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Use compact memory format for uniform chunk section data.

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Many chunk sections contain parts of their data that are the same for
every block they contain. In these cases we can save memory by saving
a single value instead of an array of 4096 copies of that value. Block light
and block data are most likely to be uniform followed closely by sky light
data. Block ids are far less likely to be uniform but give the largest
saving when they are. Because of this we use a compact format for every
part of the chunk. Memory saved from this technique will vary based on the
world but seems to be about 50% on normal Minecraft generated chunks.
This commit is contained in:
Travis Watkins 2014-06-21 11:38:28 -05:00
parent 5adbab524d
commit 6364f59ac4
1 changed files with 272 additions and 59 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

331
src/main/java/net/minecraft/server/ChunkSection.java
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@ -1,5 +1,7 @@
package net.minecraft.server;
import java.util.Arrays; // CraftBukkit
public class ChunkSection {
private int yPos;
@ -10,34 +12,83 @@ public class ChunkSection {
private NibbleArray blockData;
private NibbleArray emittedLight;
private NibbleArray skyLight;
// CraftBukkit start - Compact storage
private byte compactId;
private byte compactExtId;
private byte compactData;
private byte compactEmitted;
private byte compactSky;
// Pre-generated (read-only!) NibbleArrays for every possible value, used for chunk saving
private static NibbleArray[] compactPregen = new NibbleArray[16];
static {
for (int i = 0; i < 16; i++) {
compactPregen[i] = expandCompactNibble((byte) i);
}
}
private static NibbleArray expandCompactNibble(byte value) {
byte[] data = new byte[2048];
Arrays.fill(data, (byte) (value | (value << 4)));
return new NibbleArray(data, 4);
}
private boolean canBeCompact(byte[] array) {
byte value = array[0];
for (int i = 1; i < array.length; i++) {
if (value != array[i]) {
return false;
}
}
return true;
}
// CraftBukkit end
public ChunkSection(int i, boolean flag) {
this.yPos = i;
/* CraftBukkit - Start as null, using compact storage
this.blockIds = new byte[4096];
this.blockData = new NibbleArray(this.blockIds.length, 4);
this.emittedLight = new NibbleArray(this.blockIds.length, 4);
if (flag) {
this.skyLight = new NibbleArray(this.blockIds.length, 4);
}
*/
if (!flag) {
this.compactSky = -1;
}
// CraftBukkit end
}
// CraftBukkit start
public ChunkSection(int y, boolean flag, byte[] blkIds, byte[] extBlkIds) {
this.yPos = y;
this.blockIds = blkIds;
this.setIdArray(blkIds);
if (extBlkIds != null) {
this.extBlockIds = new NibbleArray(extBlkIds, 4);
this.setExtendedIdArray(new NibbleArray(extBlkIds, 4));
}
this.blockData = new NibbleArray(this.blockIds.length, 4);
this.emittedLight = new NibbleArray(this.blockIds.length, 4);
if (flag) {
this.skyLight = new NibbleArray(this.blockIds.length, 4);
if (!flag) {
this.compactSky = -1;
}
this.recalcBlockCounts();
}
// CraftBukkit end
public Block getTypeId(int i, int j, int k) {
// CraftBukkit start - Compact storage
if (this.blockIds == null) {
int id = this.compactId;
if (this.extBlockIds == null) {
id |= this.compactExtId << 8;
} else {
id |= this.extBlockIds.a(i, j, k) << 8;
}
return Block.e(id); // Should be getBlockForId
}
// CraftBukkit end
int l = this.blockIds[j << 8 | k << 4 | i] & 255;
if (this.extBlockIds != null) {
@ -48,13 +99,12 @@ public class ChunkSection {
}
public void setTypeId(int i, int j, int k, Block block) {
int l = this.blockIds[j << 8 | k << 4 | i] & 255;
if (this.extBlockIds != null) {
l |= this.extBlockIds.a(i, j, k) << 8;
// CraftBukkit start - Compact storage
Block block1 = this.getTypeId(i, j, k);
if (block == block1) {
return;
}
Block block1 = Block.e(l);
// CraftBukkit end
if (block1 != Blocks.AIR) {
--this.nonEmptyBlockCount;
@ -72,10 +122,17 @@ public class ChunkSection {
int i1 = Block.b(block);
// CraftBukkit start - Compact storage
if (this.blockIds == null) {
this.blockIds = new byte[4096];
Arrays.fill(this.blockIds, this.compactId);
}
// CraftBukkit end
this.blockIds[j << 8 | k << 4 | i] = (byte) (i1 & 255);
if (i1 > 255) {
if (this.extBlockIds == null) {
this.extBlockIds = new NibbleArray(this.blockIds.length, 4);
this.extBlockIds = expandCompactNibble(this.compactExtId); // CraftBukkit - Compact storage
}
this.extBlockIds.a(i, j, k, (i1 & 3840) >> 8);
@ -85,10 +142,23 @@ public class ChunkSection {
}
public int getData(int i, int j, int k) {
// CraftBukkit start - Compact storage
if (this.blockData == null) {
return this.compactData;
}
// CraftBukkit end
return this.blockData.a(i, j, k);
}
public void setData(int i, int j, int k, int l) {
// CraftBukkit start - Compact storage
if (this.blockData == null) {
if (this.compactData == l) {
return;
}
this.blockData = expandCompactNibble(this.compactData);
}
// CraftBukkit end
this.blockData.a(i, j, k, l);
}
@ -105,71 +175,151 @@ public class ChunkSection {
}
public void setSkyLight(int i, int j, int k, int l) {
// CraftBukkit start - Compact storage
if (this.skyLight == null) {
if (this.compactSky == l) {
return;
}
this.skyLight = expandCompactNibble(this.compactSky);
}
// CraftBukkit end
this.skyLight.a(i, j, k, l);
}
public int getSkyLight(int i, int j, int k) {
// CraftBukkit start - Compact storage
if (this.skyLight == null) {
return this.compactSky;
}
// CraftBukkit end
return this.skyLight.a(i, j, k);
}
public void setEmittedLight(int i, int j, int k, int l) {
// CraftBukkit start - Compact storage
if (this.emittedLight == null) {
if (this.compactEmitted == l) {
return;
}
this.emittedLight = expandCompactNibble(this.compactEmitted);
}
// CraftBukkit end
this.emittedLight.a(i, j, k, l);
}
public int getEmittedLight(int i, int j, int k) {
// CraftBukkit start - Compact storage
if (this.emittedLight == null) {
return this.compactEmitted;
}
// CraftBukkit end
return this.emittedLight.a(i, j, k);
}
public void recalcBlockCounts() {
// CraftBukkit start - Optimize for speed
byte[] blkIds = this.blockIds;
int cntNonEmpty = 0;
int cntTicking = 0;
if (this.extBlockIds == null) { // No extended block IDs? Don't waste time messing with them
for (int off = 0; off < blkIds.length; off++) {
int l = blkIds[off] & 0xFF;
if (l > 0) {
if (Block.e(l) == null) {
blkIds[off] = 0;
if (this.blockIds == null) {
int id = this.compactId;
if (this.extBlockIds == null) {
id |= this.compactExtId << 8;
if (id > 0) {
Block block = Block.e(id); // Should be getBlockForId
if (block == null) {
this.compactId = 0;
this.compactExtId = 0;
} else {
++cntNonEmpty;
if (Block.e(l).isTicking()) {
++cntTicking;
cntNonEmpty = 4096;
if (block.isTicking()) {
cntTicking = 4096;
}
}
}
} else {
byte[] ext = this.extBlockIds.a;
for (int off = 0, off2 = 0; off < 4096;) {
byte extid = ext[off2];
int l = (id & 0xFF) | ((extid & 0xF) << 8); // Even data
if (l > 0) {
Block block = Block.e(l); // Should be getBlockForId
if (block == null) {
this.compactId = 0;
ext[off2] &= 0xF0;
} else {
++cntNonEmpty;
if (block.isTicking()) {
++cntTicking;
}
}
}
off++;
l = (id & 0xFF) | ((extid & 0xF0) << 4); // Odd data
if (l > 0) {
Block block = Block.e(l); // Should be getBlockForId
if (block == null) {
this.compactId = 0;
ext[off2] &= 0x0F;
} else {
++cntNonEmpty;
if (block.isTicking()) {
++cntTicking;
}
}
}
off++;
off2++;
}
}
} else {
byte[] ext = this.extBlockIds.a;
for (int off = 0, off2 = 0; off < blkIds.length;) {
byte extid = ext[off2];
int l = (blkIds[off] & 0xFF) | ((extid & 0xF) << 8); // Even data
if (l > 0) {
if (Block.e(l) == null) {
blkIds[off] = 0;
ext[off2] &= 0xF0;
} else {
++cntNonEmpty;
if (Block.e(l).isTicking()) {
++cntTicking;
byte[] blkIds = this.blockIds;
if (this.extBlockIds == null) { // No extended block IDs? Don't waste time messing with them
for (int off = 0; off < blkIds.length; off++) {
int l = blkIds[off] & 0xFF;
if (l > 0) {
if (Block.e(l) == null) {
blkIds[off] = 0;
} else {
++cntNonEmpty;
if (Block.e(l).isTicking()) {
++cntTicking;
}
}
}
}
off++;
l = (blkIds[off] & 0xFF) | ((extid & 0xF0) << 4); // Odd data
if (l > 0) {
if (Block.e(l) == null) {
blkIds[off] = 0;
ext[off2] &= 0x0F;
} else {
++cntNonEmpty;
if (Block.e(l).isTicking()) {
++cntTicking;
} else {
byte[] ext = this.extBlockIds.a;
for (int off = 0, off2 = 0; off < blkIds.length;) {
byte extid = ext[off2];
int l = (blkIds[off] & 0xFF) | ((extid & 0xF) << 8); // Even data
if (l > 0) {
if (Block.e(l) == null) {
blkIds[off] = 0;
ext[off2] &= 0xF0;
} else {
++cntNonEmpty;
if (Block.e(l).isTicking()) {
++cntTicking;
}
}
}
off++;
l = (blkIds[off] & 0xFF) | ((extid & 0xF0) << 4); // Odd data
if (l > 0) {
if (Block.e(l) == null) {
blkIds[off] = 0;
ext[off2] &= 0x0F;
} else {
++cntNonEmpty;
if (Block.e(l).isTicking()) {
++cntTicking;
}
}
}
off++;
off2++;
}
off++;
off2++;
}
}
this.nonEmptyBlockCount = cntNonEmpty;
@ -198,56 +348,119 @@ public class ChunkSection {
}
public byte[] getIdArray() {
// CraftBukkit start - Compact storage
if (this.blockIds == null) {
byte[] ids = new byte[4096];
Arrays.fill(ids, this.compactId);
return ids;
}
// CraftBukkit end
return this.blockIds;
}
public NibbleArray getExtendedIdArray() {
// CraftBukkit start - Compact storage
if (this.extBlockIds == null && this.compactExtId != 0) {
return compactPregen[this.compactExtId];
}
// CraftBukkit end
return this.extBlockIds;
}
public NibbleArray getDataArray() {
// CraftBukkit start - Compact storage
if (this.blockData == null) {
return compactPregen[this.compactData];
}
// CraftBukkit end
return this.blockData;
}
public NibbleArray getEmittedLightArray() {
// CraftBukkit start - Compact storage
if (this.emittedLight == null) {
return compactPregen[this.compactEmitted];
}
// CraftBukkit end
return this.emittedLight;
}
public NibbleArray getSkyLightArray() {
// CraftBukkit start - Compact storage
if (this.skyLight == null && this.compactSky != -1) {
return compactPregen[this.compactSky];
}
// CraftBukkit end
return this.skyLight;
}
public void setIdArray(byte[] abyte) {
// CraftBukkit start - Compact storage
if (abyte == null) {
this.compactId = 0;
this.blockIds = null;
return;
} else if (canBeCompact(abyte)) {
this.compactId = abyte[0];
return;
}
// CraftBukkit end
this.blockIds = this.validateByteArray(abyte); // CraftBukkit - Validate data
}
public void setExtendedIdArray(NibbleArray nibblearray) {
// CraftBukkit start - Don't hang on to an empty nibble array
boolean empty = true;
for (int i = 0; i < nibblearray.a.length; i++) {
if (nibblearray.a[i] != 0) {
empty = false;
break;
}
}
if (empty) {
// CraftBukkit start - Compact storage
if (nibblearray == null) {
this.compactExtId = 0;
this.extBlockIds = null;
return;
} else if (canBeCompact(nibblearray.a)) {
this.compactExtId = (byte) (nibblearray.a(0, 0, 0) & 0xF);
return;
}
// CraftBukkit end
this.extBlockIds = this.validateNibbleArray(nibblearray); // CraftBukkit - Validate data
}
public void setDataArray(NibbleArray nibblearray) {
// CraftBukkit start - Compact storage
if (nibblearray == null) {
this.compactData = 0;
this.blockData = null;
return;
} else if (canBeCompact(nibblearray.a)) {
this.compactData = (byte) (nibblearray.a(0, 0, 0) & 0xF);
return;
}
// CraftBukkit end
this.blockData = this.validateNibbleArray(nibblearray); // CraftBukkit - Validate data
}
public void setEmittedLightArray(NibbleArray nibblearray) {
// CraftBukkit start - Compact storage
if (nibblearray == null) {
this.compactEmitted = 0;
this.emittedLight = null;
return;
} else if (canBeCompact(nibblearray.a)) {
this.compactEmitted = (byte) (nibblearray.a(0, 0, 0) & 0xF);
return;
}
// CraftBukkit end
this.emittedLight = this.validateNibbleArray(nibblearray); // CraftBukkit - Validate data
}
public void setSkyLightArray(NibbleArray nibblearray) {
// CraftBukkit start - Compact storage
if (nibblearray == null) {
this.compactSky = -1;
this.skyLight = null;
return;
} else if (canBeCompact(nibblearray.a)) {
this.compactSky = (byte) (nibblearray.a(0, 0, 0) & 0xF);
return;
}
// CraftBukkit end
this.skyLight = this.validateNibbleArray(nibblearray); // CraftBukkit - Validate data
}
@ -255,7 +468,7 @@ public class ChunkSection {
private NibbleArray validateNibbleArray(NibbleArray nibbleArray) {
if (nibbleArray != null && nibbleArray.a.length < 2048) {
byte[] newArray = new byte[2048];
System.arraycopy(nibbleArray.a, 0, newArray, 0, ((nibbleArray.a.length > 2048) ? 2048 : nibbleArray.a.length));
System.arraycopy(nibbleArray.a, 0, newArray, 0, nibbleArray.a.length);
nibbleArray = new NibbleArray(newArray, 4);
}