mirror of
https://github.com/nodejs/node.git
synced 2024-11-29 23:16:30 +01:00
1064 lines
27 KiB
JavaScript
1064 lines
27 KiB
JavaScript
// Copyright Joyent, Inc. and other Node contributors.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to permit
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// persons to whom the Software is furnished to do so, subject to the
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// following conditions:
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//
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// The above copyright notice and this permission notice shall be included
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// in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
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// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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// USE OR OTHER DEALINGS IN THE SOFTWARE.
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var SlowBuffer = process.binding('buffer').SlowBuffer;
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var IEEE754 = require('buffer_ieee754');
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var assert = require('assert');
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function toHex(n) {
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if (n < 16) return '0' + n.toString(16);
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return n.toString(16);
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}
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SlowBuffer.prototype.inspect = function() {
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var out = [],
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len = this.length;
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for (var i = 0; i < len; i++) {
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out[i] = toHex(this[i]);
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}
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return '<SlowBuffer ' + out.join(' ') + '>';
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};
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SlowBuffer.prototype.hexSlice = function(start, end) {
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var len = this.length;
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if (!start || start < 0) start = 0;
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if (!end || end < 0 || end > len) end = len;
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var out = '';
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for (var i = start; i < end; i++) {
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out += toHex(this[i]);
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}
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return out;
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};
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SlowBuffer.prototype.toString = function(encoding, start, end) {
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encoding = String(encoding || 'utf8').toLowerCase();
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start = +start || 0;
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if (typeof end == 'undefined') end = this.length;
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// Fastpath empty strings
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if (+end == start) {
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return '';
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}
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switch (encoding) {
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case 'hex':
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return this.hexSlice(start, end);
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case 'utf8':
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case 'utf-8':
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return this.utf8Slice(start, end);
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case 'ascii':
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return this.asciiSlice(start, end);
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case 'binary':
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return this.binarySlice(start, end);
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case 'base64':
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return this.base64Slice(start, end);
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case 'ucs2':
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case 'ucs-2':
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return this.ucs2Slice(start, end);
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default:
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throw new Error('Unknown encoding');
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}
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};
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SlowBuffer.prototype.hexWrite = function(string, offset, length) {
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offset = +offset || 0;
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var remaining = this.length - offset;
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if (!length) {
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length = remaining;
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} else {
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length = +length;
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if (length > remaining) {
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length = remaining;
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}
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}
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// must be an even number of digits
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var strLen = string.length;
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if (strLen % 2) {
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throw new Error('Invalid hex string');
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}
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if (length > strLen / 2) {
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length = strLen / 2;
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}
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for (var i = 0; i < length; i++) {
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var byte = parseInt(string.substr(i * 2, 2), 16);
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if (isNaN(byte)) throw new Error('Invalid hex string');
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this[offset + i] = byte;
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}
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return i;
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};
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SlowBuffer.prototype.write = function(string, offset, length, encoding) {
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// Support both (string, offset, length, encoding)
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// and the legacy (string, encoding, offset, length)
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if (isFinite(offset)) {
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if (!isFinite(length)) {
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encoding = length;
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length = undefined;
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}
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} else { // legacy
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var swap = encoding;
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encoding = offset;
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offset = length;
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length = swap;
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}
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offset = +offset || 0;
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var remaining = this.length - offset;
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if (!length) {
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length = remaining;
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} else {
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length = +length;
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if (length > remaining) {
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length = remaining;
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}
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}
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encoding = String(encoding || 'utf8').toLowerCase();
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switch (encoding) {
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case 'hex':
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return this.hexWrite(string, offset, length);
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case 'utf8':
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case 'utf-8':
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return this.utf8Write(string, offset, length);
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case 'ascii':
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return this.asciiWrite(string, offset, length);
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case 'binary':
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return this.binaryWrite(string, offset, length);
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case 'base64':
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return this.base64Write(string, offset, length);
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case 'ucs2':
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case 'ucs-2':
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return this.ucs2Write(string, offset, length);
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default:
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throw new Error('Unknown encoding');
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}
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};
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// slice(start, end)
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SlowBuffer.prototype.slice = function(start, end) {
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if (end === undefined) end = this.length;
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if (end > this.length) {
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throw new Error('oob');
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}
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if (start > end) {
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throw new Error('oob');
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}
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return new Buffer(this, end - start, +start);
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};
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// Buffer
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function Buffer(subject, encoding, offset) {
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if (!(this instanceof Buffer)) {
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return new Buffer(subject, encoding, offset);
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}
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var type;
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// Are we slicing?
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if (typeof offset === 'number') {
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this.length = encoding;
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this.parent = subject;
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this.offset = offset;
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} else {
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// Find the length
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switch (type = typeof subject) {
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case 'number':
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this.length = subject;
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break;
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case 'string':
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this.length = Buffer.byteLength(subject, encoding);
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break;
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case 'object': // Assume object is an array
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this.length = subject.length;
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break;
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default:
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throw new Error('First argument needs to be a number, ' +
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'array or string.');
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}
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if (this.length > Buffer.poolSize) {
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// Big buffer, just alloc one.
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this.parent = new SlowBuffer(this.length);
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this.offset = 0;
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} else {
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// Small buffer.
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if (!pool || pool.length - pool.used < this.length) allocPool();
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this.parent = pool;
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this.offset = pool.used;
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pool.used += this.length;
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}
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// Treat array-ish objects as a byte array.
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if (isArrayIsh(subject)) {
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for (var i = 0; i < this.length; i++) {
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this.parent[i + this.offset] = subject[i];
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}
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} else if (type == 'string') {
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// We are a string
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this.length = this.write(subject, 0, encoding);
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}
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}
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SlowBuffer.makeFastBuffer(this.parent, this, this.offset, this.length);
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}
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function isArrayIsh(subject) {
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return Array.isArray(subject) || Buffer.isBuffer(subject) ||
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subject && typeof subject === 'object' &&
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typeof subject.length === 'number';
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}
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exports.SlowBuffer = SlowBuffer;
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exports.Buffer = Buffer;
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Buffer.poolSize = 8 * 1024;
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var pool;
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function allocPool() {
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pool = new SlowBuffer(Buffer.poolSize);
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pool.used = 0;
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}
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// Static methods
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Buffer.isBuffer = function isBuffer(b) {
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return b instanceof Buffer || b instanceof SlowBuffer;
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};
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// Inspect
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Buffer.prototype.inspect = function inspect() {
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var out = [],
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len = this.length;
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for (var i = 0; i < len; i++) {
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out[i] = toHex(this.parent[i + this.offset]);
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}
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return '<Buffer ' + out.join(' ') + '>';
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};
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Buffer.prototype.get = function get(i) {
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if (i < 0 || i >= this.length) throw new Error('oob');
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return this.parent[this.offset + i];
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};
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Buffer.prototype.set = function set(i, v) {
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if (i < 0 || i >= this.length) throw new Error('oob');
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return this.parent[this.offset + i] = v;
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};
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// write(string, offset = 0, length = buffer.length-offset, encoding = 'utf8')
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Buffer.prototype.write = function(string, offset, length, encoding) {
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// Support both (string, offset, length, encoding)
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// and the legacy (string, encoding, offset, length)
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if (isFinite(offset)) {
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if (!isFinite(length)) {
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encoding = length;
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length = undefined;
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}
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} else { // legacy
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var swap = encoding;
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encoding = offset;
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offset = length;
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length = swap;
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}
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offset = +offset || 0;
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var remaining = this.length - offset;
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if (!length) {
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length = remaining;
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} else {
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length = +length;
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if (length > remaining) {
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length = remaining;
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}
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}
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encoding = String(encoding || 'utf8').toLowerCase();
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var ret;
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switch (encoding) {
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case 'hex':
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ret = this.parent.hexWrite(string, this.offset + offset, length);
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break;
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case 'utf8':
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case 'utf-8':
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ret = this.parent.utf8Write(string, this.offset + offset, length);
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break;
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case 'ascii':
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ret = this.parent.asciiWrite(string, this.offset + offset, length);
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break;
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case 'binary':
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ret = this.parent.binaryWrite(string, this.offset + offset, length);
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break;
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case 'base64':
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// Warning: maxLength not taken into account in base64Write
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ret = this.parent.base64Write(string, this.offset + offset, length);
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break;
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case 'ucs2':
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case 'ucs-2':
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ret = this.parent.ucs2Write(string, this.offset + offset, length);
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break;
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default:
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throw new Error('Unknown encoding');
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}
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Buffer._charsWritten = SlowBuffer._charsWritten;
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return ret;
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};
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// toString(encoding, start=0, end=buffer.length)
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Buffer.prototype.toString = function(encoding, start, end) {
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encoding = String(encoding || 'utf8').toLowerCase();
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if (typeof start == 'undefined' || start < 0) {
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start = 0;
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} else if (start > this.length) {
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start = this.length;
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}
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if (typeof end == 'undefined' || end > this.length) {
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end = this.length;
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} else if (end < 0) {
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end = 0;
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}
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start = start + this.offset;
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end = end + this.offset;
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switch (encoding) {
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case 'hex':
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return this.parent.hexSlice(start, end);
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case 'utf8':
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case 'utf-8':
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return this.parent.utf8Slice(start, end);
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case 'ascii':
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return this.parent.asciiSlice(start, end);
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case 'binary':
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return this.parent.binarySlice(start, end);
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case 'base64':
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return this.parent.base64Slice(start, end);
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case 'ucs2':
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case 'ucs-2':
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return this.parent.ucs2Slice(start, end);
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default:
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throw new Error('Unknown encoding');
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}
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};
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// byteLength
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Buffer.byteLength = SlowBuffer.byteLength;
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// fill(value, start=0, end=buffer.length)
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Buffer.prototype.fill = function fill (value, start, end) {
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value || (value = 0);
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start || (start = 0);
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end || (end = this.length);
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if (typeof value === "string") {
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value = value.charCodeAt(0);
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}
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if (!(typeof value === "number") || isNaN(value)) {
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throw new Error("value is not a number");
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}
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if (end < start) throw new Error("end < start");
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// Fill 0 bytes; we're done
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if (end === start) return 0;
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if (this.length == 0) return 0;
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if (start < 0 || start >= this.length) {
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throw new Error("start out of bounds");
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}
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if (end < 0 || end > this.length) {
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throw new Error("end out of bounds");
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}
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return this.parent.fill(value,
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start + this.offset,
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end + this.offset);
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};
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// copy(targetBuffer, targetStart=0, sourceStart=0, sourceEnd=buffer.length)
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Buffer.prototype.copy = function(target, target_start, start, end) {
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var source = this;
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start || (start = 0);
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end || (end = this.length);
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target_start || (target_start = 0);
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if (end < start) throw new Error('sourceEnd < sourceStart');
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// Copy 0 bytes; we're done
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if (end === start) return 0;
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if (target.length == 0 || source.length == 0) return 0;
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if (target_start < 0 || target_start >= target.length) {
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throw new Error('targetStart out of bounds');
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}
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if (start < 0 || start >= source.length) {
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throw new Error('sourceStart out of bounds');
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}
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if (end < 0 || end > source.length) {
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throw new Error('sourceEnd out of bounds');
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}
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// Are we oob?
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if (end > this.length) {
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end = this.length;
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}
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if (target.length - target_start < end - start) {
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end = target.length - target_start + start;
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}
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return this.parent.copy(target.parent,
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target_start + target.offset,
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start + this.offset,
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end + this.offset);
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};
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// slice(start, end)
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Buffer.prototype.slice = function(start, end) {
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if (end === undefined) end = this.length;
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if (end > this.length) throw new Error('oob');
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if (start > end) throw new Error('oob');
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return new Buffer(this.parent, end - start, +start + this.offset);
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};
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// Legacy methods for backwards compatibility.
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Buffer.prototype.utf8Slice = function(start, end) {
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return this.toString('utf8', start, end);
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};
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Buffer.prototype.binarySlice = function(start, end) {
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return this.toString('binary', start, end);
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};
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Buffer.prototype.asciiSlice = function(start, end) {
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return this.toString('ascii', start, end);
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};
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Buffer.prototype.utf8Write = function(string, offset) {
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return this.write(string, offset, 'utf8');
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};
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Buffer.prototype.binaryWrite = function(string, offset) {
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return this.write(string, offset, 'binary');
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};
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Buffer.prototype.asciiWrite = function(string, offset) {
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return this.write(string, offset, 'ascii');
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};
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Buffer.prototype.readUInt8 = function(offset, endian) {
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var buffer = this;
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assert.ok(endian !== undefined && endian !== null,
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'missing endian');
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assert.ok(endian == 'big' || endian == 'little',
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'bad endian value');
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assert.ok(offset !== undefined && offset !== null,
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'missing offset');
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assert.ok(offset < buffer.length,
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'Trying to read beyond buffer length');
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return buffer[offset];
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};
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Buffer.prototype.readUInt16 = function(offset, endian) {
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var val = 0;
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var buffer = this;
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assert.ok(endian !== undefined && endian !== null,
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'missing endian');
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assert.ok(endian == 'big' || endian == 'little',
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'bad endian value');
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assert.ok(offset !== undefined && offset !== null,
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'missing offset');
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assert.ok(offset + 1 < buffer.length,
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'Trying to read beyond buffer length');
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if (endian == 'big') {
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val = buffer[offset] << 8;
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val |= buffer[offset + 1];
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} else {
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val = buffer[offset];
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val |= buffer[offset + 1] << 8;
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}
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return val;
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};
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Buffer.prototype.readUInt32 = function(offset, endian) {
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var val = 0;
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var buffer = this;
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assert.ok(endian !== undefined && endian !== null,
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'missing endian');
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assert.ok(endian == 'big' || endian == 'little',
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'bad endian value');
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assert.ok(offset !== undefined && offset !== null,
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'missing offset');
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assert.ok(offset + 3 < buffer.length,
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'Trying to read beyond buffer length');
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if (endian == 'big') {
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val = buffer[offset + 1] << 16;
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val |= buffer[offset + 2] << 8;
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val |= buffer[offset + 3];
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val = val + (buffer[offset] << 24 >>> 0);
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|
} else {
|
|
val = buffer[offset + 2] << 16;
|
|
val |= buffer[offset + 1] << 8;
|
|
val |= buffer[offset];
|
|
val = val + (buffer[offset + 3] << 24 >>> 0);
|
|
}
|
|
|
|
return val;
|
|
};
|
|
|
|
|
|
/*
|
|
* Signed integer types, yay team! A reminder on how two's complement actually
|
|
* works. The first bit is the signed bit, i.e. tells us whether or not the
|
|
* number should be positive or negative. If the two's complement value is
|
|
* positive, then we're done, as it's equivalent to the unsigned representation.
|
|
*
|
|
* Now if the number is positive, you're pretty much done, you can just leverage
|
|
* the unsigned translations and return those. Unfortunately, negative numbers
|
|
* aren't quite that straightforward.
|
|
*
|
|
* At first glance, one might be inclined to use the traditional formula to
|
|
* translate binary numbers between the positive and negative values in two's
|
|
* complement. (Though it doesn't quite work for the most negative value)
|
|
* Mainly:
|
|
* - invert all the bits
|
|
* - add one to the result
|
|
*
|
|
* Of course, this doesn't quite work in Javascript. Take for example the value
|
|
* of -128. This could be represented in 16 bits (big-endian) as 0xff80. But of
|
|
* course, Javascript will do the following:
|
|
*
|
|
* > ~0xff80
|
|
* -65409
|
|
*
|
|
* Whoh there, Javascript, that's not quite right. But wait, according to
|
|
* Javascript that's perfectly correct. When Javascript ends up seeing the
|
|
* constant 0xff80, it has no notion that it is actually a signed number. It
|
|
* assumes that we've input the unsigned value 0xff80. Thus, when it does the
|
|
* binary negation, it casts it into a signed value, (positive 0xff80). Then
|
|
* when you perform binary negation on that, it turns it into a negative number.
|
|
*
|
|
* Instead, we're going to have to use the following general formula, that works
|
|
* in a rather Javascript friendly way. I'm glad we don't support this kind of
|
|
* weird numbering scheme in the kernel.
|
|
*
|
|
* (BIT-MAX - (unsigned)val + 1) * -1
|
|
*
|
|
* The astute observer, may think that this doesn't make sense for 8-bit numbers
|
|
* (really it isn't necessary for them). However, when you get 16-bit numbers,
|
|
* you do. Let's go back to our prior example and see how this will look:
|
|
*
|
|
* (0xffff - 0xff80 + 1) * -1
|
|
* (0x007f + 1) * -1
|
|
* (0x0080) * -1
|
|
*/
|
|
Buffer.prototype.readInt8 = function(offset, endian) {
|
|
var buffer = this;
|
|
var neg;
|
|
|
|
assert.ok(endian !== undefined && endian !== null,
|
|
'missing endian');
|
|
|
|
assert.ok(endian == 'big' || endian == 'little',
|
|
'bad endian value');
|
|
|
|
assert.ok(offset !== undefined && offset !== null,
|
|
'missing offset');
|
|
|
|
assert.ok(offset < buffer.length,
|
|
'Trying to read beyond buffer length');
|
|
|
|
neg = buffer[offset] & 0x80;
|
|
if (!neg) {
|
|
return (buffer[offset]);
|
|
}
|
|
|
|
return ((0xff - buffer[offset] + 1) * -1);
|
|
};
|
|
|
|
|
|
Buffer.prototype.readInt16 = function(offset, endian) {
|
|
var buffer = this;
|
|
var neg;
|
|
|
|
assert.ok(endian !== undefined && endian !== null,
|
|
'missing endian');
|
|
|
|
assert.ok(endian == 'big' || endian == 'little',
|
|
'bad endian value');
|
|
|
|
assert.ok(offset !== undefined && offset !== null,
|
|
'missing offset');
|
|
|
|
assert.ok(offset + 1 < buffer.length,
|
|
'Trying to read beyond buffer length');
|
|
|
|
val = buffer.readUInt16(offset, endian);
|
|
neg = val & 0x8000;
|
|
if (!neg) {
|
|
return val;
|
|
}
|
|
|
|
return (0xffff - val + 1) * -1;
|
|
};
|
|
|
|
|
|
Buffer.prototype.readInt32 = function(offset, endian) {
|
|
var buffer = this;
|
|
var neg;
|
|
|
|
assert.ok(endian !== undefined && endian !== null,
|
|
'missing endian');
|
|
|
|
assert.ok(endian == 'big' || endian == 'little',
|
|
'bad endian value');
|
|
|
|
assert.ok(offset !== undefined && offset !== null,
|
|
'missing offset');
|
|
|
|
assert.ok(offset + 3 < buffer.length,
|
|
'Trying to read beyond buffer length');
|
|
|
|
val = buffer.readUInt32(offset, endian);
|
|
neg = val & 0x80000000;
|
|
if (!neg) {
|
|
return (val);
|
|
}
|
|
|
|
return (0xffffffff - val + 1) * -1;
|
|
};
|
|
|
|
|
|
Buffer.prototype.readFloat = function(offset, endian) {
|
|
var buffer = this;
|
|
|
|
assert.ok(endian !== undefined && endian !== null,
|
|
'missing endian');
|
|
|
|
assert.ok(endian == 'big' || endian == 'little',
|
|
'bad endian value');
|
|
|
|
assert.ok(offset !== undefined && offset !== null,
|
|
'missing offset');
|
|
|
|
assert.ok(offset + 3 < buffer.length,
|
|
'Trying to read beyond buffer length');
|
|
|
|
return IEEE754.readIEEE754(buffer, offset, endian, 23, 4);
|
|
};
|
|
|
|
Buffer.prototype.readDouble = function(offset, endian) {
|
|
var buffer = this;
|
|
|
|
assert.ok(endian !== undefined && endian !== null,
|
|
'missing endian');
|
|
|
|
assert.ok(endian == 'big' || endian == 'little',
|
|
'bad endian value');
|
|
|
|
assert.ok(offset !== undefined && offset !== null,
|
|
'missing offset');
|
|
|
|
assert.ok(offset + 7 < buffer.length,
|
|
'Trying to read beyond buffer length');
|
|
|
|
return IEEE754.readIEEE754(buffer, offset, endian, 52, 8);
|
|
};
|
|
|
|
|
|
/*
|
|
* We have to make sure that the value is a valid integer. This means that it is
|
|
* non-negative. It has no fractional component and that it does not exceed the
|
|
* maximum allowed value.
|
|
*
|
|
* value The number to check for validity
|
|
*
|
|
* max The maximum value
|
|
*/
|
|
function verifuint(value, max) {
|
|
assert.ok(typeof (value) == 'number',
|
|
'cannot write a non-number as a number');
|
|
|
|
assert.ok(value >= 0,
|
|
'specified a negative value for writing an unsigned value');
|
|
|
|
assert.ok(value <= max, 'value is larger than maximum value for type');
|
|
|
|
assert.ok(Math.floor(value) === value, 'value has a fractional component');
|
|
}
|
|
|
|
|
|
Buffer.prototype.writeUInt8 = function(value, offset, endian) {
|
|
var buffer = this;
|
|
|
|
assert.ok(value !== undefined && value !== null,
|
|
'missing value');
|
|
|
|
assert.ok(endian !== undefined && endian !== null,
|
|
'missing endian');
|
|
|
|
assert.ok(endian == 'big' || endian == 'little',
|
|
'bad endian value');
|
|
|
|
assert.ok(offset !== undefined && offset !== null,
|
|
'missing offset');
|
|
|
|
assert.ok(offset < buffer.length,
|
|
'trying to write beyond buffer length');
|
|
|
|
verifuint(value, 0xff);
|
|
buffer[offset] = value;
|
|
};
|
|
|
|
|
|
Buffer.prototype.writeUInt16 = function(value, offset, endian) {
|
|
var buffer = this;
|
|
|
|
assert.ok(value !== undefined && value !== null,
|
|
'missing value');
|
|
|
|
assert.ok(endian !== undefined && endian !== null,
|
|
'missing endian');
|
|
|
|
assert.ok(endian == 'big' || endian == 'little',
|
|
'bad endian value');
|
|
|
|
assert.ok(offset !== undefined && offset !== null,
|
|
'missing offset');
|
|
|
|
assert.ok(offset + 1 < buffer.length,
|
|
'trying to write beyond buffer length');
|
|
|
|
verifuint(value, 0xffff);
|
|
|
|
if (endian == 'big') {
|
|
buffer[offset] = (value & 0xff00) >>> 8;
|
|
buffer[offset + 1] = value & 0x00ff;
|
|
} else {
|
|
buffer[offset + 1] = (value & 0xff00) >>> 8;
|
|
buffer[offset] = value & 0x00ff;
|
|
}
|
|
};
|
|
|
|
|
|
Buffer.prototype.writeUInt32 = function(value, offset, endian) {
|
|
var buffer = this;
|
|
|
|
assert.ok(value !== undefined && value !== null,
|
|
'missing value');
|
|
|
|
assert.ok(endian !== undefined && endian !== null,
|
|
'missing endian');
|
|
|
|
assert.ok(endian == 'big' || endian == 'little',
|
|
'bad endian value');
|
|
|
|
assert.ok(offset !== undefined && offset !== null,
|
|
'missing offset');
|
|
|
|
assert.ok(offset + 3 < buffer.length,
|
|
'trying to write beyond buffer length');
|
|
|
|
verifuint(value, 0xffffffff);
|
|
if (endian == 'big') {
|
|
buffer[offset] = (value >>> 24) & 0xff;
|
|
buffer[offset + 1] = (value >>> 16) & 0xff;
|
|
buffer[offset + 2] = (value >>> 8) & 0xff;
|
|
buffer[offset + 3] = value & 0xff;
|
|
} else {
|
|
buffer[offset + 3] = (value >>> 24) & 0xff;
|
|
buffer[offset + 2] = (value >>> 16) & 0xff;
|
|
buffer[offset + 1] = (value >>> 8) & 0xff;
|
|
buffer[offset] = value & 0xff;
|
|
}
|
|
};
|
|
|
|
|
|
/*
|
|
* We now move onto our friends in the signed number category. Unlike unsigned
|
|
* numbers, we're going to have to worry a bit more about how we put values into
|
|
* arrays. Since we are only worrying about signed 32-bit values, we're in
|
|
* slightly better shape. Unfortunately, we really can't do our favorite binary
|
|
* & in this system. It really seems to do the wrong thing. For example:
|
|
*
|
|
* > -32 & 0xff
|
|
* 224
|
|
*
|
|
* What's happening above is really: 0xe0 & 0xff = 0xe0. However, the results of
|
|
* this aren't treated as a signed number. Ultimately a bad thing.
|
|
*
|
|
* What we're going to want to do is basically create the unsigned equivalent of
|
|
* our representation and pass that off to the wuint* functions. To do that
|
|
* we're going to do the following:
|
|
*
|
|
* - if the value is positive
|
|
* we can pass it directly off to the equivalent wuint
|
|
* - if the value is negative
|
|
* we do the following computation:
|
|
* mb + val + 1, where
|
|
* mb is the maximum unsigned value in that byte size
|
|
* val is the Javascript negative integer
|
|
*
|
|
*
|
|
* As a concrete value, take -128. In signed 16 bits this would be 0xff80. If
|
|
* you do out the computations:
|
|
*
|
|
* 0xffff - 128 + 1
|
|
* 0xffff - 127
|
|
* 0xff80
|
|
*
|
|
* You can then encode this value as the signed version. This is really rather
|
|
* hacky, but it should work and get the job done which is our goal here.
|
|
*/
|
|
|
|
/*
|
|
* A series of checks to make sure we actually have a signed 32-bit number
|
|
*/
|
|
function verifsint(value, max, min) {
|
|
assert.ok(typeof (value) == 'number',
|
|
'cannot write a non-number as a number');
|
|
|
|
assert.ok(value <= max, 'value larger than maximum allowed value');
|
|
|
|
assert.ok(value >= min, 'value smaller than minimum allowed value');
|
|
|
|
assert.ok(Math.floor(value) === value, 'value has a fractional component');
|
|
}
|
|
|
|
|
|
function verifIEEE754(value, max, min) {
|
|
assert.ok(typeof (value) == 'number',
|
|
'cannot write a non-number as a number');
|
|
|
|
assert.ok(value <= max, 'value larger than maximum allowed value');
|
|
|
|
assert.ok(value >= min, 'value smaller than minimum allowed value');
|
|
}
|
|
|
|
|
|
Buffer.prototype.writeInt8 = function(value, offset, endian) {
|
|
var buffer = this;
|
|
|
|
assert.ok(value !== undefined && value !== null,
|
|
'missing value');
|
|
|
|
assert.ok(endian !== undefined && endian !== null,
|
|
'missing endian');
|
|
|
|
assert.ok(endian == 'big' || endian == 'little',
|
|
'bad endian value');
|
|
|
|
assert.ok(offset !== undefined && offset !== null,
|
|
'missing offset');
|
|
|
|
assert.ok(offset < buffer.length,
|
|
'Trying to write beyond buffer length');
|
|
|
|
verifsint(value, 0x7f, -0xf0);
|
|
|
|
if (value >= 0) {
|
|
buffer.writeUInt8(value, offset, endian);
|
|
} else {
|
|
buffer.writeUInt8(0xff + value + 1, offset, endian);
|
|
}
|
|
};
|
|
|
|
|
|
Buffer.prototype.writeInt16 = function(value, offset, endian) {
|
|
var buffer = this;
|
|
|
|
assert.ok(value !== undefined && value !== null,
|
|
'missing value');
|
|
|
|
assert.ok(endian !== undefined && endian !== null,
|
|
'missing endian');
|
|
|
|
assert.ok(endian == 'big' || endian == 'little',
|
|
'bad endian value');
|
|
|
|
assert.ok(offset !== undefined && offset !== null,
|
|
'missing offset');
|
|
|
|
assert.ok(offset + 1 < buffer.length,
|
|
'Trying to write beyond buffer length');
|
|
|
|
verifsint(value, 0x7fff, -0xf000);
|
|
|
|
if (value >= 0) {
|
|
buffer.writeUInt16(value, offset, endian);
|
|
} else {
|
|
buffer.writeUInt16(0xffff + value + 1, offset, endian);
|
|
}
|
|
};
|
|
|
|
|
|
Buffer.prototype.writeInt32 = function(value, offset, endian) {
|
|
var buffer = this;
|
|
|
|
assert.ok(value !== undefined && value !== null,
|
|
'missing value');
|
|
|
|
assert.ok(endian !== undefined && endian !== null,
|
|
'missing endian');
|
|
|
|
assert.ok(endian == 'big' || endian == 'little',
|
|
'bad endian value');
|
|
|
|
assert.ok(offset !== undefined && offset !== null,
|
|
'missing offset');
|
|
|
|
assert.ok(offset + 3 < buffer.length,
|
|
'Trying to write beyond buffer length');
|
|
|
|
verifsint(value, 0x7fffffff, -0xf0000000);
|
|
if (value >= 0) {
|
|
buffer.writeUInt32(value, offset, endian);
|
|
} else {
|
|
buffer.writeUInt32(0xffffffff + value + 1, offset, endian);
|
|
}
|
|
};
|
|
|
|
|
|
Buffer.prototype.writeFloat = function(value, offset, endian) {
|
|
var buffer = this;
|
|
|
|
assert.ok(value !== undefined && value !== null,
|
|
'missing value');
|
|
|
|
assert.ok(endian !== undefined && endian !== null,
|
|
'missing endian');
|
|
|
|
assert.ok(endian == 'big' || endian == 'little',
|
|
'bad endian value');
|
|
|
|
assert.ok(offset !== undefined && offset !== null,
|
|
'missing offset');
|
|
|
|
assert.ok(offset + 3 < buffer.length,
|
|
'Trying to write beyond buffer length');
|
|
|
|
verifIEEE754(value, 3.4028234663852886e+38, -3.4028234663852886e+38);
|
|
IEEE754.writeIEEE754(buffer, value, offset, endian, 23, 4);
|
|
};
|
|
|
|
|
|
Buffer.prototype.writeDouble = function(value, offset, endian) {
|
|
var buffer = this;
|
|
|
|
assert.ok(value !== undefined && value !== null,
|
|
'missing value');
|
|
|
|
assert.ok(endian !== undefined && endian !== null,
|
|
'missing endian');
|
|
|
|
assert.ok(endian == 'big' || endian == 'little',
|
|
'bad endian value');
|
|
|
|
assert.ok(offset !== undefined && offset !== null,
|
|
'missing offset');
|
|
|
|
assert.ok(offset + 7 < buffer.length,
|
|
'Trying to write beyond buffer length');
|
|
|
|
verifIEEE754(value, 1.7976931348623157E+308, -1.7976931348623157E+308);
|
|
IEEE754.writeIEEE754(buffer, value, offset, endian, 52, 8);
|
|
};
|
|
|