# eric7.HexEdit.HexEditChunks

Module implementing the storage backend for the hex editor.

### Global Attributes

None

### Classes

HexEditChunk | Class implementing a container for the data chunks.
HexEditChunks | Class implementing the storage backend for the hex editor.

### Functions

None

## HexEditChunk

Class implementing a container for the data chunks.

### Derived from

None

### Class Attributes

absPos
data
dataChanged

### Class Methods

None

### Methods

None

### Static Methods

None

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## HexEditChunks

Class implementing the storage backend for the hex editor.

When HexEditWidget loads data, HexEditChunks access them using a QIODevice interface. When the app uses a QByteArray or Python bytearray interface, QBuffer is used to provide again a QIODevice like interface. No data will be changed, therefore HexEditChunks opens the QIODevice in QIODevice.OpenModeFlag.ReadOnly mode. After every access HexEditChunks closes the QIODevice. That's why external applications can overwrite files while HexEditWidget shows them.

When the the user starts to edit the data, HexEditChunks creates a local copy of a chunk of data (4 kilobytes) and notes all changes there. Parallel to that chunk, there is a second chunk, which keeps track of which bytes are changed and which are not.

### Derived from

None

### Class Attributes

BUFFER_SIZE
CHUNK_SIZE
READ_CHUNK_MASK

### Class Methods

None

### Methods

HexEditChunks | Constructor
__getChunkIndex | Private method to get the chunk index for a position.
__getitem__ | Special method to get a byte at a position.
data | Public method to get data out of the chunks.
dataChanged | Public method to test, if some data was changed.
indexOf | Public method to search the first occurrence of some data.
insert | Public method to insert a byte.
lastIndexOf | Public method to search the last occurrence of some data.
overwrite | Public method to overwrite a byte.
pos | Public method to get the current position.
removeAt | Public method to remove a byte.
setDataChanged | Public method to set highlighting info.
setIODevice | Public method to set an io device to read the binary data from.
size | Public method to get the current data size.
write | Public method to write data to an io device.

### Static Methods

None

#### HexEditChunks (Constructor)

HexEditChunks(ioDevice=None)

Constructor

ioDevice (QIODevice)
  io device to get the data from

#### HexEditChunks.__getChunkIndex

__getChunkIndex(absPos)

Private method to get the chunk index for a position.

This method checks, if there is already a copied chunk available. If there is one, it returns its index. If there is no copied chunk available, original data will be copied into a new chunk.

absPos (int)
  absolute position of the data.

Return:
  index of the chunk containing the position

Return Type:
  int

#### HexEditChunks.__getitem__

__getitem__(pos)

Special method to get a byte at a position.

Note: This realizes the [] get operator.

pos (int)
  position of byte to get

Return:
  requested byte

Return Type:
  int (range 0 to 255)

#### HexEditChunks.data

data(pos=0, maxSize=-1, highlighted=None)

Public method to get data out of the chunks.

pos (int)
  position to get bytes from
maxSize (int)
  maximum amount of bytes to get
highlighted (bytearray)
  reference to a byte array storing highlighting info

Return:
  retrieved data

Return Type:
  bytearray

#### HexEditChunks.dataChanged

dataChanged(pos)

Public method to test, if some data was changed.

pos (int)
  byte position to check

Return:
  flag indicating the changed state

Return Type:
  bool

#### HexEditChunks.indexOf

indexOf(byteArray, start)

Public method to search the first occurrence of some data.

byteArray (bytearray)
  data to search for
start (int)
  position to start the search at

Return:
  position the data was found at or -1 if nothing could be found

Return Type:
  int

#### HexEditChunks.insert

insert(pos, data)

Public method to insert a byte.

pos (int)
  position to insert at
data (int (range 0 to 255))
  byte to insert

Return:
  flag indicating success

Return Type:
  bool

#### HexEditChunks.lastIndexOf

lastIndexOf(byteArray, start)

Public method to search the last occurrence of some data.

byteArray (bytearray)
  data to search for
start (int)
  position to start the search at

Return:
  position the data was found at or -1 if nothing could be found

Return Type:
  int

#### HexEditChunks.overwrite

overwrite(pos, data)

Public method to overwrite a byte.

pos (int)
  position to overwrite
data (int (range 0 to 255))
  byte to overwrite with

Return:
  flag indicating success

Return Type:
  bool

#### HexEditChunks.pos

pos()

Public method to get the current position.

Return:
  current position

Return Type:
  int

#### HexEditChunks.removeAt

removeAt(pos)

Public method to remove a byte.

pos (int)
  position to remove

Return:
  flag indicating success

Return Type:
  bool

#### HexEditChunks.setDataChanged

setDataChanged(pos, dataChanged)

Public method to set highlighting info.

pos (int)
  position to set highlighting info for
dataChanged (bool)
  flag indicating changed data

#### HexEditChunks.setIODevice

setIODevice(ioDevice)

Public method to set an io device to read the binary data from.

ioDevice (QIODevice)
  io device to get the data from

Return:
  flag indicating successful operation

Return Type:
  bool

#### HexEditChunks.size

size()

Public method to get the current data size.

Return:
  current data size

Return Type:
  int

#### HexEditChunks.write

write(ioDevice, pos=0, count=-1)

Public method to write data to an io device.

ioDevice (QIODevice)
  io device to write the data to
pos (int)
  position to write bytes from
count (int)
  amount of bytes to write

Return:
  flag indicating success

Return Type:
  bool

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