merkle-btree
Version:
Content-addressed b-tree
1,695 lines (1,449 loc) • 80.1 kB
JavaScript
(function (global, factory) {
typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory(require('crypto')) :
typeof define === 'function' && define.amd ? define(['crypto'], factory) :
(global.merkleBtree = factory(global.crypto));
}(this, (function (crypto) { 'use strict';
function _classCallCheck$1(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
function lt(a, b) {
return a < b;
}
function lte(a, b) {
return a <= b;
}
function gt(a, b) {
return a > b;
}
function gte(a, b) {
return a >= b;
}
function any() {
return true;
}
function beginsWith(str, begin) {
return str.substring(0, begin.length) === begin;
}
var KeyElement = function KeyElement(key, value, targetHash) {
_classCallCheck$1(this, KeyElement);
this.key = key;
this.value = value;
this.targetHash = targetHash;
};
var TreeNode = function () {
function TreeNode(leftChildHash) {
var keys = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : [];
var hash = arguments[2];
_classCallCheck$1(this, TreeNode);
this.hash = hash;
this.leftChildHash = leftChildHash;
this.keys = keys;
var zero = new KeyElement("", null, leftChildHash);
if (!this.keys.length || this.keys[0].key.length) {
this.keys.unshift(zero);
}
}
TreeNode.prototype.get = function get(key, storage) {
var nextKey = this.keys[0];
for (var _iterator = this.keys, _isArray = Array.isArray(_iterator), _i = 0, _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
var _ref;
if (_isArray) {
if (_i >= _iterator.length) break;
_ref = _iterator[_i++];
} else {
_i = _iterator.next();
if (_i.done) break;
_ref = _i.value;
}
var k = _ref;
if (key < k.key) {
break;
}
nextKey = k;
}
if (nextKey.targetHash) {
return storage.get(nextKey.targetHash).then(function (serialized) {
return TreeNode.deserialize(serialized, nextKey.targetHash).get(key, storage);
});
}
if (nextKey.key === key) {
return Promise.resolve(nextKey.value);
}
return Promise.resolve(null); // not found
};
TreeNode.prototype.searchText = function searchText(query) {
var limit = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 100;
var cursor = arguments[2];
var reverse = arguments[3];
var storage = arguments[4];
var lowerBound = cursor || query;
var upperBound = undefined;
var includeLowerBound = !cursor;
var includeUpperBound = true;
if (reverse) {
lowerBound = query;
upperBound = cursor || undefined;
includeLowerBound = true;
includeUpperBound = !cursor;
}
return this.searchRange(lowerBound, upperBound, query, limit, includeLowerBound, includeUpperBound, reverse, storage);
};
TreeNode.prototype.searchRange = function searchRange(lowerBound, upperBound, queryText, limit) {
var includeLowerBound = arguments.length > 4 && arguments[4] !== undefined ? arguments[4] : true;
var includeUpperBound = arguments.length > 5 && arguments[5] !== undefined ? arguments[5] : true;
var reverse = arguments[6];
var storage = arguments[7];
var matches = [];
var _this = this;
var lowerBoundCheck = void 0,
upperBoundCheck = void 0;
if (lowerBound) {
lowerBoundCheck = includeLowerBound ? gte : gt;
} else {
lowerBoundCheck = any;
}
if (upperBound) {
upperBoundCheck = includeUpperBound ? lte : lt;
} else {
upperBoundCheck = any;
}
function iterate(i) {
if (i < 0 || i >= _this.keys.length) {
return Promise.resolve(matches);
}
if (limit && matches.length >= limit) {
matches = matches.slice(0, limit + 1);
return Promise.resolve(matches);
}
var next = reverse ? i - 1 : i + 1;
var k = _this.keys[i];
if (next >= 0 && next < _this.keys.length) {
if (!reverse && lowerBound >= _this.keys[next].key) {
// search only nodes whose keys are in the query range
return iterate(next);
}
if (reverse && upperBound < _this.keys[next].key) {
// search only nodes whose keys are in the query range
return iterate(next);
}
}
// return if search range upper / lower bound was passed
if (reverse && i + 1 < _this.keys.length && !lowerBoundCheck(_this.keys[i + 1].key, lowerBound)) {
return Promise.resolve(matches);
}
if (!reverse && !upperBoundCheck(k.key, upperBound)) {
return Promise.resolve(matches);
}
if (k.targetHash) {
// branch node
return storage.get(k.targetHash).then(function (serialized) {
var newLimit = limit ? limit - matches.length : undefined;
return TreeNode.deserialize(serialized, k.targetHash).searchRange(lowerBound, upperBound, queryText, newLimit, includeLowerBound, includeUpperBound, reverse, storage);
}).then(function (m) {
if (m) {
if (matches.length && !m.length) {
return Promise.resolve(matches); // matches were previously found but now we're out of range
}
if (queryText && !m.length) {
// text search yielded no results where they could have been
return Promise.resolve(matches);
}
Array.prototype.push.apply(matches, m);
}
return iterate(next);
});
}
// leaf node
if (k.key.length && k.value) {
if (queryText && matches.length && !beginsWith(k.key, queryText)) {
return Promise.resolve(matches); // matches were previously found but now we're out of range
}
if (lowerBoundCheck(k.key, lowerBound) && upperBoundCheck(k.key, upperBound)) {
// leaf node with matching key
if (!queryText || beginsWith(k.key, queryText)) {
matches.push({ key: k.key, value: k.value });
}
}
}
return iterate(next);
}
return iterate(reverse ? this.keys.length - 1 : 0);
};
TreeNode.prototype.save = function save(storage) {
var _this2 = this;
return storage.put(this.serialize()).then(function (hash) {
_this2.hash = hash;
return _this2.hash;
});
};
TreeNode.prototype._getLeafInsertIndex = function _getLeafInsertIndex(key) {
var _getNextSmallestIndex2 = this._getNextSmallestIndex(key),
index = _getNextSmallestIndex2.index,
exists = _getNextSmallestIndex2.exists;
var leafInsertIndex = index + 1;
if (key > this.keys[this.keys.length - 1].key) {
leafInsertIndex = this.keys.length;
}
return { leafInsertIndex: leafInsertIndex, exists: exists };
};
TreeNode.prototype._getNextSmallestIndex = function _getNextSmallestIndex(key) {
var index = 0,
exists = void 0;
for (var i = 1; i < this.keys.length; i++) {
if (key === this.keys[i].key) {
exists = true;
break;
}
if (key < this.keys[i].key) {
break;
}
index = i;
}
return { index: index, exists: exists };
};
TreeNode.prototype._splitNode = function _splitNode(storage) {
var medianIndex = Math.floor(this.keys.length / 2);
var median = this.keys[medianIndex];
var leftChild = new TreeNode(null, this.keys.slice(0, medianIndex));
var putLeftChild = storage.put(leftChild.serialize());
var rightSet = this.keys.slice(medianIndex, this.keys.length);
if (this.keys[0].targetHash) {
// branch node
rightSet.shift();
}
var rightChild = new TreeNode(this.keys[medianIndex].targetHash, rightSet);
var putRightChild = storage.put(rightChild.serialize());
return Promise.all([putLeftChild, putRightChild, this._removeIfNotEmpty(storage)]).then(function (_ref2) {
var leftChildHash = _ref2[0],
rightChildHash = _ref2[1];
var rightChildElement = new KeyElement(median.key, null, rightChildHash);
return new TreeNode(leftChildHash, [rightChildElement]);
});
};
TreeNode.prototype._removeIfNotEmpty = function _removeIfNotEmpty(storage) {
// TODO: this breaks stuff when multiple trees use the same storage
if (this.hash && this.keys.length > 0) {
return storage.remove(this.hash);
}
return Promise.resolve();
};
TreeNode.prototype._saveToLeafNode = function _saveToLeafNode(key, value, storage, maxChildren) {
var _this3 = this;
var keyElement = new KeyElement(key, value, null);
var _getLeafInsertIndex2 = this._getLeafInsertIndex(key),
leafInsertIndex = _getLeafInsertIndex2.leafInsertIndex,
exists = _getLeafInsertIndex2.exists;
if (exists) {
this.keys[leafInsertIndex] = keyElement;
return this._removeIfNotEmpty(storage).then(function () {
return storage.put(_this3.serialize());
}).then(function (hash) {
return new TreeNode(_this3.leftChildHash, _this3.keys, hash);
});
}
this.keys.splice(leafInsertIndex, 0, keyElement);
if (this.keys.length < maxChildren) {
return this._removeIfNotEmpty(storage).then(function () {
return storage.put(_this3.serialize());
}).then(function (hash) {
return new TreeNode(_this3.leftChildHash, _this3.keys, hash);
});
}
return this._splitNode(storage);
};
TreeNode.prototype._saveToBranchNode = function _saveToBranchNode(key, value, storage, maxChildren) {
var _this4 = this;
var _getNextSmallestIndex3 = this._getNextSmallestIndex(key),
index = _getNextSmallestIndex3.index;
var nextSmallest = this.keys[index];
return storage.get(nextSmallest.targetHash).then(function (serialized) {
return TreeNode.deserialize(serialized, nextSmallest.targetHash).put(key, value, storage, maxChildren);
}).then(function (modifiedChild) {
if (!modifiedChild.hash) {
// we split a child and need to add the median to our keys
_this4.keys[index] = new KeyElement(nextSmallest.key, null, modifiedChild.keys[0].targetHash);
_this4.keys.splice(index + 1, 0, modifiedChild.keys[modifiedChild.keys.length - 1]);
if (_this4.keys.length < maxChildren) {
return _this4._removeIfNotEmpty(storage).then(function () {
return storage.put(_this4.serialize());
}).then(function (hash) {
return new TreeNode(_this4.leftChildHash, _this4.keys, hash);
});
}
return _this4._splitNode(storage);
}
// The child element was not split
_this4.keys[index] = new KeyElement(_this4.keys[index].key, null, modifiedChild.hash);
storage.remove(_this4.hash);
return _this4._removeIfNotEmpty(storage).then(function () {
storage.put(_this4.serialize());
}).then(function (hash) {
return new TreeNode(_this4.leftChildHash, _this4.keys, hash);
});
});
};
TreeNode.prototype.put = function put(key, value, storage, maxChildren) {
if (!this.keys[0].targetHash) {
return this._saveToLeafNode(key, value, storage, maxChildren);
}
return this._saveToBranchNode(key, value, storage, maxChildren);
};
TreeNode.prototype.delete = function _delete(key, storage) {
var _this5 = this;
var nextKey = this.keys[0];
var i = void 0;
for (i = 0; i < this.keys.length; i++) {
if (key < this.keys[i].key) {
i = Math.max(i - 1, 0);
break;
}
nextKey = this.keys[i];
}
var q = Promise.resolve();
if (nextKey.targetHash) {
q = q.then(function () {
return storage.get(nextKey.targetHash).then(function (serialized) {
return TreeNode.deserialize(serialized, nextKey.targetHash).delete(key, storage);
}).then(function (newNode) {
var oldHash = nextKey.targetHash;
nextKey.targetHash = newNode.hash;
return storage.remove(oldHash);
});
});
} else if (nextKey.key === key) {
this.keys.splice(i, 1);
}
return q.then(function () {
return storage.put(_this5.serialize());
}).then(function (hash) {
return new TreeNode(_this5.leftChildHash, _this5.keys, hash);
});
};
TreeNode.prototype.size = function size(storage) {
return this.keys.reduce(function (promise, key) {
return promise.then(function (size) {
if (key.targetHash) {
return storage.get(key.targetHash).then(function (serialized) {
return TreeNode.deserialize(serialized).size(storage);
}).then(function (childSize) {
return childSize + size;
});
}
return size;
});
}, Promise.resolve(this.keys.length));
};
TreeNode.prototype.smallestKey = function smallestKey() {
if (this.keys.length) {
return this.keys[0];
}
return null;
};
TreeNode.prototype.smallestNonZeroKey = function smallestNonZeroKey() {
if (this.keys.length > 1) {
return this.keys[1];
}
return null;
};
TreeNode.prototype.rebalance = function rebalance() {};
TreeNode.prototype.print = function print(storage) {
var lvl = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 0;
var str = "node: " + this.hash + "\n";
var indentation = "";
for (var i = 0; i <= lvl; i++) {
indentation += "- ";
}
this.keys.forEach(function (key) {
str += indentation;
str += "key: " + key.key;
if (key.targetHash) {
str += " link: " + key.targetHash;
}
if (key.value) {
str += "\n" + indentation + " value: " + JSON.stringify(key.value);
}
str += "\n";
});
this.keys.forEach(function (key) {
if (key.targetHash) {
storage.get(key.targetHash).then(function (serialized) {
var child = TreeNode.deserialize(serialized, key.targetHash);
str += "\n";
str += indentation;
str += child.print(storage, lvl + 1);
});
}
});
return str;
};
TreeNode.prototype.serialize = function serialize() {
return JSON.stringify({ leftChildHash: this.leftChildHash, keys: this.keys });
};
TreeNode.prototype.toSortedList = function toSortedList(storage) {
var list = [];
var _this = this;
function getNextVal(i) {
if (i >= _this.keys.length) {
return Promise.resolve(list);
}
if (_this.keys[i].targetHash) {
return storage.get(_this.keys[i].targetHash).then(function (serialized) {
return TreeNode.deserialize(serialized, _this.keys[i].targetHash).toSortedList();
}).then(function (children) {
list = list.concat(children);
return getNextVal(i + 1);
});
} else if (_this.keys[i].key.length) {
list.push(_this.keys[i]);
}
return getNextVal(i + 1);
}
return getNextVal(0);
};
TreeNode.deserialize = function deserialize(data, hash) {
data = JSON.parse(data);
return new TreeNode(data.leftChildHash, data.keys, hash);
};
/*
Create a tree from a [{key,value,targetHash}, ...] list sorted in ascending order by k.
targetHash must be null for leaf nodes.
*/
TreeNode.fromSortedList = function fromSortedList(list, maxChildren, storage) {
function addNextParentNode(parentNodeList) {
if (list.length) {
var keys = list.splice(0, maxChildren);
return storage.put(new TreeNode(keys[0].targetHash, keys).serialize()).then(function (res) {
parentNodeList.push({ key: keys[1].key, targetHash: res, value: null });
return addNextParentNode(parentNodeList);
});
}
if (parentNodeList.length && parentNodeList[0].targetHash) {
parentNodeList[0].key = "";
}
return TreeNode.fromSortedList(parentNodeList, maxChildren, storage);
}
if (list.length > maxChildren) {
return addNextParentNode([]);
}
var targetHash = list.length ? list[0].targetHash : null;
var node = new TreeNode(targetHash, list);
return storage.put(node.serialize()).then(function (hash) {
node.hash = hash;
return node;
});
};
return TreeNode;
}();
function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
var MerkleBTree = function () {
function MerkleBTree(storage) {
var maxChildren = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 10;
var rootNode = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : new TreeNode();
_classCallCheck(this, MerkleBTree);
this.rootNode = rootNode;
this.storage = storage;
this.maxChildren = Math.max(maxChildren, 2);
}
MerkleBTree.prototype.get = function get(key) {
return this.rootNode.get(key, this.storage);
};
MerkleBTree.prototype.searchText = function searchText(query, limit, cursor) {
var reverse = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : false;
return this.rootNode.searchText(query, limit, cursor, reverse, this.storage);
};
MerkleBTree.prototype.searchRange = function searchRange(lowerBound, upperBound, limit) {
var includeLowerBound = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : true;
var includeUpperBound = arguments.length > 4 && arguments[4] !== undefined ? arguments[4] : true;
var reverse = arguments.length > 5 && arguments[5] !== undefined ? arguments[5] : false;
return this.rootNode.searchRange(lowerBound, upperBound, false, limit, includeLowerBound, includeUpperBound, reverse, this.storage);
};
MerkleBTree.prototype.put = function put(key, value) {
var _this = this;
return this.rootNode.put(key, value, this.storage, this.maxChildren).then(function (newRoot) {
_this.rootNode = newRoot;
return _this.rootNode.hash;
});
};
MerkleBTree.prototype.delete = function _delete(key) {
var _this2 = this;
return this.rootNode.delete(key, this.storage, this.maxChildren).then(function (newRoot) {
_this2.rootNode = newRoot;
return _this2.rootNode.hash;
});
};
MerkleBTree.prototype.print = function print() {
return this.rootNode.print(this.storage);
};
/* Return number of keys stored in tree */
MerkleBTree.prototype.size = function size() {
return this.rootNode.size(this.storage);
};
MerkleBTree.prototype.toSortedList = function toSortedList() {
return this.rootNode.toSortedList(this.storage);
};
MerkleBTree.prototype.save = function save() {
return this.rootNode.save(this.storage);
};
MerkleBTree.getByHash = function getByHash(hash, storage, maxChildren) {
return storage.get(hash).then(function (data) {
var rootNode = TreeNode.deserialize(data);
return new MerkleBTree(storage, maxChildren, rootNode);
});
};
MerkleBTree.fromSortedList = function fromSortedList(list, maxChildren, storage) {
return TreeNode.fromSortedList(list, maxChildren, storage).then(function (rootNode) {
return new MerkleBTree(storage, maxChildren, rootNode);
});
};
return MerkleBTree;
}();
var global$1 = typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {};
var lookup = [];
var revLookup = [];
var Arr = typeof Uint8Array !== 'undefined' ? Uint8Array : Array;
var inited = false;
function init() {
inited = true;
var code = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
for (var i = 0, len = code.length; i < len; ++i) {
lookup[i] = code[i];
revLookup[code.charCodeAt(i)] = i;
}
revLookup['-'.charCodeAt(0)] = 62;
revLookup['_'.charCodeAt(0)] = 63;
}
function toByteArray(b64) {
if (!inited) {
init();
}
var i, j, l, tmp, placeHolders, arr;
var len = b64.length;
if (len % 4 > 0) {
throw new Error('Invalid string. Length must be a multiple of 4');
}
// the number of equal signs (place holders)
// if there are two placeholders, than the two characters before it
// represent one byte
// if there is only one, then the three characters before it represent 2 bytes
// this is just a cheap hack to not do indexOf twice
placeHolders = b64[len - 2] === '=' ? 2 : b64[len - 1] === '=' ? 1 : 0;
// base64 is 4/3 + up to two characters of the original data
arr = new Arr(len * 3 / 4 - placeHolders);
// if there are placeholders, only get up to the last complete 4 chars
l = placeHolders > 0 ? len - 4 : len;
var L = 0;
for (i = 0, j = 0; i < l; i += 4, j += 3) {
tmp = revLookup[b64.charCodeAt(i)] << 18 | revLookup[b64.charCodeAt(i + 1)] << 12 | revLookup[b64.charCodeAt(i + 2)] << 6 | revLookup[b64.charCodeAt(i + 3)];
arr[L++] = tmp >> 16 & 0xFF;
arr[L++] = tmp >> 8 & 0xFF;
arr[L++] = tmp & 0xFF;
}
if (placeHolders === 2) {
tmp = revLookup[b64.charCodeAt(i)] << 2 | revLookup[b64.charCodeAt(i + 1)] >> 4;
arr[L++] = tmp & 0xFF;
} else if (placeHolders === 1) {
tmp = revLookup[b64.charCodeAt(i)] << 10 | revLookup[b64.charCodeAt(i + 1)] << 4 | revLookup[b64.charCodeAt(i + 2)] >> 2;
arr[L++] = tmp >> 8 & 0xFF;
arr[L++] = tmp & 0xFF;
}
return arr;
}
function tripletToBase64(num) {
return lookup[num >> 18 & 0x3F] + lookup[num >> 12 & 0x3F] + lookup[num >> 6 & 0x3F] + lookup[num & 0x3F];
}
function encodeChunk(uint8, start, end) {
var tmp;
var output = [];
for (var i = start; i < end; i += 3) {
tmp = (uint8[i] << 16) + (uint8[i + 1] << 8) + uint8[i + 2];
output.push(tripletToBase64(tmp));
}
return output.join('');
}
function fromByteArray(uint8) {
if (!inited) {
init();
}
var tmp;
var len = uint8.length;
var extraBytes = len % 3; // if we have 1 byte left, pad 2 bytes
var output = '';
var parts = [];
var maxChunkLength = 16383; // must be multiple of 3
// go through the array every three bytes, we'll deal with trailing stuff later
for (var i = 0, len2 = len - extraBytes; i < len2; i += maxChunkLength) {
parts.push(encodeChunk(uint8, i, i + maxChunkLength > len2 ? len2 : i + maxChunkLength));
}
// pad the end with zeros, but make sure to not forget the extra bytes
if (extraBytes === 1) {
tmp = uint8[len - 1];
output += lookup[tmp >> 2];
output += lookup[tmp << 4 & 0x3F];
output += '==';
} else if (extraBytes === 2) {
tmp = (uint8[len - 2] << 8) + uint8[len - 1];
output += lookup[tmp >> 10];
output += lookup[tmp >> 4 & 0x3F];
output += lookup[tmp << 2 & 0x3F];
output += '=';
}
parts.push(output);
return parts.join('');
}
function read(buffer, offset, isLE, mLen, nBytes) {
var e, m;
var eLen = nBytes * 8 - mLen - 1;
var eMax = (1 << eLen) - 1;
var eBias = eMax >> 1;
var nBits = -7;
var i = isLE ? nBytes - 1 : 0;
var d = isLE ? -1 : 1;
var s = buffer[offset + i];
i += d;
e = s & (1 << -nBits) - 1;
s >>= -nBits;
nBits += eLen;
for (; nBits > 0; e = e * 256 + buffer[offset + i], i += d, nBits -= 8) {}
m = e & (1 << -nBits) - 1;
e >>= -nBits;
nBits += mLen;
for (; nBits > 0; m = m * 256 + buffer[offset + i], i += d, nBits -= 8) {}
if (e === 0) {
e = 1 - eBias;
} else if (e === eMax) {
return m ? NaN : (s ? -1 : 1) * Infinity;
} else {
m = m + Math.pow(2, mLen);
e = e - eBias;
}
return (s ? -1 : 1) * m * Math.pow(2, e - mLen);
}
function write(buffer, value, offset, isLE, mLen, nBytes) {
var e, m, c;
var eLen = nBytes * 8 - mLen - 1;
var eMax = (1 << eLen) - 1;
var eBias = eMax >> 1;
var rt = mLen === 23 ? Math.pow(2, -24) - Math.pow(2, -77) : 0;
var i = isLE ? 0 : nBytes - 1;
var d = isLE ? 1 : -1;
var s = value < 0 || value === 0 && 1 / value < 0 ? 1 : 0;
value = Math.abs(value);
if (isNaN(value) || value === Infinity) {
m = isNaN(value) ? 1 : 0;
e = eMax;
} else {
e = Math.floor(Math.log(value) / Math.LN2);
if (value * (c = Math.pow(2, -e)) < 1) {
e--;
c *= 2;
}
if (e + eBias >= 1) {
value += rt / c;
} else {
value += rt * Math.pow(2, 1 - eBias);
}
if (value * c >= 2) {
e++;
c /= 2;
}
if (e + eBias >= eMax) {
m = 0;
e = eMax;
} else if (e + eBias >= 1) {
m = (value * c - 1) * Math.pow(2, mLen);
e = e + eBias;
} else {
m = value * Math.pow(2, eBias - 1) * Math.pow(2, mLen);
e = 0;
}
}
for (; mLen >= 8; buffer[offset + i] = m & 0xff, i += d, m /= 256, mLen -= 8) {}
e = e << mLen | m;
eLen += mLen;
for (; eLen > 0; buffer[offset + i] = e & 0xff, i += d, e /= 256, eLen -= 8) {}
buffer[offset + i - d] |= s * 128;
}
var toString = {}.toString;
var isArray = Array.isArray || function (arr) {
return toString.call(arr) == '[object Array]';
};
/*!
* The buffer module from node.js, for the browser.
*
* @author Feross Aboukhadijeh <feross@feross.org> <http://feross.org>
* @license MIT
*/
/* eslint-disable no-proto */
var INSPECT_MAX_BYTES = 50;
/**
* If `Buffer.TYPED_ARRAY_SUPPORT`:
* === true Use Uint8Array implementation (fastest)
* === false Use Object implementation (most compatible, even IE6)
*
* Browsers that support typed arrays are IE 10+, Firefox 4+, Chrome 7+, Safari 5.1+,
* Opera 11.6+, iOS 4.2+.
*
* Due to various browser bugs, sometimes the Object implementation will be used even
* when the browser supports typed arrays.
*
* Note:
*
* - Firefox 4-29 lacks support for adding new properties to `Uint8Array` instances,
* See: https://bugzilla.mozilla.org/show_bug.cgi?id=695438.
*
* - Chrome 9-10 is missing the `TypedArray.prototype.subarray` function.
*
* - IE10 has a broken `TypedArray.prototype.subarray` function which returns arrays of
* incorrect length in some situations.
* We detect these buggy browsers and set `Buffer.TYPED_ARRAY_SUPPORT` to `false` so they
* get the Object implementation, which is slower but behaves correctly.
*/
Buffer.TYPED_ARRAY_SUPPORT = global$1.TYPED_ARRAY_SUPPORT !== undefined ? global$1.TYPED_ARRAY_SUPPORT : true;
function kMaxLength() {
return Buffer.TYPED_ARRAY_SUPPORT ? 0x7fffffff : 0x3fffffff;
}
function createBuffer(that, length) {
if (kMaxLength() < length) {
throw new RangeError('Invalid typed array length');
}
if (Buffer.TYPED_ARRAY_SUPPORT) {
// Return an augmented `Uint8Array` instance, for best performance
that = new Uint8Array(length);
that.__proto__ = Buffer.prototype;
} else {
// Fallback: Return an object instance of the Buffer class
if (that === null) {
that = new Buffer(length);
}
that.length = length;
}
return that;
}
/**
* The Buffer constructor returns instances of `Uint8Array` that have their
* prototype changed to `Buffer.prototype`. Furthermore, `Buffer` is a subclass of
* `Uint8Array`, so the returned instances will have all the node `Buffer` methods
* and the `Uint8Array` methods. Square bracket notation works as expected -- it
* returns a single octet.
*
* The `Uint8Array` prototype remains unmodified.
*/
function Buffer(arg, encodingOrOffset, length) {
if (!Buffer.TYPED_ARRAY_SUPPORT && !(this instanceof Buffer)) {
return new Buffer(arg, encodingOrOffset, length);
}
// Common case.
if (typeof arg === 'number') {
if (typeof encodingOrOffset === 'string') {
throw new Error('If encoding is specified then the first argument must be a string');
}
return allocUnsafe(this, arg);
}
return from(this, arg, encodingOrOffset, length);
}
Buffer.poolSize = 8192; // not used by this implementation
// TODO: Legacy, not needed anymore. Remove in next major version.
Buffer._augment = function (arr) {
arr.__proto__ = Buffer.prototype;
return arr;
};
function from(that, value, encodingOrOffset, length) {
if (typeof value === 'number') {
throw new TypeError('"value" argument must not be a number');
}
if (typeof ArrayBuffer !== 'undefined' && value instanceof ArrayBuffer) {
return fromArrayBuffer(that, value, encodingOrOffset, length);
}
if (typeof value === 'string') {
return fromString(that, value, encodingOrOffset);
}
return fromObject(that, value);
}
/**
* Functionally equivalent to Buffer(arg, encoding) but throws a TypeError
* if value is a number.
* Buffer.from(str[, encoding])
* Buffer.from(array)
* Buffer.from(buffer)
* Buffer.from(arrayBuffer[, byteOffset[, length]])
**/
Buffer.from = function (value, encodingOrOffset, length) {
return from(null, value, encodingOrOffset, length);
};
if (Buffer.TYPED_ARRAY_SUPPORT) {
Buffer.prototype.__proto__ = Uint8Array.prototype;
Buffer.__proto__ = Uint8Array;
if (typeof Symbol !== 'undefined' && Symbol.species && Buffer[Symbol.species] === Buffer) {
// Fix subarray() in ES2016. See: https://github.com/feross/buffer/pull/97
// Object.defineProperty(Buffer, Symbol.species, {
// value: null,
// configurable: true
// })
}
}
function assertSize(size) {
if (typeof size !== 'number') {
throw new TypeError('"size" argument must be a number');
} else if (size < 0) {
throw new RangeError('"size" argument must not be negative');
}
}
function alloc(that, size, fill, encoding) {
assertSize(size);
if (size <= 0) {
return createBuffer(that, size);
}
if (fill !== undefined) {
// Only pay attention to encoding if it's a string. This
// prevents accidentally sending in a number that would
// be interpretted as a start offset.
return typeof encoding === 'string' ? createBuffer(that, size).fill(fill, encoding) : createBuffer(that, size).fill(fill);
}
return createBuffer(that, size);
}
/**
* Creates a new filled Buffer instance.
* alloc(size[, fill[, encoding]])
**/
Buffer.alloc = function (size, fill, encoding) {
return alloc(null, size, fill, encoding);
};
function allocUnsafe(that, size) {
assertSize(size);
that = createBuffer(that, size < 0 ? 0 : checked(size) | 0);
if (!Buffer.TYPED_ARRAY_SUPPORT) {
for (var i = 0; i < size; ++i) {
that[i] = 0;
}
}
return that;
}
/**
* Equivalent to Buffer(num), by default creates a non-zero-filled Buffer instance.
* */
Buffer.allocUnsafe = function (size) {
return allocUnsafe(null, size);
};
/**
* Equivalent to SlowBuffer(num), by default creates a non-zero-filled Buffer instance.
*/
Buffer.allocUnsafeSlow = function (size) {
return allocUnsafe(null, size);
};
function fromString(that, string, encoding) {
if (typeof encoding !== 'string' || encoding === '') {
encoding = 'utf8';
}
if (!Buffer.isEncoding(encoding)) {
throw new TypeError('"encoding" must be a valid string encoding');
}
var length = byteLength(string, encoding) | 0;
that = createBuffer(that, length);
var actual = that.write(string, encoding);
if (actual !== length) {
// Writing a hex string, for example, that contains invalid characters will
// cause everything after the first invalid character to be ignored. (e.g.
// 'abxxcd' will be treated as 'ab')
that = that.slice(0, actual);
}
return that;
}
function fromArrayLike(that, array) {
var length = array.length < 0 ? 0 : checked(array.length) | 0;
that = createBuffer(that, length);
for (var i = 0; i < length; i += 1) {
that[i] = array[i] & 255;
}
return that;
}
function fromArrayBuffer(that, array, byteOffset, length) {
array.byteLength; // this throws if `array` is not a valid ArrayBuffer
if (byteOffset < 0 || array.byteLength < byteOffset) {
throw new RangeError('\'offset\' is out of bounds');
}
if (array.byteLength < byteOffset + (length || 0)) {
throw new RangeError('\'length\' is out of bounds');
}
if (byteOffset === undefined && length === undefined) {
array = new Uint8Array(array);
} else if (length === undefined) {
array = new Uint8Array(array, byteOffset);
} else {
array = new Uint8Array(array, byteOffset, length);
}
if (Buffer.TYPED_ARRAY_SUPPORT) {
// Return an augmented `Uint8Array` instance, for best performance
that = array;
that.__proto__ = Buffer.prototype;
} else {
// Fallback: Return an object instance of the Buffer class
that = fromArrayLike(that, array);
}
return that;
}
function fromObject(that, obj) {
if (internalIsBuffer(obj)) {
var len = checked(obj.length) | 0;
that = createBuffer(that, len);
if (that.length === 0) {
return that;
}
obj.copy(that, 0, 0, len);
return that;
}
if (obj) {
if (typeof ArrayBuffer !== 'undefined' && obj.buffer instanceof ArrayBuffer || 'length' in obj) {
if (typeof obj.length !== 'number' || isnan(obj.length)) {
return createBuffer(that, 0);
}
return fromArrayLike(that, obj);
}
if (obj.type === 'Buffer' && isArray(obj.data)) {
return fromArrayLike(that, obj.data);
}
}
throw new TypeError('First argument must be a string, Buffer, ArrayBuffer, Array, or array-like object.');
}
function checked(length) {
// Note: cannot use `length < kMaxLength()` here because that fails when
// length is NaN (which is otherwise coerced to zero.)
if (length >= kMaxLength()) {
throw new RangeError('Attempt to allocate Buffer larger than maximum ' + 'size: 0x' + kMaxLength().toString(16) + ' bytes');
}
return length | 0;
}
Buffer.isBuffer = isBuffer;
function internalIsBuffer(b) {
return !!(b != null && b._isBuffer);
}
Buffer.compare = function compare(a, b) {
if (!internalIsBuffer(a) || !internalIsBuffer(b)) {
throw new TypeError('Arguments must be Buffers');
}
if (a === b) return 0;
var x = a.length;
var y = b.length;
for (var i = 0, len = Math.min(x, y); i < len; ++i) {
if (a[i] !== b[i]) {
x = a[i];
y = b[i];
break;
}
}
if (x < y) return -1;
if (y < x) return 1;
return 0;
};
Buffer.isEncoding = function isEncoding(encoding) {
switch (String(encoding).toLowerCase()) {
case 'hex':
case 'utf8':
case 'utf-8':
case 'ascii':
case 'latin1':
case 'binary':
case 'base64':
case 'ucs2':
case 'ucs-2':
case 'utf16le':
case 'utf-16le':
return true;
default:
return false;
}
};
Buffer.concat = function concat(list, length) {
if (!isArray(list)) {
throw new TypeError('"list" argument must be an Array of Buffers');
}
if (list.length === 0) {
return Buffer.alloc(0);
}
var i;
if (length === undefined) {
length = 0;
for (i = 0; i < list.length; ++i) {
length += list[i].length;
}
}
var buffer = Buffer.allocUnsafe(length);
var pos = 0;
for (i = 0; i < list.length; ++i) {
var buf = list[i];
if (!internalIsBuffer(buf)) {
throw new TypeError('"list" argument must be an Array of Buffers');
}
buf.copy(buffer, pos);
pos += buf.length;
}
return buffer;
};
function byteLength(string, encoding) {
if (internalIsBuffer(string)) {
return string.length;
}
if (typeof ArrayBuffer !== 'undefined' && typeof ArrayBuffer.isView === 'function' && (ArrayBuffer.isView(string) || string instanceof ArrayBuffer)) {
return string.byteLength;
}
if (typeof string !== 'string') {
string = '' + string;
}
var len = string.length;
if (len === 0) return 0;
// Use a for loop to avoid recursion
var loweredCase = false;
for (;;) {
switch (encoding) {
case 'ascii':
case 'latin1':
case 'binary':
return len;
case 'utf8':
case 'utf-8':
case undefined:
return utf8ToBytes(string).length;
case 'ucs2':
case 'ucs-2':
case 'utf16le':
case 'utf-16le':
return len * 2;
case 'hex':
return len >>> 1;
case 'base64':
return base64ToBytes(string).length;
default:
if (loweredCase) return utf8ToBytes(string).length; // assume utf8
encoding = ('' + encoding).toLowerCase();
loweredCase = true;
}
}
}
Buffer.byteLength = byteLength;
function slowToString(encoding, start, end) {
var loweredCase = false;
// No need to verify that "this.length <= MAX_UINT32" since it's a read-only
// property of a typed array.
// This behaves neither like String nor Uint8Array in that we set start/end
// to their upper/lower bounds if the value passed is out of range.
// undefined is handled specially as per ECMA-262 6th Edition,
// Section 13.3.3.7 Runtime Semantics: KeyedBindingInitialization.
if (start === undefined || start < 0) {
start = 0;
}
// Return early if start > this.length. Done here to prevent potential uint32
// coercion fail below.
if (start > this.length) {
return '';
}
if (end === undefined || end > this.length) {
end = this.length;
}
if (end <= 0) {
return '';
}
// Force coersion to uint32. This will also coerce falsey/NaN values to 0.
end >>>= 0;
start >>>= 0;
if (end <= start) {
return '';
}
if (!encoding) encoding = 'utf8';
while (true) {
switch (encoding) {
case 'hex':
return hexSlice(this, start, end);
case 'utf8':
case 'utf-8':
return utf8Slice(this, start, end);
case 'ascii':
return asciiSlice(this, start, end);
case 'latin1':
case 'binary':
return latin1Slice(this, start, end);
case 'base64':
return base64Slice(this, start, end);
case 'ucs2':
case 'ucs-2':
case 'utf16le':
case 'utf-16le':
return utf16leSlice(this, start, end);
default:
if (loweredCase) throw new TypeError('Unknown encoding: ' + encoding);
encoding = (encoding + '').toLowerCase();
loweredCase = true;
}
}
}
// The property is used by `Buffer.isBuffer` and `is-buffer` (in Safari 5-7) to detect
// Buffer instances.
Buffer.prototype._isBuffer = true;
function swap(b, n, m) {
var i = b[n];
b[n] = b[m];
b[m] = i;
}
Buffer.prototype.swap16 = function swap16() {
var len = this.length;
if (len % 2 !== 0) {
throw new RangeError('Buffer size must be a multiple of 16-bits');
}
for (var i = 0; i < len; i += 2) {
swap(this, i, i + 1);
}
return this;
};
Buffer.prototype.swap32 = function swap32() {
var len = this.length;
if (len % 4 !== 0) {
throw new RangeError('Buffer size must be a multiple of 32-bits');
}
for (var i = 0; i < len; i += 4) {
swap(this, i, i + 3);
swap(this, i + 1, i + 2);
}
return this;
};
Buffer.prototype.swap64 = function swap64() {
var len = this.length;
if (len % 8 !== 0) {
throw new RangeError('Buffer size must be a multiple of 64-bits');
}
for (var i = 0; i < len; i += 8) {
swap(this, i, i + 7);
swap(this, i + 1, i + 6);
swap(this, i + 2, i + 5);
swap(this, i + 3, i + 4);
}
return this;
};
Buffer.prototype.toString = function toString() {
var length = this.length | 0;
if (length === 0) return '';
if (arguments.length === 0) return utf8Slice(this, 0, length);
return slowToString.apply(this, arguments);
};
Buffer.prototype.equals = function equals(b) {
if (!internalIsBuffer(b)) throw new TypeError('Argument must be a Buffer');
if (this === b) return true;
return Buffer.compare(this, b) === 0;
};
Buffer.prototype.inspect = function inspect() {
var str = '';
var max = INSPECT_MAX_BYTES;
if (this.length > 0) {
str = this.toString('hex', 0, max).match(/.{2}/g).join(' ');
if (this.length > max) str += ' ... ';
}
return '<Buffer ' + str + '>';
};
Buffer.prototype.compare = function compare(target, start, end, thisStart, thisEnd) {
if (!internalIsBuffer(target)) {
throw new TypeError('Argument must be a Buffer');
}
if (start === undefined) {
start = 0;
}
if (end === undefined) {
end = target ? target.length : 0;
}
if (thisStart === undefined) {
thisStart = 0;
}
if (thisEnd === undefined) {
thisEnd = this.length;
}
if (start < 0 || end > target.length || thisStart < 0 || thisEnd > this.length) {
throw new RangeError('out of range index');
}
if (thisStart >= thisEnd && start >= end) {
return 0;
}
if (thisStart >= thisEnd) {
return -1;
}
if (start >= end) {
return 1;
}
start >>>= 0;
end >>>= 0;
thisStart >>>= 0;
thisEnd >>>= 0;
if (this === target) return 0;
var x = thisEnd - thisStart;
var y = end - start;
var len = Math.min(x, y);
var thisCopy = this.slice(thisStart, thisEnd);
var targetCopy = target.slice(start, end);
for (var i = 0; i < len; ++i) {
if (thisCopy[i] !== targetCopy[i]) {
x = thisCopy[i];
y = targetCopy[i];
break;
}
}
if (x < y) return -1;
if (y < x) return 1;
return 0;
};
// Finds either the first index of `val` in `buffer` at offset >= `byteOffset`,
// OR the last index of `val` in `buffer` at offset <= `byteOffset`.
//
// Arguments:
// - buffer - a Buffer to search
// - val - a string, Buffer, or number
// - byteOffset - an index into `buffer`; will be clamped to an int32
// - encoding - an optional encoding, relevant is val is a string
// - dir - true for indexOf, false for lastIndexOf
function bidirectionalIndexOf(buffer, val, byteOffset, encoding, dir) {
// Empty buffer means no match
if (buffer.length === 0) return -1;
// Normalize byteOffset
if (typeof byteOffset === 'string') {
encoding = byteOffset;
byteOffset = 0;
} else if (byteOffset > 0x7fffffff) {
byteOffset = 0x7fffffff;
} else if (byteOffset < -0x80000000) {
byteOffset = -0x80000000;
}
byteOffset = +byteOffset; // Coerce to Number.
if (isNaN(byteOffset)) {
// byteOffset: it it's undefined, null, NaN, "foo", etc, search whole buffer
byteOffset = dir ? 0 : buffer.length - 1;
}
// Normalize byteOffset: negative offsets start from the end of the buffer
if (byteOffset < 0) byteOffset = buffer.length + byteOffset;
if (byteOffset >= buffer.length) {
if (dir) return -1;else byteOffset = buffer.length - 1;
} else if (byteOffset < 0) {
if (dir) byteOffset = 0;else return -1;
}
// Normalize val
if (typeof val === 'string') {
val = Buffer.from(val, encoding);
}
// Finally, search either indexOf (if dir is true) or lastIndexOf
if (internalIsBuffer(val)) {
// Special case: looking for empty string/buffer always fails
if (val.length === 0) {
return -1;
}
return arrayIndexOf(buffer, val, byteOffset, encoding, dir);
} else if (typeof val === 'number') {
val = val & 0xFF; // Search for a byte value [0-255]
if (Buffer.TYPED_ARRAY_SUPPORT && typeof Uint8Array.prototype.indexOf === 'function') {
if (dir) {
return Uint8Array.prototype.indexOf.call(buffer, val, byteOffset);
} else {
return Uint8Array.prototype.lastIndexOf.call(buffer, val, byteOffset);
}
}
return arrayIndexOf(buffer, [val], byteOffset, encoding, dir);
}
throw new TypeError('val must be string, number or Buffer');
}
function arrayIndexOf(arr, val, byteOffset, encoding, dir) {
var indexSize = 1;
var arrLength = arr.length;
var valLength = val.length;
if (encoding !== undefined) {
encoding = String(encoding).toLowerCase();
if (encoding === 'ucs2' || encoding === 'ucs-2' || encoding === 'utf16le' || encoding === 'utf-16le') {
if (arr.length < 2 || val.length < 2) {
return -1;
}
indexSize = 2;
arrLength /= 2;
valLength /= 2;
byteOffset /= 2;
}
}
function read$$1(buf, i) {
if (indexSize === 1) {
return buf[i];
} else {
return buf.readUInt16BE(i * indexSize);
}
}
var i;
if (dir) {
var foundIndex = -1;
for (i = byteOffset; i < arrLength; i++) {
if (read$$1(arr, i) === read$$1(val, foundIndex === -1 ? 0 : i - foundIndex)) {
if (foundIndex === -1) foundIndex = i;
if (i - foundIndex + 1 === valLength) return foundIndex * indexSize;
} else {
if (foundIndex !== -1) i -= i - foundIndex;
foundIndex = -1;
}
}
} else {
if (byteOffset + valLength > arrLength) byteOffset = arrLength - valLength;
for (i = byteOffset; i >= 0; i--) {
var found = true;
for (var j = 0; j < valLength; j++) {
if (read$$1(arr, i + j) !== read$$1(val, j)) {
found = false;
break;
}
}
if (found) return i;
}
}
return -1;
}
Buffer.prototype.includes = function includes(val, byteOffset, encoding) {
return this.indexOf(val, byteOffset, encoding) !== -1;
};
Buffer.prototype.indexOf = function indexOf(val, byteOffset, encoding) {
return bidirectionalIndexOf(this, val, byteOffset, encoding, true);
};
Buffer.prototype.lastIndexOf = function lastIndexOf(val, byteOffset, encoding) {
return bidirectionalIndexOf(this, val, byteOffset, encoding, false);
};
function hexWrite(buf, string, offset, length) {
offset = Number(offset) || 0;
var remaining = buf.length - offset;
if (!length) {
length = remaining;
} else {
length = Number(length);
if (length > remaining) {
length = remaining;
}
}
// must be an even number of digits
var strLen = string.length;
if (strLen % 2 !== 0) throw new TypeError('Invalid hex string');
if (length > strLen / 2) {
length = strLen / 2;
}
for (var i = 0; i < length; ++i) {
var parsed = parseInt(string.substr(i * 2, 2), 16);
if (isNaN(parsed)) return i;
buf[offset + i] = parsed;
}
return i;
}
function utf8Write(buf, string, offset, length) {
return blitBuffer(utf8ToBytes(string, buf.length - offset), buf, offset, length);
}
function asciiWrite(buf, string, offset, length) {
return blitBuffer(asciiToBytes(string), buf, offset, length);
}
function latin1Write(buf, string, offset, length) {
return asciiWrite(buf, string, offset, length);
}
function base64Write(buf, string, offset, length) {
return blitBuffer(base64ToBytes(string), buf, offset, length);
}
function ucs2Write(buf, string, offset, length) {
return blitBuffer(utf16leToBytes(string, buf.length - offset), buf, offset, length);
}
Buffer.prototype.write = function write$$1(string, offset, length, encoding) {
// Buffer#write(string)
if (offset === undefined) {
encoding = 'utf8';
length = this.length;
offset = 0;
// Buffer#write(string, encoding)
} else if (length === undefined && typeof offset === 'string') {
encoding = offset;
length = this.length;
offset = 0;
// Buffer#write(string, offset[, length][, encoding])
} else if (isFinite(offset)) {
offset = offset | 0;
if (isFinite(length)) {
length = length | 0;
if (encoding === undefined) encoding = 'utf8';
} else {
encoding = length;
length = undefined;
}
// legacy write(string, encoding, offset, length) - remove in v0.13
} else {
throw new Error('Buffer.write(string, encoding, offset[, length]) is no longer supported');
}
var remaining = this.length - offset;
if (length === undefined || length > remaining) length = remaining;
if (string.length > 0 && (length < 0 || offset < 0) || offset > this.length) {
throw new RangeError('Attempt to write outside buffer bounds');
}
if (!encoding) encoding = 'utf8';
var loweredCase = false;
for (;;) {
switch (encoding) {
case 'hex':
return hexWrite(this, string, offset, length);
case 'utf8':
case 'utf-8':
return utf8Write(this, string, offset, length);
case 'ascii':
return asciiWrite(this, string, offset, length);
case 'latin1':
case 'binary':
return latin1Write(this, string, offset, length);
case 'base64':
// Warning: maxLength not taken into account in base64Write
return base64Write(this, string, offset, length);
case 'ucs2':
case 'ucs-2':
case 'utf16le':
case 'utf-16le':
return ucs2Write(this, string, offset, length);
default:
if (loweredCase) throw new TypeError('Unknown encoding: ' + encoding);
encoding = ('' + encoding).toLowerCase();
loweredCase = true;
}
}
};
Buffer.prototype.toJSON = function toJSON() {
return {
type: 'Buffer',
data: Array.prototype.slice.call(this._arr || this, 0)
};
};
function base64Slice(buf, start, end) {
if (start === 0 && end === buf.length) {
return fromByteArray(buf);
} else {
return fromByteArray(buf.slice(start, end));
}
}
function utf8Slice(buf, start, end) {
end = Math.min(buf.length, end);
var res = [];
var i = start;
while (i < end) {
var firstByte = buf[i];
var codePoint = null;
var bytesPerSequence = firstByte > 0xEF ? 4 : firstByte > 0xDF ? 3 : firstByte > 0xBF ? 2 : 1;
if (i + bytesPerSequence <= end) {
var secondByte, thirdByte, fourthByte, tempCodePoint;
switch (bytesPerSequence) {
case 1:
if (firstByte < 0x80) {
codePoint = firstByte;
}
break;
case 2:
secondByte = buf[i + 1];
if ((secondByte & 0xC0) === 0x80) {
tempCodePoint = (firstByte & 0x1F) << 0x6 | secondByte & 0x3F;
if (tempCodePoint > 0x7F) {
codePoint = tempCodePoint;
}
}
break;
case 3:
secondByte = buf[i + 1];
thirdByte = buf[i + 2];
if ((secondByte & 0xC0) === 0x80 && (thirdByte & 0xC0) === 0x80) {
tempCodePoint = (firstByte & 0xF) << 0xC | (secondByte & 0x3F) << 0x6 | thirdByte & 0x3F;
if (tempCodePoint > 0x7FF && (tempCodePoint < 0xD800 || tempCodePoint > 0xDFFF)) {
codePoint = tempCodePoint;
}
}
break;
case 4:
secondByte = buf[i + 1];