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{"version":3,"sources":["../../src/bcs/deserializer.ts"],"sourcesContent":["// Copyright © Aptos Foundation\n// SPDX-License-Identifier: Apache-2.0\n\n/* eslint-disable no-bitwise */\nimport { MAX_U32_NUMBER } from \"./consts\";\nimport { Uint8, Uint16, Uint32, Uint64, Uint128, Uint256 } from \"../types\";\n\n/**\n * This interface exists to define Deserializable<T> inputs for functions that\n * deserialize a byte buffer into a type T.\n * It is not intended to be implemented or extended, because Typescript has no support\n * for static methods in interfaces.\n */\nexport interface Deserializable<T> {\n deserialize(deserializer: Deserializer): T;\n}\n\nexport class Deserializer {\n private buffer: ArrayBuffer;\n\n private offset: number;\n\n constructor(data: Uint8Array) {\n // copies data to prevent outside mutation of buffer.\n this.buffer = new ArrayBuffer(data.length);\n new Uint8Array(this.buffer).set(data, 0);\n this.offset = 0;\n }\n\n private read(length: number): ArrayBuffer {\n if (this.offset + length > this.buffer.byteLength) {\n throw new Error(\"Reached to the end of buffer\");\n }\n\n const bytes = this.buffer.slice(this.offset, this.offset + length);\n this.offset += length;\n return bytes;\n }\n\n /**\n * Deserializes a string. UTF8 string is supported. Reads the string's bytes length \"l\" first,\n * and then reads \"l\" bytes of content. Decodes the byte array into a string.\n *\n * BCS layout for \"string\": string_length | string_content\n * where string_length is a u32 integer encoded as a uleb128 integer, equal to the number of bytes in string_content.\n *\n * @example\n * ```ts\n * const deserializer = new Deserializer(new Uint8Array([8, 49, 50, 51, 52, 97, 98, 99, 100]));\n * assert(deserializer.deserializeStr() === \"1234abcd\");\n * ```\n */\n deserializeStr(): string {\n const value = this.deserializeBytes();\n const textDecoder = new TextDecoder();\n return textDecoder.decode(value);\n }\n\n /**\n * Deserializes an array of bytes.\n *\n * BCS layout for \"bytes\": bytes_length | bytes\n * where bytes_length is a u32 integer encoded as a uleb128 integer, equal to the length of the bytes array.\n */\n deserializeBytes(): Uint8Array {\n const len = this.deserializeUleb128AsU32();\n return new Uint8Array(this.read(len));\n }\n\n /**\n * Deserializes an array of bytes. The number of bytes to read is already known.\n *\n */\n deserializeFixedBytes(len: number): Uint8Array {\n return new Uint8Array(this.read(len));\n }\n\n /**\n * Deserializes a boolean value.\n *\n * BCS layout for \"boolean\": One byte. \"0x01\" for true and \"0x00\" for false.\n */\n deserializeBool(): boolean {\n const bool = new Uint8Array(this.read(1))[0];\n if (bool !== 1 && bool !== 0) {\n throw new Error(\"Invalid boolean value\");\n }\n return bool === 1;\n }\n\n /**\n * Deserializes a uint8 number.\n *\n * BCS layout for \"uint8\": One byte. Binary format in little-endian representation.\n */\n deserializeU8(): Uint8 {\n return new DataView(this.read(1)).getUint8(0);\n }\n\n /**\n * Deserializes a uint16 number.\n *\n * BCS layout for \"uint16\": Two bytes. Binary format in little-endian representation.\n * @example\n * ```ts\n * const deserializer = new Deserializer(new Uint8Array([0x34, 0x12]));\n * assert(deserializer.deserializeU16() === 4660);\n * ```\n */\n deserializeU16(): Uint16 {\n return new DataView(this.read(2)).getUint16(0, true);\n }\n\n /**\n * Deserializes a uint32 number.\n *\n * BCS layout for \"uint32\": Four bytes. Binary format in little-endian representation.\n * @example\n * ```ts\n * const deserializer = new Deserializer(new Uint8Array([0x78, 0x56, 0x34, 0x12]));\n * assert(deserializer.deserializeU32() === 305419896);\n * ```\n */\n deserializeU32(): Uint32 {\n return new DataView(this.read(4)).getUint32(0, true);\n }\n\n /**\n * Deserializes a uint64 number.\n *\n * BCS layout for \"uint64\": Eight bytes. Binary format in little-endian representation.\n * @example\n * ```ts\n * const deserializer = new Deserializer(new Uint8Array([0x00, 0xEF, 0xCD, 0xAB, 0x78, 0x56, 0x34, 0x12]));\n * assert(deserializer.deserializeU64() === 1311768467750121216);\n * ```\n */\n deserializeU64(): Uint64 {\n const low = this.deserializeU32();\n const high = this.deserializeU32();\n\n // combine the two 32-bit values and return (little endian)\n return BigInt((BigInt(high) << BigInt(32)) | BigInt(low));\n }\n\n /**\n * Deserializes a uint128 number.\n *\n * BCS layout for \"uint128\": Sixteen bytes. Binary format in little-endian representation.\n */\n deserializeU128(): Uint128 {\n const low = this.deserializeU64();\n const high = this.deserializeU64();\n\n // combine the two 64-bit values and return (little endian)\n return BigInt((high << BigInt(64)) | low);\n }\n\n /**\n * Deserializes a uint256 number.\n *\n * BCS layout for \"uint256\": Thirty-two bytes. Binary format in little-endian representation.\n */\n deserializeU256(): Uint256 {\n const low = this.deserializeU128();\n const high = this.deserializeU128();\n\n // combine the two 128-bit values and return (little endian)\n return BigInt((high << BigInt(128)) | low);\n }\n\n /**\n * Deserializes a uleb128 encoded uint32 number.\n *\n * BCS use uleb128 encoding in two cases: (1) lengths of variable-length sequences and (2) tags of enum values\n */\n deserializeUleb128AsU32(): Uint32 {\n let value: bigint = BigInt(0);\n let shift = 0;\n\n while (value < MAX_U32_NUMBER) {\n const byte = this.deserializeU8();\n value |= BigInt(byte & 0x7f) << BigInt(shift);\n\n if ((byte & 0x80) === 0) {\n break;\n }\n shift += 7;\n }\n\n if (value > MAX_U32_NUMBER) {\n throw new Error(\"Overflow while parsing uleb128-encoded uint32 value\");\n }\n\n return Number(value);\n }\n\n /**\n * Helper function that primarily exists to support alternative syntax for deserialization.\n * That is, if we have a `const deserializer: new Deserializer(...)`, instead of having to use\n * `MyClass.deserialize(deserializer)`, we can call `deserializer.deserialize(MyClass)`.\n *\n * @example const deserializer = new Deserializer(new Uint8Array([1, 2, 3]));\n * const value = deserializer.deserialize(MyClass); // where MyClass has a `deserialize` function\n * // value is now an instance of MyClass\n * // equivalent to `const value = MyClass.deserialize(deserializer)`\n * @param cls The BCS-deserializable class to deserialize the buffered bytes into.\n *\n * @returns the deserialized value of class type T\n */\n deserialize<T>(cls: Deserializable<T>): T {\n // NOTE: `deserialize` in `cls.deserialize(this)` here is a static method defined in `cls`,\n // It is separate from the `deserialize` instance method defined here in Deserializer.\n return cls.deserialize(this);\n }\n\n /**\n * Deserializes an array of BCS Deserializable values given an existing Deserializer\n * instance with a loaded byte buffer.\n *\n * @param cls The BCS-deserializable class to deserialize the buffered bytes into.\n * @example\n * // serialize a vector of addresses\n * const addresses = new Array<AccountAddress>(\n * AccountAddress.from(\"0x1\"),\n * AccountAddress.from(\"0x2\"),\n * AccountAddress.from(\"0xa\"),\n * AccountAddress.from(\"0xb\"),\n * );\n * const serializer = new Serializer();\n * serializer.serializeVector(addresses);\n * const serializedBytes = serializer.toUint8Array();\n *\n * // deserialize the bytes into an array of addresses\n * const deserializer = new Deserializer(serializedBytes);\n * const deserializedAddresses = deserializer.deserializeVector(AccountAddress);\n * // deserializedAddresses is now an array of AccountAddress instances\n * @returns an array of deserialized values of type T\n */\n deserializeVector<T>(cls: Deserializable<T>): Array<T> {\n const length = this.deserializeUleb128AsU32();\n const vector = new Array<T>();\n for (let i = 0; i < length; i += 1) {\n vector.push(this.deserialize(cls));\n }\n return vector;\n }\n}\n"],"mappings":"yCAiBO,IAAMA,EAAN,KAAmB,CAKxB,YAAYC,EAAkB,CAE5B,KAAK,OAAS,IAAI,YAAYA,EAAK,MAAM,EACzC,IAAI,WAAW,KAAK,MAAM,EAAE,IAAIA,EAAM,CAAC,EACvC,KAAK,OAAS,CAChB,CAEQ,KAAKC,EAA6B,CACxC,GAAI,KAAK,OAASA,EAAS,KAAK,OAAO,WACrC,MAAM,IAAI,MAAM,8BAA8B,EAGhD,IAAMC,EAAQ,KAAK,OAAO,MAAM,KAAK,OAAQ,KAAK,OAASD,CAAM,EACjE,YAAK,QAAUA,EACRC,CACT,CAeA,gBAAyB,CACvB,IAAMC,EAAQ,KAAK,iBAAiB,EAEpC,OADoB,IAAI,YAAY,EACjB,OAAOA,CAAK,CACjC,CAQA,kBAA+B,CAC7B,IAAMC,EAAM,KAAK,wBAAwB,EACzC,OAAO,IAAI,WAAW,KAAK,KAAKA,CAAG,CAAC,CACtC,CAMA,sBAAsBA,EAAyB,CAC7C,OAAO,IAAI,WAAW,KAAK,KAAKA,CAAG,CAAC,CACtC,CAOA,iBAA2B,CACzB,IAAMC,EAAO,IAAI,WAAW,KAAK,KAAK,CAAC,CAAC,EAAE,CAAC,EAC3C,GAAIA,IAAS,GAAKA,IAAS,EACzB,MAAM,IAAI,MAAM,uBAAuB,EAEzC,OAAOA,IAAS,CAClB,CAOA,eAAuB,CACrB,OAAO,IAAI,SAAS,KAAK,KAAK,CAAC,CAAC,EAAE,SAAS,CAAC,CAC9C,CAYA,gBAAyB,CACvB,OAAO,IAAI,SAAS,KAAK,KAAK,CAAC,CAAC,EAAE,UAAU,EAAG,EAAI,CACrD,CAYA,gBAAyB,CACvB,OAAO,IAAI,SAAS,KAAK,KAAK,CAAC,CAAC,EAAE,UAAU,EAAG,EAAI,CACrD,CAYA,gBAAyB,CACvB,IAAMC,EAAM,KAAK,eAAe,EAC1BC,EAAO,KAAK,eAAe,EAGjC,OAAO,OAAQ,OAAOA,CAAI,GAAK,OAAO,EAAE,EAAK,OAAOD,CAAG,CAAC,CAC1D,CAOA,iBAA2B,CACzB,IAAMA,EAAM,KAAK,eAAe,EAC1BC,EAAO,KAAK,eAAe,EAGjC,OAAO,OAAQA,GAAQ,OAAO,EAAE,EAAKD,CAAG,CAC1C,CAOA,iBAA2B,CACzB,IAAMA,EAAM,KAAK,gBAAgB,EAC3BC,EAAO,KAAK,gBAAgB,EAGlC,OAAO,OAAQA,GAAQ,OAAO,GAAG,EAAKD,CAAG,CAC3C,CAOA,yBAAkC,CAChC,IAAIH,EAAgB,OAAO,CAAC,EACxBK,EAAQ,EAEZ,KAAOL,EAAQM,GAAgB,CAC7B,IAAMC,EAAO,KAAK,cAAc,EAGhC,GAFAP,GAAS,OAAOO,EAAO,GAAI,GAAK,OAAOF,CAAK,EAEvC,EAAAE,EAAO,KACV,MAEFF,GAAS,CACX,CAEA,GAAIL,EAAQM,EACV,MAAM,IAAI,MAAM,qDAAqD,EAGvE,OAAO,OAAON,CAAK,CACrB,CAeA,YAAeQ,EAA2B,CAGxC,OAAOA,EAAI,YAAY,IAAI,CAC7B,CAyBA,kBAAqBA,EAAkC,CACrD,IAAMV,EAAS,KAAK,wBAAwB,EACtCW,EAAS,IAAI,MACnB,QAASC,EAAI,EAAGA,EAAIZ,EAAQY,GAAK,EAC/BD,EAAO,KAAK,KAAK,YAAYD,CAAG,CAAC,EAEnC,OAAOC,CACT,CACF","names":["Deserializer","data","length","bytes","value","len","bool","low","high","shift","MAX_U32_NUMBER","byte","cls","vector","i"]}