Add package semver

Signed-off-by: Jan Tytgat <jan.tytgat@corelayer.eu>

pkg/semver/version.go

@@ -0,0 +1,117 @@
+package semver
+
+import (
+	"bytes"
+	"fmt"
+	"regexp"
+	"strconv"
+)
+
+const (
+	// https://semver.org/ && https://regex101.com/r/Ly7O1x/3/
+	validSemVer = `^(?P<major>0|[1-9]\d*)\.(?P<minor>0|[1-9]\d*)\.(?P<patch>0|[1-9]\d*)(?:-(?P<prerelease>(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:\+(?P<buildmetadata>[0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?$`
+)
+
+var regexSemver = regexp.MustCompile(validSemVer)
+
+type Version struct {
+	Major      int64
+	Minor      int64
+	Patch      int64
+	PreRelease PreRelease
+	Metadata   Metadata
+}
+
+func (v Version) Commit() string {
+	commit, _, err := SplitMetadata(v.Metadata)
+	if err != nil {
+		return string(v.Metadata)
+	}
+	return commit
+}
+
+func (v Version) Date() string {
+	_, date, err := SplitMetadata(v.Metadata)
+	if err != nil {
+		return string(v.Metadata)
+	}
+	return date
+}
+
+func (v Version) Release() string {
+	switch v.PreRelease {
+	case "":
+		return fmt.Sprint("stable")
+	default:
+		return string(v.PreRelease)
+	}
+}
+
+func (v Version) String() string {
+	var buf bytes.Buffer
+
+	fmt.Fprintf(&buf, "%d.%d.%d", v.Major, v.Minor, v.Patch)
+
+	if v.PreRelease != "" {
+		fmt.Fprintf(&buf, "-%s", v.PreRelease)
+	}
+
+	if v.Metadata != "" {
+		fmt.Fprintf(&buf, "+%s", v.Metadata)
+	}
+
+	return buf.String()
+}
+
+func (v Version) Number() string {
+	return fmt.Sprintf("%d.%d.%d", v.Major, v.Minor, v.Patch)
+}
+
+func Parse(v string) (Version, error) {
+	if !regexSemver.MatchString(v) {
+		return Version{}, fmt.Errorf("invalid version: %s", v)
+	}
+
+	match := regexSemver.FindStringSubmatch(v)
+	matchMap := make(map[string]string)
+	for i, name := range regexSemver.SubexpNames() {
+		if i != 0 && name != "" {
+			matchMap[name] = match[i]
+		}
+	}
+
+	var err error
+	var major int64
+	var minor int64
+	var patch int64
+	var preRelease PreRelease
+	var metadata Metadata
+
+	if major, err = strconv.ParseInt(matchMap["major"], 10, 64); err != nil {
+		return Version{}, err
+	}
+
+	if minor, err = strconv.ParseInt(matchMap["minor"], 10, 64); err != nil {
+		return Version{}, err
+	}
+
+	if patch, err = strconv.ParseInt(matchMap["patch"], 10, 64); err != nil {
+		return Version{}, err
+	}
+
+	if matchMap["prerelease"] != "" {
+		preRelease = PreRelease(matchMap["prerelease"])
+	}
+
+	if matchMap["buildmetadata"] != "" {
+		metadata = Metadata(matchMap["buildmetadata"])
+	}
+
+	return Version{
+		Major:      major,
+		Minor:      minor,
+		Patch:      patch,
+		PreRelease: preRelease,
+		Metadata:   metadata,
+	}, nil
+}