From 2d00eb9567871f15f4443281aad858ee38d6eab2 Mon Sep 17 00:00:00 2001
From: "Sascha L. Teichmann" <sascha.teichmann@intevation.de>
Date: Sun, 21 Jun 2015 22:47:06 +0200
Subject: [PATCH] Simplifications when decoding blocks from database to save
 some memory allocations.

---
 cmd/mtseeder/main.go |  5 ++---
 common/block.go      | 20 +++++++++-----------
 2 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/cmd/mtseeder/main.go b/cmd/mtseeder/main.go
index 7b8b795..cc1ab5e 100644
--- a/cmd/mtseeder/main.go
+++ b/cmd/mtseeder/main.go
@@ -45,10 +45,9 @@ func main() {
 
 	flag.Parse()
 
-	var err error
 	if !skipBaseLevel {
 		address := fmt.Sprintf("%s:%d", host, port)
-		if err = createBaseLevel(
+		if err := createBaseLevel(
 			address,
 			xMin, zMin, xMax, zMax,
 			transparent,
@@ -59,7 +58,7 @@ func main() {
 		}
 	}
 	if !skipPyramid {
-		if err = createPyramid(outDir, numWorkers); err != nil {
+		if err := createPyramid(outDir, numWorkers); err != nil {
 			log.Fatalf("Creating pyramid tiles failed: %s", err)
 		}
 	}
diff --git a/common/block.go b/common/block.go
index 5eff655..da3f891 100644
--- a/common/block.go
+++ b/common/block.go
@@ -77,29 +77,31 @@ func NewDecodedBlock(data []byte, colors *Colors) (db *DecodedBlock, err error)
 		offset = 4
 	}
 
-	buf := NewposBuf(data[offset:])
+	buf := posBuf{Data: data[offset:]}
 	var zr io.ReadCloser
-	if zr, err = zlib.NewReader(buf); err != nil {
+	if zr, err = zlib.NewReader(&buf); err != nil {
 		return
 	}
 
-	var mapContent []byte
-	mapContent, err = ioutil.ReadAll(zr)
+	mapContent := make([]byte, uncompressedLen)
+
+	var k int
+	k, err = io.ReadFull(zr, mapContent)
 	zr.Close()
 	if err != nil {
 		return
 	}
 
-	if uncompressedLen != len(mapContent) {
+	if k != uncompressedLen {
 		err = ErrMapContentSizeMismatch
 		return
 	}
 
-	offset += buf.Pos
+	offset += buf.Pos + 4
 	buf.Pos = 0
 	buf.Data = data[offset:]
 
-	if zr, err = zlib.NewReader(buf); err != nil {
+	if zr, err = zlib.NewReader(&buf); err != nil {
 		return
 	}
 
@@ -204,10 +206,6 @@ func (db *DecodedBlock) Content(x, y, z int) (content int32, found bool) {
 	return
 }
 
-func NewposBuf(data []byte) *posBuf {
-	return &posBuf{Data: data}
-}
-
 func (pb *posBuf) Read(p []byte) (int, error) {
 	pl := len(p)
 	ml := len(pb.Data)