Trie.js

'use strict';

Object.defineProperty(exports, "__esModule", {
    value: true
});
exports.Trie = exports.createTrieFromBase64 = exports.UTRIE2_INDEX_2_MASK = exports.UTRIE2_INDEX_2_BLOCK_LENGTH = exports.UTRIE2_OMITTED_BMP_INDEX_1_LENGTH = exports.UTRIE2_INDEX_1_OFFSET = exports.UTRIE2_UTF8_2B_INDEX_2_LENGTH = exports.UTRIE2_UTF8_2B_INDEX_2_OFFSET = exports.UTRIE2_INDEX_2_BMP_LENGTH = exports.UTRIE2_LSCP_INDEX_2_LENGTH = exports.UTRIE2_DATA_MASK = exports.UTRIE2_DATA_BLOCK_LENGTH = exports.UTRIE2_LSCP_INDEX_2_OFFSET = exports.UTRIE2_SHIFT_1_2 = exports.UTRIE2_INDEX_SHIFT = exports.UTRIE2_SHIFT_1 = exports.UTRIE2_SHIFT_2 = undefined;

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();

var _Util = require('./Util');

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

/** Shift size for getting the index-2 table offset. */
var UTRIE2_SHIFT_2 = exports.UTRIE2_SHIFT_2 = 5;

/** Shift size for getting the index-1 table offset. */
var UTRIE2_SHIFT_1 = exports.UTRIE2_SHIFT_1 = 6 + 5;

/**
 * Shift size for shifting left the index array values.
 * Increases possible data size with 16-bit index values at the cost
 * of compactability.
 * This requires data blocks to be aligned by UTRIE2_DATA_GRANULARITY.
 */
var UTRIE2_INDEX_SHIFT = exports.UTRIE2_INDEX_SHIFT = 2;

/**
 * Difference between the two shift sizes,
 * for getting an index-1 offset from an index-2 offset. 6=11-5
 */
var UTRIE2_SHIFT_1_2 = exports.UTRIE2_SHIFT_1_2 = UTRIE2_SHIFT_1 - UTRIE2_SHIFT_2;

/**
 * The part of the index-2 table for U+D800..U+DBFF stores values for
 * lead surrogate code _units_ not code _points_.
 * Values for lead surrogate code _points_ are indexed with this portion of the table.
 * Length=32=0x20=0x400>>UTRIE2_SHIFT_2. (There are 1024=0x400 lead surrogates.)
 */
var UTRIE2_LSCP_INDEX_2_OFFSET = exports.UTRIE2_LSCP_INDEX_2_OFFSET = 0x10000 >> UTRIE2_SHIFT_2;

/** Number of entries in a data block. 32=0x20 */
var UTRIE2_DATA_BLOCK_LENGTH = exports.UTRIE2_DATA_BLOCK_LENGTH = 1 << UTRIE2_SHIFT_2;
/** Mask for getting the lower bits for the in-data-block offset. */
var UTRIE2_DATA_MASK = exports.UTRIE2_DATA_MASK = UTRIE2_DATA_BLOCK_LENGTH - 1;

var UTRIE2_LSCP_INDEX_2_LENGTH = exports.UTRIE2_LSCP_INDEX_2_LENGTH = 0x400 >> UTRIE2_SHIFT_2;
/** Count the lengths of both BMP pieces. 2080=0x820 */
var UTRIE2_INDEX_2_BMP_LENGTH = exports.UTRIE2_INDEX_2_BMP_LENGTH = UTRIE2_LSCP_INDEX_2_OFFSET + UTRIE2_LSCP_INDEX_2_LENGTH;
/**
 * The 2-byte UTF-8 version of the index-2 table follows at offset 2080=0x820.
 * Length 32=0x20 for lead bytes C0..DF, regardless of UTRIE2_SHIFT_2.
 */
var UTRIE2_UTF8_2B_INDEX_2_OFFSET = exports.UTRIE2_UTF8_2B_INDEX_2_OFFSET = UTRIE2_INDEX_2_BMP_LENGTH;
var UTRIE2_UTF8_2B_INDEX_2_LENGTH = exports.UTRIE2_UTF8_2B_INDEX_2_LENGTH = 0x800 >> 6; /* U+0800 is the first code point after 2-byte UTF-8 */
/**
 * The index-1 table, only used for supplementary code points, at offset 2112=0x840.
 * Variable length, for code points up to highStart, where the last single-value range starts.
 * Maximum length 512=0x200=0x100000>>UTRIE2_SHIFT_1.
 * (For 0x100000 supplementary code points U+10000..U+10ffff.)
 *
 * The part of the index-2 table for supplementary code points starts
 * after this index-1 table.
 *
 * Both the index-1 table and the following part of the index-2 table
 * are omitted completely if there is only BMP data.
 */
var UTRIE2_INDEX_1_OFFSET = exports.UTRIE2_INDEX_1_OFFSET = UTRIE2_UTF8_2B_INDEX_2_OFFSET + UTRIE2_UTF8_2B_INDEX_2_LENGTH;

/**
 * Number of index-1 entries for the BMP. 32=0x20
 * This part of the index-1 table is omitted from the serialized form.
 */
var UTRIE2_OMITTED_BMP_INDEX_1_LENGTH = exports.UTRIE2_OMITTED_BMP_INDEX_1_LENGTH = 0x10000 >> UTRIE2_SHIFT_1;

/** Number of entries in an index-2 block. 64=0x40 */
var UTRIE2_INDEX_2_BLOCK_LENGTH = exports.UTRIE2_INDEX_2_BLOCK_LENGTH = 1 << UTRIE2_SHIFT_1_2;
/** Mask for getting the lower bits for the in-index-2-block offset. */
var UTRIE2_INDEX_2_MASK = exports.UTRIE2_INDEX_2_MASK = UTRIE2_INDEX_2_BLOCK_LENGTH - 1;

var createTrieFromBase64 = exports.createTrieFromBase64 = function createTrieFromBase64(base64) {
    var buffer = (0, _Util.decode)(base64);
    var view32 = Array.isArray(buffer) ? (0, _Util.polyUint32Array)(buffer) : new Uint32Array(buffer);
    var view16 = Array.isArray(buffer) ? (0, _Util.polyUint16Array)(buffer) : new Uint16Array(buffer);
    var headerLength = 24;

    var index = view16.slice(headerLength / 2, view32[4] / 2);
    var data = view32[5] === 2 ? view16.slice((headerLength + view32[4]) / 2) : view32.slice(Math.ceil((headerLength + view32[4]) / 4));

    return new Trie(view32[0], view32[1], view32[2], view32[3], index, data);
};

var Trie = exports.Trie = function () {
    function Trie(initialValue, errorValue, highStart, highValueIndex, index, data) {
        _classCallCheck(this, Trie);

        this.initialValue = initialValue;
        this.errorValue = errorValue;
        this.highStart = highStart;
        this.highValueIndex = highValueIndex;
        this.index = index;
        this.data = data;
    }

    /**
     * Get the value for a code point as stored in the Trie.
     *
     * @param codePoint the code point
     * @return the value
     */


    _createClass(Trie, [{
        key: 'get',
        value: function get(codePoint) {
            var ix = void 0;
            if (codePoint >= 0) {
                if (codePoint < 0x0d800 || codePoint > 0x0dbff && codePoint <= 0x0ffff) {
                    // Ordinary BMP code point, excluding leading surrogates.
                    // BMP uses a single level lookup.  BMP index starts at offset 0 in the Trie2 index.
                    // 16 bit data is stored in the index array itself.
                    ix = this.index[codePoint >> UTRIE2_SHIFT_2];
                    ix = (ix << UTRIE2_INDEX_SHIFT) + (codePoint & UTRIE2_DATA_MASK);
                    return this.data[ix];
                }

                if (codePoint <= 0xffff) {
                    // Lead Surrogate Code Point.  A Separate index section is stored for
                    // lead surrogate code units and code points.
                    //   The main index has the code unit data.
                    //   For this function, we need the code point data.
                    // Note: this expression could be refactored for slightly improved efficiency, but
                    //       surrogate code points will be so rare in practice that it's not worth it.
                    ix = this.index[UTRIE2_LSCP_INDEX_2_OFFSET + (codePoint - 0xd800 >> UTRIE2_SHIFT_2)];
                    ix = (ix << UTRIE2_INDEX_SHIFT) + (codePoint & UTRIE2_DATA_MASK);
                    return this.data[ix];
                }

                if (codePoint < this.highStart) {
                    // Supplemental code point, use two-level lookup.
                    ix = UTRIE2_INDEX_1_OFFSET - UTRIE2_OMITTED_BMP_INDEX_1_LENGTH + (codePoint >> UTRIE2_SHIFT_1);
                    ix = this.index[ix];
                    ix += codePoint >> UTRIE2_SHIFT_2 & UTRIE2_INDEX_2_MASK;
                    ix = this.index[ix];
                    ix = (ix << UTRIE2_INDEX_SHIFT) + (codePoint & UTRIE2_DATA_MASK);
                    return this.data[ix];
                }
                if (codePoint <= 0x10ffff) {
                    return this.data[this.highValueIndex];
                }
            }

            // Fall through.  The code point is outside of the legal range of 0..0x10ffff.
            return this.errorValue;
        }
    }]);

    return Trie;
}();