From f051ce2392bc0bfae52945e8f53fe38f2d095637 Mon Sep 17 00:00:00 2001
From: Kevin Chabowski <kevin@kch42.de>
Date: Sat, 21 Sep 2013 00:48:59 +0200
Subject: Deleting chunks implemented.

---
 README.markdown                    |  1 -
 mcmap/chunk.go                     |  5 +++++
 mcmap/examples/delchunk/.gitignore |  1 +
 mcmap/examples/delchunk/main.go    | 41 ++++++++++++++++++++++++++++++++++++++
 mcmap/region.go                    | 27 +++++++++++++++++--------
 5 files changed, 66 insertions(+), 9 deletions(-)
 create mode 100644 mcmap/examples/delchunk/.gitignore
 create mode 100644 mcmap/examples/delchunk/main.go

diff --git a/README.markdown b/README.markdown
index 3a06e1f..3e493b7 100644
--- a/README.markdown
+++ b/README.markdown
@@ -20,7 +20,6 @@ Although I tested the library with some maps, I can't guarantee that everything
 
 ## Wishlist / TODO
 
-* Removing chunks.
 * Recalculating light data.
 * Reading and modifying level.dat and other files (currently only the region files are used).
 * Test compatibility with older versions of Minecraft.
diff --git a/mcmap/chunk.go b/mcmap/chunk.go
index 9196776..dfac5a7 100644
--- a/mcmap/chunk.go
+++ b/mcmap/chunk.go
@@ -54,6 +54,8 @@ type Chunk struct {
 	blocks   []Block // Ordered YZX
 	biomes   []Biome // Ordered ZX
 
+	deleted bool
+
 	reg *Region
 }
 
@@ -132,6 +134,9 @@ func (c *Chunk) SetBiome(x, z int, bio Biome) { c.biomes[z*ChunkSizeXZ+x] = bio
 // If the chunk was modified, call MarkModified BEFORE.
 func (c *Chunk) MarkUnused() error { return c.reg.unloadChunk(int(c.x), int(c.z)) }
 
+// MarkDeleted marks this chunk as deleted. After marking it as unused, it will be deleted and can no longer be used.
+func (c *Chunk) MarkDeleted() { c.deleted = true }
+
 // RecalcHeightMap recalculates the internal height map.
 //
 // You should use this function before marking the chunk as unused, if you modified the chunk
diff --git a/mcmap/examples/delchunk/.gitignore b/mcmap/examples/delchunk/.gitignore
new file mode 100644
index 0000000..732afb9
--- /dev/null
+++ b/mcmap/examples/delchunk/.gitignore
@@ -0,0 +1 @@
+delchunk
diff --git a/mcmap/examples/delchunk/main.go b/mcmap/examples/delchunk/main.go
new file mode 100644
index 0000000..c8996a5
--- /dev/null
+++ b/mcmap/examples/delchunk/main.go
@@ -0,0 +1,41 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"github.com/kch42/gomcmap/mcmap"
+	"os"
+)
+
+func main() {
+	path := flag.String("path", "", "Path to region directory")
+	flag.Parse()
+
+	if *path == "" {
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	region, err := mcmap.OpenRegion(*path, false)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Could not open region: %s\n", err)
+		os.Exit(1)
+	}
+
+	chunk, err := region.Chunk(200, 200)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error getting chunk 200,200: %s\n", err)
+		os.Exit(1)
+	}
+
+	chunk.MarkDeleted()
+	if err := chunk.MarkUnused(); err != nil {
+		fmt.Fprintf(os.Stderr, "Could not mark chunk as unused: %s\n", err)
+		os.Exit(1)
+	}
+
+	if err := region.Save(); err != nil {
+		fmt.Fprintf(os.Stderr, "Could not save region: %s\n", err)
+		os.Exit(1)
+	}
+}
diff --git a/mcmap/region.go b/mcmap/region.go
index 34b3334..93c8693 100644
--- a/mcmap/region.go
+++ b/mcmap/region.go
@@ -157,15 +157,23 @@ func (reg *Region) cleanSuperchunks(forceSave bool) error {
 			if !(reg.autosave || forceSave) {
 				continue
 			}
+
 			fn := fmt.Sprintf("%s%cr.%d.%d.mca", reg.path, os.PathSeparator, scPos.X, scPos.Z)
-			f, err := os.Create(fn)
-			if err != nil {
-				return err
-			}
-			defer f.Close()
 
-			if err := writeRegionFile(f, sc.preChunks); err != nil {
-				return err
+			if len(sc.preChunks) == 0 {
+				if err := os.Remove(fn); err != nil {
+					return err
+				}
+			} else {
+				f, err := os.Create(fn)
+				if err != nil {
+					return err
+				}
+				defer f.Close()
+
+				if err := writeRegionFile(f, sc.preChunks); err != nil {
+					return err
+				}
 			}
 		}
 
@@ -239,7 +247,10 @@ func (reg *Region) unloadChunk(x, z int) error {
 		return nil
 	}
 
-	if chunk.modified {
+	if chunk.deleted {
+		delete(sc.preChunks, cPos)
+		sc.modified = true
+	} else if chunk.modified {
 		pc, err := chunk.toPreChunk()
 		if err != nil {
 			return err
-- 
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