From adf77e26610587831031a9471e17cf4d89847aca Mon Sep 17 00:00:00 2001
From: Tnze <cjd001113@outlook.com>
Date: Wed, 31 Mar 2021 16:00:15 +0800
Subject: [PATCH] linear palette

---
 examples/genmaps/genmaps.go    | 11 +++--
 examples/genmaps/util_funcs.go |  6 ---
 save/palette.go                | 80 ++++++++++++++++++++++++++++++++++
 3 files changed, 85 insertions(+), 12 deletions(-)
 create mode 100644 save/palette.go

diff --git a/examples/genmaps/genmaps.go b/examples/genmaps/genmaps.go
index 1361b17..e275f05 100644
--- a/examples/genmaps/genmaps.go
+++ b/examples/genmaps/genmaps.go
@@ -19,16 +19,15 @@ import (
 )
 
 var colors []color.RGBA64
-var regionWorkerNum = runtime.NumCPU()
 var sectionWorkerNum = 1
 
 var (
-	regionsFold    = flag.String("region", filepath.Join(os.Getenv("AppData"), ".minecraft", "saves", "World", "region"), "region directory path")
-	drawBigPicture = flag.Bool("bigmap", true, "draw the bit map")
+	regionWorkerNum = flag.Int("workers", runtime.NumCPU(), "worker numbers")
+	regionsFold     = flag.String("region", filepath.Join(os.Getenv("AppData"), ".minecraft", "saves", "World", "region"), "region directory path")
+	drawBigPicture  = flag.Bool("bigmap", true, "draw the big map")
 )
 
 func main() {
-	flag.Usage = usage
 	flag.Parse()
 
 	de, err := os.ReadDir(*regionsFold)
@@ -61,7 +60,7 @@ func main() {
 		*region.Region
 	}
 	// Open mca files
-	var rs = make(chan regions, regionWorkerNum)
+	var rs = make(chan regions, *regionWorkerNum)
 	go func() {
 		for _, dir := range de {
 			name := dir.Name()
@@ -95,7 +94,7 @@ func main() {
 		}
 		c := make(chan task)
 		var wg sync.WaitGroup
-		for i := 0; i < regionWorkerNum; i++ {
+		for i := 0; i < *regionWorkerNum; i++ {
 			go func() {
 				var column save.Column
 				for task := range c {
diff --git a/examples/genmaps/util_funcs.go b/examples/genmaps/util_funcs.go
index b2c4da3..4165ea2 100644
--- a/examples/genmaps/util_funcs.go
+++ b/examples/genmaps/util_funcs.go
@@ -4,7 +4,6 @@ import (
 	"bytes"
 	_ "embed"
 	"encoding/gob"
-	"fmt"
 	"github.com/Tnze/go-mc/data/block"
 	"image"
 	"image/png"
@@ -37,11 +36,6 @@ func init() {
 	}
 }
 
-func usage() {
-	_, _ = fmt.Fprintf(os.Stderr, "usage: %s [-region <region path>] \n", os.Args[0])
-	os.Exit(1)
-}
-
 func mkmax(c, n *int) {
 	if *c < *n {
 		*c = *n
diff --git a/save/palette.go b/save/palette.go
new file mode 100644
index 0000000..3552633
--- /dev/null
+++ b/save/palette.go
@@ -0,0 +1,80 @@
+package save
+
+import (
+	"github.com/Tnze/go-mc/nbt"
+	pk "github.com/Tnze/go-mc/net/packet"
+	"io"
+)
+
+type BlockState interface {
+}
+
+type palette interface {
+	id(v BlockState) int
+	value(i int) BlockState
+	io.ReaderFrom
+	io.WriterTo
+	read(r nbt.DecoderReader) (int, error)
+}
+
+type linearPalette struct {
+	onResize func(n int, v BlockState) int
+	sToID    map[BlockState]int
+	idTos    map[int]BlockState
+	values   []BlockState
+	bits     int
+}
+
+func (l *linearPalette) id(v BlockState) int {
+	for i, t := range l.values {
+		if t == v {
+			return i
+		}
+	}
+	if cap(l.values)-len(l.values) > 0 {
+		l.values = append(l.values, v)
+		return len(l.values) - 1
+	}
+	return l.onResize(l.bits+1, v)
+}
+
+func (l *linearPalette) value(i int) BlockState {
+	if i >= 0 && i < len(l.values) {
+		return l.values[i]
+	}
+	return nil
+}
+
+func (l *linearPalette) ReadFrom(r io.Reader) (n int64, err error) {
+	var size, value pk.VarInt
+	if n, err = size.ReadFrom(r); err != nil {
+		return
+	}
+	for i := 0; i < int(size); i++ {
+		if nn, err := value.ReadFrom(r); err != nil {
+			return n + nn, err
+		} else {
+			n += nn
+		}
+		l.values[i] = l.idTos[int(value)]
+	}
+	return
+}
+
+func (l *linearPalette) WriteTo(w io.Writer) (n int64, err error) {
+	if n, err = pk.VarInt(len(l.values)).WriteTo(w); err != nil {
+		return
+	}
+	for _, v := range l.values {
+		if nn, err := pk.VarInt(l.sToID[v]).WriteTo(w); err != nil {
+			return n + nn, err
+		} else {
+			n += nn
+		}
+	}
+	return
+}
+
+func (l *linearPalette) read(r nbt.DecoderReader) (int, error) {
+	panic("not implemented yet")
+}