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git-svn-id: https://weed-fs.googlecode.com/svn/trunk@20 282b0af5-e82d-9cf1-ede4-77906d7719d0

weed-fs/src/pkg/storage/needle_map.go

@@ -1,42 +1,60 @@
 package storage
 
 import (
+	"log"
 	"os"
 )
 
-type NeedleKey struct {
-	Key          uint64 "file id"
-}
-
-func (k *NeedleKey) String() string {
-	var tmp [12]byte
-	for i := uint(0); i < 8; i++ {
-		tmp[i] = byte(k.Key >> (8 * i))
-	}
-	return string(tmp[:])
-}
-
 type NeedleValue struct {
 	Offset uint32 "Volume offset" //since aligned to 8 bytes, range is 4G*8=32G
 	Size   uint32 "Size of the data portion"
 }
 
 type NeedleMap struct {
-	m map[uint64]*NeedleValue //mapping NeedleKey(Key,AlternateKey) to NeedleValue
+	indexFile *os.File
+	m         map[uint64]*NeedleValue //mapping needle key(uint64) to NeedleValue
+	bytes     []byte
 }
 
 func NewNeedleMap() *NeedleMap {
-	return &NeedleMap{m: make(map[uint64]*NeedleValue)}
+	return &NeedleMap{m: make(map[uint64]*NeedleValue), bytes: make([]byte, 16)}
 }
-func (nm *NeedleMap) load(file *os.File) {
-}
-func makeKey(key uint64) uint64 {
-	return key
+
+const (
+	RowsToRead = 1024
+)
+
+func LoadNeedleMap(file *os.File) *NeedleMap {
+	nm := NewNeedleMap()
+	nm.indexFile = file
+	bytes := make([]byte, 16*RowsToRead)
+	count, e := nm.indexFile.Read(bytes)
+	if count > 0 {
+	    fstat, _ := file.Stat()
+		log.Println("Loading index file", fstat.Name, "size", fstat.Size)
+	}
+	for count > 0 && e == nil {
+		for i := 0; i < count; i += 16 {
+			key := BytesToUint64(bytes[i : i+8])
+			offset := BytesToUint32(bytes[i+8 : i+12])
+			size := BytesToUint32(bytes[i+12 : i+16])
+			nm.m[key] = &NeedleValue{Offset: offset, Size: size}
+		}
+		count, e = nm.indexFile.Read(bytes)
+	}
+	return nm
 }
 func (nm *NeedleMap) put(key uint64, offset uint32, size uint32) {
-	nm.m[makeKey(key)] = &NeedleValue{Offset: offset, Size: size}
+	nm.m[key] = &NeedleValue{Offset: offset, Size: size}
+	Uint64toBytes(nm.bytes[0:8], key)
+	Uint32toBytes(nm.bytes[8:12], offset)
+	Uint32toBytes(nm.bytes[12:16], size)
+	nm.indexFile.Write(nm.bytes)
 }
 func (nm *NeedleMap) get(key uint64) (element *NeedleValue, ok bool) {
-	element, ok = nm.m[makeKey(key)]
+	element, ok = nm.m[key]
 	return
 }
+func (nm *NeedleMap) Close() {
+	nm.indexFile.Close()
+}