"""

Read and write ZIP files.

"""

import struct, os, time, sys

import binascii, cStringIO

try:

    import zlib # We may need its compression method

except ImportError:

    zlib = None

__all__ = ["BadZipfile", "error", "ZIP_STORED", "ZIP_DEFLATED", "is_zipfile",

           "ZipInfo", "ZipFile", "PyZipFile", "LargeZipFile" ]

class BadZipfile(Exception):

    pass

class LargeZipFile(Exception):

    """

    Raised when writing a zipfile, the zipfile requires ZIP64 extensions

    and those extensions are disabled.

    """

error = BadZipfile      # The exception raised by this module

ZIP64_LIMIT= (1 << 31) - 1

# constants for Zip file compression methods

ZIP_STORED = 0

ZIP_DEFLATED = 8

# Other ZIP compression methods not supported

# Here are some struct module formats for reading headers

structEndArchive = "<4s4H2LH"     # 9 items, end of archive, 22 bytes

stringEndArchive = "PK\005\006"   # magic number for end of archive record

structCentralDir = "<4s4B4HlLL5HLL"# 19 items, central directory, 46 bytes

stringCentralDir = "PK\001\002"   # magic number for central directory

structFileHeader = "<4s2B4HlLL2H"  # 12 items, file header record, 30 bytes

stringFileHeader = "PK\003\004"   # magic number for file header

structEndArchive64Locator = "<4slql" # 4 items, locate Zip64 header, 20 bytes

stringEndArchive64Locator = "PK\x06\x07" # magic token for locator header

structEndArchive64 = "<4sqhhllqqqq" # 10 items, end of archive (Zip64), 56 bytes

stringEndArchive64 = "PK\x06\x06" # magic token for Zip64 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."""

    try:

        fpin = open(filename, "rb")

        endrec = _EndRecData(fpin)

        fpin.close()

        if endrec:

            return True                 # file has correct magic number

    except IOError:

        pass

    return False

def _EndRecData64(fpin, offset, endrec):

    """

    Read the ZIP64 end-of-archive records and use that to update endrec

    """

    locatorSize = struct.calcsize(structEndArchive64Locator)

    fpin.seek(offset - locatorSize, 2)

    data = fpin.read(locatorSize)

    sig, diskno, reloff, disks = struct.unpack(structEndArchive64Locator, data)

    if sig != stringEndArchive64Locator:

        return endrec

    if diskno != 0 or disks != 1:

        raise BadZipfile("zipfiles that span multiple disks are not supported")

    # Assume no 'zip64 extensible data'

    endArchiveSize = struct.calcsize(structEndArchive64)

    fpin.seek(offset - locatorSize - endArchiveSize, 2)

    data = fpin.read(endArchiveSize)

    sig, sz, create_version, read_version, disk_num, disk_dir, \

            dircount, dircount2, dirsize, diroffset = \

            struct.unpack(structEndArchive64, data)

    if sig != stringEndArchive64:

        return endrec

    # Update the original endrec using data from the ZIP64 record

    endrec[1] = disk_num

    endrec[2] = disk_dir

    endrec[3] = dircount

    endrec[4] = dircount2

    endrec[5] = dirsize

    endrec[6] = diroffset

    return endrec

def _EndRecData(fpin):

    """Return data from the "End of Central Directory" record, or None.

    The data is a list of the nine items in the ZIP "End of central dir"

    record followed by a tenth item, the file seek offset of this record."""

    fpin.seek(-22, 2)               # Assume no archive comment.

    filesize = fpin.tell() + 22     # Get file size

    data = fpin.read()

    if data[0:4] == stringEndArchive and data[-2:] == "\000\000":

        endrec = struct.unpack(structEndArchive, data)

        endrec = list(endrec)

        endrec.append("")               # Append the archive comment

        endrec.append(filesize - 22)    # Append the record start offset

        if endrec[-4] == -1 or endrec[-4] == 0xffffffff:

            return _EndRecData64(fpin, -22, endrec)

        return endrec

    # Search the last END_BLOCK bytes of the file for the record signature.

    # The comment is appended to the ZIP file and has a 16 bit length.

    # So the comment may be up to 64K long.  We limit the search for the

    # signature to a few Kbytes at the end of the file for efficiency.

    # also, the signature must not appear in the comment.

    END_BLOCK = min(filesize, 1024 * 4)

    fpin.seek(filesize - END_BLOCK, 0)

    data = fpin.read()

    start = data.rfind(stringEndArchive)

    if start >= 0:     # Correct signature string was found

        endrec = struct.unpack(structEndArchive, data[start:start+22])

        endrec = list(endrec)

        comment = data[start+22:]

        if endrec[7] == len(comment):     # Comment length checks out

            # Append the archive comment and start offset

            endrec.append(comment)

            endrec.append(filesize - END_BLOCK + start)

            if endrec[-4] == -1 or endrec[-4] == 0xffffffff:

                return _EndRecData64(fpin, - END_BLOCK + start, endrec)

            return endrec

    return      # Error, return None

class ZipInfo (object):

    """Class with attributes describing each file in the ZIP archive."""

    __slots__ = (

            'orig_filename',

            'filename',

            'date_time',

            'compress_type',

            'comment',

            'extra',

            'create_system',

            'create_version',

            'extract_version',

            'reserved',

            'flag_bits',

            'volume',

            'internal_attr',

            'external_attr',

            'header_offset',

            'CRC',

            'compress_size',

            'file_size',

        )

    def __init__(self, filename="NoName", date_time=(1980,1,1,0,0,0)):

        self.orig_filename = filename   # Original file name in archive

        # Terminate the file name at the first null byte.  Null bytes in file

        # names are used as tricks by viruses in archives.

        null_byte = filename.find(chr(0))

        if null_byte >= 0:

            filename = filename[0:null_byte]

        # This is used to ensure paths in generated ZIP files always use

        # forward slashes as the directory separator, as required by the

        # ZIP format specification.

        if os.sep != "/" and os.sep in filename:

            filename = filename.replace(os.sep, "/")

        self.filename = filename        # Normalized file name

        self.date_time = date_time      # year, month, day, hour, min, sec

        # Standard values:

        self.compress_type = ZIP_STORED # Type of compression for the file

        self.comment = ""               # Comment for each file

        self.extra = ""                 # ZIP extra data

        if sys.platform == 'win32':

            self.create_system = 0          # System which created ZIP archive

        else:

            # Assume everything else is unix-y

            self.create_system = 3          # System which created ZIP archive

        self.create_version = 20        # Version which created ZIP archive

        self.extract_version = 20       # Version needed to extract archive

        self.reserved = 0               # Must be zero

        self.flag_bits = 0              # ZIP flag bits

        self.volume = 0                 # Volume number of file header

        self.internal_attr = 0          # Internal attributes

        self.external_attr = 0          # External file attributes

        # Other attributes are set by class ZipFile:

        # header_offset         Byte offset to the file header

        # CRC                   CRC-32 of the uncompressed file

        # compress_size         Size of the compressed file

        # file_size             Size of the uncompressed file

    def FileHeader(self):

        """Return the per-file header as a string."""

        dt = self.date_time

        dosdate = (dt[0] - 1980) << 9 | dt[1] << 5 | dt[2]

        dostime = dt[3] << 11 | dt[4] << 5 | (dt[5] // 2)

        if self.flag_bits & 0x08:

            # Set these to zero because we write them after the file data

            CRC = compress_size = file_size = 0

        else:

            CRC = self.CRC

            compress_size = self.compress_size

            file_size = self.file_size

        extra = self.extra

        if file_size > ZIP64_LIMIT or compress_size > ZIP64_LIMIT:

            # File is larger than what fits into a 4 byte integer,

            # fall back to the ZIP64 extension

            fmt = '<hhqq'

            extra = extra + struct.pack(fmt,

                    1, struct.calcsize(fmt)-4, file_size, compress_size)

            file_size = 0xffffffff # -1

            compress_size = 0xffffffff # -1

            self.extract_version = max(45, self.extract_version)

            self.create_version = max(45, self.extract_version)

        header = struct.pack(structFileHeader, stringFileHeader,

                 self.extract_version, self.reserved, self.flag_bits,

                 self.compress_type, dostime, dosdate, CRC,

                 compress_size, file_size,

                 len(self.filename), len(extra))

        return header + self.filename + extra

    def _decodeExtra(self):

        # Try to decode the extra field.

        extra = self.extra

        unpack = struct.unpack

        while extra:

            tp, ln = unpack('<hh', extra[:4])

            if tp == 1:

                if ln >= 24:

                    counts = unpack('<qqq', extra[4:28])

                elif ln == 16:

                    counts = unpack('<qq', extra[4:20])

                elif ln == 8:

                    counts = unpack('<q', extra[4:12])

                elif ln == 0:

                    counts = ()

                else:

                    raise RuntimeError, "Corrupt extra field %s"%(ln,)

                idx = 0

                # ZIP64 extension (large files and/or large archives)

                if self.file_size == -1 or self.file_size == 0xFFFFFFFFL:

                    self.file_size = counts[idx]

                    idx += 1

                if self.compress_size == -1 or self.compress_size == 0xFFFFFFFFL:

                    self.compress_size = counts[idx]

                    idx += 1

                if self.header_offset == -1 or self.header_offset == 0xffffffffL:

                    old = self.header_offset

                    self.header_offset = counts[idx]

                    idx+=1

            extra = extra[ln+4:]

class ZipFile:

    """ Class with methods to open, read, write, close, list zip files.

    z = ZipFile(file, mode="r", compression=ZIP_STORED, allowZip64=True)

    file: Either the path to the file, or a file-like object.

          If it is a path, the file will be opened and closed by ZipFile.

    mode: The mode can be either read "r", write "w" or append "a".

    compression: ZIP_STORED (no compression) or ZIP_DEFLATED (requires zlib).

    allowZip64: if True ZipFile will create files with ZIP64 extensions when

                needed, otherwise it will raise an exception when this would

                be necessary.

    """

    fp = None                   # Set here since __del__ checks it

    def __init__(self, file, mode="r", compression=ZIP_STORED, allowZip64=False):

        """Open the ZIP file with mode read "r", write "w" or append "a"."""

        self._allowZip64 = allowZip64

        self._didModify = False

        if compression == ZIP_STORED:

            pass

        elif compression == ZIP_DEFLATED:

            if not zlib:

                raise RuntimeError,\

                      "Compression requires the (missing) zlib module"

        else:

            raise RuntimeError, "That compression method is not supported"

        self.debug = 0  # Level of printing: 0 through 3

        self.NameToInfo = {}    # Find file info given name

        self.filelist = []      # List of ZipInfo instances for archive

        self.compression = compression  # Method of compression

        self.mode = key = mode.replace('b', '')[0]

        # Check if we were passed a file-like object

        if isinstance(file, basestring):

            self._filePassed = 0

            self.filename = file

            modeDict = {'r' : 'rb', 'w': 'wb', 'a' : 'r+b'}

            self.fp = open(file, modeDict[mode])

        else:

            self._filePassed = 1

            self.fp = file

            self.filename = getattr(file, 'name', None)

        if key == 'r':

            self._GetContents()

        elif key == 'w':

            pass

        elif key == 'a':

            try:                        # See if file is a zip file

                self._RealGetContents()

                # seek to start of directory and overwrite

                self.fp.seek(self.start_dir, 0)

            except BadZipfile:          # file is not a zip file, just append

                self.fp.seek(0, 2)

        else:

            if not self._filePassed:

                self.fp.close()

                self.fp = None

            raise RuntimeError, 'Mode must be "r", "w" or "a"'

    def _GetContents(self):

        """Read the directory, making sure we close the file if the format

        is bad."""

        try:

            self._RealGetContents()

        except BadZipfile:

            if not self._filePassed:

                self.fp.close()

                self.fp = None

            raise

    def _RealGetContents(self):

        """Read in the table of contents for the ZIP file."""

        fp = self.fp

        endrec = _EndRecData(fp)

        if not endrec:

            raise BadZipfile, "File is not a zip file"

        if self.debug > 1:

            print endrec

        size_cd = endrec[5]             # bytes in central directory

        offset_cd = endrec[6]   # offset of central directory

        self.comment = endrec[8]        # archive comment

        # endrec[9] is the offset of the "End of Central Dir" record

        if endrec[9] > ZIP64_LIMIT:

            x = endrec[9] - size_cd - 56 - 20

        else:

            x = endrec[9] - size_cd

        # "concat" is zero, unless zip was concatenated to another file

        concat = x - offset_cd

        if self.debug > 2:

            print "given, inferred, offset", offset_cd, x, concat

        # self.start_dir:  Position of start of central directory

        self.start_dir = offset_cd + concat

        fp.seek(self.start_dir, 0)

        data = fp.read(size_cd)

        fp = cStringIO.StringIO(data)

        total = 0

        while total < size_cd:

            centdir = fp.read(46)

            total = total + 46

            if centdir[0:4] != stringCentralDir:

                raise BadZipfile, "Bad magic number for central directory"

            centdir = struct.unpack(structCentralDir, centdir)

            if self.debug > 2:

                print centdir

            filename = fp.read(centdir[_CD_FILENAME_LENGTH])

            # Create ZipInfo instance to store file information

            x = ZipInfo(filename)

            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]

            (x.create_version, x.create_system, x.extract_version, x.reserved,

                x.flag_bits, x.compress_type, t, d,