Vega strike Python Modules doc: Chunk Class Reference

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Public Member Functions
def	__init__

def	getname

def	getsize

def	close

def	isatty

def	seek

def	tell

def	read

def	skip

Data Fields
	closed

	align

	file

	chunkname

	chunksize

	size_read

	offset

	seekable

Detailed Description

Definition at line 51 of file chunk.py.

Constructor & Destructor Documentation

def __init__	(	self,
		file,
		align = `1`,
		bigendian = `1`,
		inclheader = `0`
	)

Definition at line 52 of file chunk.py.

 
     def __init__(self, file, align = 1, bigendian = 1, inclheader = 0):
         import struct
         self.closed = 0
         self.align = align      # whether to align to word (2-byte) boundaries
         if bigendian:
             strflag = '>'
         else:
             strflag = '<'
         self.file = file
         self.chunkname = file.read(4)
         if len(self.chunkname) < 4:
             raise EOFError
         try:
             self.chunksize = struct.unpack(strflag+'l', file.read(4))[0]
         except struct.error:
             raise EOFError
         if inclheader:
             self.chunksize = self.chunksize - 8 # subtract header
         self.size_read = 0
         try:
             self.offset = self.file.tell()
         except (AttributeError, IOError):
             self.seekable = 0
         else:
             self.seekable = 1

Member Function Documentation

def close ( self)

Definition at line 86 of file chunk.py.

References Chunk.closed, and Chunk.skip().

 
     def close(self):
         if not self.closed:
             self.skip()
             self.closed = 1

def getname ( self)

Return the name (ID) of the current chunk.

Definition at line 78 of file chunk.py.

References Chunk.chunkname.

 
     def getname(self):
         """Return the name (ID) of the current chunk."""
         return self.chunkname

def getsize ( self)

Return the size of the current chunk.

Definition at line 82 of file chunk.py.

References Chunk.chunksize.

 
     def getsize(self):
         """Return the size of the current chunk."""
         return self.chunksize

def read	(	self,
		size = `-1`
	)

Read at most size bytes from the chunk.
If size is omitted or negative, read until the end
of the chunk.

Definition at line 120 of file chunk.py.

References Chunk.align, Chunk.chunksize, Chunk.closed, and Chunk.size_read.

 
     def read(self, size = -1):
         """Read at most size bytes from the chunk.
         If size is omitted or negative, read until the end
         of the chunk.
         """
 
         if self.closed:
             raise ValueError, "I/O operation on closed file"
         if self.size_read >= self.chunksize:
             return ''
         if size < 0:
             size = self.chunksize - self.size_read
         if size > self.chunksize - self.size_read:
             size = self.chunksize - self.size_read
         data = self.file.read(size)
         self.size_read = self.size_read + len(data)
         if self.size_read == self.chunksize and \
            self.align and \
            (self.chunksize & 1):
             dummy = self.file.read(1)
             self.size_read = self.size_read + len(dummy)
         return data

def seek	(	self,
		pos,
		whence = `0`
	)

Seek to specified position into the chunk.
Default position is 0 (start of chunk).
If the file is not seekable, this will result in an error.

Definition at line 96 of file chunk.py.

References Chunk.chunksize, Chunk.closed, Chunk.offset, Chunk.seekable, and Chunk.size_read.

 
     def seek(self, pos, whence = 0):
         """Seek to specified position into the chunk.
         Default position is 0 (start of chunk).
         If the file is not seekable, this will result in an error.
         """
 
         if self.closed:
             raise ValueError, "I/O operation on closed file"
         if not self.seekable:
             raise IOError, "cannot seek"
         if whence == 1:
             pos = pos + self.size_read
         elif whence == 2:
             pos = pos + self.chunksize
         if pos < 0 or pos > self.chunksize:
             raise RuntimeError
         self.file.seek(self.offset + pos, 0)
         self.size_read = pos

def skip ( self)

Skip the rest of the chunk.
If you are not interested in the contents of the chunk,
this method should be called so that the file points to
the start of the next chunk.

Definition at line 143 of file chunk.py.

References Chunk.align, Chunk.chunksize, Chunk.closed, sre_parse.min, openrsrc.read(), Chunk.read(), _Hqxdecoderengine.read(), _Rledecoderengine.read(), HexBin.read(), file_wrapper.read, Unpickler.read, addbase.read, Chunk.seekable, and Chunk.size_read.

 
     def skip(self):
         """Skip the rest of the chunk.
         If you are not interested in the contents of the chunk,
         this method should be called so that the file points to
         the start of the next chunk.
         """
 
         if self.closed:
             raise ValueError, "I/O operation on closed file"
         if self.seekable:
             try:
                 n = self.chunksize - self.size_read
                 # maybe fix alignment
                 if self.align and (self.chunksize & 1):
                     n = n + 1
                 self.file.seek(n, 1)
                 self.size_read = self.size_read + n
                 return
             except IOError:
                 pass
         while self.size_read < self.chunksize:
             n = min(8192, self.chunksize - self.size_read)
             dummy = self.read(n)
             if not dummy:
                 raise EOFError

Public Member Functions

Data Fields

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Field Documentation