/*
From:
http://4umi.com/web/javascript/array.htm

concat				Add one or more arrays, and return the new array. No array is modified.	1.2	3
copy				Copy all elements to a new array, by reference if possible, or by value.		
pop					Remove and return the last element of an array.	1.2	5
push				Add one or more elements to the end of an array, return the new length.	1.2	5.5
shift					Remove and return the first element.	1.2	5.5
slice					Copy and return several elements. The original array is not modified.	1.2	3
splice				Remove or replace several elements and return any deleted elements	1.2	5.5
unshift				Add an element to the beginning of an array, return the new length.	1.2	5.5

forEach			Apply a function to each element. The array is not modified.
indexOf			Return index of the first element that matches value.
insert()				Return an array with a value inserted, without overwriting existing keys.
lastIndexOf		Return index of the last element that matches value.
random			Return a random element, optionally excluding the first few elements.
shuffle				Rearrange the order of the elements in a disorderly fashion.
unique				Return an array where duplicate elements have been removed.
walk()				Apply a function to each element, return the new array.
*/

// -- Standard functions

// Array.concat() - Join two arrays
if( typeof Array.prototype.concat==='undefined' ) {
 Array.prototype.concat = function( a ) {
  for( var i = 0, b = this.copy(); i<a.length; i++ ) {
   b[b.length] = a[i];
  }
  return b;
  };
}

// Array.copy() - Copy an array
if( typeof Array.prototype.copy==='undefined' ) {
 Array.prototype.copy = function() {
  var a = [], i = this.length;
  while( i-- ) {
   a[i] = typeof this[i].copy!=='undefined' ? this[i].copy() : this[i];
  }
  return a;
 };
}

// Array.pop() - Remove and return the last element of an array
if( typeof Array.prototype.pop==='undefined' ) {
 Array.prototype.pop = function() {
  var b = this[this.length-1];
  this.length--;
  return b;
 };
}

// Array.push() - Add an element to the end of an array, return the new length
if( typeof Array.prototype.push==='undefined' ) {
 Array.prototype.push = function() {
  for( var i = 0, b = this.length, a = arguments, l = a.length; i<l; i++ ) {
   this[b+i] = a[i];
  }
  return this.length;
 };
}

// Array.shift() - Remove and return the first element
if( typeof Array.prototype.shift==='undefined' ) {
 Array.prototype.shift = function() {
  for( var i = 0, b = this[0], l = this.length-1; i<l; i++ ) {
   this[i] = this[i+1];
  }
  this.length--;
  return b;
 };
}

// Array.slice() - Copy and return several elements
if( typeof Array.prototype.slice==='undefined' ) {
 Array.prototype.slice = function( a, c ) {
  var i, l = this.length, r = [];
  if( !c ) { c = l; }
  if( c<0 ) { c = l + c; }
  if( a<0 ) { a = l - a; }
  if( c<a ) { i = a; a = c; c = i; }
  for( i = 0; i < c - a; i++ ) { r[i] = this[a+i]; }
  return r;
 };
}

// Array.splice() - Remove or replace several elements and return any deleted elements
if( typeof Array.prototype.splice==='undefined' ) {
 Array.prototype.splice = function( a, c ) {
  var i = 0, e = arguments, d = this.copy(), f = a, l = this.length;
  if( !c ) { c = l - a; }
  for( i; i < e.length - 2; i++ ) { this[a + i] = e[i + 2]; }
  for( a; a < l - c; a++ ) { this[a + e.length - 2] = d[a - c]; }
  this.length -= c - e.length + 2;
  return d.slice( f, f + c );
 };
}

// Array.unshift() - Add an element to the beginning of an array
if( typeof Array.prototype.unshift==='undefined' ) {
 Array.prototype.unshift = function() {
  this.reverse();
  var a = arguments, i = a.length;
  while(i--) { this.push(a[i]); }
  this.reverse();
  return this.length;
 };
}

// -- 4umi additional functions

// Array.forEach( function ) - Apply a function to each element
Array.prototype.forEach = function( f ) {
 var i = this.length, j, l = this.length;
 for( i=0; i<l; i++ ) { if( ( j = this[i] ) ) { f( j ); } }
};

// Array.indexOf( value, begin, strict ) - Return index of the first element that matches value
Array.prototype.indexOf = function( v, b, s ) {
 for( var i = +b || 0, l = this.length; i < l; i++ ) {
  if( this[i]===v || s && this[i]==v ) { return i; }
 }
 return -1;
};

// Array.insert( index, value ) - Insert value at index, without overwriting existing keys
Array.prototype.insert = function( i, v ) {
 if( i>=0 ) {
  var a = this.slice(), b = a.splice( i );
  a[i] = v;
  return a.concat( b );
 }
};

// Array.lastIndexOf( value, begin, strict ) - Return index of the last element that matches value
Array.prototype.lastIndexOf = function( v, b, s ) {
 b = +b || 0;
 var i = this.length; while(i-->b) {
  if( this[i]===v || s && this[i]==v ) { return i; }
 }
 return -1;
};

// Array.random( range ) - Return a random element, optionally up to or from range
Array.prototype.random = function( r ) {
 var i = 0, l = this.length;
 if( !r ) { r = this.length; }
 else if( r > 0 ) { r = r % l; }
 else { i = r; r = l + r % l; }
 return this[ Math.floor( r * Math.random() - i ) ];
};

// Array.shuffle( deep ) - Randomly interchange elements
Array.prototype.shuffle = function( b ) {
 var i = this.length, j, t;
 while( i ) {
  j = Math.floor( ( i-- ) * Math.random() );
  t = b && typeof this[i].shuffle!=='undefined' ? this[i].shuffle() : this[i];
  this[i] = this[j];
  this[j] = t;
 }
 return this;
};

// Array.unique( strict ) - Remove duplicate values
Array.prototype.unique = function( b ) {
 var a = [], i, l = this.length;
 for( i=0; i<l; i++ ) {
  if( a.indexOf( this[i], 0, b ) < 0 ) { a.push( this[i] ); }
 }
 return a;
};

// Array.walk() - Change each value according to a callback function
Array.prototype.walk = function( f ) {
 var a = [], i = this.length;
 while(i--) { a.push( f( this[i] ) ); }
 return a.reverse();
};