diff options
Diffstat (limited to 'Lib/zipfile.py')
| -rw-r--r-- | Lib/zipfile.py | 58 |
1 files changed, 51 insertions, 7 deletions
diff --git a/Lib/zipfile.py b/Lib/zipfile.py index 2e5bfac..5a7345b 100644 --- a/Lib/zipfile.py +++ b/Lib/zipfile.py @@ -27,6 +27,41 @@ stringCentralDir = "PK\001\002" # magic number for central directory structFileHeader = "<4s2B4H3l2H" # 12 items, file header record, 30 bytes stringFileHeader = "PK\003\004" # magic number for file header +# indexes of entries in the central directory structure +_CD_SIGNATURE = 0 +_CD_CREATE_VERSION = 1 +_CD_CREATE_SYSTEM = 2 +_CD_EXTRACT_VERSION = 3 +_CD_EXTRACT_SYSTEM = 4 # is this meaningful? +_CD_FLAG_BITS = 5 +_CD_COMPRESS_TYPE = 6 +_CD_TIME = 7 +_CD_DATE = 8 +_CD_CRC = 9 +_CD_COMPRESSED_SIZE = 10 +_CD_UNCOMPRESSED_SIZE = 11 +_CD_FILENAME_LENGTH = 12 +_CD_EXTRA_FIELD_LENGTH = 13 +_CD_COMMENT_LENGTH = 14 +_CD_DISK_NUMBER_START = 15 +_CD_INTERNAL_FILE_ATTRIBUTES = 16 +_CD_EXTERNAL_FILE_ATTRIBUTES = 17 +_CD_LOCAL_HEADER_OFFSET = 18 + +# indexes of entries in the local file header structure +_FH_SIGNATURE = 0 +_FH_EXTRACT_VERSION = 1 +_FH_EXTRACT_SYSTEM = 2 # is this meaningful? +_FH_GENERAL_PURPOSE_FLAG_BITS = 3 +_FH_COMPRESSION_METHOD = 4 +_FH_LAST_MOD_TIME = 5 +_FH_LAST_MOD_DATE = 6 +_FH_CRC = 7 +_FH_COMPRESSED_SIZE = 8 +_FH_UNCOMPRESSED_SIZE = 9 +_FH_FILENAME_LENGTH = 10 +_FH_EXTRA_FIELD_LENGTH = 11 + def is_zipfile(filename): """Quickly see if file is a ZIP file by checking the magic number. @@ -159,14 +194,16 @@ class ZipFile: centdir = struct.unpack(structCentralDir, centdir) if self.debug > 2: print centdir - filename = fp.read(centdir[12]) + filename = fp.read(centdir[_CD_FILENAME_LENGTH]) # Create ZipInfo instance to store file information x = ZipInfo(filename) - x.extra = fp.read(centdir[13]) - x.comment = fp.read(centdir[14]) - total = total + centdir[12] + centdir[13] + centdir[14] - x.header_offset = centdir[18] + concat - x.file_offset = x.header_offset + 30 + centdir[12] + centdir[13] + x.extra = fp.read(centdir[_CD_EXTRA_FIELD_LENGTH]) + x.comment = fp.read(centdir[_CD_COMMENT_LENGTH]) + total = (total + centdir[_CD_FILENAME_LENGTH] + + centdir[_CD_EXTRA_FIELD_LENGTH] + + centdir[_CD_COMMENT_LENGTH]) + x.header_offset = centdir[_CD_LOCAL_HEADER_OFFSET] + concat + # file_offset must be computed below... (x.create_version, x.create_system, x.extract_version, x.reserved, x.flag_bits, x.compress_type, t, d, x.CRC, x.compress_size, x.file_size) = centdir[1:12] @@ -184,7 +221,14 @@ class ZipFile: if fheader[0:4] != stringFileHeader: raise BadZipfile, "Bad magic number for file header" fheader = struct.unpack(structFileHeader, fheader) - fname = fp.read(fheader[10]) + # file_offset is computed here, since the extra field for + # the central directory and for the local file header + # refer to different fields, and they can have different + # lengths + data.file_offset = (data.header_offset + 30 + + fheader[_FH_FILENAME_LENGTH] + + fheader[_FH_EXTRA_FIELD_LENGTH]) + fname = fp.read(fheader[_FH_FILENAME_LENGTH]) if fname != data.filename: raise RuntimeError, \ 'File name in directory "%s" and header "%s" differ.' % ( |