tildefriends/core/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 #9, October 30, 2016
|*|
|*|	https://developer.mozilla.org/en-US/Add-ons/Code_snippets/StringView
|*|	https://developer.mozilla.org/en-US/docs/User:fusionchess
|*|	https://github.com/madmurphy/stringview.js
|*|
|*|	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 eqLen = (3 - (aBytes.length % 3)) % 3, sB64Enc = "";

	for (var nMod3, nLen = aBytes.length, nUint24 = 0, nIdx = 0; nIdx < nLen; nIdx++) {
		nMod3 = nIdx % 3;
		/* Uncomment the following line in order to split the output in lines 76-character long: */
		/*
		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	eqLen === 0 ?
			sB64Enc
		:
			sB64Enc.substring(0, sB64Enc.length - eqLen) + (eqLen === 1 ? "=" : "==");


};


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;
	}

	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;

};