python chunk模块

chunk模块用于读取TIFF格式的文件，打开应该使用二进制模式

TIFF 标签图像文件格式

import chunk

import chunk 

f=open('E:\\test.tiff','rb') 

print(type(f)) 

html=chunk.Chunk(f) 

print(html.getname()) 

print(html.getsize())

help('chunk')

Help on module chunk:

NAME

chunk - Simple class to read IFF chunks.

DESCRIPTION

An IFF chunk (used in formats such as AIFF, TIFF, RMFF (RealMedia File

Format)) has the following structure:

+----------------+

| ID (4 bytes)   |

+----------------+

| size (4 bytes) |

+----------------+

| data           |

| ...            |

+----------------+

The ID is a 4-byte string which identifies the type of chunk.

The size field (a 32-bit value, encoded using big-endian byte order)

gives the size of the whole chunk, including the 8-byte header.

Usually an IFF-type file consists of one or more chunks.  The proposed

usage of the Chunk class defined here is to instantiate an instance at

the start of each chunk and read from the instance until it reaches

the end, after which a new instance can be instantiated.  At the end

of the file, creating a new instance will fail with an EOFError

exception.

Usage:

while True:

try:

chunk = Chunk(file)

except EOFError:

break

chunktype = chunk.getname()

while True:

data = chunk.read(nbytes)

if not data:

pass

# do something with data

The interface is file-like.  The implemented methods are:

read, close, seek, tell, isatty.

Extra methods are: skip() (called by close, skips to the end of the chunk),

getname() (returns the name (ID) of the chunk)

The __init__ method has one required argument, a file-like object

(including a chunk instance), and one optional argument, a flag which

specifies whether or not chunks are aligned on 2-byte boundaries.  The

default is 1, i.e. aligned.

CLASSES

builtins.object

Chunk

class Chunk(builtins.object)

|  Methods defined here:

|

|  __init__(self, file, align=True, bigendian=True, inclheader=False)

|      Initialize self.  See help(type(self)) for accurate signature.

|

|  close(self)

|

|  getname(self)

|      Return the name (ID) of the current chunk.

|

|  getsize(self)

|      Return the size of the current chunk.

|

|  isatty(self)

|

|  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.

|

|  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.

|

|  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.

|

|  tell(self)

|

|  ----------------------------------------------------------------------

|  Data descriptors defined here:

|

|  __dict__

|      dictionary for instance variables (if defined)

|

|  __weakref__

|      list of weak references to the object (if defined)

FILE

c:\python3.5\lib\chunk.py

 

 

摘自：

https://www.cnblogs.com/dengyg200891/p/4947685.html