Create Go Module

 - Unpack directory v0 to move all the content to the root directory.
 - ./v0/* converted to ./*
 - all the test cases were fixed to remove one directory less indexing for test files
 - add go.mod
 - go version 1.13 is used to have a relatively stable versioning system

Signed-off-by: RishabhBhatnagar <bhatnagarrishabh4@gmail.com>

1 files changed, 43 insertions, 0 deletions

diff --git a/utils/verification.go b/utils/verification.go
new file mode 100644
index 0000000..5fbf62b
--- /dev/null
+++ b/utils/verification.go
@@ -0,0 +1,43 @@
+// Package utils contains various utility functions to support the
+// main tools-golang packages.
+// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+package utils
+
+import (
+	"crypto/sha1"
+	"fmt"
+	"sort"
+	"strings"
+
+	"github.com/spdx/tools-golang/spdx"
+)
+
+// GetVerificationCode2_1 takes a slice of files and an optional filename
+// for an "excludes" file, and returns a Package Verification Code calculated
+// according to SPDX spec version 2.1, section 3.9.4.
+func GetVerificationCode2_1(files []*spdx.File2_1, excludeFile string) (string, error) {
+	// create slice of strings - unsorted SHA1s for all files
+	shas := []string{}
+	for i, f := range files {
+		if f == nil {
+			return "", fmt.Errorf("got nil file in index %d", i)
+		}
+		if f.FileName != excludeFile {
+			shas = append(shas, f.FileChecksumSHA1)
+		}
+	}
+
+	// sort the strings
+	sort.Strings(shas)
+
+	// concatenate them into one string, with no trailing separators
+	shasConcat := strings.Join(shas, "")
+
+	// and get its SHA1 value
+	hsha1 := sha1.New()
+	hsha1.Write([]byte(shasConcat))
+	bs := hsha1.Sum(nil)
+	code := fmt.Sprintf("%x", bs)
+
+	return code, nil
+}