Class Deserializer

A class that provides methods for deserializing various data types from a byte buffer. It supports deserialization of primitive types, strings, and complex objects using a BCS (Binary Common Serialization) layout.

Constructors

constructor

Methods

deserialize deserializeBool deserializeBytes deserializeFixedBytes deserializeOption deserializeOptionStr deserializeStr deserializeU128 deserializeU16 deserializeU256 deserializeU32 deserializeU64 deserializeU8 deserializeUleb128AsU32 deserializeVector remaining

Constructors

constructor

  • new Deserializer(data): Deserializer

  • Creates a new instance of the class with a copy of the provided data buffer. This prevents outside mutation of the buffer.

    Parameters

    • data: Uint8Array

      The data to be copied into the internal buffer as a Uint8Array.

    Returns Deserializer

Methods

deserialize

  • deserialize<T>(cls): T

  • Helper function that primarily exists to support alternative syntax for deserialization. That is, if we have a const deserializer: new Deserializer(...), instead of having to use MyClass.deserialize(deserializer), we can call deserializer.deserialize(MyClass).

    Type Parameters

    • T

    Parameters

    • cls: Deserializable<T>

      The BCS-deserializable class to deserialize the buffered bytes into.

    Returns T

    the deserialized value of class type T

    Example

    const deserializer = new Deserializer(new Uint8Array([1, 2, 3]));
    const value = deserializer.deserialize(MyClass); // where MyClass has a `deserialize` function
    // value is now an instance of MyClass
    // equivalent to `const value = MyClass.deserialize(deserializer)`

deserializeBool

  • deserializeBool(): boolean

  • Deserializes a boolean value from a byte stream.

    The BCS layout for a boolean uses one byte, where "0x01" represents true and "0x00" represents false. An error is thrown if the byte value is not valid.

    Returns boolean

    The deserialized boolean value.

    Throws

    Throws an error if the boolean value is invalid.

deserializeBytes

  • deserializeBytes(): Uint8Array

  • Deserializes an array of bytes.

    The BCS layout for "bytes" consists of a bytes_length followed by the bytes themselves, where bytes_length is a u32 integer encoded as a uleb128 integer, indicating the length of the bytes array.

    Returns Uint8Array

    The deserialized array of bytes.

deserializeFixedBytes

  • deserializeFixedBytes(len): Uint8Array

  • Deserializes an array of bytes of a specified length.

    Parameters

    • len: number

      The number of bytes to read from the source.

    Returns Uint8Array

deserializeOption

  • deserializeOption<T>(cls): undefined | T

  • Deserializes an optional deserializable class.

    BCS layout for Optional: 0 if none, else 1 | BCS representation of class.

    Type Parameters

    • T

    Parameters

    • cls: Deserializable<T>

      The BCS-deserializable class to deserialize the buffered bytes into.

    Returns undefined | T

    The deserialized value of class type T or undefined if no value exists.

    Example

    const deserializer = new Deserializer(new Uint8Array([1, 2, 3]));
    const value = deserializer.deserializeOption(MyClass); // where MyClass has a `deserialize` function
    // value is now an instance of MyClass

    const deserializer = new Deserializer(new Uint8Array([0]));
    const value = deserializer.deserializeOption(MyClass); // where MyClass has a `deserialize` function
    // value is undefined

deserializeOptionStr

  • deserializeOptionStr(): undefined | string

  • Deserializes an optional string.

    The BCS layout for Optional is 0 if none, else 1 followed by the string length and string content.

    Returns undefined | string

    The deserialized string if it exists, otherwise undefined.

    Example

    const deserializer = new Deserializer(new Uint8Array([0x00]));
    assert(deserializer.deserializeOptionStr() === undefined);
    const deserializer = new Deserializer(new Uint8Array([1, 8, 49, 50, 51, 52, 97, 98, 99, 100]));
    assert(deserializer.deserializeOptionStr() === "1234abcd");

deserializeStr

  • deserializeStr(): string

  • Deserializes a UTF-8 encoded string from a byte array. It first reads the length of the string in bytes, followed by the actual byte content, and decodes it into a string.

    BCS layout for "string": string_length | string_content where string_length is a u32 integer encoded as a uleb128 integer, equal to the number of bytes in string_content.

    Returns string

    Example

    const deserializer = new Deserializer(new Uint8Array([8, 49, 50, 51, 52, 97, 98, 99, 100]));
    assert(deserializer.deserializeStr() === "1234abcd");

deserializeU128

  • deserializeU128(): bigint

  • Deserializes a uint128 number from its binary representation. This function combines two 64-bit values to return a single uint128 value in little-endian format.

    Returns bigint

    The deserialized uint128 number.

deserializeU16

  • deserializeU16(): number

  • Deserializes a uint16 number from a binary format in little-endian representation.

    BCS layout for "uint16": Two bytes.

    Returns number

    Example

    const deserializer = new Deserializer(new Uint8Array([0x34, 0x12]));
    assert(deserializer.deserializeU16() === 4660);

deserializeU256

  • deserializeU256(): bigint

  • Deserializes a uint256 number from its binary representation.

    The BCS layout for "uint256" consists of thirty-two bytes in little-endian format.

    Returns bigint

    The deserialized uint256 number.

deserializeU32

  • deserializeU32(): number

  • Deserializes a uint32 number from a binary format in little-endian representation.

    BCS layout for "uint32": Four bytes.

    Returns number

    Example

    const deserializer = new Deserializer(new Uint8Array([0x78, 0x56, 0x34, 0x12]));
    assert(deserializer.deserializeU32() === 305419896);

deserializeU64

  • deserializeU64(): bigint

  • Deserializes a uint64 number.

    This function combines two 32-bit values to return a 64-bit unsigned integer in little-endian representation.

    Returns bigint

    Example

    const deserializer = new Deserializer(new Uint8Array([0x00, 0xEF, 0xCD, 0xAB, 0x78, 0x56, 0x34, 0x12]));
    assert(deserializer.deserializeU64() === 1311768467750121216);

deserializeU8

  • deserializeU8(): number

  • Deserializes a uint8 number from the binary data.

    BCS layout for "uint8": One byte. Binary format in little-endian representation.

    Returns number

    The deserialized uint8 number.

deserializeUleb128AsU32

  • deserializeUleb128AsU32(): number

  • Deserializes a uleb128 encoded uint32 number.

    This function is used for interpreting lengths of variable-length sequences and tags of enum values in BCS encoding.

    Returns number

    The deserialized uint32 value.

    Throws

    Throws an error if the parsed value exceeds the maximum uint32 number.

deserializeVector

  • deserializeVector<T>(cls): T[]

  • Deserializes an array of BCS Deserializable values given an existing Deserializer instance with a loaded byte buffer.

    Type Parameters

    • T

    Parameters

    • cls: Deserializable<T>

      The BCS-deserializable class to deserialize the buffered bytes into.

    Returns T[]

    An array of deserialized values of type T.

    Example

    // serialize a vector of addresses
    const addresses = new Array<AccountAddress>(
      AccountAddress.from("0x1"),
      AccountAddress.from("0x2"),
      AccountAddress.from("0xa"),
      AccountAddress.from("0xb"),
    );
    const serializer = new Serializer();
    serializer.serializeVector(addresses);
    const serializedBytes = serializer.toUint8Array();

    // deserialize the bytes into an array of addresses
    const deserializer = new Deserializer(serializedBytes);
    const deserializedAddresses = deserializer.deserializeVector(AccountAddress);
    // deserializedAddresses is now an array of AccountAddress instances

remaining

  • remaining(): number

  • Returns the number of bytes remaining in the buffer.

    This information is useful to determine if there's more data to be read.

    Returns number

    The number of bytes remaining in the buffer.

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