Implemented binary marshalling/unmarshalling

Makefile

@@ -22,6 +22,8 @@ fuzz:
 	go test -fuzz=FuzzNewVersion -fuzztime=15s .
 	go test -fuzz=FuzzStrictNewVersion -fuzztime=15s .
 	go test -fuzz=FuzzNewConstraint -fuzztime=15s .
+	go test -fuzz=FuzzMarshalBinary -fuzztime=15s .
+	go test -fuzz=FuzzUnmarshalBinary -fuzztime=15s .
 
 $(GOLANGCI_LINT):
 	# Install golangci-lint. The configuration for it is in the .golangci.yml

benchmark_test.go

@@ -245,3 +245,49 @@ func BenchmarkStrictNewVersionMetaDash(b *testing.B) {
 	b.ResetTimer()
 	benchStrictNewVersion("1.0.0-alpha.1+meta.data", b)
 }
+
+/* Marshalling benchmarks */
+
+func BenchmarkTextMarshal(b *testing.B) {
+	v := MustParse("1.0.0-alpha.1+meta.data")
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = v.MarshalText()
+	}
+}
+
+func BenchmarkBinaryMarshal(b *testing.B) {
+	v := MustParse("1.0.0-alpha.1+meta.data")
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = v.MarshalBinary()
+	}
+}
+
+func BenchmarkTextUnmarshal(b *testing.B) {
+	var v Version
+	text, err := MustParse("1.0.0-alpha.1+meta.data").MarshalText()
+	if err != nil {
+		panic(err)
+	}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_ = v.UnmarshalText(text)
+	}
+}
+
+func BenchmarkBinaryUnmarshal(b *testing.B) {
+	var v Version
+	data, err := MustParse("1.0.0-alpha.1+meta.data").MarshalBinary()
+	if err != nil {
+		panic(err)
+	}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_ = v.UnmarshalText(data)
+	}
+}

version.go

@@ -3,6 +3,7 @@ package semver
 import (
 	"bytes"
 	"database/sql/driver"
+	"encoding/binary"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -471,6 +472,79 @@ func (v Version) MarshalText() ([]byte, error) {
 	return []byte(v.String()), nil
 }
 
+// UnmarshalBinary implements the encoding.BinaryUnmarshaler interface.
+func (v *Version) UnmarshalBinary(data []byte) (err error) {
+	var nums [3]uint64
+	r := bytes.NewReader(data)
+	for i := range nums {
+		nums[i], err = binary.ReadUvarint(r)
+		if err != nil {
+			return ErrInvalidSemVer
+		}
+	}
+
+	var strings [2][]byte
+	var i int
+	// range doesn't advance i to 2
+	// (used to determine whether `break` happened)
+	for i = 0; i < len(strings); i++ {
+		length, err := binary.ReadUvarint(r)
+		if err != nil {
+			break
+		}
+		if length == 0 {
+			continue
+		}
+		if length > uint64(r.Len()) {
+			// Parsed length can't be larger than the remaining
+			// length of the data; without this check a maliciously crafted
+			// `data` can make us attempt to allocate a huge buffer
+			break
+		}
+		// We allocate here instead of returning a slice of data:
+		// data might be a slice of some enormous binary blob. It would be bad
+		// if our reference to the tiny prerelease string would prevent GC
+		// from collecting the whole large slice.
+		strings[i] = make([]byte, length)
+		_, err = r.Read(strings[i])
+		if err != nil {
+			break
+		}
+	}
+	switch i {
+	case 0: // `break` during prerelease string parsing
+		return ErrInvalidPrerelease
+	case 1: // `break` during metadata string parsing
+		return ErrInvalidMetadata
+	}
+
+	*v = Version{
+		major:    nums[0],
+		minor:    nums[1],
+		patch:    nums[2],
+		pre:      string(strings[0]),
+		metadata: string(strings[1]),
+	}
+	return nil
+}
+
+// MarshalBinary implements the encoding.BinaryMarshaler interface.
+func (v Version) MarshalBinary() ([]byte, error) {
+	// Once semver has 1.19 as a minimal supported go version -
+	// this can be rewritten with binary.AppendUvarint and
+	// we can allocate a smaller buffer, assuming 5 Uvarints are (usually) <128
+	buf := make([]byte, 5*binary.MaxVarintLen64+len(v.pre)+len(v.metadata))
+	n := 0
+	n += binary.PutUvarint(buf[n:], v.major)
+	n += binary.PutUvarint(buf[n:], v.minor)
+	n += binary.PutUvarint(buf[n:], v.patch)
+	n += binary.PutUvarint(buf[n:], uint64(len(v.pre)))
+	n += copy(buf[n:], v.pre)
+	n += binary.PutUvarint(buf[n:], uint64(len(v.metadata)))
+	n += copy(buf[n:], v.metadata)
+	return buf[:n], nil
+}
+
 // Scan implements the SQL.Scanner interface.
 func (v *Version) Scan(value interface{}) error {
 	var s string

version_test.go

@@ -4,6 +4,7 @@ import (
 	"database/sql"
 	"encoding/json"
 	"fmt"
+	"math"
 	"testing"
 )
 
@@ -608,6 +609,37 @@ func TestTextUnmarshal(t *testing.T) {
 	}
 }
 
+func TestBinaryMarshallingRoundtrip(t *testing.T) {
+	maxUint64 := uint64(math.MaxUint64)
+	tests := []struct {
+		version string
+	}{
+		{"1.2.3"},
+		{fmt.Sprintf("%d.%d.%d-beta.1+build.123", maxUint64, maxUint64, maxUint64)},
+		{"1.2.3-loooooooooooongString+loooooooooooooooooooongerString"},
+	}
+
+	for _, tc := range tests {
+		v, err := NewVersion(tc.version)
+		if err != nil {
+			t.Errorf("Error creating version: %s", err)
+		}
+		data, err := v.MarshalBinary()
+		if err != nil {
+			t.Errorf("Error marshaling version: %s", err)
+		}
+		var v2 Version
+		err = v2.UnmarshalBinary(data)
+		if err != nil {
+			t.Errorf("Error unmarshaling version: %s", err)
+		}
+
+		if tc.version != v2.String() {
+			t.Errorf("Expected version=%q, but got %q", tc.version, v2.String())
+		}
+	}
+}
+
 func TestSQLScanner(t *testing.T) {
 	sVer := "1.1.1"
 	x, err := StrictNewVersion(sVer)
@@ -705,3 +737,54 @@ func FuzzStrictNewVersion(f *testing.F) {
 		_, _ = StrictNewVersion(a)
 	})
 }
+
+func FuzzMarshalBinary(f *testing.F) {
+	testcases := [][]any{
+		{uint64(1), uint64(2), uint64(3), "alpha.1", "bar"},
+		{uint64(0), uint64(math.MaxUint64), uint64(0), "", ""},
+	}
+
+	for _, tc := range testcases {
+		f.Add(tc...)
+	}
+
+	f.Fuzz(func(t *testing.T, major uint64, minor uint64, patch uint64, pre string, metadata string) {
+		v := New(major, minor, patch, pre, metadata)
+		data, err := v.MarshalBinary()
+		if err != nil {
+			t.Error("MarshalBinary is unfallable, but error is not nil!")
+		}
+		var v2 Version
+		err = v2.UnmarshalBinary(data)
+		if err != nil {
+			t.Fatal("Failed to unmarshal marshaled value")
+		}
+		completelyEqual := (v.major == v2.major &&
+			v.minor == v2.minor &&
+			v.patch == v2.patch &&
+			v.pre == v2.pre &&
+			v.metadata == v2.metadata)
+		if !completelyEqual {
+			t.Errorf("Marshaling changed the data! Expected %s, got %s", v.String(), v2.String())
+		}
+	})
+}
+
+func FuzzUnmarshalBinary(f *testing.F) {
+	testcases := [][]byte{
+		[]byte(""),
+		[]byte("\x01\x02\x03\aalpha.1\x03bar"),
+		[]byte("\xff\xff\x03\xff\xff\xff\xff\x0f" +
+			"\xff\xff\xff\xff\xff\xff\xff\xff\xff\x01\aalpha.1\x03bar"),
+		[]byte("\x00\x00\x94\xc5@\xee\xd1\xd1\xd1\xff\x7f0"),
+	}
+
+	for _, tc := range testcases {
+		f.Add(tc)
+	}
+
+	f.Fuzz(func(t *testing.T, data []byte) {
+		var v Version
+		_ = v.UnmarshalBinary(data)
+	})
+}