654 lines
12 KiB
JavaScript
654 lines
12 KiB
JavaScript
/*!
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* encoding.js - encoding utils for bcoin
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* Copyright (c) 2014-2015, Fedor Indutny (MIT License)
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* Copyright (c) 2014-2016, Christopher Jeffrey (MIT License).
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* https://github.com/bcoin-org/bcoin
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*/
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'use strict';
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var assert = require('assert');
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var BN = require('bn.js');
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var encoding = exports;
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/**
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* UINT32_MAX
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* @const {BN}
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*/
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encoding.U32_MAX = new BN(0xffffffff);
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/**
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* UINT64_MAX
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* @const {BN}
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*/
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encoding.U64_MAX = new BN('ffffffffffffffff', 'hex');
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/**
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* Read uint64le.
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* @param {Buffer} data
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* @param {Number} off
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* @returns {BN}
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*/
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encoding.readU64 = function readU64(data, off) {
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var num;
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off = off >>> 0;
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num = data.slice(off, off + 8);
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return new BN(num, 'le');
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};
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/**
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* Read uint64be.
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* @param {Buffer} data
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* @param {Number} off
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* @returns {BN}
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*/
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encoding.readU64BE = function readU64BE(data, off) {
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var num;
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off = off >>> 0;
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num = data.slice(off, off + 8);
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return new BN(num, 'be');
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};
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/**
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* Read int64le.
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* @param {Buffer} data
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* @param {Number} off
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* @returns {BN}
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*/
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encoding.read64 = function read64(data, off) {
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var num;
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off = off >>> 0;
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num = data.slice(off, off + 8);
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if (num[num.length - 1] & 0x80)
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return new BN(num, 'le').notn(64).addn(1).neg();
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return new BN(num, 'le');
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};
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/**
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* Read int64be.
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* @param {Buffer} data
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* @param {Number} off
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* @returns {BN}
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*/
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encoding.read64BE = function read64BE(data, off) {
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var num;
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off = off >>> 0;
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num = data.slice(off, off + 8);
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if (num[0] & 0x80)
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return new BN(num, 'be').notn(64).addn(1).neg();
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return new BN(num, 'be');
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};
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/**
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* Write uint64le.
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* @param {BN|Number} value
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*/
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encoding.writeU64 = function writeU64(dst, num, off) {
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return encoding.write64(dst, num, off);
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};
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/**
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* Write uint64be.
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* @param {BN|Number} value
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*/
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encoding.writeU64BE = function writeU64BE(dst, num, off) {
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return encoding.write64BE(dst, num, off);
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};
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/**
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* Write a javascript number as a uint64le (faster than big numbers).
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* @param {Number} value
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* @throws on num > MAX_SAFE_INTEGER
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*/
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encoding.writeU64N = function writeU64N(dst, num, off) {
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return encoding.write64N(dst, num, off);
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};
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/**
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* Write a javascript number as a uint64be (faster than big numbers).
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* @param {Number} value
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* @throws on num > MAX_SAFE_INTEGER
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*/
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encoding.writeU64NBE = function writeU64NBE(dst, num, off) {
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return encoding.write64NBE(dst, num, off);
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};
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/**
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* Max safe integer (53 bits).
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* @const {Number}
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* @default
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*/
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encoding.MAX_SAFE_INTEGER = 0x1fffffffffffff;
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/**
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* Max 52 bit integer (safe for additions).
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* `(MAX_SAFE_INTEGER - 1) / 2`
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* @const {Number}
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* @default
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*/
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encoding.MAX_SAFE_ADDITION = 0xfffffffffffff;
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/**
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* Write a javascript number as an int64le (faster than big numbers).
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* @param {Number} value
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* @throws on num > MAX_SAFE_INTEGER
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*/
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encoding.write64N = function write64N(dst, num, off, be) {
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var negative, hi, lo;
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assert(typeof num === 'number');
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off = off >>> 0;
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negative = num < 0;
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if (negative) {
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num = -num;
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num -= 1;
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}
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assert(num <= encoding.MAX_SAFE_INTEGER, 'Number exceeds 2^53-1');
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lo = num % 0x100000000;
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hi = (num - lo) / 0x100000000;
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if (negative) {
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hi = ~hi >>> 0;
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lo = ~lo >>> 0;
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}
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if (be) {
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dst[off + 0] = (hi >>> 24) & 0xff;
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dst[off + 1] = (hi >>> 16) & 0xff;
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dst[off + 2] = (hi >>> 8) & 0xff;
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dst[off + 3] = (hi >>> 0) & 0xff;
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dst[off + 4] = (lo >>> 24) & 0xff;
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dst[off + 5] = (lo >>> 16) & 0xff;
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dst[off + 6] = (lo >>> 8) & 0xff;
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dst[off + 7] = (lo >>> 0) & 0xff;
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} else {
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dst[off + 0] = (lo >>> 0) & 0xff;
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dst[off + 1] = (lo >>> 8) & 0xff;
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dst[off + 2] = (lo >>> 16) & 0xff;
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dst[off + 3] = (lo >>> 24) & 0xff;
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dst[off + 4] = (hi >>> 0) & 0xff;
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dst[off + 5] = (hi >>> 8) & 0xff;
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dst[off + 6] = (hi >>> 16) & 0xff;
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dst[off + 7] = (hi >>> 24) & 0xff;
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}
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return off + 8;
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};
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/**
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* Write a javascript number as an int64be (faster than big numbers).
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* @param {Number} value
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* @throws on num > MAX_SAFE_INTEGER
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*/
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encoding.write64NBE = function write64NBE(dst, num, off) {
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return encoding.write64N(dst, num, off, true);
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};
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/**
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* Read uint64le as a js number.
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* @param {Buffer} data
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* @param {Number} off
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* @param {Boolean} force53 - Read only 53 bits, but maintain the sign.
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* @returns {Number}
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* @throws on num > MAX_SAFE_INTEGER
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*/
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encoding.readU64N = function readU64N(data, off, force53, be) {
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var hi, lo;
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off = off >>> 0;
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if (be) {
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hi = data.readUInt32BE(off, true);
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lo = data.readUInt32BE(off + 4, true);
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} else {
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hi = data.readUInt32LE(off + 4, true);
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lo = data.readUInt32LE(off, true);
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}
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if (force53)
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hi &= 0x1fffff;
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assert((hi & 0xffe00000) === 0, 'Number exceeds 2^53-1');
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return (hi * 0x100000000) + lo;
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};
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/**
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* Read uint64be as a js number.
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* @param {Buffer} data
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* @param {Number} off
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* @param {Boolean} force53 - Read only 53 bits, but maintain the sign.
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* @returns {Number}
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* @throws on num > MAX_SAFE_INTEGER
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*/
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encoding.readU64NBE = function readU64NBE(data, off, force53) {
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return encoding.readU64N(data, off, force53, true);
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};
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/**
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* Read int64le as a js number.
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* @param {Buffer} data
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* @param {Number} off
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* @param {Boolean} force53 - Read only 53 bits, but maintain the sign.
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* @returns {Number}
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* @throws on num > MAX_SAFE_INTEGER
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*/
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encoding.read64N = function read64N(data, off, force53, be) {
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var hi, lo;
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off = off >>> 0;
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if (be) {
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hi = data.readUInt32BE(off, true);
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lo = data.readUInt32BE(off + 4, true);
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} else {
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hi = data.readUInt32LE(off + 4, true);
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lo = data.readUInt32LE(off, true);
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}
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if (hi & 0x80000000) {
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hi = ~hi >>> 0;
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lo = ~lo >>> 0;
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if (force53)
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hi &= 0x1fffff;
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assert((hi & 0xffe00000) === 0, 'Number exceeds 2^53-1');
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return -(hi * 0x100000000 + lo + 1);
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}
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if (force53)
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hi &= 0x1fffff;
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assert((hi & 0xffe00000) === 0, 'Number exceeds 2^53-1');
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return hi * 0x100000000 + lo;
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};
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/**
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* Read int64be as a js number.
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* @param {Buffer} data
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* @param {Number} off
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* @param {Boolean} force53 - Read only 53 bits, but maintain the sign.
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* @returns {Number}
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* @throws on num > MAX_SAFE_INTEGER
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*/
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encoding.read64NBE = function read64NBE(data, off, force53) {
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return encoding.read64N(data, off, force53, true);
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};
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/**
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* Write int64le.
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* @param {Buffer} dst
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* @param {BN|Number} num
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* @param {Number} off
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* @returns {Number} Number of bytes written.
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*/
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encoding.write64 = function write64(dst, num, off) {
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var i;
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if (typeof num === 'number')
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return encoding.write64N(dst, num, off);
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off = off >>> 0;
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if (num.isNeg())
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num = num.neg().inotn(64).iaddn(1);
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if (num.bitLength() > 64)
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num = num.uand(encoding.U64_MAX);
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num = num.toArray('le', 8);
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for (i = 0; i < num.length; i++)
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dst[off++] = num[i];
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return off;
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};
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/**
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* Write int64be.
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* @param {Buffer} dst
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* @param {BN|Number} num
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* @param {Number} off
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* @returns {Number} Number of bytes written.
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*/
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encoding.write64BE = function write64BE(dst, num, off) {
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var i;
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if (typeof num === 'number')
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return encoding.write64NBE(dst, num, off);
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off = off >>> 0;
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if (num.isNeg())
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num = num.neg().inotn(64).iaddn(1);
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if (num.bitLength() > 64)
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num = num.uand(encoding.U64_MAX);
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num = num.toArray('be', 8);
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for (i = 0; i < num.length; i++)
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dst[off++] = num[i];
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return off;
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};
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/**
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* Read a varint.
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* @param {Buffer} data
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* @param {Number} off
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* @param {Boolean?} big - Whether to read as a big number.
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* @returns {Object}
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*/
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encoding.readVarint = function readVarint(data, off, big) {
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var value, size;
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off = off >>> 0;
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assert(off < data.length);
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switch (data[off]) {
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case 0xff:
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size = 9;
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assert(off + size <= data.length);
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if (big) {
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value = encoding.readU64(data, off + 1);
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assert(value.bitLength() > 32);
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} else {
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value = encoding.readU64N(data, off + 1);
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assert(value > 0xffffffff);
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}
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break;
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case 0xfe:
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size = 5;
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assert(off + size <= data.length);
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value = data.readUInt32LE(off + 1, true);
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assert(value > 0xffff);
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if (big)
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value = new BN(value);
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break;
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case 0xfd:
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size = 3;
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assert(off + size <= data.length);
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value = data[off + 1] | (data[off + 2] << 8);
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assert(value >= 0xfd);
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if (big)
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value = new BN(value);
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break;
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default:
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size = 1;
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value = data[off];
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if (big)
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value = new BN(value);
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break;
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}
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return { size: size, value: value };
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};
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/**
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* Write a varint.
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* @param {Buffer} dst
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* @param {BN|Number} num
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* @param {Number} off
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* @returns {Number} Number of bytes written.
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*/
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encoding.writeVarint = function writeVarint(dst, num, off) {
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off = off >>> 0;
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if (BN.isBN(num)) {
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if (num.bitLength() > 32) {
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dst[off] = 0xff;
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encoding.writeU64(dst, num, off + 1);
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return off + 9;
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}
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num = num.toNumber();
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}
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num = +num;
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if (num < 0xfd) {
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dst[off] = num & 0xff;
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return off + 1;
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}
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if (num <= 0xffff) {
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dst[off] = 0xfd;
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dst[off + 1] = num & 0xff;
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dst[off + 2] = (num >>> 8) & 0xff;
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return off + 3;
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}
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if (num <= 0xffffffff) {
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dst[off] = 0xfe;
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dst[off + 1] = num & 0xff;
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dst[off + 2] = (num >>> 8) & 0xff;
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dst[off + 3] = (num >>> 16) & 0xff;
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dst[off + 4] = (num >>> 24) & 0xff;
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return off + 5;
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}
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dst[off] = 0xff;
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encoding.writeU64N(dst, num, off + 1);
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return off + 9;
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};
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/**
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* Calculate size of varint.
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* @param {BN|Number} num
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* @returns {Number} size
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*/
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encoding.sizeVarint = function sizeVarint(num) {
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if (BN.isBN(num)) {
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if (num.bitLength() > 32)
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return 9;
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num = num.toNumber();
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}
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if (num < 0xfd)
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return 1;
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if (num <= 0xffff)
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return 3;
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if (num <= 0xffffffff)
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return 5;
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return 9;
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};
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/**
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* Read a varint (type 2).
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* @param {Buffer} data
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* @param {Number} off
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* @param {Boolean?} big - Whether to read as a big number.
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* @returns {Object}
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*/
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encoding.readVarint2 = function readVarint2(data, off, big) {
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var num = 0;
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var size = 0;
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var bnum, ch;
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off = off >>> 0;
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for (;;) {
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assert(off < data.length);
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ch = data[off++];
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size++;
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if (num >= 0x3fffffffffff) {
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assert(big, 'Number exceeds 2^53-1.');
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bnum = new BN(num);
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num = 0;
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}
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if (bnum) {
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assert(bnum.bitLength() <= 256);
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bnum.iushln(7).iaddn(ch & 0x7f);
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if ((ch & 0x80) === 0)
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break;
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bnum.iaddn(1);
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continue;
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}
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num = (num * 0x80) + (ch & 0x7f);
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if ((ch & 0x80) === 0)
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break;
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num++;
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}
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if (bnum)
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return { size: size, value: bnum };
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if (big)
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num = new BN(num);
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return { size: size, value: num };
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};
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/**
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* Write a varint (type 2).
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* @param {Buffer} dst
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* @param {BN|Number} num
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* @param {Number} off
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* @returns {Number} Number of bytes written.
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*/
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encoding.writeVarint2 = function writeVarint2(dst, num, off) {
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var tmp = [];
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var len = 0;
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if (BN.isBN(num)) {
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if (num.bitLength() > 53) {
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for (;;) {
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tmp[len] = (num.words[0] & 0x7f) | (len ? 0x80 : 0x00);
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if (num.cmpn(0x7f) <= 0)
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break;
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num.iushrn(7).isubn(1);
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len++;
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}
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assert(off + len <= dst.length);
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do {
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dst[off++] = tmp[len];
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} while (len--);
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return off;
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}
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num = num.toNumber();
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}
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off = off >>> 0;
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num = +num;
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for (;;) {
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tmp[len] = (num & 0x7f) | (len ? 0x80 : 0x00);
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if (num <= 0x7f)
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break;
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num = ((num - (num % 0x80)) / 0x80) - 1;
|
|
len++;
|
|
}
|
|
|
|
assert(off + len <= dst.length);
|
|
|
|
do {
|
|
dst[off++] = tmp[len];
|
|
} while (len--);
|
|
|
|
return off;
|
|
};
|
|
|
|
/**
|
|
* Calculate size of varint (type 2).
|
|
* @param {BN|Number} num
|
|
* @returns {Number} size
|
|
*/
|
|
|
|
encoding.sizeVarint2 = function sizeVarint2(num) {
|
|
var size = 0;
|
|
|
|
if (BN.isBN(num)) {
|
|
if (num.bitLength() > 53) {
|
|
num = num.clone();
|
|
|
|
for (;;) {
|
|
size++;
|
|
if (num.cmpn(0x7f) <= 0)
|
|
break;
|
|
num.iushrn(7).isubn(1);
|
|
}
|
|
|
|
return size;
|
|
}
|
|
|
|
num = num.toNumber();
|
|
}
|
|
|
|
num = +num;
|
|
|
|
for (;;) {
|
|
size++;
|
|
if (num <= 0x7f)
|
|
break;
|
|
num = ((num - (num % 0x80)) / 0x80) - 1;
|
|
}
|
|
|
|
return size;
|
|
};
|
|
|
|
/**
|
|
* Serialize number as a u32le.
|
|
* @param {Number} num
|
|
* @returns {Buffer}
|
|
*/
|
|
|
|
encoding.U32 = function U32(num) {
|
|
var data = new Buffer(4);
|
|
data.writeUInt32LE(num, 0, true);
|
|
return data;
|
|
};
|