| 1 | import { SourceData } from "./crypto";
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| 2 | /**
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| 3 | * @public
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| 4 | *
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| 5 | * An object that provides a checksum of data provided in chunks to `update`.
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| 6 | * The checksum may be performed incrementally as chunks are received or all
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| 7 | * at once when the checksum is finalized, depending on the underlying
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| 8 | * implementation.
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| 9 | *
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| 10 | * It's recommended to compute checksum incrementally to avoid reading the
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| 11 | * entire payload in memory.
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| 12 | *
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| 13 | * A class that implements this interface may accept an optional secret key in its
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| 14 | * constructor while computing checksum value, when using HMAC. If provided,
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| 15 | * this secret key would be used when computing checksum.
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| 16 | */
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| 17 | export interface Checksum {
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| 18 | /**
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| 19 | * Constant length of the digest created by the algorithm in bytes.
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| 20 | */
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| 21 | digestLength?: number;
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| 22 | /**
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| 23 | * Creates a new checksum object that contains a deep copy of the internal
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| 24 | * state of the current `Checksum` object.
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| 25 | */
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| 26 | copy?(): Checksum;
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| 27 | /**
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| 28 | * Returns the digest of all of the data passed.
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| 29 | */
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| 30 | digest(): Promise<Uint8Array>;
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| 31 | /**
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| 32 | * Allows marking a checksum for checksums that support the ability
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| 33 | * to mark and reset.
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| 34 | *
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| 35 | * @param readLimit - The maximum limit of bytes that can be read
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| 36 | * before the mark position becomes invalid.
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| 37 | */
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| 38 | mark?(readLimit: number): void;
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| 39 | /**
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| 40 | * Resets the checksum to its initial value.
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| 41 | */
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| 42 | reset(): void;
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| 43 | /**
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| 44 | * Adds a chunk of data for which checksum needs to be computed.
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| 45 | * This can be called many times with new data as it is streamed.
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| 46 | *
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| 47 | * Implementations may override this method which passes second param
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| 48 | * which makes Checksum object stateless.
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| 49 | *
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| 50 | * @param chunk - The buffer to update checksum with.
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| 51 | */
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| 52 | update(chunk: Uint8Array): void;
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| 53 | }
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| 54 | /**
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| 55 | * @public
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| 56 | *
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| 57 | * A constructor for a Checksum that may be used to calculate an HMAC. Implementing
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| 58 | * classes should not directly hold the provided key in memory beyond the
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| 59 | * lexical scope of the constructor.
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| 60 | */
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| 61 | export interface ChecksumConstructor {
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| 62 | new (secret?: SourceData): Checksum;
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| 63 | }
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