/*! asn1hex-1.1.js (c) 2012 Kenji Urushima | kjur.github.com/jsrsasign/license
 */
//
// asn1hex.js - Hexadecimal represented ASN.1 string library
//
// version: 1.1 (09-May-2012)
//
// Copyright (c) 2010-2012 Kenji Urushima (kenji.urushima@gmail.com)
//
// This software is licensed under the terms of the MIT License.
// http://kjur.github.com/jsrsasign/license/
//
// The above copyright and license notice shall be 
// included in all copies or substantial portions of the Software.
//
// Depends on:
//

// MEMO:
//   f('3082025b02...', 2) ... 82025b ... 3bytes
//   f('020100', 2) ... 01 ... 1byte
//   f('0203001...', 2) ... 03 ... 1byte
//   f('02818003...', 2) ... 8180 ... 2bytes
//   f('3080....0000', 2) ... 80 ... -1
//
//   Requirements:
//   - ASN.1 type octet length MUST be 1. 
//     (i.e. ASN.1 primitives like SET, SEQUENCE, INTEGER, OCTETSTRING ...)
//   - 
/**
 * get byte length for ASN.1 L(length) bytes
 * @name getByteLengthOfL_AtObj
 * @memberOf ASN1HEX
 * @function
 * @param {String} s hexadecimal string of ASN.1 DER encoded data
 * @param {Number} pos string index
 * @return byte length for ASN.1 L(length) bytes
 */
function _asnhex_getByteLengthOfL_AtObj(s, pos) {
  if (s.substring(pos + 2, pos + 3) != '8') return 1;
  var i = parseInt(s.substring(pos + 3, pos + 4));
  if (i == 0) return -1; 		// length octet '80' indefinite length
  if (0 < i && i < 10) return i + 1;	// including '8?' octet;
  return -2;				// malformed format
}


/**
 * get hexadecimal string for ASN.1 L(length) bytes
 * @name getHexOfL_AtObj
 * @memberOf ASN1HEX
 * @function
 * @param {String} s hexadecimal string of ASN.1 DER encoded data
 * @param {Number} pos string index
 * @return {String} hexadecimal string for ASN.1 L(length) bytes
 */
function _asnhex_getHexOfL_AtObj(s, pos) {
  var len = _asnhex_getByteLengthOfL_AtObj(s, pos);
  if (len < 1) return '';
  return s.substring(pos + 2, pos + 2 + len * 2);
}

//
//   getting ASN.1 length value at the position 'idx' of
//   hexa decimal string 's'.
//
//   f('3082025b02...', 0) ... 82025b ... ???
//   f('020100', 0) ... 01 ... 1
//   f('0203001...', 0) ... 03 ... 3
//   f('02818003...', 0) ... 8180 ... 128
/**
 * get integer value of ASN.1 length for ASN.1 data
 * @name getIntOfL_AtObj
 * @memberOf ASN1HEX
 * @function
 * @param {String} s hexadecimal string of ASN.1 DER encoded data
 * @param {Number} pos string index
 * @return ASN.1 L(length) integer value
 */
function _asnhex_getIntOfL_AtObj(s, pos) {
  var hLength = _asnhex_getHexOfL_AtObj(s, pos);
  if (hLength == '') return -1;
  var bi;
  if (parseInt(hLength.substring(0, 1)) < 8) {
     bi = parseBigInt(hLength, 16);
  } else {
     bi = parseBigInt(hLength.substring(2), 16);
  }
  return bi.intValue();
}

/**
 * get ASN.1 value starting string position for ASN.1 object refered by index 'idx'.
 * @name getStartPosOfV_AtObj
 * @memberOf ASN1HEX
 * @function
 * @param {String} s hexadecimal string of ASN.1 DER encoded data
 * @param {Number} pos string index
 */
function _asnhex_getStartPosOfV_AtObj(s, pos) {
  var l_len = _asnhex_getByteLengthOfL_AtObj(s, pos);
  if (l_len < 0) return l_len;
  return pos + (l_len + 1) * 2;
}

/**
 * get hexadecimal string of ASN.1 V(value)
 * @name getHexOfV_AtObj
 * @memberOf ASN1HEX
 * @function
 * @param {String} s hexadecimal string of ASN.1 DER encoded data
 * @param {Number} pos string index
 * @return {String} hexadecimal string of ASN.1 value.
 */
function _asnhex_getHexOfV_AtObj(s, pos) {
  var pos1 = _asnhex_getStartPosOfV_AtObj(s, pos);
  var len = _asnhex_getIntOfL_AtObj(s, pos);
  return s.substring(pos1, pos1 + len * 2);
}

/**
 * get hexadecimal string of ASN.1 TLV at
 * @name getHexOfTLV_AtObj
 * @memberOf ASN1HEX
 * @function
 * @param {String} s hexadecimal string of ASN.1 DER encoded data
 * @param {Number} pos string index
 * @return {String} hexadecimal string of ASN.1 TLV.
 * @since 1.1
 */
function _asnhex_getHexOfTLV_AtObj(s, pos) {
  var hT = s.substr(pos, 2);
  var hL = _asnhex_getHexOfL_AtObj(s, pos);
  var hV = _asnhex_getHexOfV_AtObj(s, pos);
  return hT + hL + hV;
}

/**
 * get next sibling starting index for ASN.1 object string
 * @name getPosOfNextSibling_AtObj
 * @memberOf ASN1HEX
 * @function
 * @param {String} s hexadecimal string of ASN.1 DER encoded data
 * @param {Number} pos string index
 * @return next sibling starting index for ASN.1 object string
 */
function _asnhex_getPosOfNextSibling_AtObj(s, pos) {
  var pos1 = _asnhex_getStartPosOfV_AtObj(s, pos);
  var len = _asnhex_getIntOfL_AtObj(s, pos);
  return pos1 + len * 2;
}

/**
 * get array of indexes of child ASN.1 objects
 * @name getPosArrayOfChildren_AtObj
 * @memberOf ASN1HEX
 * @function
 * @param {String} s hexadecimal string of ASN.1 DER encoded data
 * @param {Number} start string index of ASN.1 object
 * @return {Array of Number} array of indexes for childen of ASN.1 objects
 */
function _asnhex_getPosArrayOfChildren_AtObj(h, pos) {
  var a = new Array();
  var p0 = _asnhex_getStartPosOfV_AtObj(h, pos);
  a.push(p0);

  var len = _asnhex_getIntOfL_AtObj(h, pos);
  var p = p0;
  var k = 0;
  while (1) {
    var pNext = _asnhex_getPosOfNextSibling_AtObj(h, p);
    if (pNext == null || (pNext - p0  >= (len * 2))) break;
    if (k >= 200) break;

    a.push(pNext);
    p = pNext;

    k++;
  }

  return a;
}

/**
 * get string index of nth child object of ASN.1 object refered by h, idx
 * @name getNthChildIndex_AtObj
 * @memberOf ASN1HEX
 * @function
 * @param {String} h hexadecimal string of ASN.1 DER encoded data
 * @param {Number} idx start string index of ASN.1 object
 * @param {Number} nth for child
 * @return {Number} string index of nth child.
 * @since 1.1
 */
function _asnhex_getNthChildIndex_AtObj(h, idx, nth) {
  var a = _asnhex_getPosArrayOfChildren_AtObj(h, idx);
  return a[nth];
}

// ========== decendant methods ==============================

/**
 * get string index of nth child object of ASN.1 object refered by h, idx
 * @name getDecendantIndexByNthList
 * @memberOf ASN1HEX
 * @function
 * @param {String} h hexadecimal string of ASN.1 DER encoded data
 * @param {Number} currentIndex start string index of ASN.1 object
 * @param {Array of Number} nthList array list of nth
 * @return {Number} string index refered by nthList
 * @since 1.1
 */
function _asnhex_getDecendantIndexByNthList(h, currentIndex, nthList) {
  if (nthList.length == 0) {
    return currentIndex;
  }
  var firstNth = nthList.shift();
  var a = _asnhex_getPosArrayOfChildren_AtObj(h, currentIndex);
  return _asnhex_getDecendantIndexByNthList(h, a[firstNth], nthList);
}

/**
 * get hexadecimal string of ASN.1 TLV refered by current index and nth index list.
 * @name getDecendantHexTLVByNthList
 * @memberOf ASN1HEX
 * @function
 * @param {String} h hexadecimal string of ASN.1 DER encoded data
 * @param {Number} currentIndex start string index of ASN.1 object
 * @param {Array of Number} nthList array list of nth
 * @return {Number} hexadecimal string of ASN.1 TLV refered by nthList
 * @since 1.1
 */
function _asnhex_getDecendantHexTLVByNthList(h, currentIndex, nthList) {
  var idx = _asnhex_getDecendantIndexByNthList(h, currentIndex, nthList);
  return _asnhex_getHexOfTLV_AtObj(h, idx);
}

/**
 * get hexadecimal string of ASN.1 V refered by current index and nth index list.
 * @name getDecendantHexVByNthList
 * @memberOf ASN1HEX
 * @function
 * @param {String} h hexadecimal string of ASN.1 DER encoded data
 * @param {Number} currentIndex start string index of ASN.1 object
 * @param {Array of Number} nthList array list of nth
 * @return {Number} hexadecimal string of ASN.1 V refered by nthList
 * @since 1.1
 */
function _asnhex_getDecendantHexVByNthList(h, currentIndex, nthList) {
  var idx = _asnhex_getDecendantIndexByNthList(h, currentIndex, nthList);
  return _asnhex_getHexOfV_AtObj(h, idx);
}

// ========== class definition ==============================

/**
 * ASN.1 DER encoded hexadecimal string utility class
 * @class ASN.1 DER encoded hexadecimal string utility class
 * @author Kenji Urushima
 * @version 1.1 (09 May 2012)
 * @see <a href="http://kjur.github.com/jsrsasigns/">'jwrsasign'(RSA Sign JavaScript Library) home page http://kjur.github.com/jsrsasign/</a>
 * @since 1.1
 */
function ASN1HEX() {
  return ASN1HEX;
}

ASN1HEX.getByteLengthOfL_AtObj = _asnhex_getByteLengthOfL_AtObj;
ASN1HEX.getHexOfL_AtObj = _asnhex_getHexOfL_AtObj;
ASN1HEX.getIntOfL_AtObj = _asnhex_getIntOfL_AtObj;
ASN1HEX.getStartPosOfV_AtObj = _asnhex_getStartPosOfV_AtObj;
ASN1HEX.getHexOfV_AtObj = _asnhex_getHexOfV_AtObj;
ASN1HEX.getHexOfTLV_AtObj = _asnhex_getHexOfTLV_AtObj;
ASN1HEX.getPosOfNextSibling_AtObj = _asnhex_getPosOfNextSibling_AtObj;
ASN1HEX.getPosArrayOfChildren_AtObj = _asnhex_getPosArrayOfChildren_AtObj;
ASN1HEX.getNthChildIndex_AtObj = _asnhex_getNthChildIndex_AtObj;
ASN1HEX.getDecendantIndexByNthList = _asnhex_getDecendantIndexByNthList;
ASN1HEX.getDecendantHexVByNthList = _asnhex_getDecendantHexVByNthList;
ASN1HEX.getDecendantHexTLVByNthList = _asnhex_getDecendantHexTLVByNthList;