TCF 2.0: Fix legitimate interest vendor parsing

vendorconsent/tcf2/bitfield.go

@@ -26,6 +26,14 @@ type consentBitField struct {
 	maxVendorID uint16
 }
 
+func (f *consentBitField) MaxVendorID() uint16 {
+	if f == nil {
+		return 0
+	}
+
+	return f.maxVendorID
+}
+
 func (f *consentBitField) VendorConsent(id uint16) bool {
 	if id < 1 || id > f.maxVendorID {
 		return false

vendorconsent/tcf2/metadata.go

@@ -44,6 +44,7 @@ type ConsentMetadata struct {
 }
 
 type vendorConsentsResolver interface {
+	MaxVendorID() uint16
 	VendorConsent(id uint16) bool
 }
 
@@ -118,6 +119,10 @@ func (c ConsentMetadata) ConsentLanguage() string {
 	return string([]byte{leftChar + 65, rightChar + 65}) // Unicode A-Z is 65-90
 }
 
+func (c ConsentMetadata) VendorLegitInterestMaxID() uint16 {
+	return c.vendorLegitimateInterests.MaxVendorID()
+}
+
 func (c ConsentMetadata) VendorListVersion() uint16 {
 	// The vendor list version is stored in bits 120 - 131
 	rightByte := ((c.data[16] & 0xf0) >> 4) | ((c.data[15] & 0x0f) << 4)

vendorconsent/tcf2/rangesection.go

@@ -9,17 +9,19 @@ import (
 
 func parseRangeSection(metadata ConsentMetadata, maxVendorID uint16, startbit uint) (*rangeSection, uint, error) {
 	data := metadata.data
-	// This makes an int from bits 230-241
+
 	if len(data) < 31 {
 		return nil, 0, fmt.Errorf("vendor consent strings using RangeSections require at least 31 bytes. Got %d", len(data))
 	}
-	numEntries, err := bitutils.ParseUInt12(data, 230)
+
+	// This makes an int from bits [startBit, startBit + 12)
+	numEntries, err := bitutils.ParseUInt12(data, startbit)
 	if err != nil {
 		return nil, 0, err
 	}
 
 	// Parse out the "exceptions" here.
-	currentOffset := uint(242)
+	currentOffset := startbit + 12
 	consents := make([]rangeConsent, numEntries)
 	for i := uint16(0); i < numEntries; i++ {
 		thisConsent, bitsConsumed, err := parseRangeConsent(data, currentOffset, maxVendorID)
@@ -98,6 +100,14 @@ type rangeSection struct {
 	maxVendorID uint16
 }
 
+func (p *rangeSection) MaxVendorID() uint16 {
+	if p == nil {
+		return 0
+	}
+
+	return p.maxVendorID
+}
+
 // VendorConsents implementation
 func (p rangeSection) VendorConsent(id uint16) bool {
 	if id < 1 || id > p.maxVendorID {

vendorconsent/tcf2/rangesection_test.go

@@ -8,14 +8,14 @@ import (
 func TestRangeSectionConsent(t *testing.T) {
 	// String built using http://iabtcf.com/#/encode
 	// This sample encodes a mix of Single- and Range-typed consent exceptions.
-	consent, err := Parse(decode(t, "COyiILmOyiILmADACHENAPCAAAAAAAAAAAAAE5QBgALgAqgD8AQACSwEygJyAAAAAA"))
+	consent, err := Parse(decode(t, "COyfVVoOyfVVoADACHENAwCAAAAAAAAAAAAAE5QBgALgAqgD8AQACSwEygJyAnSAMABgAFkAgQCDASeAmYBOgAA"))
 	assertNilError(t, err)
 	assertUInt8sEqual(t, 2, consent.Version())
 	assertUInt16sEqual(t, 3, consent.CmpID())
 	assertUInt16sEqual(t, 2, consent.CmpVersion())
 	assertUInt8sEqual(t, 7, consent.ConsentScreen())
 	assertStringsEqual(t, "EN", consent.ConsentLanguage())
-	assertUInt16sEqual(t, 15, consent.VendorListVersion())
+	assertUInt16sEqual(t, 48, consent.VendorListVersion())
 	assertUInt16sEqual(t, 626, consent.MaxVendorID())
 
 	//  The above encoder doesn't support setting purposes.
@@ -27,11 +27,24 @@ func TestRangeSectionConsent(t *testing.T) {
 
 	vendorsWithConsent := buildMap(23, 42, 126, 127, 128, 587, 613, 626)
 	for i := uint16(1); i <= consent.MaxVendorID(); i++ {
-		_, ok := vendorsWithConsent[uint(i)]
-		if ok != consent.VendorConsent(i) {
+		_, expected := vendorsWithConsent[uint(i)]
+		actual := consent.VendorConsent(i)
+		if expected != actual {
 			fmt.Printf("Vendor: %d failed\n", i)
 		}
-		assertBoolsEqual(t, ok, consent.VendorConsent(i))
+		assertBoolsEqual(t, expected, actual)
+	}
+
+	// TODO func VendorLegitInterest() should be added to api.VendorConsents
+	consentMetadata := consent.(ConsentMetadata)
+	vendorsLegitimateInterestWithConsent := buildMap(24, 44, 129, 130, 131, 591, 614, 628)
+	for i := uint16(1); i <= consentMetadata.VendorLegitInterestMaxID(); i++ {
+		_, expected := vendorsLegitimateInterestWithConsent[uint(i)]
+		actual := consentMetadata.VendorLegitInterest(i)
+		if expected != actual {
+			fmt.Printf("VendorLegitInterest: %d failed\n", i)
+		}
+		assertBoolsEqual(t, expected, actual)
 	}
 }