128 lines
4.0 KiB
JavaScript
128 lines
4.0 KiB
JavaScript
/* crc32.js (C) 2014-present SheetJS -- http://sheetjs.com */
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/* vim: set ts=2: */
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/*exported CRC32 */
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/*:: declare var DO_NOT_EXPORT_CRC:?boolean; */
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/*:: declare function define(cb:()=>any):void; */
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var CRC32/*:CRC32Module*/;
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(function (factory/*:(a:any)=>void*/)/*:void*/ {
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/*jshint ignore:start */
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/*eslint-disable */
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if(typeof DO_NOT_EXPORT_CRC === 'undefined') {
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if('object' === typeof exports) {
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factory(exports);
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} else if ('function' === typeof define && define.amd) {
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define(function () {
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var module/*:CRC32Module*/ = /*::(*/{}/*:: :any)*/;
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factory(module);
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return module;
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});
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} else {
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factory(CRC32 = /*::(*/{}/*:: :any)*/);
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}
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} else {
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factory(CRC32 = /*::(*/{}/*:: :any)*/);
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}
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/*eslint-enable */
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/*jshint ignore:end */
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}(function(CRC32/*:CRC32Module*/) {
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CRC32.version = '1.2.0';
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/*::
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type CRC32Type = number;
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type ABuf = Array<number> | Buffer | Uint8Array;
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type CRC32TableType = Array<number> | Int32Array;
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*/
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/* see perf/crc32table.js */
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/*global Int32Array */
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function signed_crc_table()/*:CRC32TableType*/ {
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var c = 0, table/*:Array<number>*/ = new Array(256);
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for(var n =0; n != 256; ++n){
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c = n;
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c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
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c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
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c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
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c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
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c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
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c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
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c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
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c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
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table[n] = c;
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}
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return typeof Int32Array !== 'undefined' ? new Int32Array(table) : table;
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}
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var T = signed_crc_table();
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/*# charCodeAt is the best approach for binary strings */
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function crc32_bstr(bstr/*:string*/, seed/*:?CRC32Type*/)/*:CRC32Type*/ {
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var C = seed/*:: ? 0 : 0 */ ^ -1, L = bstr.length - 1;
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for(var i = 0; i < L;) {
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C = (C>>>8) ^ T[(C^bstr.charCodeAt(i++))&0xFF];
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C = (C>>>8) ^ T[(C^bstr.charCodeAt(i++))&0xFF];
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}
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if(i === L) C = (C>>>8) ^ T[(C ^ bstr.charCodeAt(i))&0xFF];
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return C ^ -1;
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}
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function crc32_buf(buf/*:ABuf*/, seed/*:?CRC32Type*/)/*:CRC32Type*/ {
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if(buf.length > 10000) return crc32_buf_8(buf, seed);
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var C = seed/*:: ? 0 : 0 */ ^ -1, L = buf.length - 3;
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for(var i = 0; i < L;) {
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C = (C>>>8) ^ T[(C^buf[i++])&0xFF];
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C = (C>>>8) ^ T[(C^buf[i++])&0xFF];
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C = (C>>>8) ^ T[(C^buf[i++])&0xFF];
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C = (C>>>8) ^ T[(C^buf[i++])&0xFF];
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}
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while(i < L+3) C = (C>>>8) ^ T[(C^buf[i++])&0xFF];
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return C ^ -1;
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}
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function crc32_buf_8(buf/*:ABuf*/, seed/*:?CRC32Type*/)/*:CRC32Type*/ {
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var C = seed/*:: ? 0 : 0 */ ^ -1, L = buf.length - 7;
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for(var i = 0; i < L;) {
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C = (C>>>8) ^ T[(C^buf[i++])&0xFF];
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C = (C>>>8) ^ T[(C^buf[i++])&0xFF];
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C = (C>>>8) ^ T[(C^buf[i++])&0xFF];
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C = (C>>>8) ^ T[(C^buf[i++])&0xFF];
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C = (C>>>8) ^ T[(C^buf[i++])&0xFF];
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C = (C>>>8) ^ T[(C^buf[i++])&0xFF];
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C = (C>>>8) ^ T[(C^buf[i++])&0xFF];
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C = (C>>>8) ^ T[(C^buf[i++])&0xFF];
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}
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while(i < L+7) C = (C>>>8) ^ T[(C^buf[i++])&0xFF];
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return C ^ -1;
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}
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/*# much much faster to intertwine utf8 and crc */
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function crc32_str(str/*:string*/, seed/*:?CRC32Type*/)/*:CRC32Type*/ {
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var C = seed/*:: ? 0 : 0 */ ^ -1;
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for(var i = 0, L=str.length, c, d; i < L;) {
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c = str.charCodeAt(i++);
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if(c < 0x80) {
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C = (C>>>8) ^ T[(C ^ c)&0xFF];
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} else if(c < 0x800) {
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C = (C>>>8) ^ T[(C ^ (192|((c>>6)&31)))&0xFF];
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C = (C>>>8) ^ T[(C ^ (128|(c&63)))&0xFF];
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} else if(c >= 0xD800 && c < 0xE000) {
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c = (c&1023)+64; d = str.charCodeAt(i++)&1023;
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C = (C>>>8) ^ T[(C ^ (240|((c>>8)&7)))&0xFF];
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C = (C>>>8) ^ T[(C ^ (128|((c>>2)&63)))&0xFF];
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C = (C>>>8) ^ T[(C ^ (128|((d>>6)&15)|((c&3)<<4)))&0xFF];
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C = (C>>>8) ^ T[(C ^ (128|(d&63)))&0xFF];
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} else {
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C = (C>>>8) ^ T[(C ^ (224|((c>>12)&15)))&0xFF];
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C = (C>>>8) ^ T[(C ^ (128|((c>>6)&63)))&0xFF];
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C = (C>>>8) ^ T[(C ^ (128|(c&63)))&0xFF];
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}
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}
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return C ^ -1;
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}
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CRC32.table = T;
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// $FlowIgnore
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CRC32.bstr = crc32_bstr;
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// $FlowIgnore
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CRC32.buf = crc32_buf;
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// $FlowIgnore
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CRC32.str = crc32_str;
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}));
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