boost regex and ifstream

Question

Is there a way to use the regex class of boost to search in a file without completely reading it into memory?

I currently read a file per line and this makes the parsing quite complicate compared to searching via regex. I do it per line because the files can be huge and I don't want to waste to much RAM.

The regex expression I would like to use is, and it works fine if I use it for Example in Notepad++

Block *\{([^\}]*?)MY_TOOL_Library([^\}]*?)\}

Similar question: http://stackoverflow.com/questions/457595/can-you-use-boost-regex-to-parse-a-stream — Ferruccio, Aug 10 '12 at 09:23

James Kanze · Answer 1 · 2012-08-10T08:24:57.327

2

I don't think boost regex implements this. They require a bi-directional iterator.

Formally, "regular expressions" (in the mathematical sense) allow one pass parsing, and can be made to work with a forward iterator. But boost, like most other regular expressions, implements capture (an extension to the formal definition), and I think that this precludes a true one pass algorithm (or makes it extremely difficult).

edited Aug 10 '12 at 08:24

answered Aug 10 '12 at 07:55

James Kanze

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This I already know But I asked if there is a workaround available Looks likes there is no "easy" way around.. – nobs Aug 13 '12 at 13:22

boost regex and ifstream

1 Answers1