src/eric7/Documentation/Source/eric7.HexEdit.HexEditChunks.html

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<h1>eric7.HexEdit.HexEditChunks</h1>
<p>
Module implementing the storage backend for the hex editor.
</p>

<h3>Global Attributes</h3>
<table>
<tr><td>None</td></tr>
</table>

<h3>Classes</h3>
<table>
<tr>
<td><a href="#HexEditChunk">HexEditChunk</a></td>
<td>Class implementing a container for the data chunks.</td>
</tr>
<tr>
<td><a href="#HexEditChunks">HexEditChunks</a></td>
<td>Class implementing the storage backend for the hex editor.</td>
</tr>
</table>

<h3>Functions</h3>
<table>
<tr><td>None</td></tr>
</table>

<hr />
<hr />
<a NAME="HexEditChunk" ID="HexEditChunk"></a>
<h2>HexEditChunk</h2>
<p>
    Class implementing a container for the data chunks.
</p>

<h3>Derived from</h3>
None
<h3>Class Attributes</h3>
<table>
<tr><td>absPos</td></tr>
<tr><td>data</td></tr>
<tr><td>dataChanged</td></tr>
</table>

<h3>Class Methods</h3>
<table>
<tr><td>None</td></tr>
</table>

<h3>Methods</h3>
<table>
<tr><td>None</td></tr>
</table>

<h3>Static Methods</h3>
<table>
<tr><td>None</td></tr>
</table>


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<a NAME="HexEditChunks" ID="HexEditChunks"></a>
<h2>HexEditChunks</h2>
<p>
    Class implementing the storage backend for the hex editor.
</p>
<p>
    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.
</p>
<p>
    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.
</p>

<h3>Derived from</h3>
None
<h3>Class Attributes</h3>
<table>
<tr><td>BUFFER_SIZE</td></tr>
<tr><td>CHUNK_SIZE</td></tr>
<tr><td>READ_CHUNK_MASK</td></tr>
</table>

<h3>Class Methods</h3>
<table>
<tr><td>None</td></tr>
</table>

<h3>Methods</h3>
<table>
<tr>
<td><a href="#HexEditChunks.__init__">HexEditChunks</a></td>
<td>Constructor</td>
</tr>
<tr>
<td><a href="#HexEditChunks.__getChunkIndex">__getChunkIndex</a></td>
<td>Private method to get the chunk index for a position.</td>
</tr>
<tr>
<td><a href="#HexEditChunks.__getitem__">__getitem__</a></td>
<td>Special method to get a byte at a position.</td>
</tr>
<tr>
<td><a href="#HexEditChunks.data">data</a></td>
<td>Public method to get data out of the chunks.</td>
</tr>
<tr>
<td><a href="#HexEditChunks.dataChanged">dataChanged</a></td>
<td>Public method to test, if some data was changed.</td>
</tr>
<tr>
<td><a href="#HexEditChunks.indexOf">indexOf</a></td>
<td>Public method to search the first occurrence of some data.</td>
</tr>
<tr>
<td><a href="#HexEditChunks.insert">insert</a></td>
<td>Public method to insert a byte.</td>
</tr>
<tr>
<td><a href="#HexEditChunks.lastIndexOf">lastIndexOf</a></td>
<td>Public method to search the last occurrence of some data.</td>
</tr>
<tr>
<td><a href="#HexEditChunks.overwrite">overwrite</a></td>
<td>Public method to overwrite a byte.</td>
</tr>
<tr>
<td><a href="#HexEditChunks.pos">pos</a></td>
<td>Public method to get the current position.</td>
</tr>
<tr>
<td><a href="#HexEditChunks.removeAt">removeAt</a></td>
<td>Public method to remove a byte.</td>
</tr>
<tr>
<td><a href="#HexEditChunks.setDataChanged">setDataChanged</a></td>
<td>Public method to set highlighting info.</td>
</tr>
<tr>
<td><a href="#HexEditChunks.setIODevice">setIODevice</a></td>
<td>Public method to set an io device to read the binary data from.</td>
</tr>
<tr>
<td><a href="#HexEditChunks.size">size</a></td>
<td>Public method to get the current data size.</td>
</tr>
<tr>
<td><a href="#HexEditChunks.write">write</a></td>
<td>Public method to write data to an io device.</td>
</tr>
</table>

<h3>Static Methods</h3>
<table>
<tr><td>None</td></tr>
</table>


<a NAME="HexEditChunks.__init__" ID="HexEditChunks.__init__"></a>
<h4>HexEditChunks (Constructor)</h4>
<b>HexEditChunks</b>(<i>ioDevice=None</i>)
<p>
        Constructor
</p>

<dl>

<dt><i>ioDevice</i> (QIODevice)</dt>
<dd>
io device to get the data from
</dd>
</dl>
<a NAME="HexEditChunks.__getChunkIndex" ID="HexEditChunks.__getChunkIndex"></a>
<h4>HexEditChunks.__getChunkIndex</h4>
<b>__getChunkIndex</b>(<i>absPos</i>)
<p>
        Private method to get the chunk index for a position.
</p>
<p>
        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.
</p>

<dl>

<dt><i>absPos</i> (int)</dt>
<dd>
absolute position of the data.
</dd>
</dl>
<dl>
<dt>Return:</dt>
<dd>
index of the chunk containing the position
</dd>
</dl>
<dl>
<dt>Return Type:</dt>
<dd>
int
</dd>
</dl>
<a NAME="HexEditChunks.__getitem__" ID="HexEditChunks.__getitem__"></a>
<h4>HexEditChunks.__getitem__</h4>
<b>__getitem__</b>(<i>pos</i>)
<p>
        Special method to get a byte at a position.
</p>
<p>
        Note: This realizes the [] get operator.
</p>

<dl>

<dt><i>pos</i> (int)</dt>
<dd>
position of byte to get
</dd>
</dl>
<dl>
<dt>Return:</dt>
<dd>
requested byte
</dd>
</dl>
<dl>
<dt>Return Type:</dt>
<dd>
int (range 0 to 255)
</dd>
</dl>
<a NAME="HexEditChunks.data" ID="HexEditChunks.data"></a>
<h4>HexEditChunks.data</h4>
<b>data</b>(<i>pos=0, maxSize=-1, highlighted=None</i>)
<p>
        Public method to get data out of the chunks.
</p>

<dl>

<dt><i>pos</i> (int)</dt>
<dd>
position to get bytes from
</dd>
<dt><i>maxSize</i> (int)</dt>
<dd>
maximum amount of bytes to get
</dd>
<dt><i>highlighted</i> (bytearray)</dt>
<dd>
reference to a byte array storing highlighting info
</dd>
</dl>
<dl>
<dt>Return:</dt>
<dd>
retrieved data
</dd>
</dl>
<dl>
<dt>Return Type:</dt>
<dd>
bytearray
</dd>
</dl>
<a NAME="HexEditChunks.dataChanged" ID="HexEditChunks.dataChanged"></a>
<h4>HexEditChunks.dataChanged</h4>
<b>dataChanged</b>(<i>pos</i>)
<p>
        Public method to test, if some data was changed.
</p>

<dl>

<dt><i>pos</i> (int)</dt>
<dd>
byte position to check
</dd>
</dl>
<dl>
<dt>Return:</dt>
<dd>
flag indicating the changed state
</dd>
</dl>
<dl>
<dt>Return Type:</dt>
<dd>
bool
</dd>
</dl>
<a NAME="HexEditChunks.indexOf" ID="HexEditChunks.indexOf"></a>
<h4>HexEditChunks.indexOf</h4>
<b>indexOf</b>(<i>byteArray, start</i>)
<p>
        Public method to search the first occurrence of some data.
</p>

<dl>

<dt><i>byteArray</i> (bytearray)</dt>
<dd>
data to search for
</dd>
<dt><i>start</i> (int)</dt>
<dd>
position to start the search at
</dd>
</dl>
<dl>
<dt>Return:</dt>
<dd>
position the data was found at or -1 if nothing could be found
</dd>
</dl>
<dl>
<dt>Return Type:</dt>
<dd>
int
</dd>
</dl>
<a NAME="HexEditChunks.insert" ID="HexEditChunks.insert"></a>
<h4>HexEditChunks.insert</h4>
<b>insert</b>(<i>pos, data</i>)
<p>
        Public method to insert a byte.
</p>

<dl>

<dt><i>pos</i> (int)</dt>
<dd>
position to insert at
</dd>
<dt><i>data</i> (int (range 0 to 255))</dt>
<dd>
byte to insert
</dd>
</dl>
<dl>
<dt>Return:</dt>
<dd>
flag indicating success
</dd>
</dl>
<dl>
<dt>Return Type:</dt>
<dd>
bool
</dd>
</dl>
<a NAME="HexEditChunks.lastIndexOf" ID="HexEditChunks.lastIndexOf"></a>
<h4>HexEditChunks.lastIndexOf</h4>
<b>lastIndexOf</b>(<i>byteArray, start</i>)
<p>
        Public method to search the last occurrence of some data.
</p>

<dl>

<dt><i>byteArray</i> (bytearray)</dt>
<dd>
data to search for
</dd>
<dt><i>start</i> (int)</dt>
<dd>
position to start the search at
</dd>
</dl>
<dl>
<dt>Return:</dt>
<dd>
position the data was found at or -1 if nothing could be found
</dd>
</dl>
<dl>
<dt>Return Type:</dt>
<dd>
int
</dd>
</dl>
<a NAME="HexEditChunks.overwrite" ID="HexEditChunks.overwrite"></a>
<h4>HexEditChunks.overwrite</h4>
<b>overwrite</b>(<i>pos, data</i>)
<p>
        Public method to overwrite a byte.
</p>

<dl>

<dt><i>pos</i> (int)</dt>
<dd>
position to overwrite
</dd>
<dt><i>data</i> (int (range 0 to 255))</dt>
<dd>
byte to overwrite with
</dd>
</dl>
<dl>
<dt>Return:</dt>
<dd>
flag indicating success
</dd>
</dl>
<dl>
<dt>Return Type:</dt>
<dd>
bool
</dd>
</dl>
<a NAME="HexEditChunks.pos" ID="HexEditChunks.pos"></a>
<h4>HexEditChunks.pos</h4>
<b>pos</b>(<i></i>)
<p>
        Public method to get the current position.
</p>

<dl>
<dt>Return:</dt>
<dd>
current position
</dd>
</dl>
<dl>
<dt>Return Type:</dt>
<dd>
int
</dd>
</dl>
<a NAME="HexEditChunks.removeAt" ID="HexEditChunks.removeAt"></a>
<h4>HexEditChunks.removeAt</h4>
<b>removeAt</b>(<i>pos</i>)
<p>
        Public method to remove a byte.
</p>

<dl>

<dt><i>pos</i> (int)</dt>
<dd>
position to remove
</dd>
</dl>
<dl>
<dt>Return:</dt>
<dd>
flag indicating success
</dd>
</dl>
<dl>
<dt>Return Type:</dt>
<dd>
bool
</dd>
</dl>
<a NAME="HexEditChunks.setDataChanged" ID="HexEditChunks.setDataChanged"></a>
<h4>HexEditChunks.setDataChanged</h4>
<b>setDataChanged</b>(<i>pos, dataChanged</i>)
<p>
        Public method to set highlighting info.
</p>

<dl>

<dt><i>pos</i> (int)</dt>
<dd>
position to set highlighting info for
</dd>
<dt><i>dataChanged</i> (bool)</dt>
<dd>
flag indicating changed data
</dd>
</dl>
<a NAME="HexEditChunks.setIODevice" ID="HexEditChunks.setIODevice"></a>
<h4>HexEditChunks.setIODevice</h4>
<b>setIODevice</b>(<i>ioDevice</i>)
<p>
        Public method to set an io device to read the binary data from.
</p>

<dl>

<dt><i>ioDevice</i> (QIODevice)</dt>
<dd>
io device to get the data from
</dd>
</dl>
<dl>
<dt>Return:</dt>
<dd>
flag indicating successful operation
</dd>
</dl>
<dl>
<dt>Return Type:</dt>
<dd>
bool
</dd>
</dl>
<a NAME="HexEditChunks.size" ID="HexEditChunks.size"></a>
<h4>HexEditChunks.size</h4>
<b>size</b>(<i></i>)
<p>
        Public method to get the current data size.
</p>

<dl>
<dt>Return:</dt>
<dd>
current data size
</dd>
</dl>
<dl>
<dt>Return Type:</dt>
<dd>
int
</dd>
</dl>
<a NAME="HexEditChunks.write" ID="HexEditChunks.write"></a>
<h4>HexEditChunks.write</h4>
<b>write</b>(<i>ioDevice, pos=0, count=-1</i>)
<p>
        Public method to write data to an io device.
</p>

<dl>

<dt><i>ioDevice</i> (QIODevice)</dt>
<dd>
io device to write the data to
</dd>
<dt><i>pos</i> (int)</dt>
<dd>
position to write bytes from
</dd>
<dt><i>count</i> (int)</dt>
<dd>
amount of bytes to write
</dd>
</dl>
<dl>
<dt>Return:</dt>
<dd>
flag indicating success
</dd>
</dl>
<dl>
<dt>Return Type:</dt>
<dd>
bool
</dd>
</dl>
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