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Add new SerializeAs option for TerminatedSizedString.
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This allows to keep the existing TerminatedString behaviour when a field
length constraint is applied, where it essentially becomes a SizedString.
Whilst also allowing new behaviour that would keep the terminated string
aspect, but truncate / pad the terminated string around the length constraint

Test case shows non-standard terminator (\n or 0x0A), and non-standard
padding byte 0x0D just to prove that these work as expected also.

Possibly fixes jefffhaynes#171 (confirmation required)

Signed-off-by: Bevan Weiss <[email protected]>
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bevanweiss committed May 20, 2023
1 parent f16adc6 commit cb1369c
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Showing 6 changed files with 117 additions and 27 deletions.
19 changes: 19 additions & 0 deletions BinarySerializer.Test/SerializeAs/SerializeAsTest.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -50,5 +50,24 @@ public void CollectionPaddingValue()
var actualItems = actual.Items.Select(i => i.Trim()).ToList();
CollectionAssert.AreEqual(expected.Items, actualItems);
}

[TestMethod]
public void SerializeAsTerminatedStringWithPadding()
{
var expected = new TerminatedSizedStringClass { Value = "hi" };
var actual = Roundtrip(expected, new byte[] { 0x68, 0x69, 0x0A, 0x0D, 0x0D });

Assert.AreEqual(expected.Value, actual.Value);
}

[TestMethod]
public void SerializeAsTerminatedStringWithTruncation()
{
var expected = new TerminatedSizedStringClass { Value = "hi test" };
var actual = Roundtrip(expected, new byte[] { 0x68, 0x69, 0x20, 0x74, 0x0A });

// we expect to have truncated to only have 4 characters (and the terminator)
Assert.AreEqual(expected.Value.Substring(0,4), actual.Value);
}
}
}
9 changes: 9 additions & 0 deletions BinarySerializer.Test/SerializeAs/TerminatedSizedStringClass.cs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,9 @@
namespace BinarySerialization.Test.SerializeAs
{
class TerminatedSizedStringClass
{
[FieldLength(5)]
[SerializeAs(SerializedType.TerminatedSizedString, StringTerminator = '\n', PaddingValue = 0x0D)]
public string Value { get; set; }
}
}
3 changes: 2 additions & 1 deletion BinarySerializer/Graph/TypeGraph/EnumTypeNode.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -46,7 +46,8 @@ private void InitializeEnumValues()
if (enumAttributes.Any(enumAttribute => enumAttribute.Value != null) ||
serializedType == SerializedType.TerminatedString ||
serializedType == SerializedType.SizedString ||
serializedType == SerializedType.LengthPrefixedString)
serializedType == SerializedType.LengthPrefixedString ||
serializedType == SerializedType.TerminatedSizedString)
{
EnumInfo.EnumValues = enumAttributes.ToDictionary(enumAttribute => enumAttribute.Key,
enumAttribute =>
Expand Down
7 changes: 5 additions & 2 deletions BinarySerializer/Graph/TypeGraph/TypeNode.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,7 @@ internal abstract class TypeNode : Node<TypeNode>
{SerializedType.TerminatedString, default(string)},
{SerializedType.SizedString, default(string)},
{SerializedType.LengthPrefixedString, default(string)},
{SerializedType.TerminatedSizedString, default(string)},
{SerializedType.ByteArray, default(byte[])}
};

Expand Down Expand Up @@ -154,7 +155,8 @@ protected TypeNode(TypeNode parent, Type parentType, MemberInfo memberInfo, Type
}
#pragma warning restore 618

if (_serializedType.Value == SerializedType.TerminatedString)
if (_serializedType.Value == SerializedType.TerminatedString ||
_serializedType.Value == SerializedType.TerminatedSizedString)
{
AreStringsTerminated = true;
StringTerminator = serializeAsAttribute.StringTerminator;
Expand All @@ -170,7 +172,8 @@ protected TypeNode(TypeNode parent, Type parentType, MemberInfo memberInfo, Type
IsNullable = serializedType == SerializedType.Default ||
serializedType == SerializedType.ByteArray ||
serializedType == SerializedType.TerminatedString ||
serializedType == SerializedType.SizedString;
serializedType == SerializedType.SizedString ||
serializedType == SerializedType.TerminatedSizedString;
}

// setup bindings
Expand Down
98 changes: 75 additions & 23 deletions BinarySerializer/Graph/ValueGraph/ValueValueNode.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -133,16 +133,19 @@ public void Serialize(AsyncBinaryWriter writer, object value, SerializedType ser

// see if we're dealing with something that needs to be padded
if (serializedType != SerializedType.ByteArray &&
serializedType != SerializedType.TerminatedString)
serializedType != SerializedType.TerminatedString &&
serializedType != SerializedType.TerminatedSizedString)
{
return;
}

var data = new byte[constLength.TotalByteCount];

if (serializedType == SerializedType.TerminatedString && data.Length > 0)
if ((serializedType == SerializedType.TerminatedString ||
serializedType == SerializedType.TerminatedSizedString)
&& data.Length > 0)
{
var terminatorData = GetNullTermination();
var terminatorData = GetTermination();
Array.Copy(terminatorData, data, terminatorData.Length);
}

Expand Down Expand Up @@ -224,7 +227,7 @@ public void Serialize(AsyncBinaryWriter writer, object value, SerializedType ser
var encoding = GetFieldEncoding();
var data = encoding.GetBytes(value.ToString());

var dataLength = GetNullTerminatedArrayLength(data, constLength, maxLength);
var dataLength = GetTerminatedArrayLength(data, constLength, maxLength);

writer.Write(data, dataLength);

Expand All @@ -234,7 +237,8 @@ public void Serialize(AsyncBinaryWriter writer, object value, SerializedType ser
}
case SerializedType.SizedString:
{
var data = GetFieldEncoding().GetBytes(value.ToString());
var encoding = GetFieldEncoding();
var data = encoding.GetBytes(value.ToString());

var dataLength = GetArrayLength(data, constLength, maxLength);

Expand All @@ -251,6 +255,25 @@ public void Serialize(AsyncBinaryWriter writer, object value, SerializedType ser
writer.Write(value.ToString());
break;
}
case SerializedType.TerminatedSizedString:
{
var encoding = GetFieldEncoding();
var data = encoding.GetBytes(value.ToString());

var dataLength = GetTerminatedArrayLength(data, constLength, maxLength);

writer.Write(data, dataLength);

var stringTerminatorData = encoding.GetBytes(new[] { TypeNode.StringTerminator });
writer.Write(stringTerminatorData, stringTerminatorData.Length);

var fillLength = maxLength < constLength ? maxLength : constLength;
var padLength = fillLength - (dataLength + stringTerminatorData.Length);
if (padLength > 0)
writer.Write(GetFieldPaddingValue(), padLength);

break;
}

default:
throw new NotSupportedException(TypeNotSupportedMessage);
Expand Down Expand Up @@ -286,16 +309,19 @@ public async Task SerializeAsync(AsyncBinaryWriter writer, object value, Seriali

// see if we're dealing with something that needs to be padded
if (serializedType != SerializedType.ByteArray &&
serializedType != SerializedType.TerminatedString)
serializedType != SerializedType.TerminatedString &&
serializedType != SerializedType.TerminatedSizedString)
{
return;
}

var data = new byte[constLength.TotalByteCount];

if (serializedType == SerializedType.TerminatedString && data.Length > 0)
if ((serializedType == SerializedType.TerminatedString ||
serializedType == SerializedType.TerminatedSizedString)
&& data.Length > 0)
{
var terminatorData = GetNullTermination();
var terminatorData = GetTermination();
Array.Copy(terminatorData, data, terminatorData.Length);
}

Expand Down Expand Up @@ -376,11 +402,11 @@ public async Task SerializeAsync(AsyncBinaryWriter writer, object value, Seriali
{
var data = GetFieldEncoding().GetBytes(value.ToString());

var dataLength = GetNullTerminatedArrayLength(data, constLength, maxLength);
var dataLength = GetTerminatedArrayLength(data, constLength, maxLength);

await writer.WriteAsync(data, dataLength, cancellationToken).ConfigureAwait(false);

var stringTerminatorData = GetNullTermination();
var stringTerminatorData = GetTermination();
await writer.WriteAsync(TypeNode.StringTerminator, stringTerminatorData.Length, cancellationToken)
.ConfigureAwait(false);

Expand All @@ -404,6 +430,25 @@ await writer.WriteAsync(TypeNode.StringTerminator, stringTerminatorData.Length,
writer.Write(value.ToString());
break;
}
case SerializedType.TerminatedSizedString:
{
var encoding = GetFieldEncoding();
var data = encoding.GetBytes(value.ToString());

var dataLength = GetTerminatedArrayLength(data, constLength, maxLength);

await writer.WriteAsync(data, dataLength, cancellationToken);

var stringTerminatorData = encoding.GetBytes(new[] { TypeNode.StringTerminator });
await writer.WriteAsync(stringTerminatorData, stringTerminatorData.Length, cancellationToken);

var fillLength = maxLength < constLength ? maxLength : constLength;
var padLength = fillLength - (dataLength + stringTerminatorData.Length);
if (padLength > 0)
await writer.WriteAsync(GetFieldPaddingValue(), padLength, cancellationToken);

break;
}

default:

Expand Down Expand Up @@ -467,7 +512,8 @@ public void Deserialize(BinaryReader reader, SerializedType serializedType, Fiel
break;
}
case SerializedType.TerminatedString:
{
case SerializedType.TerminatedSizedString:
{
var data = ReadTerminated(reader, effectiveLengthValue, TypeNode.StringTerminator);
value = GetFieldEncoding().GetString(data, 0, data.Length);
break;
Expand Down Expand Up @@ -540,7 +586,8 @@ public async Task DeserializeAsync(AsyncBinaryReader reader, SerializedType seri
break;
}
case SerializedType.TerminatedString:
{
case SerializedType.TerminatedSizedString:
{
var data = await ReadTerminatedAsync(reader, (int) effectiveLengthValue.ByteCount, TypeNode.StringTerminator,
cancellationToken)
.ConfigureAwait(false);
Expand Down Expand Up @@ -675,7 +722,7 @@ private FieldLength GetConstLength(FieldLength length)
return constLength;
}

private byte[] GetNullTermination()
private byte[] GetTermination()
{
return GetFieldEncoding().GetBytes(new[] { TypeNode.StringTerminator });
}
Expand All @@ -684,8 +731,10 @@ private static FieldLength GetMaxLength(BoundedStream stream, SerializedType ser
{
FieldLength maxLength = null;

if (serializedType == SerializedType.ByteArray || serializedType == SerializedType.SizedString ||
serializedType == SerializedType.TerminatedString)
if (serializedType == SerializedType.ByteArray ||
serializedType == SerializedType.SizedString ||
serializedType == SerializedType.TerminatedString ||
serializedType == SerializedType.TerminatedSizedString)
{
// try to get bounded length
maxLength = stream.AvailableForWriting;
Expand All @@ -711,20 +760,22 @@ private static FieldLength GetArrayLength(byte[] data, FieldLength constLength,
return length;
}

private FieldLength GetNullTerminatedArrayLength(byte[] data, FieldLength constLength, FieldLength maxLength)
private FieldLength GetTerminatedArrayLength(byte[] data, FieldLength constLength, FieldLength maxLength)
{
FieldLength length = data.Length;
var nullTermination = GetNullTermination();
var nullTerminationLength = new FieldLength(nullTermination.Length);
var termination = GetTermination();
var terminationLength = new FieldLength(termination.Length);

if (constLength != null)
if (constLength != null &&
constLength < length + terminationLength)
{
length = constLength - nullTerminationLength;
length = constLength - terminationLength;
}

if (maxLength != null && length > maxLength)
if (maxLength != null &&
maxLength < length + terminationLength)
{
length = maxLength - nullTerminationLength;
length = maxLength - terminationLength;
}

return length;
Expand Down Expand Up @@ -776,7 +827,8 @@ private FieldLength GetEffectiveLengthValue(BinaryReader reader, SerializedType
{
if (serializedType == SerializedType.ByteArray ||
serializedType == SerializedType.SizedString ||
serializedType == SerializedType.TerminatedString)
serializedType == SerializedType.TerminatedString ||
serializedType == SerializedType.TerminatedSizedString)
{
// try to get bounded length
var baseStream = (BoundedStream) reader.BaseStream;
Expand Down
8 changes: 7 additions & 1 deletion BinarySerializer/SerializedType.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -90,6 +90,12 @@ public enum SerializedType
/// <summary>
/// An encoded string prefixed with a LEB128-encoded length. This is equivalent to how BinaryWriter encodes a string.
/// </summary>
LengthPrefixedString
LengthPrefixedString,

/// <summary>
/// An encoded string with a terminator, which is null (zero) by default or can be specified by setting StringTerminator.
/// Also has a maximum length storage available
/// </summary>
TerminatedSizedString,
}
}

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