401 lines
9.5 KiB
JavaScript
401 lines
9.5 KiB
JavaScript
'use strict';
|
|
|
|
const { Buffer } = require('buffer');
|
|
const symbol = Symbol.for('BufferList');
|
|
|
|
function BufferList(buf) {
|
|
if (!(this instanceof BufferList)) {
|
|
return new BufferList(buf);
|
|
}
|
|
|
|
BufferList._init.call(this, buf);
|
|
}
|
|
|
|
BufferList._init = function _init(buf) {
|
|
Object.defineProperty(this, symbol, { value: true });
|
|
|
|
this._bufs = [];
|
|
this.length = 0;
|
|
|
|
if (buf) {
|
|
this.append(buf);
|
|
}
|
|
};
|
|
|
|
BufferList.prototype._new = function _new(buf) {
|
|
return new BufferList(buf);
|
|
};
|
|
|
|
BufferList.prototype._offset = function _offset(offset) {
|
|
if (offset === 0) {
|
|
return [0, 0];
|
|
}
|
|
|
|
let tot = 0;
|
|
|
|
for (let i = 0; i < this._bufs.length; i++) {
|
|
const _t = tot + this._bufs[i].length;
|
|
if (offset < _t || i === this._bufs.length - 1) {
|
|
return [i, offset - tot];
|
|
}
|
|
tot = _t;
|
|
}
|
|
};
|
|
|
|
BufferList.prototype._reverseOffset = function (blOffset) {
|
|
const bufferId = blOffset[0];
|
|
let offset = blOffset[1];
|
|
|
|
for (let i = 0; i < bufferId; i++) {
|
|
offset += this._bufs[i].length;
|
|
}
|
|
|
|
return offset;
|
|
};
|
|
|
|
BufferList.prototype.get = function get(index) {
|
|
if (index > this.length || index < 0) {
|
|
return undefined;
|
|
}
|
|
|
|
const offset = this._offset(index);
|
|
|
|
return this._bufs[offset[0]][offset[1]];
|
|
};
|
|
|
|
BufferList.prototype.slice = function slice(start, end) {
|
|
if (typeof start === 'number' && start < 0) {
|
|
start += this.length;
|
|
}
|
|
|
|
if (typeof end === 'number' && end < 0) {
|
|
end += this.length;
|
|
}
|
|
|
|
return this.copy(null, 0, start, end);
|
|
};
|
|
|
|
BufferList.prototype.copy = function copy(dst, dstStart, srcStart, srcEnd) {
|
|
if (typeof srcStart !== 'number' || srcStart < 0) {
|
|
srcStart = 0;
|
|
}
|
|
|
|
if (typeof srcEnd !== 'number' || srcEnd > this.length) {
|
|
srcEnd = this.length;
|
|
}
|
|
|
|
if (srcStart >= this.length) {
|
|
return dst || Buffer.alloc(0);
|
|
}
|
|
|
|
if (srcEnd <= 0) {
|
|
return dst || Buffer.alloc(0);
|
|
}
|
|
|
|
const copy = !!dst;
|
|
const off = this._offset(srcStart);
|
|
const len = srcEnd - srcStart;
|
|
let bytes = len;
|
|
let bufoff = (copy && dstStart) || 0;
|
|
let start = off[1];
|
|
|
|
// copy/slice everything
|
|
if (srcStart === 0 && srcEnd === this.length) {
|
|
if (!copy) {
|
|
// slice, but full concat if multiple buffers
|
|
return this._bufs.length === 1 ?
|
|
this._bufs[0]
|
|
: Buffer.concat(this._bufs, this.length);
|
|
}
|
|
|
|
// copy, need to copy individual buffers
|
|
for (let i = 0; i < this._bufs.length; i++) {
|
|
this._bufs[i].copy(dst, bufoff);
|
|
bufoff += this._bufs[i].length;
|
|
}
|
|
|
|
return dst;
|
|
}
|
|
|
|
// easy, cheap case where it's a subset of one of the buffers
|
|
if (bytes <= this._bufs[off[0]].length - start) {
|
|
return copy ?
|
|
this._bufs[off[0]].copy(dst, dstStart, start, start + bytes)
|
|
: this._bufs[off[0]].slice(start, start + bytes);
|
|
}
|
|
|
|
if (!copy) {
|
|
// a slice, we need something to copy in to
|
|
dst = Buffer.allocUnsafe(len);
|
|
}
|
|
|
|
for (let i = off[0]; i < this._bufs.length; i++) {
|
|
const l = this._bufs[i].length - start;
|
|
|
|
if (bytes > l) {
|
|
this._bufs[i].copy(dst, bufoff, start);
|
|
bufoff += l;
|
|
} else {
|
|
this._bufs[i].copy(dst, bufoff, start, start + bytes);
|
|
bufoff += l;
|
|
break;
|
|
}
|
|
|
|
bytes -= l;
|
|
|
|
if (start) {
|
|
start = 0;
|
|
}
|
|
}
|
|
|
|
// safeguard so that we don't return uninitialized memory
|
|
if (dst.length > bufoff) return dst.slice(0, bufoff);
|
|
|
|
return dst;
|
|
};
|
|
|
|
BufferList.prototype.shallowSlice = function shallowSlice(start, end) {
|
|
start = start || 0;
|
|
end = typeof end !== 'number' ? this.length : end;
|
|
|
|
if (start < 0) {
|
|
start += this.length;
|
|
}
|
|
|
|
if (end < 0) {
|
|
end += this.length;
|
|
}
|
|
|
|
if (start === end) {
|
|
return this._new();
|
|
}
|
|
|
|
const startOffset = this._offset(start);
|
|
const endOffset = this._offset(end);
|
|
const buffers = this._bufs.slice(startOffset[0], endOffset[0] + 1);
|
|
|
|
if (endOffset[1] === 0) {
|
|
buffers.pop();
|
|
} else {
|
|
buffers[buffers.length - 1] = buffers[buffers.length - 1].slice(
|
|
0,
|
|
endOffset[1]
|
|
);
|
|
}
|
|
|
|
if (startOffset[1] !== 0) {
|
|
buffers[0] = buffers[0].slice(startOffset[1]);
|
|
}
|
|
|
|
return this._new(buffers);
|
|
};
|
|
|
|
BufferList.prototype.toString = function toString(encoding, start, end) {
|
|
return this.slice(start, end).toString(encoding);
|
|
};
|
|
|
|
BufferList.prototype.consume = function consume(bytes) {
|
|
// first, normalize the argument, in accordance with how Buffer does it
|
|
bytes = Math.trunc(bytes);
|
|
// do nothing if not a positive number
|
|
if (Number.isNaN(bytes) || bytes <= 0) return this;
|
|
|
|
while (this._bufs.length) {
|
|
if (bytes >= this._bufs[0].length) {
|
|
bytes -= this._bufs[0].length;
|
|
this.length -= this._bufs[0].length;
|
|
this._bufs.shift();
|
|
} else {
|
|
this._bufs[0] = this._bufs[0].slice(bytes);
|
|
this.length -= bytes;
|
|
break;
|
|
}
|
|
}
|
|
|
|
return this;
|
|
};
|
|
|
|
BufferList.prototype.duplicate = function duplicate() {
|
|
const copy = this._new();
|
|
|
|
for (let i = 0; i < this._bufs.length; i++) {
|
|
copy.append(this._bufs[i]);
|
|
}
|
|
|
|
return copy;
|
|
};
|
|
|
|
BufferList.prototype.append = function append(buf) {
|
|
if (buf == null) {
|
|
return this;
|
|
}
|
|
|
|
if (buf.buffer) {
|
|
// append a view of the underlying ArrayBuffer
|
|
this._appendBuffer(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength));
|
|
} else if (Array.isArray(buf)) {
|
|
for (let i = 0; i < buf.length; i++) {
|
|
this.append(buf[i]);
|
|
}
|
|
} else if (this._isBufferList(buf)) {
|
|
// unwrap argument into individual BufferLists
|
|
for (let i = 0; i < buf._bufs.length; i++) {
|
|
this.append(buf._bufs[i]);
|
|
}
|
|
} else {
|
|
// coerce number arguments to strings, since Buffer(number) does
|
|
// uninitialized memory allocation
|
|
if (typeof buf === 'number') {
|
|
buf = buf.toString();
|
|
}
|
|
|
|
this._appendBuffer(Buffer.from(buf));
|
|
}
|
|
|
|
return this;
|
|
};
|
|
|
|
BufferList.prototype._appendBuffer = function appendBuffer(buf) {
|
|
this._bufs.push(buf);
|
|
this.length += buf.length;
|
|
};
|
|
|
|
BufferList.prototype.indexOf = function (search, offset, encoding) {
|
|
if (encoding === undefined && typeof offset === 'string') {
|
|
encoding = offset;
|
|
offset = undefined;
|
|
}
|
|
|
|
if (typeof search === 'function' || Array.isArray(search)) {
|
|
throw new TypeError(
|
|
'The "value" argument must be one of type string, Buffer, BufferList, or Uint8Array.'
|
|
);
|
|
} else if (typeof search === 'number') {
|
|
search = Buffer.from([search]);
|
|
} else if (typeof search === 'string') {
|
|
search = Buffer.from(search, encoding);
|
|
} else if (this._isBufferList(search)) {
|
|
search = search.slice();
|
|
} else if (Array.isArray(search.buffer)) {
|
|
search = Buffer.from(search.buffer, search.byteOffset, search.byteLength);
|
|
} else if (!Buffer.isBuffer(search)) {
|
|
search = Buffer.from(search);
|
|
}
|
|
|
|
offset = Number(offset || 0);
|
|
|
|
if (isNaN(offset)) {
|
|
offset = 0;
|
|
}
|
|
|
|
if (offset < 0) {
|
|
offset = this.length + offset;
|
|
}
|
|
|
|
if (offset < 0) {
|
|
offset = 0;
|
|
}
|
|
|
|
if (search.length === 0) {
|
|
return offset > this.length ? this.length : offset;
|
|
}
|
|
|
|
const blOffset = this._offset(offset);
|
|
let blIndex = blOffset[0]; // index of which internal buffer we're working on
|
|
let buffOffset = blOffset[1]; // offset of the internal buffer we're working on
|
|
|
|
// scan over each buffer
|
|
for (; blIndex < this._bufs.length; blIndex++) {
|
|
const buff = this._bufs[blIndex];
|
|
|
|
while (buffOffset < buff.length) {
|
|
const availableWindow = buff.length - buffOffset;
|
|
|
|
if (availableWindow >= search.length) {
|
|
const nativeSearchResult = buff.indexOf(search, buffOffset);
|
|
|
|
if (nativeSearchResult !== -1) {
|
|
return this._reverseOffset([blIndex, nativeSearchResult]);
|
|
}
|
|
|
|
buffOffset = buff.length - search.length + 1; // end of native search window
|
|
} else {
|
|
const revOffset = this._reverseOffset([blIndex, buffOffset]);
|
|
|
|
if (this._match(revOffset, search)) {
|
|
return revOffset;
|
|
}
|
|
|
|
buffOffset++;
|
|
}
|
|
}
|
|
|
|
buffOffset = 0;
|
|
}
|
|
|
|
return -1;
|
|
};
|
|
|
|
BufferList.prototype._match = function (offset, search) {
|
|
if (this.length - offset < search.length) {
|
|
return false;
|
|
}
|
|
|
|
for (let searchOffset = 0; searchOffset < search.length; searchOffset++) {
|
|
if (this.get(offset + searchOffset) !== search[searchOffset]) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
};
|
|
(function () {
|
|
const methods = {
|
|
readDoubleBE: 8,
|
|
readDoubleLE: 8,
|
|
readFloatBE: 4,
|
|
readFloatLE: 4,
|
|
readInt32BE: 4,
|
|
readInt32LE: 4,
|
|
readUInt32BE: 4,
|
|
readUInt32LE: 4,
|
|
readInt16BE: 2,
|
|
readInt16LE: 2,
|
|
readUInt16BE: 2,
|
|
readUInt16LE: 2,
|
|
readInt8: 1,
|
|
readUInt8: 1,
|
|
readIntBE: null,
|
|
readIntLE: null,
|
|
readUIntBE: null,
|
|
readUIntLE: null,
|
|
};
|
|
|
|
for (const m in methods) {
|
|
(function (m) {
|
|
if (methods[m] === null) {
|
|
BufferList.prototype[m] = function (offset, byteLength) {
|
|
return this.slice(offset, offset + byteLength)[m](0, byteLength);
|
|
};
|
|
} else {
|
|
BufferList.prototype[m] = function (offset = 0) {
|
|
return this.slice(offset, offset + methods[m])[m](0);
|
|
};
|
|
}
|
|
})(m);
|
|
}
|
|
})();
|
|
|
|
// Used internally by the class and also as an indicator of this object being
|
|
// a `BufferList`. It's not possible to use `instanceof BufferList` in a browser
|
|
// environment because there could be multiple different copies of the
|
|
// BufferList class and some `BufferList`s might be `BufferList`s.
|
|
BufferList.prototype._isBufferList = function _isBufferList(b) {
|
|
return b instanceof BufferList || BufferList.isBufferList(b);
|
|
};
|
|
|
|
BufferList.isBufferList = function isBufferList(b) {
|
|
return b != null && b[symbol];
|
|
};
|
|
|
|
module.exports = BufferList;
|