text: fix infinite loop in Wrap

If the last word is greater than the limit, we wouldn't set the next line break at all, and it would be left at 0, causing an infinite loop in the final loop to apply the line breaks. To fix this, recognize that the last word must be on the last line, so its length doesn't matter. Always set the last word's next break to the end of the text. Fixes #1. Closes #2.
kr · Sep 5, 2015 · bb797dc · bb797dc
1 parent e373e13
commit bb797dc
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Showing 2 changed files with 19 additions and 1 deletion.
diff --git a/wrap.go b/wrap.go
@@ -58,7 +58,7 @@ func WrapWords(words [][]byte, spc, lim, pen int) [][][]byte {
 		cost[i] = math.MaxInt32
 	}
 	for i := n - 1; i >= 0; i-- {
-		if length[i][n-1] <= lim {
+		if length[i][n-1] <= lim || i == n-1 {
 			cost[i] = 0
 			nbrk[i] = n
 		} else {

diff --git a/wrap_test.go b/wrap_test.go
@@ -42,3 +42,21 @@ func TestWrapOneLine(t *testing.T) {
 		t.Fail()
 	}
 }
+
+func TestWrapBug1(t *testing.T) {
+	cases := []struct {
+		limit int
+		text  string
+		want  string
+	}{
+		{4, "aaaaa", "aaaaa"},
+		{4, "a aaaaa", "a\naaaaa"},
+	}
+
+	for _, test := range cases {
+		got := Wrap(test.text, test.limit)
+		if got != test.want {
+			t.Errorf("Wrap(%q, %d) = %q want %q", test.text, test.limit, got, test.want)
+		}
+	}
+}