initial commit

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)
+}