Fastest way to read binary into int[] in java?

Question

In java, what is the fastest way to read a huge binary file into int[]. I saw this solution

Fastest way to read huge number of int from binary file

But there is two solutions, and I don't know which is better. Also they seem to give a fixed maximum size for the int[], but how can I do it with a variable size? Like how can I set it to fit the amount of data in the binary exactly. Is there a way to know how many ints are there in the file?

Thanks

Well if you know how big the file is, and y you know how many bytes are in an int, you can calculate how many ints are in the file. — yshavit, Aug 25 '15 at 00:00
Assuming you're not using a variable length encoding, there are 4 bytes per int. So, the number of ints is just bytesInTheFile / 4. — yshavit, Aug 25 '15 at 00:03

score 0 · Answer 1 · edited Aug 25 '15 at 01:59

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You could have some variables to calculate the time in both solutions, then compare the two.

while (bytesRead != -1) {
  double start = System.currentTimeMillis();
   while(doingstuff){}
  double timeTaken = System.currentTimeMillis() - start;
}

As for the array, you could use a arraylist which is expandable.

ArrayList<int> binary = new ArrayList<int>();
binary.add(stuff);

edited Aug 25 '15 at 01:59

kristianp

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answered Aug 25 '15 at 01:19

Psicoses

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System.nanoTime() is better for micro benchmarking. – bhspencer Aug 25 '15 at 01:21
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Also this should be a comment and not an answer. – bhspencer Aug 25 '15 at 01:21

Fastest way to read binary into int[] in java?

1 Answers1