json-java/src/main/java/org/json/JSONTokener.java at master · ok3141/json-java · GitHub

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package org.json;

import java.io.*;

import java.nio.charset.Charset;

import java.util.ArrayList;

import java.util.List;

Public Domain.

/**

* 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 2014-05-03

public class JSONTokener {

/** current read character position on the current line. */

private long character;

/** flag to indicate if the end of the input has been found. */

private boolean eof;

/** current read index of the input. */

private long index;

/** current line of the input. */

private long line;

/** previous character read from the input. */

private char previous;

/** Reader for the input. */

private final Reader reader;

/** flag to indicate that a previous character was requested. */

private boolean usePrevious;

/** the number of characters read in the previous line. */

private long characterPreviousLine;

private final List<Character> smallCharMemory;

private int arrayLevel = 0;

/**

* Construct a JSONTokener from a Reader. The caller must close the 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.characterPreviousLine = 0;

this.line = 1;

this.smallCharMemory = new ArrayList<Character>(2);

}

/**

* Construct a JSONTokener from an InputStream. The caller must close the input stream.

* @param inputStream The source.

public JSONTokener(InputStream inputStream) {

this(new InputStreamReader(inputStream, Charset.forName("UTF-8")));

}

/**

* 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 Thrown if trying to step back more than 1 step

* or if already at the start of the string

public void back() throws JSONException {

if (this.usePrevious || this.index <= 0) {

throw new JSONException("Stepping back two steps is not supported");

}

this.decrementIndexes();

this.usePrevious = true;

this.eof = false;

}

/**

* Decrements the indexes for the {@link #back()} method based on the previous character read.

private void decrementIndexes() {

this.index--;

if(this.previous=='\r' || this.previous == '\n') {

this.line--;

this.character=this.characterPreviousLine ;

} else if(this.character > 0){

this.character--;

}

/**

* 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;

}

/**

* Checks if the end of the input has been reached.

* @return true if at the end of the file and we didn't step back

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 thrown if there is an error stepping forward

* or backward while checking for more data.

public boolean more() throws JSONException {

if(this.usePrevious) {

return true;

}

try {

this.reader.mark(1);

} catch (IOException e) {

throw new JSONException("Unable to preserve stream position", e);

}

try {

// -1 is EOF, but next() can not consume the null character '\0'

if(this.reader.read() <= 0) {

this.eof = true;

return false;

}

this.reader.reset();

} catch (IOException e) {

throw new JSONException("Unable to read the next character from the stream", e);

}

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 Thrown if there is an error reading the source string.

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;

return 0;

}

this.incrementIndexes(c);

this.previous = (char) c;

return this.previous;

}

private void insertCharacterInCharMemory(Character c) {

boolean foundSameCharRef = checkForEqualCharRefInMicroCharMemory(c);

if(foundSameCharRef){

return;

}

if(smallCharMemory.size() < 2){

smallCharMemory.add(c);

return;

}

smallCharMemory.set(0, smallCharMemory.get(1));

smallCharMemory.remove(1);

smallCharMemory.add(c);

}

private boolean checkForEqualCharRefInMicroCharMemory(Character c) {

boolean isNotEmpty = !smallCharMemory.isEmpty();

if (isNotEmpty) {

Character lastChar = smallCharMemory.get(smallCharMemory.size() - 1);

return c.compareTo(lastChar) == 0;

}

// list is empty so there's no equal characters

return false;

}

/**

* Retrieves the previous char from memory.

* @return previous char stored in memory.

public char getPreviousChar() {

return smallCharMemory.get(0);

}

public int getArrayLevel(){

return this.arrayLevel;

}

/**

* Get the last character read from the input or '\0' if nothing has been read yet.

* @return the last character read from the input.

protected char getPrevious() { return this.previous;}

/**

* Increments the internal indexes according to the previous character

* read and the character passed as the current character.

* @param c the current character read.

private void incrementIndexes(int c) {

if(c > 0) {

this.index++;

if(c=='\r') {

this.line++;

this.characterPreviousLine = this.character;

this.character=0;

}else if (c=='\n') {

if(this.previous != '\r') {

this.line++;

this.characterPreviousLine = this.character;

}

this.character=0;

} else {

this.character++;

}

/**

* 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) {

if(n > 0) {

throw this.syntaxError("Expected '" + c + "' and instead saw '" +

n + "'");

}

throw this.syntaxError("Expected '" + c + "' and instead saw ''");

}

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 Thrown if there is an error reading the source string.

* @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 > ' ') {

insertCharacterInCharMemory(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 or unbalanced quotes if strictMode == true.

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. " +

"Character with int code " + (int) c + " is not allowed within a quoted 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':

String next = this.next(4);

try {

sb.append((char) Integer.parseInt(next, 16));

} catch (NumberFormatException e) {

throw this.syntaxError("Illegal escape. " +

"\\u must be followed by a 4 digit hexadecimal number. \\" + next

+ " is not valid.",

e);

}

break;

case '"':

case '\'':

case '\\':

case '/':

sb.append(c);

break;

default:

throw this.syntaxError("Illegal escape. Escape sequence \\" + c + " is not valid.");

}

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 Thrown if there is an error while searching

* for the delimiter

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 Thrown if there is an error while searching

* for the delimiter

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.

* @return An object.

* @throws JSONException If syntax error.

public Object nextValue() throws JSONException {

return nextValue(new JSONParserConfiguration());

}

/**

* Get the next value. The value can be a Boolean, Double, Integer, JSONArray, JSONObject, Long, or String, or the

* JSONObject.NULL object. The strictMode parameter controls the behavior of the method when parsing the value.

* @param jsonParserConfiguration which carries options such as strictMode, these methods will

* strictly adhere to the JSON syntax, throwing a JSONException for any deviations.

* @return An object.

* @throws JSONException If syntax error.

public Object nextValue(JSONParserConfiguration jsonParserConfiguration) throws JSONException {

char c = this.nextClean();

switch (c) {

case '{':

this.back();

try {

return new JSONObject(this, jsonParserConfiguration);

} catch (StackOverflowError e) {

throw new JSONException("JSON Array or Object depth too large to process.", e);

}

case '[':

this.back();

try {

this.arrayLevel++;

return new JSONArray(this, jsonParserConfiguration);

} catch (StackOverflowError e) {

throw new JSONException("JSON Array or Object depth too large to process.", e);

}

default:

return nextSimpleValue(c, jsonParserConfiguration);

}

/**

* This method is used to get a JSONObject from the JSONTokener. The strictMode parameter controls the behavior of

* the method when parsing the JSONObject.

* @param jsonParserConfiguration which carries options such as strictMode, these methods will

* strictly adhere to the JSON syntax, throwing a JSONException for any deviations.

* deviations.

* @return A JSONObject which is the next value in the JSONTokener.

* @throws JSONException If the JSONObject or JSONArray depth is too large to process.

private JSONObject getJsonObject(JSONParserConfiguration jsonParserConfiguration) {

try {

return new JSONObject(this, jsonParserConfiguration);

} catch (StackOverflowError e) {

throw new JSONException("JSON Array or Object depth too large to process.", e);

}

/**

* This method is used to get a JSONArray from the JSONTokener.

* @return A JSONArray which is the next value in the JSONTokener.

* @throws JSONException If the JSONArray depth is too large to process.

private JSONArray getJsonArray() {

try {

return new JSONArray(this);

} catch (StackOverflowError e) {

throw new JSONException("JSON Array or Object depth too large to process.", e);

}

/**

* Get the next simple value from the JSON input. Simple values include strings (wrapped in single or double

* quotes), numbers, booleans, and null. This method is called when the next character is not '{' or '['.

* @param c The starting character.

* @param jsonParserConfiguration The configuration object containing parsing options.

* @return The parsed simple value.

* @throws JSONException If there is a syntax error or the value does not adhere to the configuration rules.

Object nextSimpleValue(char c, JSONParserConfiguration jsonParserConfiguration) {

boolean strictMode = jsonParserConfiguration.isStrictMode();

if (strictMode && c == '\'') {

throw this.syntaxError("Single quote wrap not allowed in strict mode");

}

if (c == '"' || c == '\'') {

return this.nextString(c);

}

return parsedUnquotedText(c, strictMode);

}

/**

* Parses unquoted text from the JSON input. This could be the values true, false, or null, or it can be a number.

* Non-standard forms are also accepted. Characters are accumulated until the end of the text or a formatting

* character is reached.

* @param c The starting character.

* @return The parsed object.

* @throws JSONException If the parsed string is empty.

private Object parsedUnquotedText(char c, boolean strictMode) {

StringBuilder sb = new StringBuilder();

while (c >= ' ' && ",:]}/\\\"[{;=#".indexOf(c) < 0) {

sb.append(c);

c = this.next();

}

if (!this.eof) {

this.back();

}

String string = sb.toString().trim();

if (string.isEmpty()) {

throw this.syntaxError("Missing value");

}

Object stringToValue = JSONObject.stringToValue(string);

return strictMode ? getValidNumberBooleanOrNullFromObject(stringToValue) : stringToValue;

}

private Object getValidNumberBooleanOrNullFromObject(Object value) {

if (value instanceof Number || value instanceof Boolean || value.equals(JSONObject.NULL)) {

return value;

}

throw this.syntaxError(String.format("Value '%s' is not surrounded by quotes", value));

}

/**

* 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 Thrown if there is an error while searching

* for the to character

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) {

// in some readers, reset() may throw an exception if

// the remaining portion of the input is greater than

// the mark size (1,000,000 above).

this.reader.reset();

this.index = startIndex;

this.character = startCharacter;

this.line = startLine;

return 0;

}

} while (c != to);

this.reader.mark(1);

} catch (IOException exception) {

throw new JSONException(exception);

}

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 JSONException to signal a syntax error.

* @param message The error message.

* @param causedBy The throwable that caused the error.

* @return A JSONException object, suitable for throwing

public JSONException syntaxError(String message, Throwable causedBy) {

return new JSONException(message + this.toString(), causedBy);

}

/**

* 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 + "]";

}

/**

* Closes the underlying reader, releasing any resources associated with it.

* @throws IOException If an I/O error occurs while closing the reader.

public void close() throws IOException {

if(reader!=null){

reader.close();

}

json-java/src/main/java/org/json/JSONTokener.java at master · ok3141/json-java · GitHub

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