utils: switch to standard library min and max functions (#4218)

These functions were added in Go 1.21.

internal/ackhandler/packet_number_generator.go

@@ -80,5 +80,5 @@ func (p *skippingPacketNumberGenerator) Pop() (bool, protocol.PacketNumber) {
 func (p *skippingPacketNumberGenerator) generateNewSkip() {
 	// make sure that there are never two consecutive packet numbers that are skipped
 	p.nextToSkip = p.next + 3 + protocol.PacketNumber(p.rng.Int31n(int32(2*p.period)))
-	p.period = utils.Min(2*p.period, p.maxPeriod)
+	p.period = min(2*p.period, p.maxPeriod)
 }

internal/ackhandler/received_packet_tracker.go

@@ -179,7 +179,7 @@ func (h *receivedPacketTracker) GetAckFrame(onlyIfQueued bool) *wire.AckFrame {
 		ack = &wire.AckFrame{}
 	}
 	ack.Reset()
-	ack.DelayTime = utils.Max(0, now.Sub(h.largestObservedRcvdTime))
+	ack.DelayTime = max(0, now.Sub(h.largestObservedRcvdTime))
 	ack.ECT0 = h.ect0
 	ack.ECT1 = h.ect1
 	ack.ECNCE = h.ecnce

internal/ackhandler/sent_packet_handler.go

@@ -245,7 +245,7 @@ func (h *sentPacketHandler) SentPacket(
 
 	pnSpace := h.getPacketNumberSpace(encLevel)
 	if h.logger.Debug() && pnSpace.history.HasOutstandingPackets() {
-		for p := utils.Max(0, pnSpace.largestSent+1); p < pn; p++ {
+		for p := max(0, pnSpace.largestSent+1); p < pn; p++ {
 			h.logger.Debugf("Skipping packet number %d", p)
 		}
 	}
@@ -336,7 +336,7 @@ func (h *sentPacketHandler) ReceivedAck(ack *wire.AckFrame, encLevel protocol.En
 			// don't use the ack delay for Initial and Handshake packets
 			var ackDelay time.Duration
 			if encLevel == protocol.Encryption1RTT {
-				ackDelay = utils.Min(ack.DelayTime, h.rttStats.MaxAckDelay())
+				ackDelay = min(ack.DelayTime, h.rttStats.MaxAckDelay())
 			}
 			h.rttStats.UpdateRTT(rcvTime.Sub(p.SendTime), ackDelay, rcvTime)
 			if h.logger.Debug() {
@@ -354,7 +354,7 @@ func (h *sentPacketHandler) ReceivedAck(ack *wire.AckFrame, encLevel protocol.En
 		}
 	}
 
-	pnSpace.largestAcked = utils.Max(pnSpace.largestAcked, largestAcked)
+	pnSpace.largestAcked = max(pnSpace.largestAcked, largestAcked)
 
 	if err := h.detectLostPackets(rcvTime, encLevel); err != nil {
 		return false, err
@@ -446,7 +446,7 @@ func (h *sentPacketHandler) detectAndRemoveAckedPackets(ack *wire.AckFrame, encL
 
 	for _, p := range h.ackedPackets {
 		if p.LargestAcked != protocol.InvalidPacketNumber && encLevel == protocol.Encryption1RTT {
-			h.lowestNotConfirmedAcked = utils.Max(h.lowestNotConfirmedAcked, p.LargestAcked+1)
+			h.lowestNotConfirmedAcked = max(h.lowestNotConfirmedAcked, p.LargestAcked+1)
 		}
 
 		for _, f := range p.Frames {
@@ -607,11 +607,11 @@ func (h *sentPacketHandler) detectLostPackets(now time.Time, encLevel protocol.E
 	pnSpace := h.getPacketNumberSpace(encLevel)
 	pnSpace.lossTime = time.Time{}
 
-	maxRTT := float64(utils.Max(h.rttStats.LatestRTT(), h.rttStats.SmoothedRTT()))
+	maxRTT := float64(max(h.rttStats.LatestRTT(), h.rttStats.SmoothedRTT()))
 	lossDelay := time.Duration(timeThreshold * maxRTT)
 
 	// Minimum time of granularity before packets are deemed lost.
-	lossDelay = utils.Max(lossDelay, protocol.TimerGranularity)
+	lossDelay = max(lossDelay, protocol.TimerGranularity)
 
 	// Packets sent before this time are deemed lost.
 	lostSendTime := now.Add(-lossDelay)
@@ -890,7 +890,7 @@ func (h *sentPacketHandler) ResetForRetry(now time.Time) error {
 	// Otherwise, we don't know which Initial the Retry was sent in response to.
 	if h.ptoCount == 0 {
 		// Don't set the RTT to a value lower than 5ms here.
-		h.rttStats.UpdateRTT(utils.Max(minRTTAfterRetry, now.Sub(firstPacketSendTime)), 0, now)
+		h.rttStats.UpdateRTT(max(minRTTAfterRetry, now.Sub(firstPacketSendTime)), 0, now)
 		if h.logger.Debug() {
 			h.logger.Debugf("\tupdated RTT: %s (σ: %s)", h.rttStats.SmoothedRTT(), h.rttStats.MeanDeviation())
 		}

internal/congestion/cubic.go

@@ -5,7 +5,6 @@ import (
 	"time"
 
 	"github.com/quic-go/quic-go/internal/protocol"
-	"github.com/quic-go/quic-go/internal/utils"
 )
 
 // This cubic implementation is based on the one found in Chromiums's QUIC
@@ -187,7 +186,7 @@ func (c *Cubic) CongestionWindowAfterAck(
 		targetCongestionWindow = c.originPointCongestionWindow - deltaCongestionWindow
 	}
 	// Limit the CWND increase to half the acked bytes.
-	targetCongestionWindow = utils.Min(targetCongestionWindow, currentCongestionWindow+c.ackedBytesCount/2)
+	targetCongestionWindow = min(targetCongestionWindow, currentCongestionWindow+c.ackedBytesCount/2)
 
 	// Increase the window by approximately Alpha * 1 MSS of bytes every
 	// time we ack an estimated tcp window of bytes.  For small

internal/congestion/cubic_sender.go

@@ -178,7 +178,7 @@ func (c *cubicSender) OnPacketAcked(
 	priorInFlight protocol.ByteCount,
 	eventTime time.Time,
 ) {
-	c.largestAckedPacketNumber = utils.Max(ackedPacketNumber, c.largestAckedPacketNumber)
+	c.largestAckedPacketNumber = max(ackedPacketNumber, c.largestAckedPacketNumber)
 	if c.InRecovery() {
 		return
 	}
@@ -246,7 +246,7 @@ func (c *cubicSender) maybeIncreaseCwnd(
 			c.numAckedPackets = 0
 		}
 	} else {
-		c.congestionWindow = utils.Min(c.maxCongestionWindow(), c.cubic.CongestionWindowAfterAck(ackedBytes, c.congestionWindow, c.rttStats.MinRTT(), eventTime))
+		c.congestionWindow = min(c.maxCongestionWindow(), c.cubic.CongestionWindowAfterAck(ackedBytes, c.congestionWindow, c.rttStats.MinRTT(), eventTime))
 	}
 }
 

internal/congestion/hybrid_slow_start.go

@@ -4,7 +4,6 @@ import (
 	"time"
 
 	"github.com/quic-go/quic-go/internal/protocol"
-	"github.com/quic-go/quic-go/internal/utils"
 )
 
 // Note(pwestin): the magic clamping numbers come from the original code in
@@ -75,8 +74,8 @@ func (s *HybridSlowStart) ShouldExitSlowStart(latestRTT time.Duration, minRTT ti
 		// Divide minRTT by 8 to get a rtt increase threshold for exiting.
 		minRTTincreaseThresholdUs := int64(minRTT / time.Microsecond >> hybridStartDelayFactorExp)
 		// Ensure the rtt threshold is never less than 2ms or more than 16ms.
-		minRTTincreaseThresholdUs = utils.Min(minRTTincreaseThresholdUs, hybridStartDelayMaxThresholdUs)
-		minRTTincreaseThreshold := time.Duration(utils.Max(minRTTincreaseThresholdUs, hybridStartDelayMinThresholdUs)) * time.Microsecond
+		minRTTincreaseThresholdUs = min(minRTTincreaseThresholdUs, hybridStartDelayMaxThresholdUs)
+		minRTTincreaseThreshold := time.Duration(max(minRTTincreaseThresholdUs, hybridStartDelayMinThresholdUs)) * time.Microsecond
 
 		if s.currentMinRTT > (minRTT + minRTTincreaseThreshold) {
 			s.hystartFound = true

internal/congestion/pacer.go

@@ -4,7 +4,6 @@ import (
 	"time"
 
 	"github.com/quic-go/quic-go/internal/protocol"
-	"github.com/quic-go/quic-go/internal/utils"
 )
 
 const maxBurstSizePackets = 10
@@ -52,11 +51,11 @@ func (p *pacer) Budget(now time.Time) protocol.ByteCount {
 	if budget < 0 { // protect against overflows
 		budget = protocol.MaxByteCount
 	}
-	return utils.Min(p.maxBurstSize(), budget)
+	return min(p.maxBurstSize(), budget)
 }
 
 func (p *pacer) maxBurstSize() protocol.ByteCount {
-	return utils.Max(
+	return max(
 		protocol.ByteCount(uint64((protocol.MinPacingDelay+protocol.TimerGranularity).Nanoseconds())*p.adjustedBandwidth())/1e9,
 		maxBurstSizePackets*p.maxDatagramSize,
 	)
@@ -77,7 +76,7 @@ func (p *pacer) TimeUntilSend() time.Time {
 	if diff%bw > 0 {
 		d++
 	}
-	return p.lastSentTime.Add(utils.Max(protocol.MinPacingDelay, time.Duration(d)*time.Nanosecond))
+	return p.lastSentTime.Add(max(protocol.MinPacingDelay, time.Duration(d)*time.Nanosecond))
 }
 
 func (p *pacer) SetMaxDatagramSize(s protocol.ByteCount) {

internal/flowcontrol/base_flow_controller.go

@@ -107,7 +107,7 @@ func (c *baseFlowController) maybeAdjustWindowSize() {
 	now := time.Now()
 	if now.Sub(c.epochStartTime) < time.Duration(4*fraction*float64(rtt)) {
 		// window is consumed too fast, try to increase the window size
-		newSize := utils.Min(2*c.receiveWindowSize, c.maxReceiveWindowSize)
+		newSize := min(2*c.receiveWindowSize, c.maxReceiveWindowSize)
 		if newSize > c.receiveWindowSize && (c.allowWindowIncrease == nil || c.allowWindowIncrease(newSize-c.receiveWindowSize)) {
 			c.receiveWindowSize = newSize
 		}

internal/flowcontrol/connection_flow_controller.go

@@ -87,7 +87,7 @@ func (c *connectionFlowController) EnsureMinimumWindowSize(inc protocol.ByteCoun
 	c.mutex.Lock()
 	if inc > c.receiveWindowSize {
 		c.logger.Debugf("Increasing receive flow control window for the connection to %d kB, in response to stream flow control window increase", c.receiveWindowSize/(1<<10))
-		newSize := utils.Min(inc, c.maxReceiveWindowSize)
+		newSize := min(inc, c.maxReceiveWindowSize)
 		if delta := newSize - c.receiveWindowSize; delta > 0 && c.allowWindowIncrease(delta) {
 			c.receiveWindowSize = newSize
 		}

internal/flowcontrol/stream_flow_controller.go

@@ -123,7 +123,7 @@ func (c *streamFlowController) AddBytesSent(n protocol.ByteCount) {
 }
 
 func (c *streamFlowController) SendWindowSize() protocol.ByteCount {
-	return utils.Min(c.baseFlowController.sendWindowSize(), c.connection.SendWindowSize())
+	return min(c.baseFlowController.sendWindowSize(), c.connection.SendWindowSize())
 }
 
 func (c *streamFlowController) shouldQueueWindowUpdate() bool {

internal/handshake/aead.go

@@ -5,7 +5,6 @@ import (
 	"encoding/binary"
 
 	"github.com/quic-go/quic-go/internal/protocol"
-	"github.com/quic-go/quic-go/internal/utils"
 )
 
 func createAEAD(suite *cipherSuite, trafficSecret []byte, v protocol.VersionNumber) cipher.AEAD {
@@ -82,7 +81,7 @@ func (o *longHeaderOpener) Open(dst, src []byte, pn protocol.PacketNumber, ad []
 	// It uses the nonce provided here and XOR it with the IV.
 	dec, err := o.aead.Open(dst, o.nonceBuf, src, ad)
 	if err == nil {
-		o.highestRcvdPN = utils.Max(o.highestRcvdPN, pn)
+		o.highestRcvdPN = max(o.highestRcvdPN, pn)
 	} else {
 		err = ErrDecryptionFailed
 	}

internal/handshake/updatable_aead.go

@@ -172,7 +172,7 @@ func (a *updatableAEAD) Open(dst, src []byte, rcvTime time.Time, pn protocol.Pac
 		}
 	}
 	if err == nil {
-		a.highestRcvdPN = utils.Max(a.highestRcvdPN, pn)
+		a.highestRcvdPN = max(a.highestRcvdPN, pn)
 	}
 	return dec, err
 }

internal/utils/minmax.go

@@ -3,27 +3,11 @@ package utils
 import (
 	"math"
 	"time"
-
-	"golang.org/x/exp/constraints"
 )
 
 // InfDuration is a duration of infinite length
 const InfDuration = time.Duration(math.MaxInt64)
 
-func Max[T constraints.Ordered](a, b T) T {
-	if a < b {
-		return b
-	}
-	return a
-}
-
-func Min[T constraints.Ordered](a, b T) T {
-	if a < b {
-		return a
-	}
-	return b
-}
-
 // MinNonZeroDuration return the minimum duration that's not zero.
 func MinNonZeroDuration(a, b time.Duration) time.Duration {
 	if a == 0 {
@@ -32,7 +16,7 @@ func MinNonZeroDuration(a, b time.Duration) time.Duration {
 	if b == 0 {
 		return a
 	}
-	return Min(a, b)
+	return min(a, b)
 }
 
 // MinTime returns the earlier time

internal/utils/minmax_test.go

@@ -8,16 +8,6 @@ import (
 )
 
 var _ = Describe("Min / Max", func() {
-	It("returns the maximum", func() {
-		Expect(Max(5, 7)).To(Equal(7))
-		Expect(Max(5.5, 5.7)).To(Equal(5.7))
-	})
-
-	It("returns the minimum", func() {
-		Expect(Min(5, 7)).To(Equal(5))
-		Expect(Min(5.5, 5.7)).To(Equal(5.5))
-	})
-
 	It("returns the maximum time", func() {
 		a := time.Now()
 		b := a.Add(time.Second)

internal/utils/rtt_stats.go

@@ -55,7 +55,7 @@ func (r *RTTStats) PTO(includeMaxAckDelay bool) time.Duration {
 	if r.SmoothedRTT() == 0 {
 		return 2 * defaultInitialRTT
 	}
-	pto := r.SmoothedRTT() + Max(4*r.MeanDeviation(), protocol.TimerGranularity)
+	pto := r.SmoothedRTT() + max(4*r.MeanDeviation(), protocol.TimerGranularity)
 	if includeMaxAckDelay {
 		pto += r.MaxAckDelay()
 	}
@@ -126,6 +126,6 @@ func (r *RTTStats) OnConnectionMigration() {
 // is larger. The mean deviation is increased to the most recent deviation if
 // it's larger.
 func (r *RTTStats) ExpireSmoothedMetrics() {
-	r.meanDeviation = Max(r.meanDeviation, (r.smoothedRTT - r.latestRTT).Abs())
-	r.smoothedRTT = Max(r.smoothedRTT, r.latestRTT)
+	r.meanDeviation = max(r.meanDeviation, (r.smoothedRTT - r.latestRTT).Abs())
+	r.smoothedRTT = max(r.smoothedRTT, r.latestRTT)
 }

internal/wire/transport_parameters.go

@@ -294,7 +294,7 @@ func (p *TransportParameters) readNumericTransportParameter(
 			return fmt.Errorf("initial_max_streams_uni too large: %d (maximum %d)", p.MaxUniStreamNum, protocol.MaxStreamCount)
 		}
 	case maxIdleTimeoutParameterID:
-		p.MaxIdleTimeout = utils.Max(protocol.MinRemoteIdleTimeout, time.Duration(val)*time.Millisecond)
+		p.MaxIdleTimeout = max(protocol.MinRemoteIdleTimeout, time.Duration(val)*time.Millisecond)
 	case maxUDPPayloadSizeParameterID:
 		if val < 1200 {
 			return fmt.Errorf("invalid value for max_packet_size: %d (minimum 1200)", val)