From e452ff0f0ad35becd023e539e025e9ff0c5f5414 Mon Sep 17 00:00:00 2001
From: soypat <graded.sp@gmail.com>
Date: Sat, 8 Feb 2025 01:33:26 -0300
Subject: [PATCH] keep fixing ring queue things

---
 tcp/txqueue.go      | 20 ++------------------
 tcp/txqueue_test.go | 45 +++++++++++++++++++++++++++++++++++----------
 2 files changed, 37 insertions(+), 28 deletions(-)

diff --git a/tcp/txqueue.go b/tcp/txqueue.go
index b057b82..f83721f 100644
--- a/tcp/txqueue.go
+++ b/tcp/txqueue.go
@@ -260,24 +260,8 @@ func (tx *ringTx) nextPkt() int {
 //
 //	|   acked(free)  |          sent         |          unsent          |             free       |
 //	0       freeEnd=first.off       last.end==unsent.off        freeStart=unsent.end         Size()
-func (tx *ringTx) lims() (freeStart, freeEnd, sentEndorUnsentStart int) {
-	freeStart = tx.unsentend
-	if freeStart == 0 {
-		freeStart = tx.unsentoff
-	}
-	first := tx.pkt(tx.firstPkt())
-	if first.sent() {
-		freeEnd = first.off
-		sentEndorUnsentStart = tx.unsentoff
-	} else if tx.unsentend != 0 {
-		// sent section empty and unsent not empty.
-		freeEnd = tx.unsentoff
-		sentEndorUnsentStart = tx.unsentoff
-	} else {
-		freeEnd = tx.unsentoff
-		sentEndorUnsentStart = tx.unsentoff
-	}
-	return freeStart, freeEnd, sentEndorUnsentStart
+func (tx *ringTx) lims() (unsentStart, unsentEnd, sentStart, sentEnd int) {
+	return tx.unsentoff, tx.unsentend, tx.sentoff, tx.sentend
 }
 
 func (pkt *ringidx) sent() bool {
diff --git a/tcp/txqueue_test.go b/tcp/txqueue_test.go
index bbd0732..13c7048 100644
--- a/tcp/txqueue_test.go
+++ b/tcp/txqueue_test.go
@@ -12,6 +12,9 @@ func TestTxQueue(t *testing.T) {
 	rng := rand.New(rand.NewSource(1))
 
 	var rtx ringTx
+	defer func() {
+		testQueueSanity(t, &rtx)
+	}()
 	increasingComplexityTests := []struct {
 		name string
 		test func(*testing.T)
@@ -169,16 +172,38 @@ func testQueueSanity(t *testing.T, rtx *ringTx) {
 		t.Fatal("\n" + rtx.string())
 		t.Fatalf("want size=%d, got size=%d (free+sent+unsent=%d+%d+%d)", sz, gotSz, free, sent, unsent)
 	}
-	freeStart, freeEnd, sentEnd := rtx.lims()
-	gotFreeEnd := rtx.addOff(freeStart, free)
-	gotSentEnd := rtx.addOff(freeEnd, sent)
-	gotUnsentEnd := rtx.addOff(sentEnd, unsent)
-	if free != 0 && gotFreeEnd != freeEnd {
-		t.Fatalf("want freeEnd=%d, got %d", freeEnd, gotFreeEnd)
-	} else if sent != 0 && gotSentEnd != sentEnd {
-		t.Fatalf("want sentEnd=%d, got %d", sentEnd, gotSentEnd)
-	} else if unsent != 0 && gotUnsentEnd != freeStart {
-		t.Fatalf("want unsentEnd=%d, got %d (freeStart)", freeStart, gotUnsentEnd)
+	rsent, _ := rtx.sentRing()
+	sentEmpty := rsent.Buffered() == 0
+	runsent, _ := rtx.unsentRing()
+	unsentEmpty := runsent.Buffered() == 0
+	all := rtx.sentAndUnsentBuffer()
+	allEmpty := all.Buffered() == 0
+	if !sentEmpty {
+		if all.Off != rsent.Off {
+			t.Fatalf("want entire buffer start %d to equal sent start %d", all.Off, rsent.Off)
+		} else if rsent.End == 0 {
+			t.Fatalf("expected not empty sent buffer End to be !=0, got %d", rsent.End)
+		}
+		gotSentEnd := rtx.addOff(rsent.Off, sent)
+		if gotSentEnd != rsent.End {
+			t.Fatalf("calculated sent end mismatches lim sent end %d != %d", gotSentEnd, rsent.End)
+		}
+	}
+	if !unsentEmpty {
+		if all.End != runsent.End {
+			t.Fatalf("want entire buffer end %d to equal unsent end %d", all.End, runsent.End)
+		} else if runsent.End == 0 {
+			t.Fatalf("expected not empty unsent buffer End to be !=0, got %d", runsent.End)
+		}
+		gotUnsentEnd := rtx.addOff(runsent.Off, unsent)
+		if gotUnsentEnd != runsent.End {
+			t.Fatalf("calculated unsent end mismatches lim unsent end %d != %d", gotUnsentEnd, runsent.End)
+		}
+	}
+	if allEmpty && (!sentEmpty || !unsentEmpty) {
+		t.Fatalf("all buffer empty but sent|unsent(%v/%v) not empty", sentEmpty, unsentEmpty)
+	} else if !allEmpty && sentEmpty && unsentEmpty {
+		t.Fatal("all buffer not empty but sent&unsentempty")
 	}
 }