stringview.js

"use strict";

/*\
|*|
|*|  :: Number.isInteger() polyfill ::
|*|
|*|  https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isInteger
|*|
\*/

if (!Number.isInteger) {
  Number.isInteger = function isInteger (nVal) {
    return typeof nVal === "number" && isFinite(nVal) && nVal > -9007199254740992 && nVal < 9007199254740992 && Math.floor(nVal) === nVal;
  };
}

/*\
|*|
|*|  StringView - Mozilla Developer Network
|*|
|*|  Revision #8, October 6, 2014
|*|
|*|  https://developer.mozilla.org/en-US/docs/Web/JavaScript/Typed_arrays/StringView
|*|  https://developer.mozilla.org/en-US/docs/User:fusionchess
|*|
|*|  This framework is released under the GNU Lesser General Public License, version 3 or later.
|*|  http://www.gnu.org/licenses/lgpl-3.0.html
|*|
\*/

function StringView (vInput, sEncoding /* optional (default: UTF-8) */, nOffset /* optional */, nLength /* optional */) {

  var fTAView, aWhole, aRaw, fPutOutptCode, fGetOutptChrSize, nInptLen, nStartIdx = isFinite(nOffset) ? nOffset : 0, nTranscrType = 15;

  if (sEncoding) { this.encoding = sEncoding.toString(); }

  encSwitch: switch (this.encoding) {
    case "UTF-8":
      fPutOutptCode = StringView.putUTF8CharCode;
      fGetOutptChrSize = StringView.getUTF8CharLength;
      fTAView = Uint8Array;
      break encSwitch;
    case "UTF-16":
      fPutOutptCode = StringView.putUTF16CharCode;
      fGetOutptChrSize = StringView.getUTF16CharLength;
      fTAView = Uint16Array;
      break encSwitch;
    case "UTF-32":
      fTAView = Uint32Array;
      nTranscrType &= 14;
      break encSwitch;
    default:
      /* case "ASCII", or case "BinaryString" or unknown cases */
      fTAView = Uint8Array;
      nTranscrType &= 14;
  }

  typeSwitch: switch (typeof vInput) {
    case "string":
      /* the input argument is a primitive string: a new buffer will be created. */
      nTranscrType &= 7;
      break typeSwitch;
    case "object":
      classSwitch: switch (vInput.constructor) {
        case StringView:
          /* the input argument is a stringView: a new buffer will be created. */
          nTranscrType &= 3;
          break typeSwitch;
        case String:
          /* the input argument is an objectified string: a new buffer will be created. */
          nTranscrType &= 7;
          break typeSwitch;
        case ArrayBuffer:
          /* the input argument is an arrayBuffer: the buffer will be shared. */
          aWhole = new fTAView(vInput);
          nInptLen = this.encoding === "UTF-32" ?
              vInput.byteLength >>> 2
            : this.encoding === "UTF-16" ?
              vInput.byteLength >>> 1
            :
              vInput.byteLength;
          aRaw = nStartIdx === 0 && (!isFinite(nLength) || nLength === nInptLen) ?
            aWhole
            : new fTAView(vInput, nStartIdx, !isFinite(nLength) ? nInptLen - nStartIdx : nLength);

          break typeSwitch;
        case Uint32Array:
        case Uint16Array:
        case Uint8Array:
          /* the input argument is a typedArray: the buffer, and possibly the array itself, will be shared. */
          fTAView = vInput.constructor;
          nInptLen = vInput.length;
          aWhole = vInput.byteOffset === 0 && vInput.length === (
            fTAView === Uint32Array ?
              vInput.buffer.byteLength >>> 2
            : fTAView === Uint16Array ?
              vInput.buffer.byteLength >>> 1
            :
              vInput.buffer.byteLength
          ) ? vInput : new fTAView(vInput.buffer);
          aRaw = nStartIdx === 0 && (!isFinite(nLength) || nLength === nInptLen) ?
            vInput
            : vInput.subarray(nStartIdx, isFinite(nLength) ? nStartIdx + nLength : nInptLen);

          break typeSwitch;
        default:
          /* the input argument is an array or another serializable object: a new typedArray will be created. */
          aWhole = new fTAView(vInput);
          nInptLen = aWhole.length;
          aRaw = nStartIdx === 0 && (!isFinite(nLength) || nLength === nInptLen) ?
            aWhole
            : aWhole.subarray(nStartIdx, isFinite(nLength) ? nStartIdx + nLength : nInptLen);
      }
      break typeSwitch;
    default:
      /* the input argument is a number, a boolean or a function: a new typedArray will be created. */
      aWhole = aRaw = new fTAView(Number(vInput) || 0);

  }

  if (nTranscrType < 8) {

    var vSource, nOutptLen, nCharStart, nCharEnd, nEndIdx, fGetInptChrSize, fGetInptChrCode;

    if (nTranscrType & 4) { /* input is string */

      vSource = vInput;
      nOutptLen = nInptLen = vSource.length;
      nTranscrType ^= this.encoding === "UTF-32" ? 0 : 2;
      /* ...or...: nTranscrType ^= Number(this.encoding !== "UTF-32") << 1; */
      nStartIdx = nCharStart = nOffset ? Math.max((nOutptLen + nOffset) % nOutptLen, 0) : 0;
      nEndIdx = nCharEnd = (Number.isInteger(nLength) ? Math.min(Math.max(nLength, 0) + nStartIdx, nOutptLen) : nOutptLen) - 1;

    } else { /* input is stringView */

      vSource = vInput.rawData;
      nInptLen = vInput.makeIndex();
      nStartIdx = nCharStart = nOffset ? Math.max((nInptLen + nOffset) % nInptLen, 0) : 0;
      nOutptLen = Number.isInteger(nLength) ? Math.min(Math.max(nLength, 0), nInptLen - nCharStart) : nInptLen;
      nEndIdx = nCharEnd = nOutptLen + nCharStart;

      if (vInput.encoding === "UTF-8") {
        fGetInptChrSize = StringView.getUTF8CharLength;
        fGetInptChrCode = StringView.loadUTF8CharCode;
      } else if (vInput.encoding === "UTF-16") {
        fGetInptChrSize = StringView.getUTF16CharLength;
        fGetInptChrCode = StringView.loadUTF16CharCode;
      } else {
        nTranscrType &= 1;
      }

    }

    if (nOutptLen === 0 || nTranscrType < 4 && vSource.encoding === this.encoding && nCharStart === 0 && nOutptLen === nInptLen) {

      /* the encoding is the same, the length too and the offset is 0... or the input is empty! */

      nTranscrType = 7;

    }

    conversionSwitch: switch (nTranscrType) {

      case 0:

      /* both the source and the new StringView have a fixed-length encoding... */

        aWhole = new fTAView(nOutptLen);
        for (var nOutptIdx = 0; nOutptIdx < nOutptLen; aWhole[nOutptIdx] = vSource[nStartIdx + nOutptIdx++]);
        break conversionSwitch;

      case 1:

      /* the source has a fixed-length encoding but the new StringView has a variable-length encoding... */

        /* mapping... */

        nOutptLen = 0;

        for (var nInptIdx = nStartIdx; nInptIdx < nEndIdx; nInptIdx++) {
          nOutptLen += fGetOutptChrSize(vSource[nInptIdx]);
        }

        aWhole = new fTAView(nOutptLen);

        /* transcription of the source... */

        for (var nInptIdx = nStartIdx, nOutptIdx = 0; nOutptIdx < nOutptLen; nInptIdx++) {
          nOutptIdx = fPutOutptCode(aWhole, vSource[nInptIdx], nOutptIdx);
        }

        break conversionSwitch;

      case 2:

      /* the source has a variable-length encoding but the new StringView has a fixed-length encoding... */

        /* mapping... */

        nStartIdx = 0;

        var nChrCode;

        for (nChrIdx = 0; nChrIdx < nCharStart; nChrIdx++) {
          nChrCode = fGetInptChrCode(vSource, nStartIdx);
          nStartIdx += fGetInptChrSize(nChrCode);
        }

        aWhole = new fTAView(nOutptLen);

        /* transcription of the source... */

        for (var nInptIdx = nStartIdx, nOutptIdx = 0; nOutptIdx < nOutptLen; nInptIdx += fGetInptChrSize(nChrCode), nOutptIdx++) {
          nChrCode = fGetInptChrCode(vSource, nInptIdx);
          aWhole[nOutptIdx] = nChrCode;
        }

        break conversionSwitch;

      case 3:

      /* both the source and the new StringView have a variable-length encoding... */

        /* mapping... */

        nOutptLen = 0;

        var nChrCode;

        for (var nChrIdx = 0, nInptIdx = 0; nChrIdx < nCharEnd; nInptIdx += fGetInptChrSize(nChrCode)) {
          nChrCode = fGetInptChrCode(vSource, nInptIdx);
          if (nChrIdx === nCharStart) { nStartIdx = nInptIdx; }
          if (++nChrIdx > nCharStart) { nOutptLen += fGetOutptChrSize(nChrCode); }
        }

        aWhole = new fTAView(nOutptLen);

        /* transcription... */

        for (var nInptIdx = nStartIdx, nOutptIdx = 0; nOutptIdx < nOutptLen; nInptIdx += fGetInptChrSize(nChrCode)) {
          nChrCode = fGetInptChrCode(vSource, nInptIdx);
          nOutptIdx = fPutOutptCode(aWhole, nChrCode, nOutptIdx);
        }

        break conversionSwitch;

      case 4:

      /* DOMString to ASCII or BinaryString or other unknown encodings */

        aWhole = new fTAView(nOutptLen);

        /* transcription... */

        for (var nIdx = 0; nIdx < nOutptLen; nIdx++) {
          aWhole[nIdx] = vSource.charCodeAt(nIdx) & 0xff;
        }

        break conversionSwitch;

      case 5:

      /* DOMString to UTF-8 or to UTF-16 */

        /* mapping... */

        nOutptLen = 0;

        for (var nMapIdx = 0; nMapIdx < nInptLen; nMapIdx++) {
          if (nMapIdx === nCharStart) { nStartIdx = nOutptLen; }
          nOutptLen += fGetOutptChrSize(vSource.charCodeAt(nMapIdx));
          if (nMapIdx === nCharEnd) { nEndIdx = nOutptLen; }
        }

        aWhole = new fTAView(nOutptLen);

        /* transcription... */

        for (var nOutptIdx = 0, nChrIdx = 0; nOutptIdx < nOutptLen; nChrIdx++) {
          nOutptIdx = fPutOutptCode(aWhole, vSource.charCodeAt(nChrIdx), nOutptIdx);
        }

        break conversionSwitch;

      case 6:

      /* DOMString to UTF-32 */

        aWhole = new fTAView(nOutptLen);

        /* transcription... */

        for (var nIdx = 0; nIdx < nOutptLen; nIdx++) {
          aWhole[nIdx] = vSource.charCodeAt(nIdx);
        }

        break conversionSwitch;

      case 7:

        aWhole = new fTAView(nOutptLen ? vSource : 0);
        break conversionSwitch;

    }

    aRaw = nTranscrType > 3 && (nStartIdx > 0 || nEndIdx < aWhole.length - 1) ? aWhole.subarray(nStartIdx, nEndIdx) : aWhole;

  }

  this.buffer = aWhole.buffer;
  this.bufferView = aWhole;
  this.rawData = aRaw;

  Object.freeze(this);

}

/* CONSTRUCTOR'S METHODS */

StringView.loadUTF8CharCode = function (aChars, nIdx) {

  var nLen = aChars.length, nPart = aChars[nIdx];

  return nPart > 251 && nPart < 254 && nIdx + 5 < nLen ?
      /* (nPart - 252 << 30) may be not safe in ECMAScript! So...: */
      /* six bytes */ (nPart - 252) * 1073741824 + (aChars[nIdx + 1] - 128 << 24) + (aChars[nIdx + 2] - 128 << 18) + (aChars[nIdx + 3] - 128 << 12) + (aChars[nIdx + 4] - 128 << 6) + aChars[nIdx + 5] - 128
    : nPart > 247 && nPart < 252 && nIdx + 4 < nLen ?
      /* five bytes */ (nPart - 248 << 24) + (aChars[nIdx + 1] - 128 << 18) + (aChars[nIdx + 2] - 128 << 12) + (aChars[nIdx + 3] - 128 << 6) + aChars[nIdx + 4] - 128
    : nPart > 239 && nPart < 248 && nIdx + 3 < nLen ?
      /* four bytes */(nPart - 240 << 18) + (aChars[nIdx + 1] - 128 << 12) + (aChars[nIdx + 2] - 128 << 6) + aChars[nIdx + 3] - 128
    : nPart > 223 && nPart < 240 && nIdx + 2 < nLen ?
      /* three bytes */ (nPart - 224 << 12) + (aChars[nIdx + 1] - 128 << 6) + aChars[nIdx + 2] - 128
    : nPart > 191 && nPart < 224 && nIdx + 1 < nLen ?
      /* two bytes */ (nPart - 192 << 6) + aChars[nIdx + 1] - 128
    :
      /* one byte */ nPart;

};

StringView.putUTF8CharCode = function (aTarget, nChar, nPutAt) {

  var nIdx = nPutAt;

  if (nChar < 0x80 /* 128 */) {
    /* one byte */
    aTarget[nIdx++] = nChar;
  } else if (nChar < 0x800 /* 2048 */) {
    /* two bytes */
    aTarget[nIdx++] = 0xc0 /* 192 */ + (nChar >>> 6);
    aTarget[nIdx++] = 0x80 /* 128 */ + (nChar & 0x3f /* 63 */);
  } else if (nChar < 0x10000 /* 65536 */) {
    /* three bytes */
    aTarget[nIdx++] = 0xe0 /* 224 */ + (nChar >>> 12);
    aTarget[nIdx++] = 0x80 /* 128 */ + ((nChar >>> 6) & 0x3f /* 63 */);
    aTarget[nIdx++] = 0x80 /* 128 */ + (nChar & 0x3f /* 63 */);
  } else if (nChar < 0x200000 /* 2097152 */) {
    /* four bytes */
    aTarget[nIdx++] = 0xf0 /* 240 */ + (nChar >>> 18);
    aTarget[nIdx++] = 0x80 /* 128 */ + ((nChar >>> 12) & 0x3f /* 63 */);
    aTarget[nIdx++] = 0x80 /* 128 */ + ((nChar >>> 6) & 0x3f /* 63 */);
    aTarget[nIdx++] = 0x80 /* 128 */ + (nChar & 0x3f /* 63 */);
  } else if (nChar < 0x4000000 /* 67108864 */) {
    /* five bytes */
    aTarget[nIdx++] = 0xf8 /* 248 */ + (nChar >>> 24);
    aTarget[nIdx++] = 0x80 /* 128 */ + ((nChar >>> 18) & 0x3f /* 63 */);
    aTarget[nIdx++] = 0x80 /* 128 */ + ((nChar >>> 12) & 0x3f /* 63 */);
    aTarget[nIdx++] = 0x80 /* 128 */ + ((nChar >>> 6) & 0x3f /* 63 */);
    aTarget[nIdx++] = 0x80 /* 128 */ + (nChar & 0x3f /* 63 */);
  } else /* if (nChar <= 0x7fffffff) */ { /* 2147483647 */
    /* six bytes */
    aTarget[nIdx++] = 0xfc /* 252 */ + /* (nChar >>> 30) may be not safe in ECMAScript! So...: */ (nChar / 1073741824);
    aTarget[nIdx++] = 0x80 /* 128 */ + ((nChar >>> 24) & 0x3f /* 63 */);
    aTarget[nIdx++] = 0x80 /* 128 */ + ((nChar >>> 18) & 0x3f /* 63 */);
    aTarget[nIdx++] = 0x80 /* 128 */ + ((nChar >>> 12) & 0x3f /* 63 */);
    aTarget[nIdx++] = 0x80 /* 128 */ + ((nChar >>> 6) & 0x3f /* 63 */);
    aTarget[nIdx++] = 0x80 /* 128 */ + (nChar & 0x3f /* 63 */);
  }

  return nIdx;

};

StringView.getUTF8CharLength = function (nChar) {
  return nChar < 0x80 ? 1 : nChar < 0x800 ? 2 : nChar < 0x10000 ? 3 : nChar < 0x200000 ? 4 : nChar < 0x4000000 ? 5 : 6;
};

StringView.loadUTF16CharCode = function (aChars, nIdx) {

  /* UTF-16 to DOMString decoding algorithm */
  var nFrstChr = aChars[nIdx];

  return nFrstChr > 0xD7BF /* 55231 */ && nIdx + 1 < aChars.length ?
    (nFrstChr - 0xD800 /* 55296 */ << 10) + aChars[nIdx + 1] + 0x2400 /* 9216 */
    : nFrstChr;

};

StringView.putUTF16CharCode = function (aTarget, nChar, nPutAt) {

  var nIdx = nPutAt;

  if (nChar < 0x10000 /* 65536 */) {
    /* one element */
    aTarget[nIdx++] = nChar;
  } else {
    /* two elements */
    aTarget[nIdx++] = 0xD7C0 /* 55232 */ + (nChar >>> 10);
    aTarget[nIdx++] = 0xDC00 /* 56320 */ + (nChar & 0x3FF /* 1023 */);
  }

  return nIdx;

};

StringView.getUTF16CharLength = function (nChar) {
  return nChar < 0x10000 ? 1 : 2;
};

/* Array of bytes to base64 string decoding */

StringView.b64ToUint6 = function (nChr) {

  return nChr > 64 && nChr < 91 ?
      nChr - 65
    : nChr > 96 && nChr < 123 ?
      nChr - 71
    : nChr > 47 && nChr < 58 ?
      nChr + 4
    : nChr === 43 ?
      62
    : nChr === 47 ?
      63
    :
      0;

};

StringView.uint6ToB64 = function (nUint6) {

  return nUint6 < 26 ?
      nUint6 + 65
    : nUint6 < 52 ?
      nUint6 + 71
    : nUint6 < 62 ?
      nUint6 - 4
    : nUint6 === 62 ?
      43
    : nUint6 === 63 ?
      47
    :
      65;

};

/* Base64 string to array encoding */

StringView.bytesToBase64 = function (aBytes) {

  var sB64Enc = "";

  for (var nMod3, nLen = aBytes.length, nUint24 = 0, nIdx = 0; nIdx < nLen; nIdx++) {
    nMod3 = nIdx % 3;
    if (nIdx > 0 && (nIdx * 4 / 3) % 76 === 0) { sB64Enc += "\r\n"; }
    nUint24 |= aBytes[nIdx] << (16 >>> nMod3 & 24);
    if (nMod3 === 2 || aBytes.length - nIdx === 1) {
      sB64Enc += String.fromCharCode(StringView.uint6ToB64(nUint24 >>> 18 & 63), StringView.uint6ToB64(nUint24 >>> 12 & 63), StringView.uint6ToB64(nUint24 >>> 6 & 63), StringView.uint6ToB64(nUint24 & 63));
      nUint24 = 0;
    }
  }

  return sB64Enc.replace(/A(?=A$|$)/g, "=");

};


StringView.base64ToBytes = function (sBase64, nBlockBytes) {

  var
    sB64Enc = sBase64.replace(/[^A-Za-z0-9\+\/]/g, ""), nInLen = sB64Enc.length,
    nOutLen = nBlockBytes ? Math.ceil((nInLen * 3 + 1 >>> 2) / nBlockBytes) * nBlockBytes : nInLen * 3 + 1 >>> 2, aBytes = new Uint8Array(nOutLen);

  for (var nMod3, nMod4, nUint24 = 0, nOutIdx = 0, nInIdx = 0; nInIdx < nInLen; nInIdx++) {
    nMod4 = nInIdx & 3;
    nUint24 |= StringView.b64ToUint6(sB64Enc.charCodeAt(nInIdx)) << 18 - 6 * nMod4;
    if (nMod4 === 3 || nInLen - nInIdx === 1) {
      for (nMod3 = 0; nMod3 < 3 && nOutIdx < nOutLen; nMod3++, nOutIdx++) {
        aBytes[nOutIdx] = nUint24 >>> (16 >>> nMod3 & 24) & 255;
      }
      nUint24 = 0;
    }
  }

  return aBytes;

};

StringView.makeFromBase64 = function (sB64Inpt, sEncoding, nByteOffset, nLength) {

  return new StringView(sEncoding === "UTF-16" || sEncoding === "UTF-32" ? StringView.base64ToBytes(sB64Inpt, sEncoding === "UTF-16" ? 2 : 4).buffer : StringView.base64ToBytes(sB64Inpt), sEncoding, nByteOffset, nLength);

};

/* DEFAULT VALUES */

StringView.prototype.encoding = "UTF-8"; /* Default encoding... */

/* INSTANCES' METHODS */

StringView.prototype.makeIndex = function (nChrLength, nStartFrom) {

  var

    aTarget = this.rawData, nChrEnd, nRawLength = aTarget.length,
    nStartIdx = nStartFrom || 0, nIdxEnd = nStartIdx, nStopAtChr = isNaN(nChrLength) ? Infinity : nChrLength;

  if (nChrLength + 1 > aTarget.length) { throw new RangeError("StringView.prototype.makeIndex - The offset can\'t be major than the length of the array - 1."); }

  switch (this.encoding) {

    case "UTF-8":

      var nPart;

      for (nChrEnd = 0; nIdxEnd < nRawLength && nChrEnd < nStopAtChr; nChrEnd++) {
        nPart = aTarget[nIdxEnd];
        nIdxEnd += nPart > 251 && nPart < 254 && nIdxEnd + 5 < nRawLength ? 6
          : nPart > 247 && nPart < 252 && nIdxEnd + 4 < nRawLength ? 5
          : nPart > 239 && nPart < 248 && nIdxEnd + 3 < nRawLength ? 4
          : nPart > 223 && nPart < 240 && nIdxEnd + 2 < nRawLength ? 3
          : nPart > 191 && nPart < 224 && nIdxEnd + 1 < nRawLength ? 2
          : 1;
      }

      break;

    case "UTF-16":

      for (nChrEnd = nStartIdx; nIdxEnd < nRawLength && nChrEnd < nStopAtChr; nChrEnd++) {
        nIdxEnd += aTarget[nIdxEnd] > 0xD7BF /* 55231 */ && nIdxEnd + 1 < aTarget.length ? 2 : 1;
      }

      break;

    default:

      nIdxEnd = nChrEnd = isFinite(nChrLength) ? nChrLength : nRawLength - 1;

  }

  if (nChrLength) { return nIdxEnd; }

  return nChrEnd;

};

StringView.prototype.toBase64 = function (bWholeBuffer) {

  return StringView.bytesToBase64(
    bWholeBuffer ?
      (
        this.bufferView.constructor === Uint8Array ?
          this.bufferView
        :
          new Uint8Array(this.buffer)
      )
    : this.rawData.constructor === Uint8Array ?
      this.rawData
    :
      new Uint8Array(this.buffer, this.rawData.byteOffset, this.rawData.length << (this.rawData.constructor === Uint16Array ? 1 : 2))
    );

};

StringView.prototype.subview = function (nCharOffset /* optional */, nCharLength /* optional */) {

  var

    nChrLen, nCharStart, nStrLen, bVariableLen = this.encoding === "UTF-8" || this.encoding === "UTF-16",
    nStartOffset = nCharOffset, nStringLength, nRawLen = this.rawData.length;

  if (nRawLen === 0) {
    return new StringView(this.buffer, this.encoding);
  }

  nStringLength = bVariableLen ? this.makeIndex() : nRawLen;
  nCharStart = nCharOffset ? Math.max((nStringLength + nCharOffset) % nStringLength, 0) : 0;
  nStrLen = Number.isInteger(nCharLength) ? Math.max(nCharLength, 0) + nCharStart > nStringLength ? nStringLength - nCharStart : nCharLength : nStringLength;

  if (nCharStart === 0 && nStrLen === nStringLength) { return this; }

  if (bVariableLen) {
    nStartOffset = this.makeIndex(nCharStart);
    nChrLen = this.makeIndex(nStrLen, nStartOffset) - nStartOffset;
  } else {
    nStartOffset = nCharStart;
    //nChrLen = nStrLen - nCharStart;  // this can generate a negative length which blows up StringView ctor with Array index out of bounds error
    nChrLen = nCharLength - nCharStart;
  }

  if (this.encoding === "UTF-16") {
    nStartOffset <<= 1;
  } else if (this.encoding === "UTF-32") {
    nStartOffset <<= 2;
  }

  return new StringView(this.buffer, this.encoding, nStartOffset, nChrLen);

};

StringView.prototype.forEachChar = function (fCallback, oThat, nChrOffset, nChrLen) {

  var aSource = this.rawData, nRawEnd, nRawIdx;

  if (this.encoding === "UTF-8" || this.encoding === "UTF-16") {

    var fGetInptChrSize, fGetInptChrCode;

    if (this.encoding === "UTF-8") {
      fGetInptChrSize = StringView.getUTF8CharLength;
      fGetInptChrCode = StringView.loadUTF8CharCode;
    } else if (this.encoding === "UTF-16") {
      fGetInptChrSize = StringView.getUTF16CharLength;
      fGetInptChrCode = StringView.loadUTF16CharCode;
    }

    nRawIdx = isFinite(nChrOffset) ? this.makeIndex(nChrOffset) : 0;
    nRawEnd = isFinite(nChrLen) ? this.makeIndex(nChrLen, nRawIdx) : aSource.length;

    for (var nChrCode, nChrIdx = 0; nRawIdx < nRawEnd; nChrIdx++) {
      nChrCode = fGetInptChrCode(aSource, nRawIdx);
      fCallback.call(oThat || null, nChrCode, nChrIdx, nRawIdx, aSource);
      nRawIdx += fGetInptChrSize(nChrCode);
    }

  } else {

    nRawIdx = isFinite(nChrOffset) ? nChrOffset : 0;
    nRawEnd = isFinite(nChrLen) ? nChrLen + nRawIdx : aSource.length;

    for (nRawIdx; nRawIdx < nRawEnd; nRawIdx++) {
      fCallback.call(oThat || null, aSource[nRawIdx], nRawIdx, nRawIdx, aSource);
    }

  }

};

StringView.prototype.valueOf = StringView.prototype.toString = function () {

  if (this.encoding !== "UTF-8" && this.encoding !== "UTF-16") {
    /* ASCII, UTF-32 or BinaryString to DOMString */
    return String.fromCharCode.apply(null, this.rawData);
  }

  var fGetCode, fGetIncr, sView = "";

  if (this.encoding === "UTF-8") {
    fGetIncr = StringView.getUTF8CharLength;
    fGetCode = StringView.loadUTF8CharCode;
  } else if (this.encoding === "UTF-16") {
    fGetIncr = StringView.getUTF16CharLength;
    fGetCode = StringView.loadUTF16CharCode;
  }

  for (var nChr, nLen = this.rawData.length, nIdx = 0; nIdx < nLen; nIdx += fGetIncr(nChr)) {
    nChr = fGetCode(this.rawData, nIdx);
    sView += String.fromCharCode(nChr);
  }

  return sView;

};