diff options
Diffstat (limited to 'deps/npm/node_modules/block-stream/block-stream.js')
| -rw-r--r-- | deps/npm/node_modules/block-stream/block-stream.js | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/deps/npm/node_modules/block-stream/block-stream.js b/deps/npm/node_modules/block-stream/block-stream.js new file mode 100644 index 0000000000..008de035c2 --- /dev/null +++ b/deps/npm/node_modules/block-stream/block-stream.js @@ -0,0 +1,209 @@ +// write data to it, and it'll emit data in 512 byte blocks. +// if you .end() or .flush(), it'll emit whatever it's got, +// padded with nulls to 512 bytes. + +module.exports = BlockStream + +var Stream = require("stream").Stream + , inherits = require("inherits") + , assert = require("assert").ok + , debug = process.env.DEBUG ? console.error : function () {} + +function BlockStream (size, opt) { + this.writable = this.readable = true + this._opt = opt || {} + this._chunkSize = size || 512 + this._offset = 0 + this._buffer = [] + this._bufferLength = 0 + if (this._opt.nopad) this._zeroes = false + else { + this._zeroes = new Buffer(this._chunkSize) + for (var i = 0; i < this._chunkSize; i ++) { + this._zeroes[i] = 0 + } + } +} + +inherits(BlockStream, Stream) + +BlockStream.prototype.write = function (c) { + // debug(" BS write", c) + if (this._ended) throw new Error("BlockStream: write after end") + if (c && !Buffer.isBuffer(c)) c = new Buffer(c + "") + if (c.length) { + this._buffer.push(c) + this._bufferLength += c.length + } + // debug("pushed onto buffer", this._bufferLength) + if (this._bufferLength >= this._chunkSize) { + if (this._paused) { + // debug(" BS paused, return false, need drain") + this._needDrain = true + return false + } + this._emitChunk() + } + return true +} + +BlockStream.prototype.pause = function () { + // debug(" BS pausing") + this._paused = true +} + +BlockStream.prototype.resume = function () { + // debug(" BS resume") + this._paused = false + return this._emitChunk() +} + +BlockStream.prototype.end = function (chunk) { + // debug("end", chunk) + if (typeof chunk === "function") cb = chunk, chunk = null + if (chunk) this.write(chunk) + this._ended = true + this.flush() +} + +BlockStream.prototype.flush = function () { + this._emitChunk(true) +} + +BlockStream.prototype._emitChunk = function (flush) { + // debug("emitChunk flush=%j emitting=%j paused=%j", flush, this._emitting, this._paused) + + // emit a <chunkSize> chunk + if (flush && this._zeroes) { + // debug(" BS push zeroes", this._bufferLength) + // push a chunk of zeroes + var padBytes = (this._bufferLength % this._chunkSize) + if (padBytes !== 0) padBytes = this._chunkSize - padBytes + if (padBytes > 0) { + // debug("padBytes", padBytes, this._zeroes.slice(0, padBytes)) + this._buffer.push(this._zeroes.slice(0, padBytes)) + this._bufferLength += padBytes + // debug(this._buffer[this._buffer.length - 1].length, this._bufferLength) + } + } + + if (this._emitting || this._paused) return + this._emitting = true + + // debug(" BS entering loops") + var bufferIndex = 0 + while (this._bufferLength >= this._chunkSize && + (flush || !this._paused)) { + // debug(" BS data emission loop", this._bufferLength) + + var out + , outOffset = 0 + , outHas = this._chunkSize + + while (outHas > 0 && (flush || !this._paused) ) { + // debug(" BS data inner emit loop", this._bufferLength) + var cur = this._buffer[bufferIndex] + , curHas = cur.length - this._offset + // debug("cur=", cur) + // debug("curHas=%j", curHas) + // If it's not big enough to fill the whole thing, then we'll need + // to copy multiple buffers into one. However, if it is big enough, + // then just slice out the part we want, to save unnecessary copying. + // Also, need to copy if we've already done some copying, since buffers + // can't be joined like cons strings. + if (out || curHas < outHas) { + out = out || new Buffer(this._chunkSize) + cur.copy(out, outOffset, + this._offset, this._offset + Math.min(curHas, outHas)) + } else if (cur.length === outHas && this._offset === 0) { + // shortcut -- cur is exactly long enough, and no offset. + out = cur + } else { + // slice out the piece of cur that we need. + out = cur.slice(this._offset, this._offset + outHas) + } + + if (curHas > outHas) { + // means that the current buffer couldn't be completely output + // update this._offset to reflect how much WAS written + this._offset += outHas + outHas = 0 + } else { + // output the entire current chunk. + // toss it away + outHas -= curHas + outOffset += curHas + bufferIndex ++ + this._offset = 0 + } + } + + this._bufferLength -= this._chunkSize + assert(out.length === this._chunkSize) + // debug("emitting data", out) + // debug(" BS emitting, paused=%j", this._paused, this._bufferLength) + this.emit("data", out) + out = null + } + // debug(" BS out of loops", this._bufferLength) + + // whatever is left, it's not enough to fill up a block, or we're paused + this._buffer = this._buffer.slice(bufferIndex) + if (this._paused) { + // debug(" BS paused, leaving", this._bufferLength) + this._needsDrain = true + this._emitting = false + return + } + + // if flushing, and not using null-padding, then need to emit the last + // chunk(s) sitting in the queue. We know that it's not enough to + // fill up a whole block, because otherwise it would have been emitted + // above, but there may be some offset. + var l = this._buffer.length + if (flush && !this._zeroes && l) { + if (l === 1) { + if (this._offset) { + this.emit("data", this._buffer[0].slice(this._offset)) + } else { + this.emit("data", this._buffer[0]) + } + } else { + var outHas = this._bufferLength + , out = new Buffer(outHas) + , outOffset = 0 + for (var i = 0; i < l; i ++) { + var cur = this._buffer[i] + , curHas = cur.length - this._offset + cur.copy(out, outOffset, this._offset) + this._offset = 0 + outOffset += curHas + this._bufferLength -= curHas + } + this.emit("data", out) + } + // truncate + this._buffer.length = 0 + this._bufferLength = 0 + this._offset = 0 + } + + // now either drained or ended + // debug("either draining, or ended", this._bufferLength, this._ended) + // means that we've flushed out all that we can so far. + if (this._needDrain) { + // debug("emitting drain", this._bufferLength) + this._needDrain = false + this.emit("drain") + } + + if ((this._bufferLength === 0) && this._ended && !this._endEmitted) { + // debug("emitting end", this._bufferLength) + this._endEmitted = true + this.emit("end") + } + + this._emitting = false + + // debug(" BS no longer emitting", flush, this._paused, this._emitting, this._bufferLength, this._chunkSize) +} |