diff --git a/doc/api/buffer.markdown b/doc/api/buffer.markdown index 82a36eedc6f..ff95304ed6f 100644 --- a/doc/api/buffer.markdown +++ b/doc/api/buffer.markdown @@ -148,6 +148,26 @@ Example: // ½ + ¼ = ¾: 9 characters, 12 bytes +### Class Method: Buffer.concat(list, [totalLength]) + +* `list` {Array} List of Buffer objects to concat +* `totalLength` {Number} Total length of the buffers when concatenated + +Returns a buffer which is the result of concatenating all the buffers in +the list together. + +If the list has no items, or if the totalLength is 0, then it returns a +zero-length buffer. + +If the list has exactly one item, then the first item of the list is +returned. + +If the list has more than one item, then a new Buffer is created. + +If totalLength is not provided, it is read from the buffers in the list. +However, this adds an additional loop to the function, so it is faster +to provide the length explicitly. + ### buf.length * Number diff --git a/lib/buffer.js b/lib/buffer.js index 7a65fa13c79..ee81eac8016 100644 --- a/lib/buffer.js +++ b/lib/buffer.js @@ -469,6 +469,38 @@ Buffer.prototype.fill = function fill(value, start, end) { }; +Buffer.concat = function(list, length) { + if (!Array.isArray(list)) { + throw new Error('Usage: Buffer.concat(list, [length])'); + } + + if (list.length === 0) { + return new Buffer(0); + } else if (list.length === 1) { + return list[0]; + } + + if (typeof length !== 'number') { + length = 0; + for (var i = 0; i < list.length; i++) { + var buf = list[i]; + length += buf.length; + } + } + + 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; +}; + + + + // copy(targetBuffer, targetStart=0, sourceStart=0, sourceEnd=buffer.length) Buffer.prototype.copy = function(target, target_start, start, end) { var source = this; diff --git a/test/simple/test-buffer-concat.js b/test/simple/test-buffer-concat.js new file mode 100644 index 00000000000..858d6924f95 --- /dev/null +++ b/test/simple/test-buffer-concat.js @@ -0,0 +1,41 @@ +// 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. + +var common = require('../common'); +var assert = require('assert'); + +var zero = []; +var one = [ new Buffer('asdf') ]; +var long = []; +for (var i = 0; i < 10; i++) long.push(new Buffer('asdf')); + +var flatZero = Buffer.concat(zero); +var flatOne = Buffer.concat(one); +var flatLong = Buffer.concat(long); +var flatLongLen = Buffer.concat(long, 40); + +assert(flatZero.length === 0); +assert(flatOne.toString() === 'asdf'); +assert(flatOne === one[0]); +assert(flatLong.toString() === (new Array(10+1).join('asdf'))); +assert(flatLongLen.toString() === (new Array(10+1).join('asdf'))); + +console.log("ok");