package com.jdroid.java.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; /* * 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. */ /** * 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); eof = false; usePrevious = false; previous = 0; index = 0; character = 1; 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 (usePrevious || (index <= 0)) { throw new JSONException("Stepping back two steps is not supported"); } index -= 1; character -= 1; usePrevious = true; 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 eof && !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 (usePrevious) { usePrevious = false; c = previous; } else { try { c = reader.read(); } catch (IOException exception) { throw new JSONException(exception); } if (c <= 0) { // End of stream eof = true; c = 0; } } index += 1; if (previous == '\r') { line += 1; character = c == '\n' ? 0 : 1; } else if (c == '\n') { line += 1; character = 0; } else { character += 1; } previous = (char)c; return 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; StringBuffer sb = new StringBuffer(); 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 { StringBuffer sb = new StringBuffer(); 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; StringBuffer sb = new StringBuffer(); 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. */ StringBuffer sb = new StringBuffer(); 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 = index; long startCharacter = character; long startLine = line; reader.mark(1000000); do { c = this.next(); if (c == 0) { reader.reset(); index = startIndex; character = startCharacter; 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 " + index + " [character " + character + " line " + line + "]"; } }