From 78251f11c91b2504edfc02b760ef53bd352b856c Mon Sep 17 00:00:00 2001
From: n-peugnet <n.peugnet@free.fr>
Date: Thu, 26 Aug 2021 19:21:46 +0200
Subject: add SketchChunk function

---
 repo.go | 35 +++++++++++++++++++----------------
 1 file changed, 19 insertions(+), 16 deletions(-)

(limited to 'repo.go')

diff --git a/repo.go b/repo.go
index f893b47..833bfdf 100644
--- a/repo.go
+++ b/repo.go
@@ -64,7 +64,7 @@ func (r *Repo) Commit(source string) {
 	reader, writer := io.Pipe()
 	oldChunks := make(chan Chunk, 16)
 	files := listFiles(source)
-	go loadChunks(versions, oldChunks)
+	go r.loadChunks(versions, oldChunks)
 	go concatFiles(files, writer)
 	hashes := hashChunks(oldChunks)
 	chunks := r.matchStream(reader, hashes)
@@ -75,7 +75,7 @@ func (r *Repo) Commit(source string) {
 }
 
 func (r *Repo) loadVersions() []string {
-	versions := make([]string, 0)
+	var versions []string
 	files, err := os.ReadDir(r.path)
 	if err != nil {
 		log.Fatalln(err)
@@ -155,7 +155,7 @@ func storeFileList(dest string, files []File) {
 }
 
 func loadFileList(path string) []File {
-	files := make([]File, 0)
+	var files []File
 	err := readFile(path, &files)
 	if err != nil {
 		log.Println(err)
@@ -181,7 +181,7 @@ func storeChunks(dest string, chunks <-chan []byte) {
 	}
 }
 
-func loadChunks(versions []string, chunks chan<- Chunk) {
+func (r *Repo) loadChunks(versions []string, chunks chan<- Chunk) {
 	for i, v := range versions {
 		p := path.Join(v, chunksName)
 		entries, err := os.ReadDir(p)
@@ -198,6 +198,7 @@ func loadChunks(versions []string, chunks chan<- Chunk) {
 				log.Printf("Error reading chunk '%s': %s", f, err.Error())
 			}
 			c := Chunk{
+				Repo: r,
 				Id: &ChunkId{
 					Ver: i,
 					Idx: uint64(j),
@@ -230,26 +231,26 @@ func readChunk(stream io.Reader) ([]byte, error) {
 
 func (r *Repo) matchStream(stream io.Reader, hashes map[uint64]ChunkId) []Chunk {
 	var b byte
-	chunks := make([]Chunk, 0)
-	buff, err := readChunk(stream)
+	var chunks []Chunk
+	bufStream := bufio.NewReaderSize(stream, chunkSize)
+	buff, err := readChunk(bufStream)
 	if err == io.EOF {
-		chunks = append(chunks, Chunk{Value: buff})
+		chunks = append(chunks, Chunk{Repo: r, Value: buff})
 		return chunks
 	}
-	bufStream := bufio.NewReader(stream)
 	hasher := rabinkarp64.New()
 	hasher.Write(buff)
-	buff = make([]byte, 0, chunkSize)
+	buff = buff[0:0]
 	for err != io.EOF {
 		h := hasher.Sum64()
 		chunkId, exists := hashes[h]
 		if exists {
 			if len(buff) > 0 {
 				log.Printf("Add new partial chunk of size: %d\n", len(buff))
-				chunks = append(chunks, Chunk{Value: buff})
+				chunks = append(chunks, Chunk{Repo: r, Value: buff})
 			}
-			log.Printf("Found existing chunk with offset %d: %d\n", len(buff), chunkId)
-			chunks = append(chunks, Chunk{Id: &chunkId})
+			log.Printf("Add existing chunk: %d\n", chunkId)
+			chunks = append(chunks, Chunk{Repo: r, Id: &chunkId})
 			buff = make([]byte, 0, chunkSize)
 			for i := 0; i < chunkSize && err == nil; i++ {
 				b, err = bufStream.ReadByte()
@@ -259,7 +260,7 @@ func (r *Repo) matchStream(stream io.Reader, hashes map[uint64]ChunkId) []Chunk
 		}
 		if len(buff) == chunkSize {
 			log.Println("Add new chunk")
-			chunks = append(chunks, Chunk{Value: buff})
+			chunks = append(chunks, Chunk{Repo: r, Value: buff})
 			buff = make([]byte, 0, chunkSize)
 		}
 		b, err = bufStream.ReadByte()
@@ -269,19 +270,21 @@ func (r *Repo) matchStream(stream io.Reader, hashes map[uint64]ChunkId) []Chunk
 		}
 	}
 	if len(buff) > 0 {
-		chunks = append(chunks, Chunk{Value: buff})
+		chunks = append(chunks, Chunk{Repo: r, Value: buff})
 	}
 	return chunks
 }
 
+// extractNewChunks extracts new chunks from an array of chunks and
+// returns them in an array of consecutive new chunk's array
 func extractNewChunks(chunks []Chunk) (ret [][]Chunk) {
 	var i int
-	ret = append(ret, make([]Chunk, 0))
+	ret = append(ret, nil)
 	for _, c := range chunks {
 		if c.isStored() {
 			if len(ret[i]) != 0 {
 				i++
-				ret = append(ret, make([]Chunk, 0))
+				ret = append(ret, nil)
 			}
 		} else {
 			ret[i] = append(ret[i], c)
-- 
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