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190 lines
6.5 KiB
190 lines
6.5 KiB
var cnBase58 = (function () {
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var b58 = {};
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var alphabet_str = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
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var alphabet = [];
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for (var i = 0; i < alphabet_str.length; i++) {
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alphabet.push(alphabet_str.charCodeAt(i));
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}
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var encoded_block_sizes = [0, 2, 3, 5, 6, 7, 9, 10, 11];
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var alphabet_size = alphabet.length;
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var full_block_size = 8;
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var full_encoded_block_size = 11;
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var UINT64_MAX = new JSBigInt(2).pow(64);
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function hextobin(hex) {
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if (hex.length % 2 !== 0) throw "Hex string has invalid length!";
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var res = new Uint8Array(hex.length / 2);
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for (var i = 0; i < hex.length / 2; ++i) {
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res[i] = parseInt(hex.slice(i * 2, i * 2 + 2), 16);
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}
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return res;
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}
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function bintohex(bin) {
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var out = [];
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for (var i = 0; i < bin.length; ++i) {
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out.push(("0" + bin[i].toString(16)).slice(-2));
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}
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return out.join("");
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}
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function strtobin(str) {
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var res = new Uint8Array(str.length);
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for (var i = 0; i < str.length; i++) {
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res[i] = str.charCodeAt(i);
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}
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return res;
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}
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function bintostr(bin) {
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var out = [];
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for (var i = 0; i < bin.length; i++) {
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out.push(String.fromCharCode(bin[i]));
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}
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return out.join("");
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}
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function uint8_be_to_64(data) {
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if (data.length < 1 || data.length > 8) {
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throw "Invalid input length";
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}
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var res = JSBigInt.ZERO;
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var twopow8 = new JSBigInt(2).pow(8);
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var i = 0;
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switch (9 - data.length) {
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case 1:
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res = res.add(data[i++]);
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case 2:
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res = res.multiply(twopow8).add(data[i++]);
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case 3:
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res = res.multiply(twopow8).add(data[i++]);
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case 4:
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res = res.multiply(twopow8).add(data[i++]);
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case 5:
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res = res.multiply(twopow8).add(data[i++]);
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case 6:
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res = res.multiply(twopow8).add(data[i++]);
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case 7:
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res = res.multiply(twopow8).add(data[i++]);
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case 8:
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res = res.multiply(twopow8).add(data[i++]);
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break;
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default:
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throw "Impossible condition";
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}
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return res;
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}
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function uint64_to_8be(num, size) {
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var res = new Uint8Array(size);
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if (size < 1 || size > 8) {
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throw "Invalid input length";
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}
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var twopow8 = new JSBigInt(2).pow(8);
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for (var i = size - 1; i >= 0; i--) {
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res[i] = num.remainder(twopow8).toJSValue();
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num = num.divide(twopow8);
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}
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return res;
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}
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b58.encode_block = function (data, buf, index) {
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if (data.length < 1 || data.length > full_encoded_block_size) {
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throw "Invalid block length: " + data.length;
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}
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var num = uint8_be_to_64(data);
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var i = encoded_block_sizes[data.length] - 1;
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// while num > 0
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while (num.compare(0) === 1) {
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var div = num.divRem(alphabet_size);
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// remainder = num % alphabet_size
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var remainder = div[1];
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// num = num / alphabet_size
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num = div[0];
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buf[index + i] = alphabet[remainder.toJSValue()];
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i--;
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}
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return buf;
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};
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b58.encode = function (hex) {
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var data = hextobin(hex);
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if (data.length === 0) {
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return "";
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}
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var full_block_count = Math.floor(data.length / full_block_size);
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var last_block_size = data.length % full_block_size;
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var res_size = full_block_count * full_encoded_block_size + encoded_block_sizes[last_block_size];
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var res = new Uint8Array(res_size);
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var i;
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for (i = 0; i < res_size; ++i) {
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res[i] = alphabet[0];
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}
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for (i = 0; i < full_block_count; i++) {
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res = b58.encode_block(data.subarray(i * full_block_size, i * full_block_size + full_block_size), res, i * full_encoded_block_size);
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}
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if (last_block_size > 0) {
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res = b58.encode_block(data.subarray(full_block_count * full_block_size, full_block_count * full_block_size + last_block_size), res, full_block_count * full_encoded_block_size)
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}
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return bintostr(res);
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};
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b58.decode_block = function (data, buf, index) {
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if (data.length < 1 || data.length > full_encoded_block_size) {
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throw "Invalid block length: " + data.length;
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}
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var res_size = encoded_block_sizes.indexOf(data.length);
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if (res_size <= 0) {
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throw "Invalid block size";
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}
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var res_num = new JSBigInt(0);
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var order = new JSBigInt(1);
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for (var i = data.length - 1; i >= 0; i--) {
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var digit = alphabet.indexOf(data[i]);
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if (digit < 0) {
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throw "Invalid symbol";
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}
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var product = order.multiply(digit).add(res_num);
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// if product > UINT64_MAX
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if (product.compare(UINT64_MAX) === 1) {
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throw "Overflow";
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}
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res_num = product;
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order = order.multiply(alphabet_size);
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}
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if (res_size < full_block_size && (new JSBigInt(2).pow(8 * res_size).compare(res_num) <= 0)) {
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throw "Overflow 2";
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}
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buf.set(uint64_to_8be(res_num, res_size), index);
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return buf;
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};
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b58.decode = function (enc) {
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enc = strtobin(enc);
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if (enc.length === 0) {
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return "";
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}
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var full_block_count = Math.floor(enc.length / full_encoded_block_size);
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var last_block_size = enc.length % full_encoded_block_size;
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var last_block_decoded_size = encoded_block_sizes.indexOf(last_block_size);
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if (last_block_decoded_size < 0) {
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throw "Invalid encoded length";
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}
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var data_size = full_block_count * full_block_size + last_block_decoded_size;
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var data = new Uint8Array(data_size);
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for (var i = 0; i < full_block_count; i++) {
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data = b58.decode_block(enc.subarray(i * full_encoded_block_size, i * full_encoded_block_size + full_encoded_block_size), data, i * full_block_size);
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}
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if (last_block_size > 0) {
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data = b58.decode_block(enc.subarray(full_block_count * full_encoded_block_size, full_block_count * full_encoded_block_size + last_block_size), data, full_block_count * full_block_size);
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}
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return bintohex(data);
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};
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return b58;
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})(); |