bitcoinjs-lib/src/bufferutils.js

'use strict';
Object.defineProperty(exports, '__esModule', { value: true });
exports.BufferReader =
  exports.BufferWriter =
  exports.cloneBuffer =
  exports.reverseBuffer =
  exports.writeUInt64LE =
  exports.readUInt64LE =
  exports.varuint =
    void 0;
const types = require('./types');
const { typeforce } = types;
const varuint = require('varuint-bitcoin');
exports.varuint = varuint;
// https://github.com/feross/buffer/blob/master/index.js#L1127
function verifuint(value, max) {
  if (typeof value !== 'number')
    throw new Error('cannot write a non-number as a number');
  if (value < 0)
    throw new Error('specified a negative value for writing an unsigned value');
  if (value > max) throw new Error('RangeError: value out of range');
  if (Math.floor(value) !== value)
    throw new Error('value has a fractional component');
}
function readUInt64LE(buffer, offset) {
  const a = buffer.readUInt32LE(offset);
  let b = buffer.readUInt32LE(offset + 4);
  b *= 0x100000000;
  verifuint(b + a, 0x001fffffffffffff);
  return b + a;
}
exports.readUInt64LE = readUInt64LE;
function writeUInt64LE(buffer, value, offset) {
  verifuint(value, 0x001fffffffffffff);
  buffer.writeInt32LE(value & -1, offset);
  buffer.writeUInt32LE(Math.floor(value / 0x100000000), offset + 4);
  return offset + 8;
}
exports.writeUInt64LE = writeUInt64LE;
function reverseBuffer(buffer) {
  if (buffer.length < 1) return buffer;
  let j = buffer.length - 1;
  let tmp = 0;
  for (let i = 0; i < buffer.length / 2; i++) {
    tmp = buffer[i];
    buffer[i] = buffer[j];
    buffer[j] = tmp;
    j--;
  }
  return buffer;
}
exports.reverseBuffer = reverseBuffer;
function cloneBuffer(buffer) {
  const clone = Buffer.allocUnsafe(buffer.length);
  buffer.copy(clone);
  return clone;
}
exports.cloneBuffer = cloneBuffer;
/**
 * Helper class for serialization of bitcoin data types into a pre-allocated buffer.
 */
class BufferWriter {
  static withCapacity(size) {
    return new BufferWriter(Buffer.alloc(size));
  }
  constructor(buffer, offset = 0) {
    this.buffer = buffer;
    this.offset = offset;
    typeforce(types.tuple(types.Buffer, types.UInt32), [buffer, offset]);
  }
  writeUInt8(i) {
    this.offset = this.buffer.writeUInt8(i, this.offset);
  }
  writeInt32(i) {
    this.offset = this.buffer.writeInt32LE(i, this.offset);
  }
  writeUInt32(i) {
    this.offset = this.buffer.writeUInt32LE(i, this.offset);
  }
  writeUInt64(i) {
    this.offset = writeUInt64LE(this.buffer, i, this.offset);
  }
  writeVarInt(i) {
    varuint.encode(i, this.buffer, this.offset);
    this.offset += varuint.encode.bytes;
  }
  writeSlice(slice) {
    if (this.buffer.length < this.offset + slice.length) {
      throw new Error('Cannot write slice out of bounds');
    }
    this.offset += slice.copy(this.buffer, this.offset);
  }
  writeVarSlice(slice) {
    this.writeVarInt(slice.length);
    this.writeSlice(slice);
  }
  writeVector(vector) {
    this.writeVarInt(vector.length);
    vector.forEach(buf => this.writeVarSlice(buf));
  }
  end() {
    if (this.buffer.length === this.offset) {
      return this.buffer;
    }
    throw new Error(`buffer size ${this.buffer.length}, offset ${this.offset}`);
  }
}
exports.BufferWriter = BufferWriter;
/**
 * Helper class for reading of bitcoin data types from a buffer.
 */
class BufferReader {
  constructor(buffer, offset = 0) {
    this.buffer = buffer;
    this.offset = offset;
    typeforce(types.tuple(types.Buffer, types.UInt32), [buffer, offset]);
  }
  readUInt8() {
    const result = this.buffer.readUInt8(this.offset);
    this.offset++;
    return result;
  }
  readInt32() {
    const result = this.buffer.readInt32LE(this.offset);
    this.offset += 4;
    return result;
  }
  readUInt32() {
    const result = this.buffer.readUInt32LE(this.offset);
    this.offset += 4;
    return result;
  }
  readUInt64() {
    const result = readUInt64LE(this.buffer, this.offset);
    this.offset += 8;
    return result;
  }
  readVarInt() {
    const vi = varuint.decode(this.buffer, this.offset);
    this.offset += varuint.decode.bytes;
    return vi;
  }
  readSlice(n) {
    if (this.buffer.length < this.offset + n) {
      throw new Error('Cannot read slice out of bounds');
    }
    const result = this.buffer.slice(this.offset, this.offset + n);
    this.offset += n;
    return result;
  }
  readVarSlice() {
    return this.readSlice(this.readVarInt());
  }
  readVector() {
    const count = this.readVarInt();
    const vector = [];
    for (let i = 0; i < count; i++) vector.push(this.readVarSlice());
    return vector;
  }
}
exports.BufferReader = BufferReader;