properly extend strings (#95)

* properly extend strings * revert unintended changes --------- Co-authored-by: Steven Allen <[email protected]>
whyrusleeping · Jun 9, 2024 · 7054243 · 7054243
1 parent 88ce035
commit 7054243
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diff --git a/testgen/main.go b/testgen/main.go
@@ -50,4 +50,15 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
+
+	err = cbg.Gen{
+		MaxArrayLength:  10,
+		MaxByteLength:   9,
+		MaxStringLength: 10000,
+	}.WriteTupleEncodersToFile("testing/cbor_options_gen2.go", "testing",
+		types.LongString{},
+	)
+	if err != nil {
+		panic(err)
+	}
 }
diff --git a/testing/cbor_options_gen2.go b/testing/cbor_options_gen2.go
diff --git a/testing/roundtrip_test.go b/testing/roundtrip_test.go
@@ -54,6 +54,10 @@ func TestNilPreserveWorks(t *testing.T) {
 	testTypeRoundtrips(t, reflect.TypeOf(TestSliceNilPreserve{}))
 }
 
+func TestLongStrings(t *testing.T) {
+	testTypeRoundtrips(t, reflect.TypeOf(LongString{}))
+}
+
 type RoundTripOptions struct {
 	Golden []byte
 }

diff --git a/testing/types.go b/testing/types.go
@@ -1,6 +1,9 @@
 package testing
 
 import (
+	"math/rand"
+	"reflect"
+
 	"github.com/ipfs/go-cid"
 
 	cbg "github.com/whyrusleeping/cbor-gen"
@@ -179,3 +182,15 @@ type LimitedStruct struct {
 	Byts []byte
 	Str  string
 }
+
+type LongString struct {
+	Val string
+}
+
+func (ls LongString) Generate(rand *rand.Rand, size int) reflect.Value {
+	ols := new(LongString)
+	s := make([]byte, 9999)
+	rand.Read(s)
+	ols.Val = string(s)
+	return reflect.ValueOf(ols).Elem()
+}
diff --git a/utils.go b/utils.go
@@ -386,6 +386,9 @@ func ReadStringWithMax(r io.Reader, maxLength uint64) (string, error) {
 	}
 
 	bufp := stringBufPool.Get().(*[]byte)
+	if cap(*bufp) < int(l) {
+		*bufp = append((*bufp)[:cap(*bufp)], make([]byte, int(l)-cap(*bufp))...)
+	}
 	buf := (*bufp)[:l] // shares same backing array as pooled slice
 	defer func() {
 		// optimizes to memclr