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import {Hash, parse as parseHash} from '../hash';
export function chunkDataKey(hash: Hash): string {  return `c/${hash}/d`;}
export function chunkMetaKey(hash: Hash): string {  return `c/${hash}/m`;}
export function chunkRefCountKey(hash: Hash): string {  return `c/${hash}/r`;}
export function headKey(name: string): string {  return `h/${name}`;}
export const enum KeyType {  ChunkData,  ChunkMeta,  ChunkRefCount,  Head,}
export type Key =  | {      type: KeyType.ChunkData;      hash: Hash;    }  | {      type: KeyType.ChunkMeta;      hash: Hash;    }  | {      type: KeyType.ChunkRefCount;      hash: Hash;    }  | {      type: KeyType.Head;      name: string;    };
export function parse(key: string): Key {  const invalidKey = () => new Error(`Invalid key: '${key}'`);  const hash = () => parseHash(key.substring(2, key.length - 2));
  // '/'  if (key.charCodeAt(1) === 47) {    switch (key.charCodeAt(0)) {      // c      case 99: {        if (key.length < 4 || key.charCodeAt(key.length - 2) !== 47) {          throw invalidKey();        }        switch (key.charCodeAt(key.length - 1)) {          case 100: // d            return {              type: KeyType.ChunkData,              hash: hash(),            };          case 109: // m            return {              type: KeyType.ChunkMeta,              hash: hash(),            };          case 114: // r            return {              type: KeyType.ChunkRefCount,              hash: hash(),            };        }        break;      }      case 104: // h        return {          type: KeyType.Head,          name: key.substring(2),        };    }  }  throw invalidKey();}