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A comment on Microsoft is updating Notepad. Parent comment

Re:Microsoft is updating Notepad by pkaye on Thursday July 12, 2018 @07:06PM (#17519353)
How does an editor handle loading from disk and updating when someones inserts to the head of a file? Everything needs to be shifted.
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Re:Microsoft is updating Notepad by ars on Thursday July 12, 2018 @08:10PM (#17519638)
You use a https://en.wikipedia.org/wiki/Rope_(data_structure) and not a flat string.

You only flatten the string when it's time to write to disk.

For autosave files make sure to store the changes to the rope, not the full text.

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Re:Microsoft is updating Notepad by lighttower on Thursday July 12, 2018 @10:50PM (#17520170)
There is a comment somewhere on HN from the guy that wrote the mapping trick that Word (or WordPerfect) invented way back. They were saving changes to the file rather than flattening. I wish I could find it now.
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Re:Microsoft is updating Notepad by ygra on Friday July 13, 2018 @01:02AM (#17520633)
The data structure is called a piece table, if that ids your search.
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Re:Microsoft is updating Notepad by pkaye on Friday July 13, 2018 @05:39PM (#17526955)
According to Wikipedia, it looks like Visual Studio Code is using this data structure.
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