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Asked: 2026-05-23T08:34:48+00:00

I would like to delete parts from a binary file, using C++. The binary

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I would like to delete parts from a binary file, using C++. The binary file is about about 5-10 MB.

What I would like to do:

  1. Search for a ANSI string “something”
  2. Once I found this string, I would like to delete the following n bytes, for example the following 1 MB of data. I would like to delete those character, not to fill them with NULL, thus make the file smaller.
  3. I would like to save the modified file into a new binary file, what is the same as the original file, except for the missing n bytes what I have deleted.

Can you give me some advice / best practices how to do this the most efficiently? Should I load the file into memory first?

How can I search efficiently for an ANSI string? I mean possibly I have to skip a few megabytes of data before I find that string. >> I have been told I should ask it in an other question, so its here:
How to look for an ANSI string in a binary file?

How can I delete n bytes and write it out to a new file efficiently?

OK, I don’t need it to be super efficient, the file will not be bigger than 10 MB and its OK if it runs for a few seconds.

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1 Answer

  1. Editorial Team

    There are a number of fast string search routines that perform much better than testing each and every character. For example, when trying to find “something”, only every 9th character needs to be tested.

    Here’s an example I wrote for an earlier question: code review: finding </body> tag reverse search on a non-null terminated char str

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