lib/buffer.js
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
'use strict';
var buffer = process.binding('buffer');
var smalloc = process.binding('smalloc');
var util = require('util');
var alloc = smalloc.alloc;
var truncate = smalloc.truncate;
var sliceOnto = smalloc.sliceOnto;
var kMaxLength = smalloc.kMaxLength;
var internal = {};
exports.Buffer = Buffer;
exports.SlowBuffer = SlowBuffer;
exports.INSPECT_MAX_BYTES = 50;
Buffer.poolSize = 8 * 1024;
var poolSize, poolOffset, allocPool;
function createPool() {
poolSize = Buffer.poolSize;
allocPool = alloc({}, poolSize);
poolOffset = 0;
}
createPool();
function Buffer(subject, encoding) {
if (!util.isBuffer(this))
return new Buffer(subject, encoding);
if (util.isNumber(subject)) {
this.length = +subject;
} else if (util.isString(subject)) {
if (!util.isString(encoding) || encoding.length === 0)
encoding = 'utf8';
this.length = Buffer.byteLength(subject, encoding);
// Handle Arrays, Buffers, Uint8Arrays or JSON.
} else if (util.isObject(subject)) {
if (subject.type === 'Buffer' && util.isArray(subject.data))
subject = subject.data;
this.length = +subject.length;
} else {
throw new TypeError('must start with number, buffer, array or string');
}
if (this.length > kMaxLength) {
throw new RangeError('Attempt to allocate Buffer larger than maximum ' +
'size: 0x' + kMaxLength.toString(16) + ' bytes');
}
if (this.length < 0)
this.length = 0;
else
this.length >>>= 0; // Coerce to uint32.
this.parent = undefined;
if (this.length <= (Buffer.poolSize >>> 1) && this.length > 0) {
if (this.length > poolSize - poolOffset)
createPool();
this.parent = sliceOnto(allocPool,
this,
poolOffset,
poolOffset + this.length);
poolOffset += this.length;
// Ensure aligned slices
if (poolOffset & 0x7) {
poolOffset |= 0x7;
poolOffset++;
}
} else {
alloc(this, this.length);
}
if (util.isNumber(subject)) {
return;
}
if (util.isString(subject)) {
// In the case of base64 it's possible that the size of the buffer
// allocated was slightly too large. In this case we need to rewrite
// the length to the actual length written.
var len = this.write(subject, encoding);
// Buffer was truncated after decode, realloc internal ExternalArray
if (len !== this.length) {
var prevLen = this.length;
this.length = len;
truncate(this, this.length);
// Only need to readjust the poolOffset if the allocation is a slice.
if (this.parent != undefined)
poolOffset -= (prevLen - len);
}
} else if (util.isBuffer(subject)) {
subject.copy(this, 0, 0, this.length);
} else if (util.isNumber(subject.length) || util.isArray(subject)) {
// Really crappy way to handle Uint8Arrays, but V8 doesn't give a simple
// way to access the data from the C++ API.
for (var i = 0; i < this.length; i++)
this[i] = subject[i];
}
}
function SlowBuffer(length) {
length = length >>> 0;
if (length > kMaxLength) {
throw new RangeError('Attempt to allocate Buffer larger than maximum ' +
'size: 0x' + kMaxLength.toString(16) + ' bytes');
}
var b = new NativeBuffer(length);
alloc(b, length);
return b;
}
// Bypass all checks for instantiating unallocated Buffer required for
// Objects created in C++. Significantly faster than calling the Buffer
// function.
function NativeBuffer(length) {
this.length = length >>> 0;
// Set this to keep the object map the same.
this.parent = undefined;
}
NativeBuffer.prototype = Buffer.prototype;
// add methods to Buffer prototype
buffer.setupBufferJS(NativeBuffer, internal);
// Static methods
Buffer.isBuffer = function isBuffer(b) {
return util.isBuffer(b);
};
Buffer.compare = function compare(a, b) {
if (!(a instanceof Buffer) ||
!(b instanceof Buffer))
throw new TypeError('Arguments must be Buffers');
return internal.compare(a, b);
};
Buffer.isEncoding = function(encoding) {
switch ((encoding + '').toLowerCase()) {
case 'hex':
case 'utf8':
case 'utf-8':
case 'ascii':
case 'binary':
case 'base64':
case 'ucs2':
case 'ucs-2':
case 'utf16le':
case 'utf-16le':
case 'raw':
return true;
default:
return false;
}
};
Buffer.concat = function(list, length) {
if (!util.isArray(list))
throw new TypeError('list argument must be an Array of Buffers.');
if (util.isUndefined(length)) {
length = 0;
for (var i = 0; i < list.length; i++)
length += list[i].length;
} else {
length = length >>> 0;
}
if (list.length === 0)
return new Buffer(0);
else if (list.length === 1)
return list[0];
var buffer = new Buffer(length);
var pos = 0;
for (var i = 0; i < list.length; i++) {
var buf = list[i];
buf.copy(buffer, pos);
pos += buf.length;
}
return buffer;
};
Buffer.byteLength = function(str, enc) {
var ret;
str = str + '';
switch (enc) {
case 'ascii':
case 'binary':
case 'raw':
ret = str.length;
break;
case 'ucs2':
case 'ucs-2':
case 'utf16le':
case 'utf-16le':
ret = str.length * 2;
break;
case 'hex':
ret = str.length >>> 1;
break;
default:
ret = internal.byteLength(str, enc);
}
return ret;
};
// toString(encoding, start=0, end=buffer.length)
Buffer.prototype.toString = function(encoding, start, end) {
var loweredCase = false;
start = start >>> 0;
end = util.isUndefined(end) || end === Infinity ? this.length : end >>> 0;
if (!encoding) encoding = 'utf8';
if (start < 0) start = 0;
if (end > this.length) end = this.length;
if (end <= start) return '';
while (true) {
switch (encoding) {
case 'hex':
return this.hexSlice(start, end);
case 'utf8':
case 'utf-8':
return this.utf8Slice(start, end);
case 'ascii':
return this.asciiSlice(start, end);
case 'binary':
return this.binarySlice(start, end);
case 'base64':
return this.base64Slice(start, end);
case 'ucs2':
case 'ucs-2':
case 'utf16le':
case 'utf-16le':
return this.ucs2Slice(start, end);
default:
if (loweredCase)
throw new TypeError('Unknown encoding: ' + encoding);
encoding = (encoding + '').toLowerCase();
loweredCase = true;
}
}
};
Buffer.prototype.equals = function equals(b) {
if (!(b instanceof Buffer))
throw new TypeError('Argument must be a Buffer');
return internal.compare(this, b) === 0;
};
// Inspect
Buffer.prototype.inspect = function inspect() {
var str = '';
var max = exports.INSPECT_MAX_BYTES;
if (this.length > 0) {
str = this.toString('hex', 0, max).match(/.{2}/g).join(' ');
if (this.length > max)
str += ' ... ';
}
return '<' + this.constructor.name + ' ' + str + '>';
};
Buffer.prototype.compare = function compare(b) {
if (!(b instanceof Buffer))
throw new TypeError('Argument must be a Buffer');
return internal.compare(this, b);
};
Buffer.prototype.fill = function fill(val, start, end) {
start = start >> 0;
end = (end === undefined) ? this.length : end >> 0;
if (start < 0 || end > this.length)
throw new RangeError('out of range index');
if (end <= start)
return this;
if (typeof val !== 'string') {
val = val >>> 0;
} else if (val.length === 1) {
var code = val.charCodeAt(0);
if (code < 256)
val = code;
}
internal.fill(this, val, start, end);
return this;
};
// XXX remove in v0.13
Buffer.prototype.get = util.deprecate(function get(offset) {
offset = ~~offset;
if (offset < 0 || offset >= this.length)
throw new RangeError('index out of range');
return this[offset];
}, '.get() is deprecated. Access using array indexes instead.');
// XXX remove in v0.13
Buffer.prototype.set = util.deprecate(function set(offset, v) {
offset = ~~offset;
if (offset < 0 || offset >= this.length)
throw new RangeError('index out of range');
return this[offset] = v;
}, '.set() is deprecated. Set using array indexes instead.');
// TODO(trevnorris): fix these checks to follow new standard
// write(string, offset = 0, length = buffer.length, encoding = 'utf8')
var writeWarned = false;
var writeMsg = '.write(string, encoding, offset, length) is deprecated.' +
' Use write(string[, offset[, length]][, encoding]) instead.';
Buffer.prototype.write = function(string, offset, length, encoding) {
// Buffer#write(string);
if (util.isUndefined(offset)) {
encoding = 'utf8';
length = this.length;
offset = 0;
// Buffer#write(string, encoding)
} else if (util.isUndefined(length) && util.isString(offset)) {
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 (util.isUndefined(encoding))
encoding = 'utf8';
} else {
encoding = length;
length = undefined;
}
// XXX legacy write(string, encoding, offset, length) - remove in v0.13
} else {
if (!writeWarned) {
if (process.throwDeprecation)
throw new Error(writeMsg);
else if (process.traceDeprecation)
console.trace(writeMsg);
else
console.error(writeMsg);
writeWarned = true;
}
var swap = encoding;
encoding = offset;
offset = length >>> 0;
length = swap;
}
var remaining = this.length - offset;
if (util.isUndefined(length) || length > remaining)
length = remaining;
encoding = !!encoding ? (encoding + '').toLowerCase() : 'utf8';
if (string.length > 0 && (length < 0 || offset < 0))
throw new RangeError('attempt to write outside buffer bounds');
var ret;
switch (encoding) {
case 'hex':
ret = this.hexWrite(string, offset, length);
break;
case 'utf8':
case 'utf-8':
ret = this.utf8Write(string, offset, length);
break;
case 'ascii':
ret = this.asciiWrite(string, offset, length);
break;
case 'binary':
ret = this.binaryWrite(string, offset, length);
break;
case 'base64':
// Warning: maxLength not taken into account in base64Write
ret = this.base64Write(string, offset, length);
break;
case 'ucs2':
case 'ucs-2':
case 'utf16le':
case 'utf-16le':
ret = this.ucs2Write(string, offset, length);
break;
default:
throw new TypeError('Unknown encoding: ' + encoding);
}
return ret;
};
Buffer.prototype.toJSON = function() {
return {
type: 'Buffer',
data: Array.prototype.slice.call(this, 0)
};
};
// TODO(trevnorris): currently works like Array.prototype.slice(), which
// doesn't follow the new standard for throwing on out of range indexes.
Buffer.prototype.slice = function(start, end) {
var len = this.length;
start = ~~start;
end = util.isUndefined(end) ? len : ~~end;
if (start < 0) {
start += len;
if (start < 0)
start = 0;
} else if (start > len) {
start = len;
}
if (end < 0) {
end += len;
if (end < 0)
end = 0;
} else if (end > len) {
end = len;
}
if (end < start)
end = start;
var buf = new NativeBuffer();
sliceOnto(this, buf, start, end);
buf.length = end - start;
if (buf.length > 0)
buf.parent = util.isUndefined(this.parent) ? this : this.parent;
return buf;
};
function checkOffset(offset, ext, length) {
if (offset + ext > length)
throw new RangeError('index out of range');
}
Buffer.prototype.readUIntLE = function(offset, byteLength, noAssert) {
offset = offset >>> 0;
byteLength = byteLength >>> 0;
if (!noAssert)
checkOffset(offset, byteLength, this.length);
var val = this[offset];
var mul = 1;
var i = 0;
while (++i < byteLength && (mul *= 0x100))
val += this[offset + i] * mul;
return val;
};
Buffer.prototype.readUIntBE = function(offset, byteLength, noAssert) {
offset = offset >>> 0;
byteLength = byteLength >>> 0;
if (!noAssert)
checkOffset(offset, byteLength, this.length);
var val = this[offset + --byteLength];
var mul = 1;
while (byteLength > 0 && (mul *= 0x100))
val += this[offset + --byteLength] * mul;
return val;
};
Buffer.prototype.readUInt8 = function(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 1, this.length);
return this[offset];
};
Buffer.prototype.readUInt16LE = function(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 2, this.length);
return this[offset] | (this[offset + 1] << 8);
};
Buffer.prototype.readUInt16BE = function(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 2, this.length);
return (this[offset] << 8) | this[offset + 1];
};
Buffer.prototype.readUInt32LE = function(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 4, this.length);
return ((this[offset]) |
(this[offset + 1] << 8) |
(this[offset + 2] << 16)) +
(this[offset + 3] * 0x1000000);
};
Buffer.prototype.readUInt32BE = function(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 4, this.length);
return (this[offset] * 0x1000000) +
((this[offset + 1] << 16) |
(this[offset + 2] << 8) |
this[offset + 3]);
};
Buffer.prototype.readIntLE = function(offset, byteLength, noAssert) {
offset = offset >>> 0;
byteLength = byteLength >>> 0;
if (!noAssert)
checkOffset(offset, byteLength, this.length);
var val = this[offset];
var mul = 1;
var i = 0;
while (++i < byteLength && (mul *= 0x100))
val += this[offset + i] * mul;
mul *= 0x80;
if (val >= mul)
val -= Math.pow(2, 8 * byteLength);
return val;
};
Buffer.prototype.readIntBE = function(offset, byteLength, noAssert) {
offset = offset >>> 0;
byteLength = byteLength >>> 0;
if (!noAssert)
checkOffset(offset, byteLength, this.length);
var i = byteLength;
var mul = 1;
var val = this[offset + --i];
while (i > 0 && (mul *= 0x100))
val += this[offset + --i] * mul;
mul *= 0x80;
if (val >= mul)
val -= Math.pow(2, 8 * byteLength);
return val;
};
Buffer.prototype.readInt8 = function(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 1, this.length);
var val = this[offset];
return !(val & 0x80) ? val : (0xff - val + 1) * -1;
};
Buffer.prototype.readInt16LE = function(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 2, this.length);
var val = this[offset] | (this[offset + 1] << 8);
return (val & 0x8000) ? val | 0xFFFF0000 : val;
};
Buffer.prototype.readInt16BE = function(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 2, this.length);
var val = this[offset + 1] | (this[offset] << 8);
return (val & 0x8000) ? val | 0xFFFF0000 : val;
};
Buffer.prototype.readInt32LE = function(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 4, this.length);
return (this[offset]) |
(this[offset + 1] << 8) |
(this[offset + 2] << 16) |
(this[offset + 3] << 24);
};
Buffer.prototype.readInt32BE = function(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 4, this.length);
return (this[offset] << 24) |
(this[offset + 1] << 16) |
(this[offset + 2] << 8) |
(this[offset + 3]);
};
Buffer.prototype.readFloatLE = function readFloatLE(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 4, this.length);
return internal.readFloatLE(this, offset);
};
Buffer.prototype.readFloatBE = function readFloatBE(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 4, this.length);
return internal.readFloatBE(this, offset);
};
Buffer.prototype.readDoubleLE = function readDoubleLE(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 8, this.length);
return internal.readDoubleLE(this, offset);
};
Buffer.prototype.readDoubleBE = function readDoubleBE(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 8, this.length);
return internal.readDoubleBE(this, offset);
};
function checkInt(buffer, value, offset, ext, max, min) {
if (!(buffer instanceof Buffer))
throw new TypeError('buffer must be a Buffer instance');
if (value > max || value < min)
throw new TypeError('value is out of bounds');
if (offset + ext > buffer.length)
throw new RangeError('index out of range');
}
Buffer.prototype.writeUIntLE = function(value, offset, byteLength, noAssert) {
value = +value;
offset = offset >>> 0;
byteLength = byteLength >>> 0;
if (!noAssert)
checkInt(this, value, offset, byteLength, Math.pow(2, 8 * byteLength), 0);
var mul = 1;
var i = 0;
this[offset] = value;
while (++i < byteLength && (mul *= 0x100))
this[offset + i] = (value / mul) >>> 0;
return offset + byteLength;
};
Buffer.prototype.writeUIntBE = function(value, offset, byteLength, noAssert) {
value = +value;
offset = offset >>> 0;
byteLength = byteLength >>> 0;
if (!noAssert)
checkInt(this, value, offset, byteLength, Math.pow(2, 8 * byteLength), 0);
var i = byteLength - 1;
var mul = 1;
this[offset + i] = value;
while (--i >= 0 && (mul *= 0x100))
this[offset + i] = (value / mul) >>> 0;
return offset + byteLength;
};
Buffer.prototype.writeUInt8 = function(value, offset, noAssert) {
value = +value;
offset = offset >>> 0;
if (!noAssert)
checkInt(this, value, offset, 1, 0xff, 0);
this[offset] = value;
return offset + 1;
};
Buffer.prototype.writeUInt16LE = function(value, offset, noAssert) {
value = +value;
offset = offset >>> 0;
if (!noAssert)
checkInt(this, value, offset, 2, 0xffff, 0);
this[offset] = value;
this[offset + 1] = (value >>> 8);
return offset + 2;
};
Buffer.prototype.writeUInt16BE = function(value, offset, noAssert) {
value = +value;
offset = offset >>> 0;
if (!noAssert)
checkInt(this, value, offset, 2, 0xffff, 0);
this[offset] = (value >>> 8);
this[offset + 1] = value;
return offset + 2;
};
Buffer.prototype.writeUInt32LE = function(value, offset, noAssert) {
value = +value;
offset = offset >>> 0;
if (!noAssert)
checkInt(this, value, offset, 4, 0xffffffff, 0);
this[offset + 3] = (value >>> 24);
this[offset + 2] = (value >>> 16);
this[offset + 1] = (value >>> 8);
this[offset] = value;
return offset + 4;
};
Buffer.prototype.writeUInt32BE = function(value, offset, noAssert) {
value = +value;
offset = offset >>> 0;
if (!noAssert)
checkInt(this, value, offset, 4, 0xffffffff, 0);
this[offset] = (value >>> 24);
this[offset + 1] = (value >>> 16);
this[offset + 2] = (value >>> 8);
this[offset + 3] = value;
return offset + 4;
};
Buffer.prototype.writeIntLE = function(value, offset, byteLength, noAssert) {
value = +value;
offset = offset >>> 0;
if (!noAssert) {
checkInt(this,
value,
offset,
byteLength,
Math.pow(2, 8 * byteLength - 1) - 1,
-Math.pow(2, 8 * byteLength - 1));
}
var i = 0;
var mul = 1;
var sub = value < 0 ? 1 : 0;
this[offset] = value;
while (++i < byteLength && (mul *= 0x100))
this[offset + i] = ((value / mul) >> 0) - sub;
return offset + byteLength;
};
Buffer.prototype.writeIntBE = function(value, offset, byteLength, noAssert) {
value = +value;
offset = offset >>> 0;
if (!noAssert) {
checkInt(this,
value,
offset,
byteLength,
Math.pow(2, 8 * byteLength - 1) - 1,
-Math.pow(2, 8 * byteLength - 1));
}
var i = byteLength - 1;
var mul = 1;
var sub = value < 0 ? 1 : 0;
this[offset + i] = value;
while (--i >= 0 && (mul *= 0x100))
this[offset + i] = ((value / mul) >> 0) - sub;
return offset + byteLength;
};
Buffer.prototype.writeInt8 = function(value, offset, noAssert) {
value = +value;
offset = offset >>> 0;
if (!noAssert)
checkInt(this, value, offset, 1, 0x7f, -0x80);
this[offset] = value;
return offset + 1;
};
Buffer.prototype.writeInt16LE = function(value, offset, noAssert) {
value = +value;
offset = offset >>> 0;
if (!noAssert)
checkInt(this, value, offset, 2, 0x7fff, -0x8000);
this[offset] = value;
this[offset + 1] = (value >>> 8);
return offset + 2;
};
Buffer.prototype.writeInt16BE = function(value, offset, noAssert) {
value = +value;
offset = offset >>> 0;
if (!noAssert)
checkInt(this, value, offset, 2, 0x7fff, -0x8000);
this[offset] = (value >>> 8);
this[offset + 1] = value;
return offset + 2;
};
Buffer.prototype.writeInt32LE = function(value, offset, noAssert) {
value = +value;
offset = offset >>> 0;
if (!noAssert)
checkInt(this, value, offset, 4, 0x7fffffff, -0x80000000);
this[offset] = value;
this[offset + 1] = (value >>> 8);
this[offset + 2] = (value >>> 16);
this[offset + 3] = (value >>> 24);
return offset + 4;
};
Buffer.prototype.writeInt32BE = function(value, offset, noAssert) {
value = +value;
offset = offset >>> 0;
if (!noAssert)
checkInt(this, value, offset, 4, 0x7fffffff, -0x80000000);
this[offset] = (value >>> 24);
this[offset + 1] = (value >>> 16);
this[offset + 2] = (value >>> 8);
this[offset + 3] = value;
return offset + 4;
};
function checkFloat(buffer, value, offset, ext) {
if (!(buffer instanceof Buffer))
throw new TypeError('buffer must be a Buffer instance');
if (offset + ext > buffer.length)
throw new RangeError('index out of range');
}
Buffer.prototype.writeFloatLE = function writeFloatLE(val, offset, noAssert) {
val = +val;
offset = offset >>> 0;
if (!noAssert)
checkFloat(this, val, offset, 4);
internal.writeFloatLE(this, val, offset);
return offset + 4;
};
Buffer.prototype.writeFloatBE = function writeFloatBE(val, offset, noAssert) {
val = +val;
offset = offset >>> 0;
if (!noAssert)
checkFloat(this, val, offset, 4);
internal.writeFloatBE(this, val, offset);
return offset + 4;
};
Buffer.prototype.writeDoubleLE = function writeDoubleLE(val, offset, noAssert) {
val = +val;
offset = offset >>> 0;
if (!noAssert)
checkFloat(this, val, offset, 8);
internal.writeDoubleLE(this, val, offset);
return offset + 8;
};
Buffer.prototype.writeDoubleBE = function writeDoubleBE(val, offset, noAssert) {
val = +val;
offset = offset >>> 0;
if (!noAssert)
checkFloat(this, val, offset, 8);
internal.writeDoubleBE(this, val, offset);
return offset + 8;
};