chunk serialization

level/packet.go

@@ -2,17 +2,21 @@ package level
 
 import (
 	"encoding/binary"
+	"errors"
 	"io"
 	"math"
 
 	"github.com/admin-else/strom/proto_base"
+	"github.com/admin-else/strom/util"
 )
 
 const (
-	BlocksPerChunkSection = 4096
-	BiomesPerChunkSection = 64
+	BlocksPerChunkSection = 16 * 16 * 16
+	BiomesPerChunkSection = 4 * 4 * 4
 )
 
+var InvalidPalletIndexErr = errors.New("invalid palette index")
+
 func UnpackArrayPalette(r io.Reader, bitsPerEntry uint8, numberOfEntries int) (data []int32, err error) {
 	palletLen, err := proto_base.DecodeVarInt(r)
 	if err != nil {
@@ -28,13 +32,39 @@ func UnpackArrayPalette(r io.Reader, bitsPerEntry uint8, numberOfEntries int) (d
 		pallet = append(pallet, entry)
 	}
 	data, err = UnpackLongData(r, bitsPerEntry, numberOfEntries)
+
 	for i, b := range data {
-		data[i] = pallet[b] // maybe check bounds?
+		if b < 0 || b >= palletLen {
+			err = InvalidPalletIndexErr
+			return
+		}
+		data[i] = pallet[b]
 	}
 
 	return
 }
 
+func PackArrayPallet(unique map[int32]struct{}, data []int32, w io.Writer) (err error) {
+	pallet := util.SetToSliceOrdered(unique) // this may improve performance in combination with zlib i dont know tho
+	err = proto_base.EncodeVarInt(w, int32(len(pallet)))
+	if err != nil {
+		return
+	}
+	var palletMap = make(map[int32]int32)
+	for i, entry := range pallet {
+		palletMap[entry] = int32(i)
+		err = proto_base.EncodeVarInt(w, entry)
+		if err != nil {
+			return
+		}
+	}
+	var palletedData = make([]int32, len(data))
+	for i, entry := range data {
+		palletedData[i] = palletMap[entry]
+	}
+	return PackLongData(palletedData, w)
+}
+
 func UnpackLongData(r io.Reader, bitsPerEntry uint8, numberOfEntries int) (data []int32, err error) {
 	entriesPerLong := int(64 / bitsPerEntry)
 	numberOfLongs := int(math.Ceil(float64(numberOfEntries) / float64(entriesPerLong)))
@@ -52,6 +82,16 @@ func UnpackLongData(r io.Reader, bitsPerEntry uint8, numberOfEntries int) (data
 	return
 }
 
+func PackLongData(data []int32, w io.Writer) (err error) {
+	unique := util.GetUniqueSlice(data)
+	bpe := int32(math.Ceil(math.Log2(float64(len(unique)))))
+	dataL := DataToLongs(data, bpe)
+	for _, entry := range dataL {
+		err = binary.Write(w, binary.BigEndian, entry)
+	}
+	return
+}
+
 func UnpackSingleValuePalette(r io.Reader, numberOfEntries int) (data []int32, err error) {
 	entry, err := proto_base.DecodeVarInt(r)
 	if err != nil {
@@ -75,6 +115,22 @@ func LongsToData(data []uint64, n, bpe int32) (ret []int32) {
 	return
 }
 
+func DataToLongs(data []int32, bpe int32) (ret []uint64) {
+	elementsPerLong := 64 / bpe
+	retLen := int32(math.Ceil(float64(len(data)) / float64(elementsPerLong)))
+	ret = make([]uint64, retLen)
+	for i := range retLen {
+		for j := range elementsPerLong {
+			dataI := i*elementsPerLong + j
+			if dataI >= int32(len(data)) {
+				break
+			}
+			ret[i] |= uint64(data[dataI]) << (uint32(j) * uint32(bpe))
+		}
+	}
+	return
+}
+
 func GetEntryFromLongs(data []uint64, i, bpe int32) (ret int32) {
 	mask := (uint64(1) << uint32(bpe)) - 1
 	elementsPerLong := 64 / bpe
@@ -103,6 +159,21 @@ func UnpackBlockData(r io.Reader) (blocks []int32, err error) {
 	return
 }
 
+func PackBlockData(blocks []int32, w io.Writer) (err error) {
+	unique := util.GetUniqueSlice(blocks)
+	bpe := int32(math.Ceil(math.Log2(float64(len(unique)))))
+
+	switch bpe {
+	case 0:
+		err = proto_base.EncodeVarInt(w, blocks[0])
+	case 1, 2, 3:
+		err = PackArrayPallet(unique, blocks, w)
+	default:
+		err = PackLongData(blocks, w)
+	}
+	return
+}
+
 func UnpackBiomeData(r io.Reader) (biomes []int32, err error) {
 	// net.minecraft.world.chunk.PaletteProvider#forBiomes
 	var bitsPerEntry uint8
@@ -124,6 +195,21 @@ func UnpackBiomeData(r io.Reader) (biomes []int32, err error) {
 	return
 }
 
+func PackBiomeData(biomes []int32, w io.Writer) (err error) {
+	unique := util.GetUniqueSlice(biomes)
+	bpe := int32(math.Ceil(math.Log2(float64(len(unique)))))
+
+	switch bpe {
+	case 0:
+		err = proto_base.EncodeVarInt(w, biomes[0])
+	case 1, 2, 3:
+		err = PackArrayPallet(unique, biomes, w)
+	default:
+		err = PackLongData(biomes, w)
+	}
+	return
+}
+
 func UnpackSection(r io.Reader) (blocks, biomes []int32, err error) {
 	var blockCount int16
 	err = binary.Read(r, binary.BigEndian, &blockCount)
@@ -150,3 +236,39 @@ func UnpackNSections(r io.Reader, n int) (blocks, biomes [][]int32, err error) {
 	}
 	return
 }
+
+var LenMustMatchErr = errors.New("length must match")
+var BiomeMust64LongErr = errors.New("biome section must be 64 long")
+var BlockMust4096LongErr = errors.New("block section must be 4096 long")
+
+func PackSection(blocks, biomes []int32, w io.Writer) (err error) {
+	if len(blocks) != BlocksPerChunkSection {
+		return BlockMust4096LongErr
+	}
+	if len(biomes) != BiomesPerChunkSection {
+		return BiomeMust64LongErr
+	}
+	err = proto_base.EncodeVarInt(w, BlocksPerChunkSection-int32(util.CountSlice(blocks, 0)))
+	if err != nil {
+		return
+	}
+	err = PackBlockData(blocks, w)
+	if err != nil {
+		return
+	}
+	err = PackBiomeData(biomes, w)
+	return
+}
+
+func PackSections(blocks, biomes [][]int32, w io.Writer) (err error) {
+	if len(blocks) != len(biomes) {
+		return LenMustMatchErr
+	}
+	for i, blocksSection := range blocks {
+		err = PackSection(blocksSection, biomes[i], w)
+		if err != nil {
+			return
+		}
+	}
+	return
+}