/*
  Copyright (c) 2007-2010 Alessandro Warth <awarth@cs.ucla.edu>

  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.
*/

// try to use StringBuffer instead of string concatenation to improve performance

function StringBuffer() {
  this.strings = []
  for (var idx = 0; idx < arguments.length; idx++)
    this.nextPutAll(arguments[idx])
}
StringBuffer.prototype.nextPutAll = function(s) { this.strings.push(s) }
StringBuffer.prototype.contents   = function()  { return this.strings.join("") }
String.prototype.writeStream      = function() { return new StringBuffer(this) }

// make Arrays print themselves sensibly

printOn = function(x, ws) {
  if (x === undefined || x === null)
    ws.nextPutAll("" + x)
  else if (x.constructor === Array) {
    ws.nextPutAll("[")
    for (var idx = 0; idx < x.length; idx++) {
      if (idx > 0)
        ws.nextPutAll(", ")
      printOn(x[idx], ws)
    }
    ws.nextPutAll("]")
  }
  else
    ws.nextPutAll(x.toString())
}

Array.prototype.toString = function() { var ws = "".writeStream(); printOn(this, ws); return ws.contents() }

// delegation

objectThatDelegatesTo = function(x, props) {
  var f = function() { }
  f.prototype = x
  var r = new f()
  for (var p in props)
    if (props.hasOwnProperty(p))
      r[p] = props[p]
  return r
}

// some reflective stuff

ownPropertyNames = function(x) {
  var r = []
  for (name in x)
    if (x.hasOwnProperty(name))
      r.push(name)
  return r
}

isImmutable = function(x) {
   return x === null || x === undefined || typeof x === "boolean" || typeof x === "number" || typeof x === "string"
}

String.prototype.digitValue  = function() { return this.charCodeAt(0) - "0".charCodeAt(0) }

isSequenceable = function(x) { return typeof x == "string" || x.constructor === Array }

// some functional programming stuff

Array.prototype.map = function(f) {
  var r = []
  for (var idx = 0; idx < this.length; idx++)
    r[idx] = f(this[idx])
  return r
}

Array.prototype.reduce = function(f, z) {
  var r = z
  for (var idx = 0; idx < this.length; idx++)
    r = f(r, this[idx])
  return r
}

Array.prototype.delimWith = function(d) {
  return this.reduce(
    function(xs, x) {
      if (xs.length > 0)
        xs.push(d)
      xs.push(x)
      return xs
    },
   [])
}

// Squeak's ReadStream, kind of

function ReadStream(anArrayOrString) {
  this.src = anArrayOrString
  this.pos = 0
}
ReadStream.prototype.atEnd = function() { return this.pos >= this.src.length }
ReadStream.prototype.next  = function() { return this.src.at(this.pos++) }

// escape characters

escapeStringFor = new Object()
for (var c = 0; c < 256; c++)
  escapeStringFor[c] = String.fromCharCode(c)
escapeStringFor["\\".charCodeAt(0)] = "\\\\"
escapeStringFor['"'.charCodeAt(0)]  = '\\"'
escapeStringFor["'".charCodeAt(0)]  = "\\'"
escapeStringFor["\r".charCodeAt(0)] = "\\r"
escapeStringFor["\n".charCodeAt(0)] = "\\n"
escapeStringFor["\t".charCodeAt(0)] = "\\t"
escapeChar = function(c) {
  var charCode = c.charCodeAt(0)
  return charCode > 255 ? String.fromCharCode(charCode) : escapeStringFor[charCode]
}

function unescape(s) {
  if (s.charAt(0) == '\\')
    switch (s.charAt(1)) {
      case '\\': return '\\'
      case 'r':  return '\r'
      case 'n':  return '\n'
      case 't':  return '\t'
      default:   return s.charAt(1)
    }
  else
    return s
}

String.prototype.toProgramString = function() {
  var ws = "\"".writeStream()
  for (var idx = 0; idx < this.length; idx++)
    ws.nextPutAll(escapeChar(this.charAt(idx)))
  ws.nextPutAll("\"")
  return ws.contents()
}

// C-style tempnam function

function tempnam(s) { return (s ? s : "_tmpnam_") + tempnam.n++ }
tempnam.n = 0

// unique tags for objects (useful for making "hash tables")

getTag = (function() {
  var numIdx = 0
  return function(x) {
    if (x === null || x === undefined)
      return x
    switch (typeof x) {
      case "boolean": return x == true ? "Btrue" : "Bfalse"
      case "string":  return "S" + x
      case "number":  return "N" + x
      default:        return x.hasOwnProperty("_id_") ? this._id_ : this._id_ = "R" + numIdx++
    }
  }
})()