-
-
Notifications
You must be signed in to change notification settings - Fork 14
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Add BigInt support and Unicode handling (#9)
Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com> Co-authored-by: Dustin Hagemeier <dustin@commit.international>
- Loading branch information
3 people
committed
Nov 18, 2019
1 parent
7a72892
commit cbdc497
Showing
5 changed files
with
121 additions
and
24 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,20 +1,81 @@ | ||
| 'use strict'; | ||
| const OFFSET_BASIS_32 = 2166136261; | ||
|
|
||
| const fnv1a = string => { | ||
| let hash = OFFSET_BASIS_32; | ||
| // FNV_PRIMES and FNV_OFFSETS from | ||
| // http://www.isthe.com/chongo/tech/comp/fnv/index.html#FNV-param | ||
| // | ||
| // Defining these as strings instead of BigInt literals avoids syntax errors on | ||
| // legacy platforms. | ||
|
|
||
| for (let i = 0; i < string.length; i++) { | ||
| hash ^= string.charCodeAt(i); | ||
| const FNV_PRIMES = { | ||
| 32: '16777619', | ||
| 64: '1099511628211', | ||
| 128: '309485009821345068724781371', | ||
| 256: '374144419156711147060143317175368453031918731002211', | ||
| 512: '35835915874844867368919076489095108449946327955754392558399825615420669938882575126094039892345713852759', | ||
| 1024: '5016456510113118655434598811035278955030765345404790744303017523831112055108147451509157692220295382716162651878526895249385292291816524375083746691371804094271873160484737966720260389217684476157468082573' | ||
| }; | ||
|
|
||
| const FNV_OFFSETS = { | ||
| 32: '2166136261', | ||
| 64: '14695981039346656037', | ||
| 128: '144066263297769815596495629667062367629', | ||
| 256: '100029257958052580907070968620625704837092796014241193945225284501741471925557', | ||
| 512: '9659303129496669498009435400716310466090418745672637896108374329434462657994582932197716438449813051892206539805784495328239340083876191928701583869517785', | ||
| 1024: '14197795064947621068722070641403218320880622795441933960878474914617582723252296732303717722150864096521202355549365628174669108571814760471015076148029755969804077320157692458563003215304957150157403644460363550505412711285966361610267868082893823963790439336411086884584107735010676915' | ||
| }; | ||
|
|
||
| // Legacy implementation for 32-bit + Number types, older systems that don't | ||
| // support BigInt | ||
| function fnv1a(str) { | ||
| // Handle unicode code points > 0x7f | ||
| let hash = Number(FNV_OFFSETS[32]); | ||
| let unicoded = false; | ||
| for (let i = 0; i < str.length; i++) { | ||
| let v = str.charCodeAt(i); | ||
| // Non-ASCII char triggers unicode escape logic | ||
| if (v > 0x7F && !unicoded) { | ||
| str = unescape(encodeURIComponent(str)); | ||
| v = str.charCodeAt(i); | ||
| unicoded = true; | ||
| } | ||
|
|
||
| // 32-bit FNV prime: 2**24 + 2**8 + 0x93 = 16777619 | ||
| // Using bitshift for accuracy and performance. Numbers in JS suck. | ||
| hash ^= v; | ||
| hash += (hash << 1) + (hash << 4) + (hash << 7) + (hash << 8) + (hash << 24); | ||
| } | ||
|
|
||
| return hash >>> 0; | ||
| }; | ||
| } | ||
|
|
||
| function bigInt(str, {size} = {size: 32}) { | ||
| if (typeof (BigInt) === 'undefined') { | ||
| throw new TypeError('BigInt is not supported'); | ||
| } | ||
|
|
||
| if (!FNV_PRIMES[size]) { | ||
| throw new Error('`size` must be one of 32, 64, 128, 256, 512, or 1024'); | ||
| } | ||
|
|
||
| let hash = BigInt(FNV_OFFSETS[size]); | ||
| const prime = BigInt(FNV_PRIMES[size]); | ||
|
|
||
| // Handle unicode code points > 0x7f | ||
| let unicoded = false; | ||
| for (let i = 0; i < str.length; i++) { | ||
| let v = str.charCodeAt(i); | ||
| // Non-ASCII char triggers unicode escape logic | ||
| if (v > 0x7F && !unicoded) { | ||
| str = unescape(encodeURIComponent(str)); | ||
| v = str.charCodeAt(i); | ||
| unicoded = true; | ||
| } | ||
|
|
||
| hash ^= BigInt(v); | ||
| hash = BigInt.asUintN(size, hash * prime); | ||
| } | ||
|
|
||
| return hash; | ||
| } | ||
|
|
||
| module.exports = fnv1a; | ||
| // TODO: remove this in the next major version, refactor the whole definition to: | ||
| module.exports.bigInt = bigInt; | ||
| module.exports.default = fnv1a; |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters