package org.test4j.json.helper;
import org.test4j.json.JSONException;
import org.test4j.tools.commons.StringHelper;
public class JSONScanner {
public static JSONObject scnJSON(String json) {
if (json == null) {
return null;
}
if (StringHelper.isBlank(json)) {
return new JSONSingle(json);
}
char[] input = json.toCharArray();
JSONScanner scanner = new JSONScanner(input);
JSONObject o = scanner.scan();
return o;
}
private final char[] input;
private final int length;
private int index;
JSONScanner(char[] input) {
this.index = 0;
this.length = input.length;
this.input = new char[this.length + 1];
System.arraycopy(input, 0, this.input, 0, this.length);
this.input[length] = '\0';
}
public JSONObject scan() {
JSONObject json = null;
char ch = this.nextToken();
switch (ch) {
case '{':
json = this.scanJSONMap();
break;
case '[':
json = this.scanJSONArray();
break;
default:
this.index--;
json = this.scanJSONValue();
}
ch = this.nextToken();
if (ch != '\0' || this.index != this.length + 1) {
throw this.syntaxError("syntax error.");
}
return json;
}
JSONMap scanJSONMap() {
JSONMap map = new JSONMap();
char ch = this.nextToken();
this.index--;
while (ch != '}') {
JSONObject key = scanMapKey();
ch = this.nextToken();
if (ch != ':') {
throw this.syntaxError("syntax error, expected char ':'.");
}
JSONObject value = scanMapValue();
map.put(key, value);
ch = this.nextToken();
if (ch != ',' && ch != '}') {
throw this.syntaxError("syntax error, expected char '}' or ','.");
}
}
return map;
}
JSONArray scanJSONArray() {
JSONArray array = new JSONArray();
char ch = this.nextToken();
while (ch != ']') {
JSONObject json = null;
switch (ch) {
case '{':
json = this.scanJSONMap();
break;
case '[':
json = this.scanJSONArray();
break;
case '\'':
json = this.scanString('\'');
break;
case '"':
json = this.scanString('"');
break;
default:
this.index--;
json = this.scanString(',', ']', '\0');
this.index--;
}
array.add(json);
ch = this.nextToken();
if (ch != ',' && ch != ']') {
throw this.syntaxError("syntax error, expectd char ',' or ']'.");
}
if (ch == ',') {
ch = this.nextToken();
}
}
return array;
}
JSONSingle scanJSONValue() {
JSONSingle json = null;
char ch = this.nextToken();
switch (ch) {
case '\'':
json = this.scanString('\'');
break;
case '"':
json = this.scanString('"');
break;
default:
this.index--;
json = this.scanString('\0');
this.index--;
}
return json;
}
/**
* 返回json值对的key
*
* @return
*/
JSONObject scanMapKey() {
char ch = this.nextToken();
JSONObject json = null;
switch (ch) {
case '\0':
throw this.syntaxError("syntax error.");
case '{':
json = this.scanJSONMap();
break;
case '[':
json = this.scanJSONArray();
break;
case '"':
json = this.scanString('"');
break;
case '\'':
json = this.scanString('\'');
break;
default:
this.index--;
json = this.scanString(':');
this.index--;
}
return json;
}
/**
* 返回json值对的value
*
* @return
*/
JSONObject scanMapValue() {
char ch = this.nextToken();
JSONObject json = null;
switch (ch) {
case '\0':
throw this.syntaxError("syntax error");
case '{':
json = this.scanJSONMap();
break;
case '[':
json = this.scanJSONArray();
break;
case '"':
json = this.scanString('"');
break;
case '\'':
json = this.scanString('\'');
break;
default:
this.index--;
json = this.scanString(',', '}', ']');
this.index--;
}
return json;
}
private SymbolBuff symbolBuff = new SymbolBuff();
/**
* 扫描json的单值对象<br>
* String对象 或其它非 [] 和 {} 括起来的对象
*
* @param endChar
* 扫描终止符
* @param endChars
* 扫描终止符
* @return
*/
private final JSONSingle scanString(final char endChar, char... endChars) {
JSONSingle json = new JSONSingle(endChar == '\'' || endChar == '"');
json.setBeginIndex(this.index);
char ch = this.input[this.index++];
while (ch != endChar && !contain(endChars, ch)) {
if (ch == '\0') {
throw this.syntaxError("syntax error.");
} else if (ch == '\\') {
ch = this.getEscapedChar();
symbolBuff.append(ch);
} else {
symbolBuff.append(ch);
}
ch = this.input[this.index++];
}
String symbol = symbolBuff.getSymbol();
json.setValue(symbol);
json.setEndIndex(this.index);
return json;
}
/**
* 字符数组中是否包含某字符
*
* @param chars
* @param ch
* @return
*/
private static boolean contain(char[] chars, char ch) {
if (chars.length == 0 || chars == null) {
return false;
}
for (char c : chars) {
if (c == ch) {
return true;
}
}
return false;
}
/**
* 返回反义字符
*
* @return
*/
private char getEscapedChar() {
char ch = this.input[this.index++];
switch (ch) {
case '"':
return '"';
case '\'':
return '\'';
case '\\':
return '\\';
case '/':
return '/';
case 'b':
return 'b';
case 'f':
case 'F':
return '\f';
case 'n':
return '\n';
case 'r':
return '\r';
case 't':
return '\t';
case 'u':
char u1 = this.input[this.index++];
char u2 = this.input[this.index++];
char u3 = this.input[this.index++];
char u4 = this.input[this.index++];
int val = Integer.parseInt(new String(new char[] { u1, u2, u3, u4 }), 16);
return (char) val;
default:
return ch;
// throw this.syntaxError("syntax error.");
}
}
char nextToken() {
if (this.index > this.length) {
throw this.syntaxError("syntax error end.");
}
this.skipWhitespace();
char ch = input[index];
index++;
return ch;
}
/**
* 跳过空白字符
*/
final int skipWhitespace() {
char ch = input[index];
while (StringHelper.isSpace(ch)) {
index++;
ch = input[index];
}
return index;
}
private static boolean[] singleValueFlags = new boolean[256];
static {
for (char ch = '0'; ch <= '9'; ch++) {
singleValueFlags[ch] = true;
}
for (char ch = 'a'; ch <= 'z'; ch++) {
singleValueFlags[ch] = true;
}
for (char ch = 'A'; ch <= 'Z'; ch++) {
singleValueFlags[ch] = true;
}
singleValueFlags['-'] = true;
singleValueFlags['+'] = true;
singleValueFlags['.'] = true;
singleValueFlags[':'] = true;
}
private JSONException syntaxError(String message) {
StringBuffer error = new StringBuffer(message);
error.append("\n syntax error at position:" + this.index);
error.append("\n string parsed is:\n");
error.append(new String(this.input, 0, this.index));
return new JSONException(error.toString());
}
}