org.h2.util.json.JSONTextSource Maven / Gradle / Ivy
/*
* Copyright 2004-2021 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.util.json;
/**
* JSON text source.
*/
public abstract class JSONTextSource {
/**
* The output.
*/
final JSONTarget target;
private final StringBuilder builder;
JSONTextSource(JSONTarget target) {
this.target = target;
builder = new StringBuilder();
}
/**
* Parse the text and write it to the output.
*/
final void parse() {
boolean comma = false;
for (int ch; (ch = nextCharAfterWhitespace()) >= 0;) {
if (ch == '}' || ch == ']') {
if (comma) {
throw new IllegalArgumentException();
}
if (ch == '}') {
target.endObject();
} else {
target.endArray();
}
continue;
}
if (ch == ',') {
if (comma || !target.isValueSeparatorExpected()) {
throw new IllegalArgumentException();
}
comma = true;
continue;
}
if (comma != target.isValueSeparatorExpected()) {
throw new IllegalArgumentException();
}
comma = false;
switch (ch) {
case 'f':
readKeyword1("false");
target.valueFalse();
break;
case 'n':
readKeyword1("null");
target.valueNull();
break;
case 't':
readKeyword1("true");
target.valueTrue();
break;
case '{':
target.startObject();
break;
case '[':
target.startArray();
break;
case '"': {
String s = readString();
if (target.isPropertyExpected()) {
if (nextCharAfterWhitespace() != ':') {
throw new IllegalArgumentException();
}
target.member(s);
} else {
target.valueString(s);
}
break;
}
case '-':
parseNumber(false);
break;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
parseNumber(true);
break;
default:
throw new IllegalArgumentException();
}
}
}
/**
* Skip all whitespace characters, and get the next character.
*
* @return the character code
*/
abstract int nextCharAfterWhitespace();
/**
* Read the specified keyword, or (it there is no match), throw an
* IllegalArgumentException.
*
* @param keyword the expected keyword
*/
abstract void readKeyword1(String keyword);
/**
* Parse a number.
*
* @param positive whether it needs to be positive
*/
abstract void parseNumber(boolean positive);
/**
* Read the next character.
*
* @return the character code
*/
abstract int nextChar();
/**
* Read 4 hex characters (0-9, a-f, A-F), and return the Unicode character.
*
* @return the character
*/
abstract char readHex();
private String readString() {
builder.setLength(0);
boolean inSurrogate = false;
for (;;) {
int ch = nextChar();
switch (ch) {
case '"':
if (inSurrogate) {
throw new IllegalArgumentException();
}
return builder.toString();
case '\\':
ch = nextChar();
switch (ch) {
case '"':
case '/':
case '\\':
appendNonSurrogate((char) ch, inSurrogate);
break;
case 'b':
appendNonSurrogate('\b', inSurrogate);
break;
case 'f':
appendNonSurrogate('\f', inSurrogate);
break;
case 'n':
appendNonSurrogate('\n', inSurrogate);
break;
case 'r':
appendNonSurrogate('\r', inSurrogate);
break;
case 't':
appendNonSurrogate('\t', inSurrogate);
break;
case 'u':
inSurrogate = appendChar(readHex(), inSurrogate);
break;
default:
throw new IllegalArgumentException();
}
break;
default:
if (Character.isBmpCodePoint(ch)) {
inSurrogate = appendChar((char) ch, inSurrogate);
} else {
if (inSurrogate) {
throw new IllegalArgumentException();
}
builder.appendCodePoint(ch);
inSurrogate = false;
}
}
}
}
private void appendNonSurrogate(char ch, boolean inSurrogate) {
if (inSurrogate) {
throw new IllegalArgumentException();
}
builder.append(ch);
}
private boolean appendChar(char ch, boolean inSurrogate) {
if (inSurrogate != Character.isLowSurrogate(ch)) {
throw new IllegalArgumentException();
}
if (inSurrogate) {
inSurrogate = false;
} else if (Character.isHighSurrogate(ch)) {
inSurrogate = true;
}
builder.append(ch);
return inSurrogate;
}
}