read/write region into/from ram completely

[DonRudiX]

Reading und writing a whole region in one single I/O process is, as far as I understand the code, not possible at the current state of the library. That results in 1024(32x32 chunks) single read- and write-processes if you want to edit every chunk in a region.
Can you add a class 'regionRAM' or something alike thats works similar to the current region-class, but has a method to read and write the whole region at once? I am aware that this variant uses a lot more ram but for editing large worlds it would be a really good time saver.

[LB--]

I could make Region a base class and have DiskRegion and MemoryRegion derivations - would that work for you?

[DonRudiX]

I think that would work for me as long as reading and writing chunks from/into a MemoryRegion doesn't produce any I/O activity to the HDD.

[LB--]

Yes, with a MemoryRegion the entire region file will be read into memory upon construction and all operations on the region will operate on the memory.

[DonRudiX]

Sounds perfect.

[LB--]

@MasterRudi I added the MemoryRegion class in d5d55c1 - it is completely untested currently. If you want you can try it out and let me know of any issues. If you construct it with Region.ChunkCompression.None then the chunks will be fully uncompressed in memory while you work with them.

[DonRudiX]

Unfortunatly it's not working. This code produces an exception for ChunkCompression.None

test class

package test;

import java.io.File;

import com.lb_stuff.mcmodify.minecraft.IDs;

import com.lb_stuff.mcmodify.minecraft.Chunk;
import com.lb_stuff.mcmodify.minecraft.MemoryRegion;
import com.lb_stuff.mcmodify.minecraft.Region.ChunkCompression;

public class TestMemoryRegion
{
    public static void main(String[] args)
    {
        String inputFile = "data/minecraft/src/flatworld_master_r.0.0.mca";
        String outputFile = "data/r.0.0.mca";

        try
        {
            System.out.println("reading region");
            MemoryRegion mr = new MemoryRegion(new File(inputFile), ChunkCompression.None);
            //MemoryRegion mr = new MemoryRegion(new File(inputFile), ChunkCompression.GZip);
            //MemoryRegion mr = new MemoryRegion(new File(inputFile), ChunkCompression.Zlib);
            System.out.println("region read to memory");

            System.out.println("editing chunks");
            for (int i = 0; i < 32; i++)
            {
                for (int j = 0; j < 32; j++)
                {
                    Chunk c = mr.getChunk(i, j);
                    c.BlockID(1+i*32, 10, +j*32, IDs.Cobblestone);
                    mr.setChunk(i, j, c);
                }
            }
            System.out.println("editing chunks done");

            System.out.println("saving region to disk");
            mr.saveToFile(new File(outputFile));
            System.out.println("region saved to disk");
        }
        catch (Exception e1)
        {
            e1.printStackTrace();
            System.exit(0);
        }

        try
        {
            System.out.println("thread sleeping to estimated memory usage");
            Thread.sleep(5000);
        }
        catch (Exception e)
        {
            // none
        }
    }
}

Exception:

java.lang.IllegalArgumentException: There is no Id for compression scheme None
    at com.lb_stuff.mcmodify.minecraft.Region$ChunkCompression.getId(Region.java:65)
    at com.lb_stuff.mcmodify.minecraft.MemoryRegion.saveToFile(MemoryRegion.java:90)
    at test.TestMemoryRegion.main(TestMemoryRegion.java:39)

Changing the compression to to gzip or zlib does not produce the exception but the outputfile will only be like 9KB big for a flatworld inputfile.

[DonRudiX]

Sry, wrong button. I didn't want to close the Issue

[LB--]

Did you try either of the other two compression options? I'll start debugging this in an hour or so.

Changing the compression to to gzip or zlib does not produce the exception but the outputfile will only be like 9KB big for a flatworld inputfile.

What happens when Mincraft loads the region? How big was the original input file?

EDIT: I'm fixing some of the obvious issues with my implementation - stand by.

[LB--]

OK, I'm still not in an environment where I can test the code, but try 97d92e8 - the saveToFile() method now takes a Region.ChunkCompression as its second parameter (don't use None obviously).