122 lines
3.1 KiB
TypeScript
122 lines
3.1 KiB
TypeScript
|
/*************************************************************
|
||
|
|
*
|
||
|
|
* Copyright (c) 2018-2022 The MathJax Consortium
|
||
|
|
*
|
||
|
|
* 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 the License at
|
||
|
|
*
|
||
|
|
* http://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 the License.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @fileoverview Implements bit-fields with extendable field names
|
||
|
|
*
|
||
|
|
* @author dpvc@mathjax.org (Davide Cervone)
|
||
|
|
*/
|
||
|
|
|
||
|
|
export class BitField {
|
||
|
|
|
||
|
|
/**
|
||
|
|
* The largest bit available
|
||
|
|
*/
|
||
|
|
protected static MAXBIT = 1 << 31;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* The next bit to be allocated
|
||
|
|
*/
|
||
|
|
protected static next: number = 1;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* The map of names to bit positions
|
||
|
|
*/
|
||
|
|
protected static names: Map<string, number> = new Map();
|
||
|
|
|
||
|
|
/**
|
||
|
|
* The bits that are set
|
||
|
|
*/
|
||
|
|
protected bits: number = 0;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @param {string} names The names of the bit positions to reserve
|
||
|
|
*/
|
||
|
|
public static allocate(...names: string[]) {
|
||
|
|
for (const name of names) {
|
||
|
|
if (this.has(name)) {
|
||
|
|
throw new Error('Bit already allocated for ' + name);
|
||
|
|
}
|
||
|
|
if (this.next === BitField.MAXBIT) {
|
||
|
|
throw new Error('Maximum number of bits already allocated');
|
||
|
|
}
|
||
|
|
this.names.set(name, this.next);
|
||
|
|
this.next <<= 1;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @param {string} name The name of the bit to check for being defined
|
||
|
|
* @return {boolean} True if the named bit is already allocated
|
||
|
|
*/
|
||
|
|
public static has(name: string): boolean {
|
||
|
|
return this.names.has(name);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @param {string} name The name of the bit position to set
|
||
|
|
*/
|
||
|
|
public set(name: string) {
|
||
|
|
this.bits |= this.getBit(name);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @param {string} name The name of the bit position to clear
|
||
|
|
*/
|
||
|
|
public clear(name: string) {
|
||
|
|
this.bits &= ~this.getBit(name);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @param {string} name The name of the bit to check if set
|
||
|
|
* @return {boolean} True if the named bit is set
|
||
|
|
*/
|
||
|
|
public isSet(name: string): boolean {
|
||
|
|
return !!(this.bits & this.getBit(name));
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Clear all bits
|
||
|
|
*/
|
||
|
|
public reset() {
|
||
|
|
this.bits = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @param {string} name The name whose bit position is needed (error if not defined)
|
||
|
|
* @return {number} The position of the named bit
|
||
|
|
*/
|
||
|
|
protected getBit(name: string): number {
|
||
|
|
const bit = (this.constructor as typeof BitField).names.get(name);
|
||
|
|
if (!bit) {
|
||
|
|
throw new Error('Unknown bit-field name: ' + name);
|
||
|
|
}
|
||
|
|
return bit;
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @param {string[]} names The name of the positions to allocate initially
|
||
|
|
* @return {typeof AbstractBitField} The bit-field class with names allocated
|
||
|
|
*/
|
||
|
|
export function BitFieldClass(...names: string[]): typeof BitField {
|
||
|
|
const Bits = class extends BitField {};
|
||
|
|
Bits.allocate(...names);
|
||
|
|
return Bits;
|
||
|
|
}
|