ethers.js/lib.esm/utils/maths.js
2022-09-05 16:57:11 -04:00

122 lines
3.6 KiB
JavaScript

import { hexlify, isBytesLike } from "./data.js";
import { logger } from "./logger.js";
const BN_0 = BigInt(0);
const BN_1 = BigInt(1);
/**
* Convert %%value%% from a twos-compliment value of %%width%% bits.
*/
export function fromTwos(_value, _width) {
const value = logger.getBigInt(_value, "value");
const width = BigInt(logger.getNumber(_width, "width"));
// Top bit set; treat as a negative value
if (value >> (width - BN_1)) {
const mask = (BN_1 << width) - BN_1;
return -(((~value) & mask) + BN_1);
}
return value;
}
/**
* Convert %%value%% to a twos-compliment value of %%width%% bits.
*/
export function toTwos(_value, _width) {
const value = logger.getBigInt(_value, "value");
const width = BigInt(logger.getNumber(_width, "width"));
if (value < BN_0) {
const mask = (BN_1 << width) - BN_1;
return ((~(-value)) & mask) + BN_1;
}
return value;
}
/**
* Mask %%value%% with a bitmask of %%bits%% ones.
*/
export function mask(_value, _bits) {
const value = logger.getBigInt(_value, "value");
const bits = BigInt(logger.getNumber(_bits, "bits"));
return value & ((BN_1 << bits) - BN_1);
}
/*
* Converts %%value%% to a BigInt. If %%value%% is a Uint8Array, it
* is treated as Big Endian data.
*/
const Nibbles = "0123456789abcdef";
export function toBigInt(value) {
if (value instanceof Uint8Array) {
let result = "0x0";
for (const v of value) {
result += Nibbles[v >> 4];
result += Nibbles[v & 0x0f];
}
return BigInt(result);
}
return logger.getBigInt(value);
}
/*
* Converts %%value%% to a number. If %%value%% is a Uint8Array, it
* is treated as Big Endian data. Throws if the value is not safe.
*/
export function toNumber(value) {
return logger.getNumber(toBigInt(value));
}
/**
* Converts %%value%% to a Big Endian hexstring, optionally padded to
* %%width%% bytes.
*/
// Converts value to hex, optionally padding on the left to width bytes
export function toHex(_value, _width) {
const value = logger.getBigInt(_value, "value");
if (value < 0) {
throw new Error("cannot convert negative value to hex");
}
let result = value.toString(16);
if (_width == null) {
// Ensure the value is of even length
if (result.length % 2) {
result = "0" + result;
}
}
else {
const width = logger.getNumber(_width, "width");
if (width * 2 < result.length) {
throw new Error(`value ${value} exceeds width ${width}`);
}
// Pad the value to the required width
while (result.length < (width * 2)) {
result = "0" + result;
}
}
return "0x" + result;
}
/**
* Converts %%value%% to a Big Endian Uint8Array.
*/
export function toArray(_value) {
const value = logger.getBigInt(_value, "value");
if (value < 0) {
throw new Error("cannot convert negative value to hex");
}
if (value === BN_0) {
return new Uint8Array([]);
}
let hex = value.toString(16);
if (hex.length % 2) {
hex = "0" + hex;
}
const result = new Uint8Array(hex.length / 2);
for (let i = 0; i < result.length; i++) {
const offset = i * 2;
result[i] = parseInt(hex.substring(offset, offset + 2), 16);
}
return result;
}
export function toQuantity(value) {
let result = hexlify(isBytesLike(value) ? value : toArray(value)).substring(2);
while (result.substring(0, 1) === "0") {
result = result.substring(1);
}
if (result === "") {
result = "0";
}
return "0x" + result;
}
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