content: package net.minecraft.world;
  
  import net.minecraft.block.material.Material;
  import net.minecraft.block.state.IBlockState;
  import net.minecraft.init.Blocks;
  import net.minecraft.tileentity.TileEntity;
  import net.minecraft.util.BlockPos;
  import net.minecraft.util.EnumFacing;
  import net.minecraft.world.biome.BiomeGenBase;
  import net.minecraft.world.chunk.Chunk;
  
  public class ChunkCache implements IBlockAccess {
      protected int chunkX;
      protected int chunkZ;
      protected Chunk[][] chunkArray;
      protected boolean hasExtendedLevels;
      protected World worldObj;
  
      public ChunkCache(World worldIn, BlockPos posFromIn, BlockPos posToIn, int subIn) {
          this.worldObj = worldIn;
          this.chunkX = posFromIn.getX() - subIn >> 4;
          this.chunkZ = posFromIn.getZ() - subIn >> 4;
          int i = posToIn.getX() + subIn >> 4;
          int j = posToIn.getZ() + subIn >> 4;
          this.chunkArray = new Chunk[i - this.chunkX + 1][j - this.chunkZ + 1];
          this.hasExtendedLevels = true;
  
          for (int k = this.chunkX; k <= i; ++k) {
              for (int l = this.chunkZ; l <= j; ++l) {
                  this.chunkArray[k - this.chunkX][l - this.chunkZ] = worldIn.getChunkFromChunkCoords(k, l);
              }
          }
  
          for (int i1 = posFromIn.getX() >> 4; i1 <= posToIn.getX() >> 4; ++i1) {
              for (int j1 = posFromIn.getZ() >> 4; j1 <= posToIn.getZ() >> 4; ++j1) {
                  Chunk chunk = this.chunkArray[i1 - this.chunkX][j1 - this.chunkZ];
  
                  if (chunk != null && !chunk.getAreLevelsEmpty(posFromIn.getY(), posToIn.getY())) {
                      this.hasExtendedLevels = false;
                  }
              }
          }
      }
  
      public boolean extendedLevelsInChunkCache() {
          return this.hasExtendedLevels;
      }
  
      public TileEntity getTileEntity(BlockPos pos) {
          int i = (pos.getX() >> 4) - this.chunkX;
          int j = (pos.getZ() >> 4) - this.chunkZ;
          return this.chunkArray[i][j].getTileEntity(pos, Chunk.EnumCreateEntityType.IMMEDIATE);
      }
  
      public int getCombinedLight(BlockPos pos, int lightValue) {
          int i = this.getLightForExt(EnumSkyBlock.SKY, pos);
          int j = this.getLightForExt(EnumSkyBlock.BLOCK, pos);
  
          if (j < lightValue) {
              j = lightValue;
          }
  
          return i << 20 | j << 4;
      }
  
      public IBlockState getBlockState(BlockPos pos) {
          if (pos.getY() >= 0 && pos.getY() < 256) {
              int i = (pos.getX() >> 4) - this.chunkX;
              int j = (pos.getZ() >> 4) - this.chunkZ;
  
              if (i >= 0 && i < this.chunkArray.length && j >= 0 && j < this.chunkArray[i].length) {
                  Chunk chunk = this.chunkArray[i][j];
  
                  if (chunk != null) {
                      return chunk.getBlockState(pos);
                  }
              }
          }
  
          return Blocks.air.getDefaultState();
      }
  
      public BiomeGenBase getBiomeGenForCoords(BlockPos pos) {
          return this.worldObj.getBiomeGenForCoords(pos);
      }
  
      private int getLightForExt(EnumSkyBlock p_175629_1_, BlockPos pos) {
          if (p_175629_1_ == EnumSkyBlock.SKY && this.worldObj.provider.getHasNoSky()) {
              return 0;
          } else if (pos.getY() >= 0 && pos.getY() < 256) {
              if (this.getBlockState(pos).getBlock().getUseNeighborBrightness()) {
                  int l = 0;
  
                  for (EnumFacing enumfacing : EnumFacing.values()) {
                      int k = this.getLightFor(p_175629_1_, pos.offset(enumfacing));
  
                      if (k > l) {
                          l = k;
                      }
  
                      if (l >= 15) {
                          return l;
                      }
                  }
  
                  return l;
              } else {
                  int i = (pos.getX() >> 4) - this.chunkX;
                  int j = (pos.getZ() >> 4) - this.chunkZ;
                  return this.chunkArray[i][j].getLightFor(p_175629_1_, pos);
              }
          } else {
              return p_175629_1_.defaultLightValue;
          }
      }
  
      public boolean isAirBlock(BlockPos pos) {
          return this.getBlockState(pos).getBlock().getMaterial() == Material.air;
      }
  
      public int getLightFor(EnumSkyBlock p_175628_1_, BlockPos pos) {
          if (pos.getY() >= 0 && pos.getY() < 256) {
              int i = (pos.getX() >> 4) - this.chunkX;
              int j = (pos.getZ() >> 4) - this.chunkZ;
              return this.chunkArray[i][j].getLightFor(p_175628_1_, pos);
          } else {
              return p_175628_1_.defaultLightValue;
          }
      }
  
      public int getStrongPower(BlockPos pos, EnumFacing direction) {
          IBlockState iblockstate = this.getBlockState(pos);
          return iblockstate.getBlock().getStrongPower(this, pos, iblockstate, direction);
      }
  
      public WorldType getWorldType() {
          return this.worldObj.getWorldType();
      }
  }
  