/*
 * Copyright (C) 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.emay.sdk.util.json.gson.stream;

import java.io.Closeable;
import java.io.EOFException;
import java.io.IOException;
import java.io.Reader;

import cn.emay.sdk.util.json.gson.internal.JsonReaderInternalAccess;
import cn.emay.sdk.util.json.gson.internal.bind.JsonTreeReader;

/**
 * Reads a JSON (<a href="http://www.ietf.org/rfc/rfc7159.txt">RFC 7159</a>)
 * encoded value as a stream of tokens. This stream includes both literal values
 * (strings, numbers, booleans, and nulls) as well as the begin and end
 * delimiters of objects and arrays. The tokens are traversed in depth-first
 * order, the same order that they appear in the JSON document. Within JSON
 * objects, name/value pairs are represented by a single token.
 *
 * <h3>Parsing JSON</h3> To create a recursive descent parser for your own JSON
 * streams, first create an entry point method that creates a
 * {@code JsonReader}.
 *
 * <p>
 * Next, create handler methods for each structure in your JSON text. You'll
 * need a method for each object type and for each array type.
 * <ul>
 * <li>Within <strong>array handling</strong> methods, first call
 * {@link #beginArray} to consume the array's opening bracket. Then create a
 * while loop that accumulates values, terminating when {@link #hasNext} is
 * false. Finally, read the array's closing bracket by calling
 * {@link #endArray}.
 * <li>Within <strong>object handling</strong> methods, first call
 * {@link #beginObject} to consume the object's opening brace. Then create a
 * while loop that assigns values to local variables based on their name. This
 * loop should terminate when {@link #hasNext} is false. Finally, read the
 * object's closing brace by calling {@link #endObject}.
 * </ul>
 * <p>
 * When a nested object or array is encountered, delegate to the corresponding
 * handler method.
 *
 * <p>
 * When an unknown name is encountered, strict parsers should fail with an
 * exception. Lenient parsers should call {@link #skipValue()} to recursively
 * skip the value's nested tokens, which may otherwise conflict.
 *
 * <p>
 * If a value may be null, you should first check using {@link #peek()}. Null
 * literals can be consumed using either {@link #nextNull()} or
 * {@link #skipValue()}.
 *
 * <h3>Example</h3> Suppose we'd like to parse a stream of messages such as the
 * following:
 * 
 * <pre>
 *  {@code
 * [
 *   {
 *     "id": 912345678901,
 *     "text": "How do I read a JSON stream in Java?",
 *     "geo": null,
 *     "user": {
 *       "name": "json_newb",
 *       "followers_count": 41
 *      }
 *   },
 *   {
 *     "id": 912345678902,
 *     "text": "@json_newb just use JsonReader!",
 *     "geo": [50.454722, -104.606667],
 *     "user": {
 *       "name": "jesse",
 *       "followers_count": 2
 *     }
 *   }
 * ]}
 * </pre>
 * 
 * This code implements the parser for the above structure:
 * 
 * <pre>
 *    {@code
 *
 *   public List<Message> readJsonStream(InputStream in) throws IOException {
 *     JsonReader reader = new JsonReader(new InputStreamReader(in, "UTF-8"));
 *     try {
 *       return readMessagesArray(reader);
 *     } finally {
 *       reader.close();
 *     }
 *   }
 *
 *   public List<Message> readMessagesArray(JsonReader reader) throws IOException {
 *     List<Message> messages = new ArrayList<Message>();
 *
 *     reader.beginArray();
 *     while (reader.hasNext()) {
 *       messages.add(readMessage(reader));
 *     }
 *     reader.endArray();
 *     return messages;
 *   }
 *
 *   public Message readMessage(JsonReader reader) throws IOException {
 *     long id = -1;
 *     String text = null;
 *     User user = null;
 *     List<Double> geo = null;
 *
 *     reader.beginObject();
 *     while (reader.hasNext()) {
 *       String name = reader.nextName();
 *       if (name.equals("id")) {
 *         id = reader.nextLong();
 *       } else if (name.equals("text")) {
 *         text = reader.nextString();
 *       } else if (name.equals("geo") && reader.peek() != JsonToken.NULL) {
 *         geo = readDoublesArray(reader);
 *       } else if (name.equals("user")) {
 *         user = readUser(reader);
 *       } else {
 *         reader.skipValue();
 *       }
 *     }
 *     reader.endObject();
 *     return new Message(id, text, user, geo);
 *   }
 *
 *   public List<Double> readDoublesArray(JsonReader reader) throws IOException {
 *     List<Double> doubles = new ArrayList<Double>();
 *
 *     reader.beginArray();
 *     while (reader.hasNext()) {
 *       doubles.add(reader.nextDouble());
 *     }
 *     reader.endArray();
 *     return doubles;
 *   }
 *
 *   public User readUser(JsonReader reader) throws IOException {
 *     String username = null;
 *     int followersCount = -1;
 *
 *     reader.beginObject();
 *     while (reader.hasNext()) {
 *       String name = reader.nextName();
 *       if (name.equals("name")) {
 *         username = reader.nextString();
 *       } else if (name.equals("followers_count")) {
 *         followersCount = reader.nextInt();
 *       } else {
 *         reader.skipValue();
 *       }
 *     }
 *     reader.endObject();
 *     return new User(username, followersCount);
 *   }}
 * </pre>
 *
 * <h3>Number Handling</h3> This reader permits numeric values to be read as
 * strings and string values to be read as numbers. For example, both elements
 * of the JSON array {@code
 * [1, "1"]} may be read using either {@link #nextInt} or {@link #nextString}.
 * This behavior is intended to prevent lossy numeric conversions: double is
 * JavaScript's only numeric type and very large values like {@code
 * 9007199254740993} cannot be represented exactly on that platform. To minimize
 * precision loss, extremely large values should be written and read as strings
 * in JSON.
 *
 * <a name="nonexecuteprefix"/>
 * <h3>Non-Execute Prefix</h3> Web servers that serve private data using JSON
 * may be vulnerable to <a href=
 * "http://en.wikipedia.org/wiki/JSON#Cross-site_request_forgery">Cross-site
 * request forgery</a> attacks. In such an attack, a malicious site gains access
 * to a private JSON file by executing it with an HTML {@code <script>} tag.
 *
 * <p>
 * Prefixing JSON files with <code>")]}'\n"</code> makes them non-executable by
 * {@code <script>} tags, disarming the attack. Since the prefix is malformed
 * JSON, strict parsing fails when it is encountered. This class permits the
 * non-execute prefix when {@link #setLenient(boolean) lenient parsing} is
 * enabled.
 *
 * <p>
 * Each {@code JsonReader} may be used to read a single JSON stream. Instances
 * of this class are not thread safe.
 *
 * @author Jesse Wilson
 * @since 1.6
 */
public class JsonReader implements Closeable {
	/** The only non-execute prefix this parser permits */
	private static final char[] NON_EXECUTE_PREFIX = ")]}'\n".toCharArray();
	private static final long MIN_INCOMPLETE_INTEGER = Long.MIN_VALUE / 10;

	private static final int PEEKED_NONE = 0;
	private static final int PEEKED_BEGIN_OBJECT = 1;
	private static final int PEEKED_END_OBJECT = 2;
	private static final int PEEKED_BEGIN_ARRAY = 3;
	private static final int PEEKED_END_ARRAY = 4;
	private static final int PEEKED_TRUE = 5;
	private static final int PEEKED_FALSE = 6;
	private static final int PEEKED_NULL = 7;
	private static final int PEEKED_SINGLE_QUOTED = 8;
	private static final int PEEKED_DOUBLE_QUOTED = 9;
	private static final int PEEKED_UNQUOTED = 10;
	/** When this is returned, the string value is stored in peekedString. */
	private static final int PEEKED_BUFFERED = 11;
	private static final int PEEKED_SINGLE_QUOTED_NAME = 12;
	private static final int PEEKED_DOUBLE_QUOTED_NAME = 13;
	private static final int PEEKED_UNQUOTED_NAME = 14;
	/** When this is returned, the integer value is stored in peekedLong. */
	private static final int PEEKED_LONG = 15;
	private static final int PEEKED_NUMBER = 16;
	private static final int PEEKED_EOF = 17;

	/* State machine when parsing numbers */
	private static final int NUMBER_CHAR_NONE = 0;
	private static final int NUMBER_CHAR_SIGN = 1;
	private static final int NUMBER_CHAR_DIGIT = 2;
	private static final int NUMBER_CHAR_DECIMAL = 3;
	private static final int NUMBER_CHAR_FRACTION_DIGIT = 4;
	private static final int NUMBER_CHAR_EXP_E = 5;
	private static final int NUMBER_CHAR_EXP_SIGN = 6;
	private static final int NUMBER_CHAR_EXP_DIGIT = 7;

	/** The input JSON. */
	private final Reader in;

	/** True to accept non-spec compliant JSON */
	private boolean lenient = false;

	/**
	 * Use a manual buffer to easily read and unread upcoming characters, and also
	 * so we can create strings without an intermediate StringBuilder. We decode
	 * literals directly out of this buffer, so it must be at least as long as the
	 * longest token that can be reported as a number.
	 */
	private final char[] buffer = new char[1024];
	private int pos = 0;
	private int limit = 0;

	private int lineNumber = 0;
	private int lineStart = 0;

	int peeked = PEEKED_NONE;

	/**
	 * A peeked value that was composed entirely of digits with an optional leading
	 * dash. Positive values may not have a leading 0.
	 */
	private long peekedLong;

	/**
	 * The number of characters in a peeked number literal. Increment 'pos' by this
	 * after reading a number.
	 */
	private int peekedNumberLength;

	/**
	 * A peeked string that should be parsed on the next double, long or string.
	 * This is populated before a numeric value is parsed and used if that parsing
	 * fails.
	 */
	private String peekedString;

	/*
	 * The nesting stack. Using a manual array rather than an ArrayList saves 20%.
	 */
	private int[] stack = new int[32];
	private int stackSize = 0;
	{
		stack[stackSize++] = JsonScope.EMPTY_DOCUMENT;
	}

	/*
	 * The path members. It corresponds directly to stack: At indices where the
	 * stack contains an object (EMPTY_OBJECT, DANGLING_NAME or NONEMPTY_OBJECT),
	 * pathNames contains the name at this scope. Where it contains an array
	 * (EMPTY_ARRAY, NONEMPTY_ARRAY) pathIndices contains the current index in that
	 * array. Otherwise the value is undefined, and we take advantage of that by
	 * incrementing pathIndices when doing so isn't useful.
	 */
	private String[] pathNames = new String[32];
	private int[] pathIndices = new int[32];

	/**
	 * Creates a new instance that reads a JSON-encoded stream from {@code in}.
	 */
	public JsonReader(Reader in) {
		if (in == null) {
			throw new NullPointerException("in == null");
		}
		this.in = in;
	}

	/**
	 * Configure this parser to be liberal in what it accepts. By default, this
	 * parser is strict and only accepts JSON as specified by
	 * <a href="http://www.ietf.org/rfc/rfc4627.txt">RFC 4627</a>. Setting the
	 * parser to lenient causes it to ignore the following syntax errors:
	 *
	 * <ul>
	 * <li>Streams that start with the <a href="#nonexecuteprefix">non-execute
	 * prefix</a>, <code>")]}'\n"</code>.
	 * <li>Streams that include multiple top-level values. With strict parsing, each
	 * stream must contain exactly one top-level value.
	 * <li>Top-level values of any type. With strict parsing, the top-level value
	 * must be an object or an array.
	 * <li>Numbers may be {@link Double#isNaN() NaNs} or {@link Double#isInfinite()
	 * infinities}.
	 * <li>End of line comments starting with {@code //} or {@code #} and ending
	 * with a newline character.
	 * <li>C-style comments starting with {@code /*} and ending with
	 * {@code *}{@code /}. Such comments may not be nested.
	 * <li>Names that are unquoted or {@code 'single quoted'}.
	 * <li>Strings that are unquoted or {@code 'single quoted'}.
	 * <li>Array elements separated by {@code ;} instead of {@code ,}.
	 * <li>Unnecessary array separators. These are interpreted as if null was the
	 * omitted value.
	 * <li>Names and values separated by {@code =} or {@code =>} instead of
	 * {@code :}.
	 * <li>Name/value pairs separated by {@code ;} instead of {@code ,}.
	 * </ul>
	 */
	public final void setLenient(boolean lenient) {
		this.lenient = lenient;
	}

	/**
	 * Returns true if this parser is liberal in what it accepts.
	 */
	public final boolean isLenient() {
		return lenient;
	}

	/**
	 * Consumes the next token from the JSON stream and asserts that it is the
	 * beginning of a new array.
	 */
	public void beginArray() throws IOException {
		int p = peeked;
		if (p == PEEKED_NONE) {
			p = doPeek();
		}
		if (p == PEEKED_BEGIN_ARRAY) {
			push(JsonScope.EMPTY_ARRAY);
			pathIndices[stackSize - 1] = 0;
			peeked = PEEKED_NONE;
		} else {
			throw new IllegalStateException("Expected BEGIN_ARRAY but was " + peek() + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
		}
	}

	/**
	 * Consumes the next token from the JSON stream and asserts that it is the end
	 * of the current array.
	 */
	public void endArray() throws IOException {
		int p = peeked;
		if (p == PEEKED_NONE) {
			p = doPeek();
		}
		if (p == PEEKED_END_ARRAY) {
			stackSize--;
			pathIndices[stackSize - 1]++;
			peeked = PEEKED_NONE;
		} else {
			throw new IllegalStateException("Expected END_ARRAY but was " + peek() + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
		}
	}

	/**
	 * Consumes the next token from the JSON stream and asserts that it is the
	 * beginning of a new object.
	 */
	public void beginObject() throws IOException {
		int p = peeked;
		if (p == PEEKED_NONE) {
			p = doPeek();
		}
		if (p == PEEKED_BEGIN_OBJECT) {
			push(JsonScope.EMPTY_OBJECT);
			peeked = PEEKED_NONE;
		} else {
			throw new IllegalStateException("Expected BEGIN_OBJECT but was " + peek() + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
		}
	}

	/**
	 * Consumes the next token from the JSON stream and asserts that it is the end
	 * of the current object.
	 */
	public void endObject() throws IOException {
		int p = peeked;
		if (p == PEEKED_NONE) {
			p = doPeek();
		}
		if (p == PEEKED_END_OBJECT) {
			stackSize--;
			pathNames[stackSize] = null; // Free the last path name so that it can be garbage collected!
			pathIndices[stackSize - 1]++;
			peeked = PEEKED_NONE;
		} else {
			throw new IllegalStateException("Expected END_OBJECT but was " + peek() + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
		}
	}

	/**
	 * Returns true if the current array or object has another element.
	 */
	public boolean hasNext() throws IOException {
		int p = peeked;
		if (p == PEEKED_NONE) {
			p = doPeek();
		}
		return p != PEEKED_END_OBJECT && p != PEEKED_END_ARRAY;
	}

	/**
	 * Returns the type of the next token without consuming it.
	 */
	public JsonToken peek() throws IOException {
		int p = peeked;
		if (p == PEEKED_NONE) {
			p = doPeek();
		}

		switch (p) {
		case PEEKED_BEGIN_OBJECT:
			return JsonToken.BEGIN_OBJECT;
		case PEEKED_END_OBJECT:
			return JsonToken.END_OBJECT;
		case PEEKED_BEGIN_ARRAY:
			return JsonToken.BEGIN_ARRAY;
		case PEEKED_END_ARRAY:
			return JsonToken.END_ARRAY;
		case PEEKED_SINGLE_QUOTED_NAME:
		case PEEKED_DOUBLE_QUOTED_NAME:
		case PEEKED_UNQUOTED_NAME:
			return JsonToken.NAME;
		case PEEKED_TRUE:
		case PEEKED_FALSE:
			return JsonToken.BOOLEAN;
		case PEEKED_NULL:
			return JsonToken.NULL;
		case PEEKED_SINGLE_QUOTED:
		case PEEKED_DOUBLE_QUOTED:
		case PEEKED_UNQUOTED:
		case PEEKED_BUFFERED:
			return JsonToken.STRING;
		case PEEKED_LONG:
		case PEEKED_NUMBER:
			return JsonToken.NUMBER;
		case PEEKED_EOF:
			return JsonToken.END_DOCUMENT;
		default:
			throw new AssertionError();
		}
	}

	int doPeek() throws IOException {
		int peekStack = stack[stackSize - 1];
		if (peekStack == JsonScope.EMPTY_ARRAY) {
			stack[stackSize - 1] = JsonScope.NONEMPTY_ARRAY;
		} else if (peekStack == JsonScope.NONEMPTY_ARRAY) {
			// Look for a comma before the next element.
			int c = nextNonWhitespace(true);
			switch (c) {
			case ']':
				return peeked = PEEKED_END_ARRAY;
			case ';':
				checkLenient(); // fall-through
			case ',':
				break;
			default:
				throw syntaxError("Unterminated array");
			}
		} else if (peekStack == JsonScope.EMPTY_OBJECT || peekStack == JsonScope.NONEMPTY_OBJECT) {
			stack[stackSize - 1] = JsonScope.DANGLING_NAME;
			// Look for a comma before the next element.
			if (peekStack == JsonScope.NONEMPTY_OBJECT) {
				int c = nextNonWhitespace(true);
				switch (c) {
				case '}':
					return peeked = PEEKED_END_OBJECT;
				case ';':
					checkLenient(); // fall-through
				case ',':
					break;
				default:
					throw syntaxError("Unterminated object");
				}
			}
			int c = nextNonWhitespace(true);
			switch (c) {
			case '"':
				return peeked = PEEKED_DOUBLE_QUOTED_NAME;
			case '\'':
				checkLenient();
				return peeked = PEEKED_SINGLE_QUOTED_NAME;
			case '}':
				if (peekStack != JsonScope.NONEMPTY_OBJECT) {
					return peeked = PEEKED_END_OBJECT;
				} else {
					throw syntaxError("Expected name");
				}
			default:
				checkLenient();
				pos--; // Don't consume the first character in an unquoted string.
				if (isLiteral((char) c)) {
					return peeked = PEEKED_UNQUOTED_NAME;
				} else {
					throw syntaxError("Expected name");
				}
			}
		} else if (peekStack == JsonScope.DANGLING_NAME) {
			stack[stackSize - 1] = JsonScope.NONEMPTY_OBJECT;
			// Look for a colon before the value.
			int c = nextNonWhitespace(true);
			switch (c) {
			case ':':
				break;
			case '=':
				checkLenient();
				if ((pos < limit || fillBuffer(1)) && buffer[pos] == '>') {
					pos++;
				}
				break;
			default:
				throw syntaxError("Expected ':'");
			}
		} else if (peekStack == JsonScope.EMPTY_DOCUMENT) {
			if (lenient) {
				consumeNonExecutePrefix();
			}
			stack[stackSize - 1] = JsonScope.NONEMPTY_DOCUMENT;
		} else if (peekStack == JsonScope.NONEMPTY_DOCUMENT) {
			int c = nextNonWhitespace(false);
			if (c == -1) {
				return peeked = PEEKED_EOF;
			} else {
				checkLenient();
				pos--;
			}
		} else if (peekStack == JsonScope.CLOSED) {
			throw new IllegalStateException("JsonReader is closed");
		}

		int c = nextNonWhitespace(true);
		switch (c) {
		case ']':
			if (peekStack == JsonScope.EMPTY_ARRAY) {
				return peeked = PEEKED_END_ARRAY;
			}
			// fall-through to handle ",]"
		case ';':
		case ',':
			// In lenient mode, a 0-length literal in an array means 'null'.
			if (peekStack == JsonScope.EMPTY_ARRAY || peekStack == JsonScope.NONEMPTY_ARRAY) {
				checkLenient();
				pos--;
				return peeked = PEEKED_NULL;
			} else {
				throw syntaxError("Unexpected value");
			}
		case '\'':
			checkLenient();
			return peeked = PEEKED_SINGLE_QUOTED;
		case '"':
			return peeked = PEEKED_DOUBLE_QUOTED;
		case '[':
			return peeked = PEEKED_BEGIN_ARRAY;
		case '{':
			return peeked = PEEKED_BEGIN_OBJECT;
		default:
			pos--; // Don't consume the first character in a literal value.
		}

		int result = peekKeyword();
		if (result != PEEKED_NONE) {
			return result;
		}

		result = peekNumber();
		if (result != PEEKED_NONE) {
			return result;
		}

		if (!isLiteral(buffer[pos])) {
			throw syntaxError("Expected value");
		}

		checkLenient();
		return peeked = PEEKED_UNQUOTED;
	}

	private int peekKeyword() throws IOException {
		// Figure out which keyword we're matching against by its first character.
		char c = buffer[pos];
		String keyword;
		String keywordUpper;
		int peeking;
		if (c == 't' || c == 'T') {
			keyword = "true";
			keywordUpper = "TRUE";
			peeking = PEEKED_TRUE;
		} else if (c == 'f' || c == 'F') {
			keyword = "false";
			keywordUpper = "FALSE";
			peeking = PEEKED_FALSE;
		} else if (c == 'n' || c == 'N') {
			keyword = "null";
			keywordUpper = "NULL";
			peeking = PEEKED_NULL;
		} else {
			return PEEKED_NONE;
		}

		// Confirm that chars [1..length) match the keyword.
		int length = keyword.length();
		for (int i = 1; i < length; i++) {
			if (pos + i >= limit && !fillBuffer(i + 1)) {
				return PEEKED_NONE;
			}
			c = buffer[pos + i];
			if (c != keyword.charAt(i) && c != keywordUpper.charAt(i)) {
				return PEEKED_NONE;
			}
		}

		if ((pos + length < limit || fillBuffer(length + 1)) && isLiteral(buffer[pos + length])) {
			return PEEKED_NONE; // Don't match trues, falsey or nullsoft!
		}

		// We've found the keyword followed either by EOF or by a non-literal character.
		pos += length;
		return peeked = peeking;
	}

	private int peekNumber() throws IOException {
		// Like nextNonWhitespace, this uses locals 'p' and 'l' to save inner-loop field
		// access.
		char[] buffer = this.buffer;
		int p = pos;
		int l = limit;

		long value = 0; // Negative to accommodate Long.MIN_VALUE more easily.
		boolean negative = false;
		boolean fitsInLong = true;
		int last = NUMBER_CHAR_NONE;

		int i = 0;

		charactersOfNumber: for (; true; i++) {
			if (p + i == l) {
				if (i == buffer.length) {
					// Though this looks like a well-formed number, it's too long to continue
					// reading. Give up
					// and let the application handle this as an unquoted literal.
					return PEEKED_NONE;
				}
				if (!fillBuffer(i + 1)) {
					break;
				}
				p = pos;
				l = limit;
			}

			char c = buffer[p + i];
			switch (c) {
			case '-':
				if (last == NUMBER_CHAR_NONE) {
					negative = true;
					last = NUMBER_CHAR_SIGN;
					continue;
				} else if (last == NUMBER_CHAR_EXP_E) {
					last = NUMBER_CHAR_EXP_SIGN;
					continue;
				}
				return PEEKED_NONE;

			case '+':
				if (last == NUMBER_CHAR_EXP_E) {
					last = NUMBER_CHAR_EXP_SIGN;
					continue;
				}
				return PEEKED_NONE;

			case 'e':
			case 'E':
				if (last == NUMBER_CHAR_DIGIT || last == NUMBER_CHAR_FRACTION_DIGIT) {
					last = NUMBER_CHAR_EXP_E;
					continue;
				}
				return PEEKED_NONE;

			case '.':
				if (last == NUMBER_CHAR_DIGIT) {
					last = NUMBER_CHAR_DECIMAL;
					continue;
				}
				return PEEKED_NONE;

			default:
				if (c < '0' || c > '9') {
					if (!isLiteral(c)) {
						break charactersOfNumber;
					}
					return PEEKED_NONE;
				}
				if (last == NUMBER_CHAR_SIGN || last == NUMBER_CHAR_NONE) {
					value = -(c - '0');
					last = NUMBER_CHAR_DIGIT;
				} else if (last == NUMBER_CHAR_DIGIT) {
					if (value == 0) {
						return PEEKED_NONE; // Leading '0' prefix is not allowed (since it could be octal).
					}
					long newValue = value * 10 - (c - '0');
					fitsInLong &= value > MIN_INCOMPLETE_INTEGER || (value == MIN_INCOMPLETE_INTEGER && newValue < value);
					value = newValue;
				} else if (last == NUMBER_CHAR_DECIMAL) {
					last = NUMBER_CHAR_FRACTION_DIGIT;
				} else if (last == NUMBER_CHAR_EXP_E || last == NUMBER_CHAR_EXP_SIGN) {
					last = NUMBER_CHAR_EXP_DIGIT;
				}
			}
		}

		// We've read a complete number. Decide if it's a PEEKED_LONG or a
		// PEEKED_NUMBER.
		if (last == NUMBER_CHAR_DIGIT && fitsInLong && (value != Long.MIN_VALUE || negative)) {
			peekedLong = negative ? value : -value;
			pos += i;
			return peeked = PEEKED_LONG;
		} else if (last == NUMBER_CHAR_DIGIT || last == NUMBER_CHAR_FRACTION_DIGIT || last == NUMBER_CHAR_EXP_DIGIT) {
			peekedNumberLength = i;
			return peeked = PEEKED_NUMBER;
		} else {
			return PEEKED_NONE;
		}
	}

	private boolean isLiteral(char c) throws IOException {
		switch (c) {
		case '/':
		case '\\':
		case ';':
		case '#':
		case '=':
			checkLenient(); // fall-through
		case '{':
		case '}':
		case '[':
		case ']':
		case ':':
		case ',':
		case ' ':
		case '\t':
		case '\f':
		case '\r':
		case '\n':
			return false;
		default:
			return true;
		}
	}

	/**
	 * Returns the next token, a {@link com.google.gson.stream.JsonToken#NAME
	 * property name}, and consumes it.
	 *
	 * @throws java.io.IOException
	 *             if the next token in the stream is not a property name.
	 */
	public String nextName() throws IOException {
		int p = peeked;
		if (p == PEEKED_NONE) {
			p = doPeek();
		}
		String result;
		if (p == PEEKED_UNQUOTED_NAME) {
			result = nextUnquotedValue();
		} else if (p == PEEKED_SINGLE_QUOTED_NAME) {
			result = nextQuotedValue('\'');
		} else if (p == PEEKED_DOUBLE_QUOTED_NAME) {
			result = nextQuotedValue('"');
		} else {
			throw new IllegalStateException("Expected a name but was " + peek() + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
		}
		peeked = PEEKED_NONE;
		pathNames[stackSize - 1] = result;
		return result;
	}

	/**
	 * Returns the {@link com.google.gson.stream.JsonToken#STRING string} value of
	 * the next token, consuming it. If the next token is a number, this method will
	 * return its string form.
	 *
	 * @throws IllegalStateException
	 *             if the next token is not a string or if this reader is closed.
	 */
	public String nextString() throws IOException {
		int p = peeked;
		if (p == PEEKED_NONE) {
			p = doPeek();
		}
		String result;
		if (p == PEEKED_UNQUOTED) {
			result = nextUnquotedValue();
		} else if (p == PEEKED_SINGLE_QUOTED) {
			result = nextQuotedValue('\'');
		} else if (p == PEEKED_DOUBLE_QUOTED) {
			result = nextQuotedValue('"');
		} else if (p == PEEKED_BUFFERED) {
			result = peekedString;
			peekedString = null;
		} else if (p == PEEKED_LONG) {
			result = Long.toString(peekedLong);
		} else if (p == PEEKED_NUMBER) {
			result = new String(buffer, pos, peekedNumberLength);
			pos += peekedNumberLength;
		} else {
			throw new IllegalStateException("Expected a string but was " + peek() + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
		}
		peeked = PEEKED_NONE;
		pathIndices[stackSize - 1]++;
		return result;
	}

	/**
	 * Returns the {@link com.google.gson.stream.JsonToken#BOOLEAN boolean} value of
	 * the next token, consuming it.
	 *
	 * @throws IllegalStateException
	 *             if the next token is not a boolean or if this reader is closed.
	 */
	public boolean nextBoolean() throws IOException {
		int p = peeked;
		if (p == PEEKED_NONE) {
			p = doPeek();
		}
		if (p == PEEKED_TRUE) {
			peeked = PEEKED_NONE;
			pathIndices[stackSize - 1]++;
			return true;
		} else if (p == PEEKED_FALSE) {
			peeked = PEEKED_NONE;
			pathIndices[stackSize - 1]++;
			return false;
		}
		throw new IllegalStateException("Expected a boolean but was " + peek() + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
	}

	/**
	 * Consumes the next token from the JSON stream and asserts that it is a literal
	 * null.
	 *
	 * @throws IllegalStateException
	 *             if the next token is not null or if this reader is closed.
	 */
	public void nextNull() throws IOException {
		int p = peeked;
		if (p == PEEKED_NONE) {
			p = doPeek();
		}
		if (p == PEEKED_NULL) {
			peeked = PEEKED_NONE;
			pathIndices[stackSize - 1]++;
		} else {
			throw new IllegalStateException("Expected null but was " + peek() + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
		}
	}

	/**
	 * Returns the {@link com.google.gson.stream.JsonToken#NUMBER double} value of
	 * the next token, consuming it. If the next token is a string, this method will
	 * attempt to parse it as a double using {@link Double#parseDouble(String)}.
	 *
	 * @throws IllegalStateException
	 *             if the next token is not a literal value.
	 * @throws NumberFormatException
	 *             if the next literal value cannot be parsed as a double, or is
	 *             non-finite.
	 */
	public double nextDouble() throws IOException {
		int p = peeked;
		if (p == PEEKED_NONE) {
			p = doPeek();
		}

		if (p == PEEKED_LONG) {
			peeked = PEEKED_NONE;
			pathIndices[stackSize - 1]++;
			return (double) peekedLong;
		}

		if (p == PEEKED_NUMBER) {
			peekedString = new String(buffer, pos, peekedNumberLength);
			pos += peekedNumberLength;
		} else if (p == PEEKED_SINGLE_QUOTED || p == PEEKED_DOUBLE_QUOTED) {
			peekedString = nextQuotedValue(p == PEEKED_SINGLE_QUOTED ? '\'' : '"');
		} else if (p == PEEKED_UNQUOTED) {
			peekedString = nextUnquotedValue();
		} else if (p != PEEKED_BUFFERED) {
			throw new IllegalStateException("Expected a double but was " + peek() + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
		}

		peeked = PEEKED_BUFFERED;
		double result = Double.parseDouble(peekedString); // don't catch this NumberFormatException.
		if (!lenient && (Double.isNaN(result) || Double.isInfinite(result))) {
			throw new MalformedJsonException("JSON forbids NaN and infinities: " + result + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
		}
		peekedString = null;
		peeked = PEEKED_NONE;
		pathIndices[stackSize - 1]++;
		return result;
	}

	/**
	 * Returns the {@link com.google.gson.stream.JsonToken#NUMBER long} value of the
	 * next token, consuming it. If the next token is a string, this method will
	 * attempt to parse it as a long. If the next token's numeric value cannot be
	 * exactly represented by a Java {@code long}, this method throws.
	 *
	 * @throws IllegalStateException
	 *             if the next token is not a literal value.
	 * @throws NumberFormatException
	 *             if the next literal value cannot be parsed as a number, or
	 *             exactly represented as a long.
	 */
	public long nextLong() throws IOException {
		int p = peeked;
		if (p == PEEKED_NONE) {
			p = doPeek();
		}

		if (p == PEEKED_LONG) {
			peeked = PEEKED_NONE;
			pathIndices[stackSize - 1]++;
			return peekedLong;
		}

		if (p == PEEKED_NUMBER) {
			peekedString = new String(buffer, pos, peekedNumberLength);
			pos += peekedNumberLength;
		} else if (p == PEEKED_SINGLE_QUOTED || p == PEEKED_DOUBLE_QUOTED) {
			peekedString = nextQuotedValue(p == PEEKED_SINGLE_QUOTED ? '\'' : '"');
			try {
				long result = Long.parseLong(peekedString);
				peeked = PEEKED_NONE;
				pathIndices[stackSize - 1]++;
				return result;
			} catch (NumberFormatException ignored) {
				// Fall back to parse as a double below.
			}
		} else {
			throw new IllegalStateException("Expected a long but was " + peek() + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
		}

		peeked = PEEKED_BUFFERED;
		double asDouble = Double.parseDouble(peekedString); // don't catch this NumberFormatException.
		long result = (long) asDouble;
		if (result != asDouble) { // Make sure no precision was lost casting to 'long'.
			throw new NumberFormatException("Expected a long but was " + peekedString + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
		}
		peekedString = null;
		peeked = PEEKED_NONE;
		pathIndices[stackSize - 1]++;
		return result;
	}

	/**
	 * Returns the string up to but not including {@code quote}, unescaping any
	 * character escape sequences encountered along the way. The opening quote
	 * should have already been read. This consumes the closing quote, but does not
	 * include it in the returned string.
	 *
	 * @param quote
	 *            either ' or ".
	 * @throws NumberFormatException
	 *             if any unicode escape sequences are malformed.
	 */
	private String nextQuotedValue(char quote) throws IOException {
		// Like nextNonWhitespace, this uses locals 'p' and 'l' to save inner-loop field
		// access.
		char[] buffer = this.buffer;
		StringBuilder builder = new StringBuilder();
		while (true) {
			int p = pos;
			int l = limit;
			/* the index of the first character not yet appended to the builder. */
			int start = p;
			while (p < l) {
				int c = buffer[p++];

				if (c == quote) {
					pos = p;
					builder.append(buffer, start, p - start - 1);
					return builder.toString();
				} else if (c == '\\') {
					pos = p;
					builder.append(buffer, start, p - start - 1);
					builder.append(readEscapeCharacter());
					p = pos;
					l = limit;
					start = p;
				} else if (c == '\n') {
					lineNumber++;
					lineStart = p;
				}
			}

			builder.append(buffer, start, p - start);
			pos = p;
			if (!fillBuffer(1)) {
				throw syntaxError("Unterminated string");
			}
		}
	}

	/**
	 * Returns an unquoted value as a string.
	 */
	@SuppressWarnings("fallthrough")
	private String nextUnquotedValue() throws IOException {
		StringBuilder builder = null;
		int i = 0;

		findNonLiteralCharacter: while (true) {
			for (; pos + i < limit; i++) {
				switch (buffer[pos + i]) {
				case '/':
				case '\\':
				case ';':
				case '#':
				case '=':
					checkLenient(); // fall-through
				case '{':
				case '}':
				case '[':
				case ']':
				case ':':
				case ',':
				case ' ':
				case '\t':
				case '\f':
				case '\r':
				case '\n':
					break findNonLiteralCharacter;
				}
			}

			// Attempt to load the entire literal into the buffer at once.
			if (i < buffer.length) {
				if (fillBuffer(i + 1)) {
					continue;
				} else {
					break;
				}
			}

			// use a StringBuilder when the value is too long. This is too long to be a
			// number!
			if (builder == null) {
				builder = new StringBuilder();
			}
			builder.append(buffer, pos, i);
			pos += i;
			i = 0;
			if (!fillBuffer(1)) {
				break;
			}
		}

		String result;
		if (builder == null) {
			result = new String(buffer, pos, i);
		} else {
			builder.append(buffer, pos, i);
			result = builder.toString();
		}
		pos += i;
		return result;
	}

	private void skipQuotedValue(char quote) throws IOException {
		// Like nextNonWhitespace, this uses locals 'p' and 'l' to save inner-loop field
		// access.
		char[] buffer = this.buffer;
		do {
			int p = pos;
			int l = limit;
			/* the index of the first character not yet appended to the builder. */
			while (p < l) {
				int c = buffer[p++];
				if (c == quote) {
					pos = p;
					return;
				} else if (c == '\\') {
					pos = p;
					readEscapeCharacter();
					p = pos;
					l = limit;
				} else if (c == '\n') {
					lineNumber++;
					lineStart = p;
				}
			}
			pos = p;
		} while (fillBuffer(1));
		throw syntaxError("Unterminated string");
	}

	private void skipUnquotedValue() throws IOException {
		do {
			int i = 0;
			for (; pos + i < limit; i++) {
				switch (buffer[pos + i]) {
				case '/':
				case '\\':
				case ';':
				case '#':
				case '=':
					checkLenient(); // fall-through
				case '{':
				case '}':
				case '[':
				case ']':
				case ':':
				case ',':
				case ' ':
				case '\t':
				case '\f':
				case '\r':
				case '\n':
					pos += i;
					return;
				}
			}
			pos += i;
		} while (fillBuffer(1));
	}

	/**
	 * Returns the {@link com.google.gson.stream.JsonToken#NUMBER int} value of the
	 * next token, consuming it. If the next token is a string, this method will
	 * attempt to parse it as an int. If the next token's numeric value cannot be
	 * exactly represented by a Java {@code int}, this method throws.
	 *
	 * @throws IllegalStateException
	 *             if the next token is not a literal value.
	 * @throws NumberFormatException
	 *             if the next literal value cannot be parsed as a number, or
	 *             exactly represented as an int.
	 */
	public int nextInt() throws IOException {
		int p = peeked;
		if (p == PEEKED_NONE) {
			p = doPeek();
		}

		int result;
		if (p == PEEKED_LONG) {
			result = (int) peekedLong;
			if (peekedLong != result) { // Make sure no precision was lost casting to 'int'.
				throw new NumberFormatException("Expected an int but was " + peekedLong + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
			}
			peeked = PEEKED_NONE;
			pathIndices[stackSize - 1]++;
			return result;
		}

		if (p == PEEKED_NUMBER) {
			peekedString = new String(buffer, pos, peekedNumberLength);
			pos += peekedNumberLength;
		} else if (p == PEEKED_SINGLE_QUOTED || p == PEEKED_DOUBLE_QUOTED) {
			peekedString = nextQuotedValue(p == PEEKED_SINGLE_QUOTED ? '\'' : '"');
			try {
				result = Integer.parseInt(peekedString);
				peeked = PEEKED_NONE;
				pathIndices[stackSize - 1]++;
				return result;
			} catch (NumberFormatException ignored) {
				// Fall back to parse as a double below.
			}
		} else {
			throw new IllegalStateException("Expected an int but was " + peek() + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
		}

		peeked = PEEKED_BUFFERED;
		double asDouble = Double.parseDouble(peekedString); // don't catch this NumberFormatException.
		result = (int) asDouble;
		if (result != asDouble) { // Make sure no precision was lost casting to 'int'.
			throw new NumberFormatException("Expected an int but was " + peekedString + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
		}
		peekedString = null;
		peeked = PEEKED_NONE;
		pathIndices[stackSize - 1]++;
		return result;
	}

	/**
	 * Closes this JSON reader and the underlying {@link java.io.Reader}.
	 */
	public void close() throws IOException {
		peeked = PEEKED_NONE;
		stack[0] = JsonScope.CLOSED;
		stackSize = 1;
		in.close();
	}

	/**
	 * Skips the next value recursively. If it is an object or array, all nested
	 * elements are skipped. This method is intended for use when the JSON token
	 * stream contains unrecognized or unhandled values.
	 */
	public void skipValue() throws IOException {
		int count = 0;
		do {
			int p = peeked;
			if (p == PEEKED_NONE) {
				p = doPeek();
			}

			if (p == PEEKED_BEGIN_ARRAY) {
				push(JsonScope.EMPTY_ARRAY);
				count++;
			} else if (p == PEEKED_BEGIN_OBJECT) {
				push(JsonScope.EMPTY_OBJECT);
				count++;
			} else if (p == PEEKED_END_ARRAY) {
				stackSize--;
				count--;
			} else if (p == PEEKED_END_OBJECT) {
				stackSize--;
				count--;
			} else if (p == PEEKED_UNQUOTED_NAME || p == PEEKED_UNQUOTED) {
				skipUnquotedValue();
			} else if (p == PEEKED_SINGLE_QUOTED || p == PEEKED_SINGLE_QUOTED_NAME) {
				skipQuotedValue('\'');
			} else if (p == PEEKED_DOUBLE_QUOTED || p == PEEKED_DOUBLE_QUOTED_NAME) {
				skipQuotedValue('"');
			} else if (p == PEEKED_NUMBER) {
				pos += peekedNumberLength;
			}
			peeked = PEEKED_NONE;
		} while (count != 0);

		pathIndices[stackSize - 1]++;
		pathNames[stackSize - 1] = "null";
	}

	private void push(int newTop) {
		if (stackSize == stack.length) {
			int[] newStack = new int[stackSize * 2];
			int[] newPathIndices = new int[stackSize * 2];
			String[] newPathNames = new String[stackSize * 2];
			System.arraycopy(stack, 0, newStack, 0, stackSize);
			System.arraycopy(pathIndices, 0, newPathIndices, 0, stackSize);
			System.arraycopy(pathNames, 0, newPathNames, 0, stackSize);
			stack = newStack;
			pathIndices = newPathIndices;
			pathNames = newPathNames;
		}
		stack[stackSize++] = newTop;
	}

	/**
	 * Returns true once {@code limit - pos >= minimum}. If the data is exhausted
	 * before that many characters are available, this returns false.
	 */
	private boolean fillBuffer(int minimum) throws IOException {
		char[] buffer = this.buffer;
		lineStart -= pos;
		if (limit != pos) {
			limit -= pos;
			System.arraycopy(buffer, pos, buffer, 0, limit);
		} else {
			limit = 0;
		}

		pos = 0;
		int total;
		while ((total = in.read(buffer, limit, buffer.length - limit)) != -1) {
			limit += total;

			// if this is the first read, consume an optional byte order mark (BOM) if it
			// exists
			if (lineNumber == 0 && lineStart == 0 && limit > 0 && buffer[0] == '\ufeff') {
				pos++;
				lineStart++;
				minimum++;
			}

			if (limit >= minimum) {
				return true;
			}
		}
		return false;
	}

	int getLineNumber() {
		return lineNumber + 1;
	}

	int getColumnNumber() {
		return pos - lineStart + 1;
	}

	/**
	 * Returns the next character in the stream that is neither whitespace nor a
	 * part of a comment. When this returns, the returned character is always at
	 * {@code buffer[pos-1]}; this means the caller can always push back the
	 * returned character by decrementing {@code pos}.
	 */
	private int nextNonWhitespace(boolean throwOnEof) throws IOException {
		/*
		 * This code uses ugly local variables 'p' and 'l' representing the 'pos' and
		 * 'limit' fields respectively. Using locals rather than fields saves a few
		 * field reads for each whitespace character in a pretty-printed document,
		 * resulting in a 5% speedup. We need to flush 'p' to its field before any
		 * (potentially indirect) call to fillBuffer() and reread both 'p' and 'l' after
		 * any (potentially indirect) call to the same method.
		 */
		char[] buffer = this.buffer;
		int p = pos;
		int l = limit;
		while (true) {
			if (p == l) {
				pos = p;
				if (!fillBuffer(1)) {
					break;
				}
				p = pos;
				l = limit;
			}

			int c = buffer[p++];
			if (c == '\n') {
				lineNumber++;
				lineStart = p;
				continue;
			} else if (c == ' ' || c == '\r' || c == '\t') {
				continue;
			}

			if (c == '/') {
				pos = p;
				if (p == l) {
					pos--; // push back '/' so it's still in the buffer when this method returns
					boolean charsLoaded = fillBuffer(2);
					pos++; // consume the '/' again
					if (!charsLoaded) {
						return c;
					}
				}

				checkLenient();
				char peek = buffer[pos];
				switch (peek) {
				case '*':
					// skip a /* c-style comment */
					pos++;
					if (!skipTo("*/")) {
						throw syntaxError("Unterminated comment");
					}
					p = pos + 2;
					l = limit;
					continue;

				case '/':
					// skip a // end-of-line comment
					pos++;
					skipToEndOfLine();
					p = pos;
					l = limit;
					continue;

				default:
					return c;
				}
			} else if (c == '#') {
				pos = p;
				/*
				 * Skip a # hash end-of-line comment. The JSON RFC doesn't specify this
				 * behaviour, but it's required to parse existing documents. See
				 * http://b/2571423.
				 */
				checkLenient();
				skipToEndOfLine();
				p = pos;
				l = limit;
			} else {
				pos = p;
				return c;
			}
		}
		if (throwOnEof) {
			throw new EOFException("End of input" + " at line " + getLineNumber() + " column " + getColumnNumber());
		} else {
			return -1;
		}
	}

	private void checkLenient() throws IOException {
		if (!lenient) {
			throw syntaxError("Use JsonReader.setLenient(true) to accept malformed JSON");
		}
	}

	/**
	 * Advances the position until after the next newline character. If the line is
	 * terminated by "\r\n", the '\n' must be consumed as whitespace by the caller.
	 */
	private void skipToEndOfLine() throws IOException {
		while (pos < limit || fillBuffer(1)) {
			char c = buffer[pos++];
			if (c == '\n') {
				lineNumber++;
				lineStart = pos;
				break;
			} else if (c == '\r') {
				break;
			}
		}
	}

	/**
	 * @param toFind
	 *            a string to search for. Must not contain a newline.
	 */
	private boolean skipTo(String toFind) throws IOException {
		outer: for (; pos + toFind.length() <= limit || fillBuffer(toFind.length()); pos++) {
			if (buffer[pos] == '\n') {
				lineNumber++;
				lineStart = pos + 1;
				continue;
			}
			for (int c = 0; c < toFind.length(); c++) {
				if (buffer[pos + c] != toFind.charAt(c)) {
					continue outer;
				}
			}
			return true;
		}
		return false;
	}

	@Override
	public String toString() {
		return getClass().getSimpleName() + " at line " + getLineNumber() + " column " + getColumnNumber();
	}

	/**
	 * Returns a <a href="http://goessner.net/articles/JsonPath/">JsonPath</a> to
	 * the current location in the JSON value.
	 */
	public String getPath() {
		StringBuilder result = new StringBuilder().append('$');
		for (int i = 0, size = stackSize; i < size; i++) {
			switch (stack[i]) {
			case JsonScope.EMPTY_ARRAY:
			case JsonScope.NONEMPTY_ARRAY:
				result.append('[').append(pathIndices[i]).append(']');
				break;

			case JsonScope.EMPTY_OBJECT:
			case JsonScope.DANGLING_NAME:
			case JsonScope.NONEMPTY_OBJECT:
				result.append('.');
				if (pathNames[i] != null) {
					result.append(pathNames[i]);
				}
				break;

			case JsonScope.NONEMPTY_DOCUMENT:
			case JsonScope.EMPTY_DOCUMENT:
			case JsonScope.CLOSED:
				break;
			}
		}
		return result.toString();
	}

	/**
	 * Unescapes the character identified by the character or characters that
	 * immediately follow a backslash. The backslash '\' should have already been
	 * read. This supports both unicode escapes "u000A" and two-character escapes
	 * "\n".
	 *
	 * @throws NumberFormatException
	 *             if any unicode escape sequences are malformed.
	 */
	private char readEscapeCharacter() throws IOException {
		if (pos == limit && !fillBuffer(1)) {
			throw syntaxError("Unterminated escape sequence");
		}

		char escaped = buffer[pos++];
		switch (escaped) {
		case 'u':
			if (pos + 4 > limit && !fillBuffer(4)) {
				throw syntaxError("Unterminated escape sequence");
			}
			// Equivalent to Integer.parseInt(stringPool.get(buffer, pos, 4), 16);
			char result = 0;
			for (int i = pos, end = i + 4; i < end; i++) {
				char c = buffer[i];
				result <<= 4;
				if (c >= '0' && c <= '9') {
					result += (c - '0');
				} else if (c >= 'a' && c <= 'f') {
					result += (c - 'a' + 10);
				} else if (c >= 'A' && c <= 'F') {
					result += (c - 'A' + 10);
				} else {
					throw new NumberFormatException("\\u" + new String(buffer, pos, 4));
				}
			}
			pos += 4;
			return result;

		case 't':
			return '\t';

		case 'b':
			return '\b';

		case 'n':
			return '\n';

		case 'r':
			return '\r';

		case 'f':
			return '\f';

		case '\n':
			lineNumber++;
			lineStart = pos;
			// fall-through

		case '\'':
		case '"':
		case '\\':
		default:
			return escaped;
		}
	}

	/**
	 * Throws a new IO exception with the given message and a context snippet with
	 * this reader's content.
	 */
	private IOException syntaxError(String message) throws IOException {
		throw new MalformedJsonException(message + " at line " + getLineNumber() + " column " + getColumnNumber() + " path " + getPath());
	}

	/**
	 * Consumes the non-execute prefix if it exists.
	 */
	private void consumeNonExecutePrefix() throws IOException {
		// fast forward through the leading whitespace
		nextNonWhitespace(true);
		pos--;

		if (pos + NON_EXECUTE_PREFIX.length > limit && !fillBuffer(NON_EXECUTE_PREFIX.length)) {
			return;
		}

		for (int i = 0; i < NON_EXECUTE_PREFIX.length; i++) {
			if (buffer[pos + i] != NON_EXECUTE_PREFIX[i]) {
				return; // not a security token!
			}
		}

		// we consumed a security token!
		pos += NON_EXECUTE_PREFIX.length;
	}

	static {
		JsonReaderInternalAccess.INSTANCE = new JsonReaderInternalAccess() {
			@Override
			public void promoteNameToValue(JsonReader reader) throws IOException {
				if (reader instanceof JsonTreeReader) {
					((JsonTreeReader) reader).promoteNameToValue();
					return;
				}
				int p = reader.peeked;
				if (p == PEEKED_NONE) {
					p = reader.doPeek();
				}
				if (p == PEEKED_DOUBLE_QUOTED_NAME) {
					reader.peeked = PEEKED_DOUBLE_QUOTED;
				} else if (p == PEEKED_SINGLE_QUOTED_NAME) {
					reader.peeked = PEEKED_SINGLE_QUOTED;
				} else if (p == PEEKED_UNQUOTED_NAME) {
					reader.peeked = PEEKED_UNQUOTED;
				} else {
					throw new IllegalStateException(
							"Expected a name but was " + reader.peek() + " " + " at line " + reader.getLineNumber() + " column " + reader.getColumnNumber() + " path " + reader.getPath());
				}
			}
		};
	}
}