, 2):
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cur_ts_pair = list(g.image_data[sli(pos+tsPos,2)])
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if ts(cur_ts_pair) != 0:
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fileSize += 256
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file_size += 256
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prevTSpair = cur_ts_pair
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else:
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lastTSpair = prevTSpair
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@ -277,17 +287,18 @@ def getFileLength(arg1, arg2):
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lastTSpair = prevTSpair
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endFound = True
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break
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fileSize -= 256
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file_size -= 256
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pos = ts(prevTSpair)
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# now find out where the file really ends by finding the last 00
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for offset in range(255, -1, -1):
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#print("pos: " + to_hex(pos))
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if g.image_data[pos+offset] != 0:
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fileSize += (offset + 1)
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file_size += (offset + 1)
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break
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return fileSize
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else: # ProDOS
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return int.from_bytes(g.image_data[sli(start+21,3)], 'little')
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file_size = unpack_u24le(g.image_data, start + 21)
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return file_size
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def getCreationDate(arg1, arg2):
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#outputs prodos creation date/time as Unix time
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@ -325,7 +336,7 @@ def getWorkingDirName(arg1, arg2=None):
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nameLength = firstByte - entryType*16
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workingDirName = g.image_data[sli(start+5, nameLength)]
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if entryType == 15: # volume directory, get casemask from header
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caseMaskDec = int.from_bytes(g.image_data[sli(start+26,2)], 'little')
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caseMaskDec = unpack_u16le(g.image_data, start + 26)
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if caseMaskDec < 32768:
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caseMask = None
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else:
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@ -359,7 +370,7 @@ def getDirEntryCount(arg1):
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return entryCount
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else: # ProDOS
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start = arg1 * 512
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return int.from_bytes(g.image_data[sli(start+37,2)], 'little')
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return unpack_u16le(g.image_data, start + 37)
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def getDirNextChunkPointer(arg1):
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if g.dos33:
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@ -367,7 +378,7 @@ def getDirNextChunkPointer(arg1):
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return list(g.image_data[sli(start+1,2)])
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else: # ProDOS
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start = arg1 * 512
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return int.from_bytes(g.image_data[sli(start+2,2)], 'little')
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return unpack_u16le(g.image_data, start + 2)
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def toProdosName(name):
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i=0
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@ -645,19 +656,16 @@ def processForkedFile(arg1):
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forkStart = arg1 * 512 # start of Forked File key block
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#print("--" + forkStart)
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forkStorageType = g.image_data[forkStart+f]
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forkKeyPointer = int.from_bytes(g.image_data[
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sli(forkStart+f+1,2) ], 'little')
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forkFileLen = int.from_bytes(g.image_data[
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sli(forkStart+f+5,3) ], 'little')
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forkKeyPointer = unpack_u16le(g.image_data, forkStart + f + 1)
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forkFileLen = unpack_u24le(g.image_data, forkStart + f + 5)
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g.activeFileSize = forkFileLen
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if g.resourceFork > 0:
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rsrcForkLen = int.from_bytes(g.image_data[
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sli(forkStart + f + 5, 3)],'little')
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rsrcForkLen = unpack_u24le(g.image_data, forkStart + f + 5)
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#print(">>>", rsrcForkLen)
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if g.use_appledouble or g.use_extended:
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print(" [resource fork]")
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if g.use_appledouble:
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g.ex_data[35:38] = rsrcForkLen.to_bytes(3, 'big')
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pack_u24be(g.ex_data, 35, rsrcForkLen)
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else:
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print(" [data fork]")
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if forkStorageType == 1: #seedling
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