package com.best.javaSdk.converter.util.jsonReader;
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import java.math.BigDecimal;
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import java.math.BigInteger;
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import java.text.CharacterIterator;
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import java.text.StringCharacterIterator;
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import java.util.ArrayList;
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import java.util.HashMap;
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import java.util.List;
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import java.util.Map;
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/**
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* 不能直接使用JSONReader，请用JSONValidatingReader，所以这里改为abstract修饰。
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*/
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public abstract class JSONReader {
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private static final Object OBJECT_END = new Object();
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private static final Object ARRAY_END = new Object();
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private static final Object COLON = new Object();
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private static final Object COMMA = new Object();
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public static final int FIRST = 0;
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public static final int CURRENT = 1;
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public static final int NEXT = 2;
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private static Map<Character, Character> escapes = new HashMap<Character, Character>();
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static {
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escapes.put(Character.valueOf('"'), Character.valueOf('"'));
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escapes.put(Character.valueOf('\\'), Character.valueOf('\\'));
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escapes.put(Character.valueOf('/'), Character.valueOf('/'));
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escapes.put(Character.valueOf('b'), Character.valueOf('\b'));
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escapes.put(Character.valueOf('f'), Character.valueOf('\f'));
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escapes.put(Character.valueOf('n'), Character.valueOf('\n'));
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escapes.put(Character.valueOf('r'), Character.valueOf('\r'));
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escapes.put(Character.valueOf('t'), Character.valueOf('\t'));
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}
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private CharacterIterator it;
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private char c;
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private Object token;
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private StringBuffer buf = new StringBuffer();
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private char next() {
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c = it.next();
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return c;
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}
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private void skipWhiteSpace() {
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while (Character.isWhitespace(c)) {
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next();
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}
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}
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/**
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* 2
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* @param ci
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* @param start
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* @return
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*/
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public Object read(CharacterIterator ci, int start) {
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it = ci;
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switch (start) {
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case FIRST:
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c = it.first();
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break;
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case CURRENT:
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c = it.current();
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break;
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case NEXT:
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c = it.next();
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break;
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}
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return read();
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}
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public Object read(CharacterIterator it) {
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return read(it, NEXT);
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}
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/**
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* 1
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* @param string
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* @return
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*/
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public Object read(String string) {
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return read(new StringCharacterIterator(string), FIRST);
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}
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/**
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* 3
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* @return
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*/
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private Object read() {
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skipWhiteSpace();
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char ch = c;
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next();
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switch (ch) {
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case '"': token = string(); break;
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case '[': token = array(); break;
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case ']': token = ARRAY_END; break;
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case ',': token = COMMA; break;
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case '{': token = object(); break;
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case '}': token = OBJECT_END; break;
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case ':': token = COLON; break;
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case 't':
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next(); next(); next(); // assumed r-u-e
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token = Boolean.TRUE;
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break;
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case'f':
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next(); next(); next(); next(); // assumed a-l-s-e
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token = Boolean.FALSE;
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break;
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case 'n':
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next(); next(); next(); // assumed u-l-l
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token = null;
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break;
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default:
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c = it.previous();
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if (Character.isDigit(c) || c == '-') {
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token = number();
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}
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}
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// System.out.println("token: " + token); // enable this line to see the token stream
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return token;
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}
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private Object object() {
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Map<Object, Object> ret = new HashMap<Object, Object>();
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Object key = read();
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while (token != OBJECT_END) {
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read(); // should be a colon
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if (token != OBJECT_END) {
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ret.put(key, read());
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if (read() == COMMA) {
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key = read();
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}
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}
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}
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return ret;
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}
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private Object array() {
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List<Object> ret = new ArrayList<Object>();
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Object value = read();
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while (token != ARRAY_END) {
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ret.add(value);
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if (read() == COMMA) {
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value = read();
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}
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}
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return ret;
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}
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private Object number() {
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int length = 0;
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boolean isFloatingPoint = false;
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buf.setLength(0);
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if (c == '-') {
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add();
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}
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length += addDigits();
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if (c == '.') {
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add();
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length += addDigits();
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isFloatingPoint = true;
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}
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if (c == 'e' || c == 'E') {
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add();
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if (c == '+' || c == '-') {
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add();
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}
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addDigits();
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isFloatingPoint = true;
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}
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String s = buf.toString();
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return isFloatingPoint ? (length < 17) ? (Object)Double.valueOf(s) : new BigDecimal(s) : (length < 19) ? (Object)Long.valueOf(s) : new BigInteger(s);
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}
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private int addDigits() {
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int ret;
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for (ret = 0; Character.isDigit(c); ++ret) {
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add();
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}
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return ret;
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}
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private Object string() {
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buf.setLength(0);
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while (c != '"') {
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if (c == '\\') {
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next();
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if (c == 'u') {
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add(unicode());
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} else {
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Object value = escapes.get(Character.valueOf(c));
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if (value != null) {
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add(((Character) value).charValue());
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}
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}
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} else {
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add();
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}
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}
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next();
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return buf.toString();
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}
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private void add(char cc) {
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buf.append(cc);
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next();
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}
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private void add() {
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add(c);
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}
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private char unicode() {
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int value = 0;
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for (int i = 0; i < 4; ++i) {
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switch (next()) {
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case '0': case '1': case '2': case '3': case '4':
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case '5': case '6': case '7': case '8': case '9':
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value = (value << 4) + c - '0';
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break;
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case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
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value = (value << 4) + c - 'k';
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break;
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case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
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value = (value << 4) + c - 'K';
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break;
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}
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}
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return (char) value;
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}
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}
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