79 lines
2.4 KiB
TypeScript
79 lines
2.4 KiB
TypeScript
/*
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* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
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* SPDX-License-Identifier: Apache-2.0.
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*/
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import {CrtError} from "./error";
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/*
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* Limits for header value validation
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*/
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export const MAX_INT8 : number = 127;
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export const MIN_INT8 : number = -128;
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export const MAX_INT16 : number = 32767;
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export const MIN_INT16 : number = -32768;
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export const MAX_INT32 : number = 2147483647;
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export const MIN_INT32 : number = -2147483648;
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export const MAX_INT64 : bigint = BigInt("9223372036854775807");
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export const MIN_INT64 : bigint = BigInt("-9223372036854775808");
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const MAX_UINT8_AS_BIGINT : bigint = BigInt("256");
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/** @internal */
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export function marshalInt64BigintAsBuffer(value: bigint) : Uint8Array {
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if (value < MIN_INT64 || value > MAX_INT64) {
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throw new CrtError("marshalInt64BigintAsBuffer expects a value that can fit in 8 bytes");
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}
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let buffer : Uint8Array = new Uint8Array(8);
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/* encode the integer as a twos-complement byte sequence */
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if (value < 0) {
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value = -value - BigInt(1);
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for (let i = 0; i < 8; ++i) {
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buffer[i] = 255 - Number(value % MAX_UINT8_AS_BIGINT);
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value /= MAX_UINT8_AS_BIGINT;
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}
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} else {
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for (let i = 0; i < 8; ++i) {
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buffer[i] = Number(value % MAX_UINT8_AS_BIGINT);
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value /= MAX_UINT8_AS_BIGINT;
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}
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}
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return buffer;
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}
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/** @internal */
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export function unmarshalInt64BigintFromBuffer(buffer: ArrayBuffer) : bigint {
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let value : bigint = BigInt(0);
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let byteView = new Uint8Array(buffer);
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if (byteView.length != 8) {
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throw new CrtError("unmarshalInt64BigintFromBuffer expects a byte buffer of length 8");
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}
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let shift: bigint = BigInt(1);
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let isNegative = (byteView[7] & 0x80) != 0;
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/* encoding is two's-complement, so treat negative and non-negative differently */
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if (isNegative) {
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for (let i = 0; i < byteView.length; ++i) {
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let byteValue: bigint = BigInt(255 - byteView[i]);
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value += (byteValue * shift);
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shift *= MAX_UINT8_AS_BIGINT;
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}
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value += BigInt(1);
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value = -value;
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} else {
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for (let i = 0; i < byteView.length; ++i) {
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let byteValue: bigint = BigInt(byteView[i]);
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value += (byteValue * shift);
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shift *= MAX_UINT8_AS_BIGINT;
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}
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}
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return value;
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}
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