@bsv/sdk
Version:
BSV Blockchain Software Development Kit
721 lines • 23.4 kB
JavaScript
import BigNumber from './BigNumber.js';
import { hash256 } from './Hash.js';
/**
* Prepends a '0' to an odd character length word to ensure it has an even number of characters.
* @param {string} word - The input word.
* @returns {string} - The word with a leading '0' if it's an odd character length; otherwise, the original word.
*/
export const zero2 = (word) => {
if (word.length % 2 === 1) {
return '0' + word;
}
else {
return word;
}
};
/**
* Converts an array of numbers to a hexadecimal string representation.
* @param {number[]} msg - The input array of numbers.
* @returns {string} - The hexadecimal string representation of the input array.
*/
export const toHex = (msg) => {
let res = '';
for (const num of msg) {
res += zero2(num.toString(16));
}
return res;
};
/**
* Converts various message formats into an array of numbers.
* Supports arrays, hexadecimal strings, base64 strings, and UTF-8 strings.
*
* @param {any} msg - The input message (array or string).
* @param {('hex' | 'utf8' | 'base64')} enc - Specifies the string encoding, if applicable.
* @returns {any[]} - Array representation of the input.
*/
export const toArray = (msg, enc) => {
if (Array.isArray(msg))
return msg.slice();
if (msg === undefined)
return [];
if (typeof msg !== 'string') {
return Array.from(msg, (item) => item | 0);
}
switch (enc) {
case 'hex':
return hexToArray(msg);
case 'base64':
return base64ToArray(msg);
default:
return utf8ToArray(msg);
}
};
const hexToArray = (msg) => {
msg = msg.replace(/[^a-z0-9]+/gi, '');
if (msg.length % 2 !== 0)
msg = '0' + msg;
const res = [];
for (let i = 0; i < msg.length; i += 2) {
res.push(parseInt(msg[i] + msg[i + 1], 16));
}
return res;
};
const base64ToArray = (msg) => {
const base64Chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
const result = [];
let currentBit = 0;
let currentByte = 0;
for (const char of msg.replace(/=+$/, '')) {
currentBit = (currentBit << 6) | base64Chars.indexOf(char);
currentByte += 6;
if (currentByte >= 8) {
currentByte -= 8;
result.push((currentBit >> currentByte) & 0xff);
currentBit &= (1 << currentByte) - 1;
}
}
return result;
};
/**
* Encodes a string into an array of bytes representing its UTF-8 encoding.
* Any lone surrogates are replaced with the Unicode replacement character (U+FFFD).
*
* @param str - The string to encode.
* @returns An array of numbers, each representing a byte in the UTF-8 encoded string.
*/
function utf8ToArray(str) {
const result = [];
for (let i = 0; i < str.length; i++) {
const cp = str.codePointAt(i);
if (cp === undefined) {
// Should never be out of range.
throw new Error(`Index out of range: ${i}`);
}
let codePoint = cp;
if (codePoint > 0xFFFF) {
// Valid surrogate pair => skip the next code unit because codePointAt
// has already combined them into a single code point.
i++;
}
else {
// Check if codePoint is a lone (unpaired) high surrogate or low surrogate.
if (codePoint >= 0xD800 && codePoint <= 0xDFFF) {
// Replace with the replacement character (U+FFFD).
codePoint = 0xFFFD;
}
}
// Encode according to the UTF-8 standard
if (codePoint <= 0x7F) {
result.push(codePoint);
}
else if (codePoint <= 0x7FF) {
result.push(0xC0 | (codePoint >> 6), 0x80 | (codePoint & 0x3F));
}
else if (codePoint <= 0xFFFF) {
result.push(0xE0 | (codePoint >> 12), 0x80 | ((codePoint >> 6) & 0x3F), 0x80 | (codePoint & 0x3F));
}
else {
result.push(0xF0 | (codePoint >> 18), 0x80 | ((codePoint >> 12) & 0x3F), 0x80 | ((codePoint >> 6) & 0x3F), 0x80 | (codePoint & 0x3F));
}
}
return result;
}
/**
* Converts an array of numbers to a UTF-8 encoded string.
* @param {number[]} arr - The input array of numbers.
* @returns {string} - The UTF-8 encoded string.
*/
export const toUTF8 = (arr) => {
let result = '';
let skip = 0;
for (let i = 0; i < arr.length; i++) {
const byte = arr[i];
// this byte is part of a multi-byte sequence, skip it
// added to avoid modifying i within the loop which is considered unsafe.
if (skip > 0) {
skip--;
continue;
}
// 1-byte sequence (0xxxxxxx)
if (byte <= 0x7f) {
result += String.fromCharCode(byte);
}
else if (byte >= 0xc0 && byte <= 0xdf) {
// 2-byte sequence (110xxxxx 10xxxxxx)
const byte2 = arr[i + 1];
skip = 1;
const codePoint = ((byte & 0x1f) << 6) | (byte2 & 0x3f);
result += String.fromCharCode(codePoint);
}
else if (byte >= 0xe0 && byte <= 0xef) {
// 3-byte sequence (1110xxxx 10xxxxxx 10xxxxxx)
const byte2 = arr[i + 1];
const byte3 = arr[i + 2];
skip = 2;
const codePoint = ((byte & 0x0f) << 12) | ((byte2 & 0x3f) << 6) | (byte3 & 0x3f);
result += String.fromCharCode(codePoint);
}
else if (byte >= 0xf0 && byte <= 0xf7) {
// 4-byte sequence (11110xxx 10xxxxxx 10xxxxxx 10xxxxxx)
const byte2 = arr[i + 1];
const byte3 = arr[i + 2];
const byte4 = arr[i + 3];
skip = 3;
const codePoint = ((byte & 0x07) << 18) |
((byte2 & 0x3f) << 12) |
((byte3 & 0x3f) << 6) |
(byte4 & 0x3f);
// Convert to UTF-16 surrogate pair
const surrogate1 = 0xd800 + ((codePoint - 0x10000) >> 10);
const surrogate2 = 0xdc00 + ((codePoint - 0x10000) & 0x3ff);
result += String.fromCharCode(surrogate1, surrogate2);
}
}
return result;
};
/**
* Encodes an array of numbers into a specified encoding ('hex' or 'utf8'). If no encoding is provided, returns the original array.
* @param {number[]} arr - The input array of numbers.
* @param {('hex' | 'utf8')} enc - The desired encoding.
* @returns {string | number[]} - The encoded message as a string (for 'hex' and 'utf8') or the original array.
*/
export const encode = (arr, enc) => {
switch (enc) {
case 'hex':
return toHex(arr);
case 'utf8':
return toUTF8(arr);
// If no encoding is provided, return the original array
default:
return arr;
}
};
/**
* Converts an array of bytes (each between 0 and 255) into a base64 encoded string.
*
* @param {number[]} byteArray - An array of numbers where each number is a byte (0-255).
* @returns {string} The base64 encoded string.
*
* @example
* const bytes = [72, 101, 108, 108, 111]; // Represents the string "Hello"
* console.log(toBase64(bytes)); // Outputs: SGVsbG8=
*/
export function toBase64(byteArray) {
const base64Chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
let result = '';
let i;
for (i = 0; i < byteArray.length; i += 3) {
const byte1 = byteArray[i];
const byte2 = i + 1 < byteArray.length ? byteArray[i + 1] : 0;
const byte3 = i + 2 < byteArray.length ? byteArray[i + 2] : 0;
const encoded1 = byte1 >> 2;
const encoded2 = ((byte1 & 0x03) << 4) | (byte2 >> 4);
const encoded3 = ((byte2 & 0x0f) << 2) | (byte3 >> 6);
const encoded4 = byte3 & 0x3f;
result += base64Chars.charAt(encoded1) + base64Chars.charAt(encoded2);
result += i + 1 < byteArray.length ? base64Chars.charAt(encoded3) : '=';
result += i + 2 < byteArray.length ? base64Chars.charAt(encoded4) : '=';
}
return result;
}
const base58chars = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz';
/**
* Converts a string from base58 to a binary array
* @param str - The string representation
* @returns The binary representation
*/
export const fromBase58 = (str) => {
if (str === '' || typeof str !== 'string') {
throw new Error(`Expected base58 string but got “${str}”`);
}
const match = str.match(/[IOl0]/gmu);
if (match !== null) {
throw new Error(`Invalid base58 character “${match.join('')}”`);
}
const lz = str.match(/^1+/gmu);
const psz = (lz !== null) ? lz[0].length : 0;
const size = ((str.length - psz) * (Math.log(58) / Math.log(256)) + 1) >>> 0;
const uint8 = new Uint8Array([
...new Uint8Array(psz),
...(str.match(/./gmu) ?? [] // ✅ Safe Fix: If null, use []
)
.map((i) => base58chars.indexOf(i))
.reduce((acc, i) => {
acc = acc.map((j) => {
const x = j * 58 + i;
i = x >> 8;
return x;
});
return acc;
}, new Uint8Array(size))
.reverse()
.filter(((lastValue) => (value) =>
// @ts-expect-error
(lastValue = lastValue || value))(false))
]);
return [...uint8];
};
/**
* Converts a binary array into a base58 string
* @param bin - The binary array to convert to base58
* @returns The base58 string representation
*/
export const toBase58 = (bin) => {
const base58Map = Array(256).fill(-1);
for (let i = 0; i < base58chars.length; ++i) {
base58Map[base58chars.charCodeAt(i)] = i;
}
const result = [];
for (const byte of bin) {
let carry = byte;
for (let j = 0; j < result.length; ++j) {
const x = (base58Map[result[j]] << 8) + carry;
result[j] = base58chars.charCodeAt(x % 58);
carry = (x / 58) | 0;
}
while (carry !== 0) {
result.push(base58chars.charCodeAt(carry % 58));
carry = (carry / 58) | 0;
}
}
for (const byte of bin) {
if (byte !== 0)
break;
else
result.push('1'.charCodeAt(0));
}
result.reverse();
return String.fromCharCode(...result);
};
/**
* Converts a binary array into a base58check string with a checksum
* @param bin - The binary array to convert to base58check
* @returns The base58check string representation
*/
export const toBase58Check = (bin, prefix = [0]) => {
let hash = hash256([...prefix, ...bin]);
hash = [...prefix, ...bin, ...hash.slice(0, 4)];
return toBase58(hash);
};
/**
* Converts a base58check string into a binary array after validating the checksum
* @param str - The base58check string to convert to binary
* @param enc - If hex, the return values will be hex strings, arrays of numbers otherwise
* @param prefixLength - The length of the prefix. Optional, defaults to 1.
* @returns The binary array representation
*/
export const fromBase58Check = (str, enc, prefixLength = 1) => {
const bin = fromBase58(str);
let prefix = bin.slice(0, prefixLength);
let data = bin.slice(prefixLength, -4);
let hash = [...prefix, ...data];
hash = hash256(hash);
bin.slice(-4).forEach((check, index) => {
if (check !== hash[index]) {
throw new Error('Invalid checksum');
}
});
if (enc === 'hex') {
prefix = toHex(prefix);
data = toHex(data);
}
return { prefix, data };
};
export class Writer {
bufs;
length;
constructor(bufs) {
this.bufs = bufs !== undefined ? bufs : [];
this.length = 0;
for (const b of this.bufs)
this.length += b.length;
}
getLength() {
return this.length;
}
toArray() {
const totalLength = this.length;
const ret = new Array(totalLength);
let offset = 0;
for (const buf of this.bufs) {
for (const value of buf) {
ret[offset++] = value;
}
}
return ret;
}
write(buf) {
this.bufs.push(buf);
this.length += buf.length;
return this;
}
writeReverse(buf) {
const buf2 = new Array(buf.length);
for (let i = 0; i < buf2.length; i++) {
buf2[i] = buf[buf.length - 1 - i];
}
this.bufs.push(buf2);
this.length += buf2.length;
return this;
}
writeUInt8(n) {
const buf = new Array(1);
buf[0] = n;
this.write(buf);
return this;
}
writeInt8(n) {
const buf = new Array(1);
buf[0] = n & 0xff;
this.write(buf);
return this;
}
writeUInt16BE(n) {
const buf = [
(n >> 8) & 0xff,
n & 0xff // low byte is just the last 8 bits
];
this.bufs.push(buf);
this.length += 2;
return this;
}
writeInt16BE(n) {
return this.writeUInt16BE(n & 0xffff); // Mask with 0xFFFF to get the lower 16 bits
}
writeUInt16LE(n) {
const buf = [
n & 0xff,
(n >> 8) & 0xff // shift right 8 bits to get the high byte
];
this.bufs.push(buf);
this.length += 2;
return this;
}
writeInt16LE(n) {
return this.writeUInt16LE(n & 0xffff); // Mask with 0xFFFF to get the lower 16 bits
}
writeUInt32BE(n) {
const buf = [
(n >> 24) & 0xff,
(n >> 16) & 0xff,
(n >> 8) & 0xff,
n & 0xff // lowest byte
];
this.bufs.push(buf);
this.length += 4;
return this;
}
writeInt32BE(n) {
return this.writeUInt32BE(n >>> 0); // Using unsigned right shift to handle negative numbers
}
writeUInt32LE(n) {
const buf = [
n & 0xff,
(n >> 8) & 0xff,
(n >> 16) & 0xff,
(n >> 24) & 0xff // highest byte
];
this.bufs.push(buf);
this.length += 4;
return this;
}
writeInt32LE(n) {
return this.writeUInt32LE(n >>> 0); // Using unsigned right shift to handle negative numbers
}
writeUInt64BEBn(bn) {
const buf = bn.toArray('be', 8);
this.write(buf);
return this;
}
writeUInt64LEBn(bn) {
const buf = bn.toArray('be', 8);
this.writeReverse(buf);
return this;
}
writeUInt64LE(n) {
const buf = new BigNumber(n).toArray('be', 8);
this.writeReverse(buf);
return this;
}
writeVarIntNum(n) {
const buf = Writer.varIntNum(n);
this.write(buf);
return this;
}
writeVarIntBn(bn) {
const buf = Writer.varIntBn(bn);
this.write(buf);
return this;
}
static varIntNum(n) {
let buf;
if (n < 0) {
return this.varIntBn(new BigNumber(n));
}
if (n < 253) {
buf = [n]; // 1 byte
}
else if (n < 0x10000) {
// 253 followed by the number in little-endian format
buf = [
253,
n & 0xff,
(n >> 8) & 0xff // high byte
];
}
else if (n < 0x100000000) {
// 254 followed by the number in little-endian format
buf = [
254,
n & 0xff,
(n >> 8) & 0xff,
(n >> 16) & 0xff,
(n >> 24) & 0xff
];
}
else {
// 255 followed by the number in little-endian format
// Since JavaScript bitwise operations work on 32 bits, we need to handle 64-bit numbers in two parts
const low = n & 0xffffffff;
const high = Math.floor(n / 0x100000000) & 0xffffffff;
buf = [
255,
low & 0xff,
(low >> 8) & 0xff,
(low >> 16) & 0xff,
(low >> 24) & 0xff,
high & 0xff,
(high >> 8) & 0xff,
(high >> 16) & 0xff,
(high >> 24) & 0xff
];
}
return buf;
}
static varIntBn(bn) {
let buf;
if (bn.isNeg()) {
bn = bn.add(OverflowUint64); // Adjust for negative numbers
}
if (bn.ltn(253)) {
const n = bn.toNumber();
// No need for bitwise operation as the value is within a byte's range
buf = [n];
}
else if (bn.ltn(0x10000)) {
const n = bn.toNumber();
// Value fits in a uint16
buf = [253, n & 0xff, (n >> 8) & 0xff];
}
else if (bn.lt(new BigNumber(0x100000000))) {
const n = bn.toNumber();
// Value fits in a uint32
buf = [
254,
n & 0xff,
(n >> 8) & 0xff,
(n >> 16) & 0xff,
(n >> 24) & 0xff
];
}
else {
const bw = new Writer();
bw.writeUInt8(255);
bw.writeUInt64LEBn(bn);
buf = bw.toArray();
}
return buf;
}
}
export class Reader {
bin;
pos;
length;
constructor(bin = [], pos = 0) {
this.bin = bin;
this.pos = pos;
this.length = bin.length;
}
eof() {
return this.pos >= this.length;
}
read(len = this.length) {
const start = this.pos;
const end = this.pos + len;
this.pos = end;
return this.bin.slice(start, end);
}
readReverse(len = this.length) {
const buf2 = new Array(len);
for (let i = 0; i < len; i++) {
buf2[i] = this.bin[this.pos + len - 1 - i];
}
this.pos += len;
return buf2;
}
readUInt8() {
const val = this.bin[this.pos];
this.pos += 1;
return val;
}
readInt8() {
const val = this.bin[this.pos];
this.pos += 1;
// If the sign bit is set, convert to negative value
return (val & 0x80) !== 0 ? val - 0x100 : val;
}
readUInt16BE() {
const val = (this.bin[this.pos] << 8) | this.bin[this.pos + 1];
this.pos += 2;
return val;
}
readInt16BE() {
const val = this.readUInt16BE();
// If the sign bit is set, convert to negative value
return (val & 0x8000) !== 0 ? val - 0x10000 : val;
}
readUInt16LE() {
const val = this.bin[this.pos] | (this.bin[this.pos + 1] << 8);
this.pos += 2;
return val;
}
readInt16LE() {
const val = this.readUInt16LE();
// If the sign bit is set, convert to negative value
const x = (val & 0x8000) !== 0 ? val - 0x10000 : val;
return x;
}
readUInt32BE() {
const val = this.bin[this.pos] * 0x1000000 + // Shift the first byte by 24 bits
((this.bin[this.pos + 1] << 16) | // Shift the second byte by 16 bits
(this.bin[this.pos + 2] << 8) | // Shift the third byte by 8 bits
this.bin[this.pos + 3]); // The fourth byte
this.pos += 4;
return val;
}
readInt32BE() {
const val = this.readUInt32BE();
// If the sign bit is set, convert to negative value
return (val & 0x80000000) !== 0 ? val - 0x100000000 : val;
}
readUInt32LE() {
const val = (this.bin[this.pos] |
(this.bin[this.pos + 1] << 8) |
(this.bin[this.pos + 2] << 16) |
(this.bin[this.pos + 3] << 24)) >>>
0;
this.pos += 4;
return val;
}
readInt32LE() {
const val = this.readUInt32LE();
// Explicitly check if the sign bit is set and then convert to a negative value
return (val & 0x80000000) !== 0 ? val - 0x100000000 : val;
}
readUInt64BEBn() {
const bin = this.bin.slice(this.pos, this.pos + 8);
const bn = new BigNumber(bin);
this.pos = this.pos + 8;
return bn;
}
readUInt64LEBn() {
const bin = this.readReverse(8);
const bn = new BigNumber(bin);
return bn;
}
readInt64LEBn() {
const bin = this.readReverse(8);
let bn = new BigNumber(bin);
if (bn.gte(OverflowInt64)) {
bn = bn.sub(OverflowUint64); // Adjust for negative numbers
}
return bn;
}
readVarIntNum(signed = true) {
const first = this.readUInt8();
let bn;
switch (first) {
case 0xfd:
return this.readUInt16LE();
case 0xfe:
return this.readUInt32LE();
case 0xff:
bn = signed ? this.readInt64LEBn() : this.readUInt64LEBn();
if (bn.lte(new BigNumber(2).pow(new BigNumber(53)))) {
return bn.toNumber();
}
else {
throw new Error('number too large to retain precision - use readVarIntBn');
}
default:
return first;
}
}
readVarInt() {
const first = this.bin[this.pos];
switch (first) {
case 0xfd:
return this.read(1 + 2);
case 0xfe:
return this.read(1 + 4);
case 0xff:
return this.read(1 + 8);
default:
return this.read(1);
}
}
readVarIntBn() {
const first = this.readUInt8();
switch (first) {
case 0xfd:
return new BigNumber(this.readUInt16LE());
case 0xfe:
return new BigNumber(this.readUInt32LE());
case 0xff:
return this.readUInt64LEBn();
default:
return new BigNumber(first);
}
}
}
export const minimallyEncode = (buf) => {
if (buf.length === 0) {
return buf;
}
// If the last byte is not 0x00 or 0x80, we are minimally encoded.
const last = buf[buf.length - 1];
if ((last & 0x7f) !== 0) {
return buf;
}
// If the script is one byte long, then we have a zero, which encodes as an
// empty array.
if (buf.length === 1) {
return [];
}
// If the next byte has it sign bit set, then we are minimaly encoded.
if ((buf[buf.length - 2] & 0x80) !== 0) {
return buf;
}
// We are not minimally encoded, we need to figure out how much to trim.
for (let i = buf.length - 1; i > 0; i--) {
// We found a non zero byte, time to encode.
if (buf[i - 1] !== 0) {
if ((buf[i - 1] & 0x80) !== 0) {
// We found a byte with it sign bit set so we need one more
// byte.
buf[i] = last;
return buf.slice(0, i + 1);
}
else {
// the sign bit is clear, we can use it.
buf[i - 1] |= last;
return buf.slice(0, i);
}
}
}
// If we found the whole thing is zeros, then we have a zero.
return [];
};
const OverflowInt64 = new BigNumber(2).pow(new BigNumber(63));
const OverflowUint64 = new BigNumber(2).pow(new BigNumber(64));
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