1 files changed, 41 insertions, 11 deletions

diff --git a/src/file-hasher/hasher.go b/src/file-hasher/hasher.go
index 27574f9..5f84646 100644
--- a/src/file-hasher/hasher.go
+++ b/src/file-hasher/hasher.go
@@ -23,32 +23,32 @@ package main
 
 import (
 	"encoding/base64"
+	"hash"
 	"io"
 	"log"
 	"os"
 	"path/filepath"
 	"sync"
 
+	"crypto/md5"
+	"crypto/sha1"
+	"crypto/sha256"
+	"crypto/sha512"
 	"golang.org/x/crypto/blake2b"
 )
 
 type FileMap map[string]string
 
-func (m FileMap) Merge(m2 FileMap) {
-	for key, value := range m2 {
-		m[key] = value
-	}
-}
-
 type Hasher struct {
 	numThreads uint
 	stdlog     *log.Logger
+	newHash    func() (hash.Hash, error)
 	filesMtx   sync.Mutex
 	Files      FileMap
 }
 
-func computeHash(path string) (string, error) {
-	hash, err := blake2b.New256(nil)
+func (h *Hasher) computeHash(path string) (string, error) {
+	hash, err := h.newHash()
 	if err != nil {
 		return "", err
 	}
@@ -75,7 +75,7 @@ func (h *Hasher) collectHashes(C <-chan string) (wg *sync.WaitGroup) {
 				if !ok {
 					return
 				}
-				if hash, err := computeHash(file); err != nil {
+				if hash, err := h.computeHash(file); err != nil {
 					h.stdlog.Printf(" - skipping (%v):  %s", err, filepath.Base(file))
 				} else {
 					h.stdlog.Printf(" - hashed:  %s", filepath.Base(file))
@@ -103,12 +103,42 @@ func (h *Hasher) ComputeHashes(w Walker) (err error) {
 	return
 }
 
-func NewHasher(numThreads uint, stdlog *log.Logger) (h *Hasher) {
+func NewHasher(algo string, numThreads uint, stdlog *log.Logger) (h *Hasher) {
 	h = &Hasher{numThreads: numThreads, stdlog: stdlog}
+
+	switch algo {
+	case "md5":
+		h.newHash = func() (hash.Hash, error) {
+			return md5.New(), nil
+		}
+	case "sha1":
+		h.newHash = func() (hash.Hash, error) {
+			return sha1.New(), nil
+		}
+	case "sha256":
+		h.newHash = func() (hash.Hash, error) {
+			return sha256.New(), nil
+		}
+	case "sha512":
+		h.newHash = func() (hash.Hash, error) {
+			return sha512.New(), nil
+		}
+	case "blake2b":
+		fallthrough
+	case "":
+		algo = "blake2b"
+		h.newHash = func() (hash.Hash, error) {
+			return blake2b.New256(nil)
+		}
+	default:
+		stdlog.Printf("*** invalid hashing algorithm: '%s'", algo)
+		return nil
+	}
+
 	h.Files = make(map[string]string)
 	if h.numThreads < 1 {
 		h.numThreads = 4
 	}
-	stdlog.Printf("*** Created blake2b based hasher (%d threads)", h.numThreads)
+	stdlog.Printf("*** Created hasher (%s, %d threads)", algo, h.numThreads)
 	return
 }