Minecraft 1.8 world updater

world_update.py

#1. Download Khroki/MCEdit-Unified.
#2. Copy this script and your existing Minecraft world into the MCEdit-Unified folder.
#3. Run the script to add the new stone types and regenerate rabbits, horses, and wolves.

from __future__ import print_function
import pymclevel
import pymclevel.minecraft_server
import time
import sys
def playerChunk(world):
    x,y,z = world.getPlayerPosition()
    return world.getChunk(int(x)>>4, int(z)>>4)

gen = pymclevel.minecraft_server.MCServerChunkGenerator('Release 1.8.1')

world = pymclevel.fromFile("world")
worldTmp = pymclevel.MCInfdevOldLevel("tmp-world", create=True, random_seed=world.RandomSeed)
print("%d chunks in old world"%len(list(world.allChunks)), file=sys.stderr)
print("%d chunks already generated"%len(list(worldTmp.allChunks)), file=sys.stderr)
chunks = list(set(world.allChunks) - set(worldTmp.allChunks))
print("Generating %d chunks..."%(len(chunks)), file=sys.stderr)

startGen = time.time()
progress = 0
for x in gen.generateChunksInLevelIter(worldTmp, chunks):
    if x[0] > progress:
        progress = x[0]
        dt = time.time()-startGen
        print("Generated %d of %d (%d:%02d)"%(x[0],x[1],int(dt/60),int(dt%60)), file=sys.stderr)
endGen = time.time()

print("Copying stone from new chunks...", file=sys.stderr)
startCopy = time.time()
progress = 0
total = len(list(world.allChunks))
for cx,cz in world.allChunks:
    chunk = world.getChunk(cx,cz)
    chunkTmp = worldTmp.getChunk(cx,cz)

    selector = (chunk.Blocks == 1) & (chunkTmp.Blocks == 1) & \
        (chunk.Data != chunkTmp.Data)
    chunk.Data[selector] = chunkTmp.Data[selector]

    entities = []
    for e in chunkTmp.Entities:
        if e['id'].value in [u'Rabbit', u'Wolf', u'EntityHorse']:
            entities.append(e)
    chunk.addEntities(entities)

    chunk.chunkChanged(calcLighting=False)
    chunk.close()
    progress += 1
    dt = time.time()-startCopy
    print("Copied %d of %d (%d:%02d)"%(progress, total, int(dt/60),int(dt%60)), file=sys.stderr)
endCopy = time.time()

startSave = time.time()
print("Saving...", file=sys.stderr)
world.saveInPlace()
world.close()
endSave = time.time()
print("Finished generation in %d:%02d"%(int((endGen-startGen)/60),int((endGen-startGen)%60)), file=sys.stderr)
print("Finished copying in %d:%02d"%(int((endCopy-startCopy)/60),int((endCopy-startCopy)%60)), file=sys.stderr)