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utils/address.js

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+
+var BN = require('bn.js');
+
+var convert = require('./convert');
+var throwError = require('./throw-error');
+var keccak256 = require('./keccak256');
+
+function getChecksumAddress(address) {
+    if (typeof(address) !== 'string' || !address.match(/^0x[0-9A-Fa-f]{40}$/)) {
+        throwError('invalid address', {input: address});
+    }
+
+    address = address.toLowerCase();
+
+    var hashed = address.substring(2).split('');
+    for (var i = 0; i < hashed.length; i++) {
+        hashed[i] = hashed[i].charCodeAt(0);
+    }
+    hashed = convert.arrayify(keccak256(hashed));
+
+    address = address.substring(2).split('');
+    for (var i = 0; i < 40; i += 2) {
+        if ((hashed[i >> 1] >> 4) >= 8) {
+            address[i] = address[i].toUpperCase();
+        }
+        if ((hashed[i >> 1] & 0x0f) >= 8) {
+            address[i + 1] = address[i + 1].toUpperCase();
+        }
+    }
+
+    return '0x' + address.join('');
+}
+
+// Shims for environments that are missing some required constants and functions
+var MAX_SAFE_INTEGER = 0x1fffffffffffff;
+
+function log10(x) {
+    if (Math.log10) { return Math.log10(x); }
+    return Math.log(x) / Math.LN10;
+}
+
+
+// See: https://en.wikipedia.org/wiki/International_Bank_Account_Number
+var ibanChecksum = (function() {
+
+    // Create lookup table
+    var ibanLookup = {};
+    for (var i = 0; i < 10; i++) { ibanLookup[String(i)] = String(i); }
+    for (var i = 0; i < 26; i++) { ibanLookup[String.fromCharCode(65 + i)] = String(10 + i); }
+
+    // How many decimal digits can we process? (for 64-bit float, this is 15)
+    var safeDigits = Math.floor(log10(MAX_SAFE_INTEGER));
+
+    return function(address) {
+        address = address.toUpperCase();
+        address = address.substring(4) + address.substring(0, 2) + '00';
+
+        var expanded = address.split('');
+        for (var i = 0; i < expanded.length; i++) {
+            expanded[i] = ibanLookup[expanded[i]];
+        }
+        expanded = expanded.join('');
+
+        // Javascript can handle integers safely up to 15 (decimal) digits
+        while (expanded.length >= safeDigits){
+            var block = expanded.substring(0, safeDigits);
+            expanded = parseInt(block, 10) % 97 + expanded.substring(block.length);
+        }
+
+        var checksum = String(98 - (parseInt(expanded, 10) % 97));
+        while (checksum.length < 2) { checksum = '0' + checksum; }
+
+        return checksum;
+    };
+})();
+
+function getAddress(address, icapFormat) {
+    var result = null;
+
+    if (typeof(address) !== 'string') {
+        throwError('invalid address', {input: address});
+    }
+
+    if (address.match(/^(0x)?[0-9a-fA-F]{40}$/)) {
+
+        // Missing the 0x prefix
+        if (address.substring(0, 2) !== '0x') { address = '0x' + address; }
+
+        result = getChecksumAddress(address);
+
+        // It is a checksummed address with a bad checksum
+        if (address.match(/([A-F].*[a-f])|([a-f].*[A-F])/) && result !== address) {
+            throwError('invalid address checksum', { input: address, expected: result });
+        }
+
+    // Maybe ICAP? (we only support direct mode)
+    } else if (address.match(/^XE[0-9]{2}[0-9A-Za-z]{30,31}$/)) {
+
+        // It is an ICAP address with a bad checksum
+        if (address.substring(2, 4) !== ibanChecksum(address)) {
+            throwError('invalid address icap checksum', { input: address });
+        }
+
+        result = (new BN(address.substring(4), 36)).toString(16);
+        while (result.length < 40) { result = '0' + result; }
+        result = getChecksumAddress('0x' + result);
+
+    } else {
+        throwError('invalid address', { input: address });
+    }
+
+    if (icapFormat) {
+        var base36 = (new BN(result.substring(2), 16)).toString(36).toUpperCase();
+        while (base36.length < 30) { base36 = '0' + base36; }
+        return 'XE' + ibanChecksum('XE00' + base36) + base36;
+    }
+
+    return result;
+}
+
+
+module.exports = {
+    getAddress: getAddress,
+}