| // Copyright 2021 The Pigweed Authors |

| // Licensed under the Apache License, Version 2.0 (the "License"); you may not |

| // use this file except in compliance with the License. You may obtain a copy of |

| // https://www.apache.org/licenses/LICENSE-2.0 |

| // Unless required by applicable law or agreed to in writing, software |

| // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |

| // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |

| // License for the specific language governing permissions and limitations under |

| /** This module defines the string to ID hash used in pw_rpc. */ |

| const HASH_CONSTANT = 65599; |

| * This is the same hash function that is used in Python pw_rpc. It is chosen |

| export function hash(input: string): number { |

| let hashValue = input.length; |

| let coefficient = HASH_CONSTANT; |

| for (let i = 0; i < input.length; i++) { |

| const ord = input.charCodeAt(i); |

| hashValue = (hashValue + coefficient * ord) % 2 ** 32; |

| coefficient = (coefficient * HASH_CONSTANT) % 2 ** 32; |