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/*
* Copyright (c) 2002 JSON.org
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
* The Software shall be used for Good, not Evil.
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package org.json;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
/**
* A JSONTokener takes a source string and extracts characters and tokens from
* it. It is used by the JSONObject and JSONArray constructors to parse JSON
* source strings.
*
* @author JSON.org
* @version 2012-02-16
*/
public class JSONTokener {
private long character;
private boolean eof;
private long index;
private long line;
private char previous;
private Reader reader;
private boolean usePrevious;
/**
* Construct a JSONTokener from a Reader.
*
* @param reader A reader.
*/
public JSONTokener(Reader reader) {
this.reader = reader.markSupported()
? reader
: new BufferedReader(reader);
this.eof = false;
this.usePrevious = false;
this.previous = 0;
this.index = 0;
this.character = 1;
this.line = 1;
}
/**
* Construct a JSONTokener from an InputStream.
*
* @param inputStream
* @throws JSONException
*/
public JSONTokener(InputStream inputStream) throws JSONException {
this(new InputStreamReader(inputStream));
}
/**
* Construct a JSONTokener from a string.
*
* @param s A source string.
*/
public JSONTokener(String s) {
this(new StringReader(s));
}
/**
* Back up one character. This provides a sort of lookahead capability, so
* that you can test for a digit or letter before attempting to parse the
* next number or identifier.
*
* @throws JSONException
*/
public void back() throws JSONException {
if (this.usePrevious || this.index <= 0) {
throw new JSONException("Stepping back two steps is not supported");
}
this.index -= 1;
this.character -= 1;
this.usePrevious = true;
this.eof = false;
}
/**
* Get the hex value of a character (base16).
*
* @param c A character between '0' and '9' or between 'A' and 'F' or
* between 'a' and 'f'.
* @return An int between 0 and 15, or -1 if c was not a hex digit.
*/
public static int dehexchar(char c) {
if (c >= '0' && c <= '9') {
return c - '0';
}
if (c >= 'A' && c <= 'F') {
return c - ('A' - 10);
}
if (c >= 'a' && c <= 'f') {
return c - ('a' - 10);
}
return -1;
}
public boolean end() {
return this.eof && !this.usePrevious;
}
/**
* Determine if the source string still contains characters that next() can
* consume.
*
* @return true if not yet at the end of the source.
* @throws JSONException
*/
public boolean more() throws JSONException {
this.next();
if (this.end()) {
return false;
}
this.back();
return true;
}
/**
* Get the next character in the source string.
*
* @return The next character, or 0 if past the end of the source string.
* @throws JSONException
*/
public char next() throws JSONException {
int c;
if (this.usePrevious) {
this.usePrevious = false;
c = this.previous;
} else {
try {
c = this.reader.read();
} catch (IOException exception) {
throw new JSONException(exception);
}
if (c <= 0) { // End of stream
this.eof = true;
c = 0;
}
}
this.index += 1;
if (this.previous == '\r') {
this.line += 1;
this.character = c == '\n' ? 0 : 1;
} else if (c == '\n') {
this.line += 1;
this.character = 0;
} else {
this.character += 1;
}
this.previous = (char) c;
return this.previous;
}
/**
* Consume the next character, and check that it matches a specified
* character.
*
* @param c The character to match.
* @return The character.
* @throws JSONException if the character does not match.
*/
public char next(char c) throws JSONException {
char n = this.next();
if (n != c) {
throw this.syntaxError("Expected '" + c + "' and instead saw '"
+ n + "'");
}
return n;
}
/**
* Get the next n characters.
*
* @param n The number of characters to take.
* @return A string of n characters.
* @throws JSONException Substring bounds error if there are not n
* characters remaining in the source string.
*/
public String next(int n) throws JSONException {
if (n == 0) {
return "";
}
char[] chars = new char[n];
int pos = 0;
while (pos < n) {
chars[pos] = this.next();
if (this.end()) {
throw this.syntaxError("Substring bounds error");
}
pos += 1;
}
return new String(chars);
}
/**
* Get the next char in the string, skipping whitespace.
*
* @throws JSONException
* @return A character, or 0 if there are no more characters.
*/
public char nextClean() throws JSONException {
for (;;) {
char c = this.next();
if (c == 0 || c > ' ') {
return c;
}
}
}
/**
* Return the characters up to the next close quote character. Backslash
* processing is done. The formal JSON format does not allow strings in
* single quotes, but an implementation is allowed to accept them.
*
* @param quote The quoting character, either
* <code>"</code> <small>(double quote)</small> or
* <code>'</code> <small>(single quote)</small>.
* @return A String.
* @throws JSONException Unterminated string.
*/
public String nextString(char quote) throws JSONException {
char c;
StringBuilder sb = new StringBuilder();
for (;;) {
c = this.next();
switch (c) {
case 0:
case '\n':
case '\r':
throw this.syntaxError("Unterminated string");
case '\\':
c = this.next();
switch (c) {
case 'b':
sb.append('\b');
break;
case 't':
sb.append('\t');
break;
case 'n':
sb.append('\n');
break;
case 'f':
sb.append('\f');
break;
case 'r':
sb.append('\r');
break;
case 'u':
sb.append((char) Integer.parseInt(this.next(4), 16));
break;
case '"':
case '\'':
case '\\':
case '/':
sb.append(c);
break;
default:
throw this.syntaxError("Illegal escape.");
}
break;
default:
if (c == quote) {
return sb.toString();
}
sb.append(c);
}
}
}
/**
* Get the text up but not including the specified character or the end of
* line, whichever comes first.
*
* @param delimiter A delimiter character.
* @return A string.
* @throws JSONException
*/
public String nextTo(char delimiter) throws JSONException {
StringBuilder sb = new StringBuilder();
for (;;) {
char c = this.next();
if (c == delimiter || c == 0 || c == '\n' || c == '\r') {
if (c != 0) {
this.back();
}
return sb.toString().trim();
}
sb.append(c);
}
}
/**
* Get the text up but not including one of the specified delimiter
* characters or the end of line, whichever comes first.
*
* @param delimiters A set of delimiter characters.
* @return A string, trimmed.
* @throws JSONException
*/
public String nextTo(String delimiters) throws JSONException {
char c;
StringBuilder sb = new StringBuilder();
for (;;) {
c = this.next();
if (delimiters.indexOf(c) >= 0 || c == 0
|| c == '\n' || c == '\r') {
if (c != 0) {
this.back();
}
return sb.toString().trim();
}
sb.append(c);
}
}
/**
* Get the next value. The value can be a Boolean, Double, Integer,
* JSONArray, JSONObject, Long, or String, or the JSONObject.NULL object.
*
* @throws JSONException If syntax error.
*
* @return An object.
*/
public Object nextValue() throws JSONException {
char c = this.nextClean();
String string;
switch (c) {
case '"':
case '\'':
return this.nextString(c);
case '{':
this.back();
return new JSONObject(this);
case '[':
this.back();
return new JSONArray(this);
}
/*
* Handle unquoted text. This could be the values true, false, or
* null, or it can be a number. An implementation (such as this one)
* is allowed to also accept non-standard forms.
*
* Accumulate characters until we reach the end of the text or a
* formatting character.
*/
StringBuilder sb = new StringBuilder();
while (c >= ' ' && ",:]}/\\\"[{;=#".indexOf(c) < 0) {
sb.append(c);
c = this.next();
}
this.back();
string = sb.toString().trim();
if ("".equals(string)) {
throw this.syntaxError("Missing value");
}
return JSONObject.stringToValue(string);
}
/**
* Skip characters until the next character is the requested character. If
* the requested character is not found, no characters are skipped.
*
* @param to A character to skip to.
* @return The requested character, or zero if the requested character is
* not found.
* @throws JSONException
*/
public char skipTo(char to) throws JSONException {
char c;
try {
long startIndex = this.index;
long startCharacter = this.character;
long startLine = this.line;
this.reader.mark(1000000);
do {
c = this.next();
if (c == 0) {
this.reader.reset();
this.index = startIndex;
this.character = startCharacter;
this.line = startLine;
return c;
}
} while (c != to);
} catch (IOException exc) {
throw new JSONException(exc);
}
this.back();
return c;
}
/**
* Make a JSONException to signal a syntax error.
*
* @param message The error message.
* @return A JSONException object, suitable for throwing
*/
public JSONException syntaxError(String message) {
return new JSONException(message + this.toString());
}
/**
* Make a printable string of this JSONTokener.
*
* @return " at {index} [character {character} line {line}]"
*/
@Override
public String toString() {
return " at " + this.index + " [character " + this.character + " line " + this.line + "]";
}
}