You should be able to do it in one iteration...
I would use a queue to store the context lines

Start by inspecting each line.

  1. If the date has changed then flush the queue and set $postContext=0;
  2. Inspect for duplicates
    1. If the line is a duplicate (of the latest item seen?), then print out and flush the queue. Set $postContext = $maxPostContext;
    2. Otherwise, add the line to the queue.
  3. If ($postContext) then print and flush the (single) item from the queue, and $postContext--;
  4. If the queue is more than $maxPreContext, then remove a line from the head of the queue.
Repeat until done.

So, basically, the queue saves up a maximum of $maxPreContext lines of context from before the duplication, and you keep printing $maxPostContext lines for context after the duplication. If another duplicate appears quickly, you don't get multiple copies of the same context because the queue has not refilled.

In reply to Re: Padding search results with context by SuicideJunkie
in thread Padding search results with context by moritz

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