Issue #26293: Fixed writing ZIP files that starts not from the start of the
file. Offsets in ZIP file now are relative to the start of the archive in
conforming to the specification.
diff --git a/Lib/zipfile.py b/Lib/zipfile.py
index 56a2479..2476717 100644
--- a/Lib/zipfile.py
+++ b/Lib/zipfile.py
@@ -1029,10 +1029,10 @@
# even if no files are added to the archive
self._didModify = True
try:
- self.start_dir = self.fp.tell()
+ self.start_dir = self._start_disk = self.fp.tell()
except (AttributeError, OSError):
self.fp = _Tellable(self.fp)
- self.start_dir = 0
+ self.start_dir = self._start_disk = 0
self._seekable = False
else:
# Some file-like objects can provide tell() but not seek()
@@ -1053,7 +1053,7 @@
# set the modified flag so central directory gets written
# even if no files are added to the archive
self._didModify = True
- self.start_dir = self.fp.tell()
+ self.start_dir = self._start_disk = self.fp.tell()
else:
raise RuntimeError("Mode must be 'r', 'w', 'x', or 'a'")
except:
@@ -1097,17 +1097,18 @@
offset_cd = endrec[_ECD_OFFSET] # offset of central directory
self._comment = endrec[_ECD_COMMENT] # archive comment
- # "concat" is zero, unless zip was concatenated to another file
- concat = endrec[_ECD_LOCATION] - size_cd - offset_cd
+ # self._start_disk: Position of the start of ZIP archive
+ # It is zero, unless ZIP was concatenated to another file
+ self._start_disk = endrec[_ECD_LOCATION] - size_cd - offset_cd
if endrec[_ECD_SIGNATURE] == stringEndArchive64:
# If Zip64 extension structures are present, account for them
- concat -= (sizeEndCentDir64 + sizeEndCentDir64Locator)
+ self._start_disk -= (sizeEndCentDir64 + sizeEndCentDir64Locator)
if self.debug > 2:
- inferred = concat + offset_cd
- print("given, inferred, offset", offset_cd, inferred, concat)
+ inferred = self._start_disk + offset_cd
+ print("given, inferred, offset", offset_cd, inferred, self._start_disk)
# self.start_dir: Position of start of central directory
- self.start_dir = offset_cd + concat
+ self.start_dir = offset_cd + self._start_disk
fp.seek(self.start_dir, 0)
data = fp.read(size_cd)
fp = io.BytesIO(data)
@@ -1147,7 +1148,7 @@
t>>11, (t>>5)&0x3F, (t&0x1F) * 2 )
x._decodeExtra()
- x.header_offset = x.header_offset + concat
+ x.header_offset = x.header_offset + self._start_disk
self.filelist.append(x)
self.NameToInfo[x.filename] = x
@@ -1627,11 +1628,10 @@
file_size = zinfo.file_size
compress_size = zinfo.compress_size
- if zinfo.header_offset > ZIP64_LIMIT:
- extra.append(zinfo.header_offset)
+ header_offset = zinfo.header_offset - self._start_disk
+ if header_offset > ZIP64_LIMIT:
+ extra.append(header_offset)
header_offset = 0xffffffff
- else:
- header_offset = zinfo.header_offset
extra_data = zinfo.extra
min_version = 0
@@ -1678,7 +1678,7 @@
# Write end-of-zip-archive record
centDirCount = len(self.filelist)
centDirSize = pos2 - self.start_dir
- centDirOffset = self.start_dir
+ centDirOffset = self.start_dir - self._start_disk
requires_zip64 = None
if centDirCount > ZIP_FILECOUNT_LIMIT:
requires_zip64 = "Files count"