com.github.housepower.misc.SQLLexer Maven / Gradle / Ivy
/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.github.housepower.misc;
import java.sql.SQLException;
public class SQLLexer {
private int pos;
private final String data;
public SQLLexer(int pos, String data) {
this.pos = pos;
this.data = data;
}
public char character() {
return eof() ? 0 : data.charAt(pos++);
}
// only support dec
public int intLiteral() {
skipAnyWhitespace();
int start = pos;
if (isCharacter('-') || isCharacter('+'))
pos++;
for (; pos < data.length(); pos++)
if (!isNumericASCII(data.charAt(pos)))
break;
return Integer.parseInt(new StringView(data, start, pos).toString());
}
public Number numberLiteral() {
skipAnyWhitespace();
int start = pos;
// @formatter:off
boolean isHex = false;
boolean isBinary = false;
boolean isDouble = false;
boolean hasExponent = false;
boolean hasSigned = false;
// @formatter:on
if (isCharacter('-') || isCharacter('+')) {
hasSigned = true;
pos++;
}
if (pos + 2 < data.length()) {
// @formatter:off
if (data.charAt(pos) == '0' && (data.charAt(pos + 1) == 'x' || data.charAt(pos + 1) == 'X'
|| data.charAt(pos + 1) == 'b' || data.charAt(pos + 1) == 'B')) {
isHex = data.charAt(pos + 1) == 'x' || data.charAt(pos + 1) == 'X';
isBinary = data.charAt(pos + 1) == 'b' || data.charAt(pos + 1) == 'B';
pos += 2;
}
// @formatter:on
}
for (; pos < data.length(); pos++) {
if (isHex ? !isHexDigit(data.charAt(pos)) : !isNumericASCII(data.charAt(pos))) {
break;
}
}
if (pos < data.length() && data.charAt(pos) == '.') {
isDouble = true;
for (pos++; pos < data.length(); pos++) {
if (isHex ? !isHexDigit(data.charAt(pos)) : !isNumericASCII(data.charAt(pos)))
break;
}
}
if (pos + 1 < data.length()
// @formatter:off
&& (isHex ? (data.charAt(pos) == 'p' || data.charAt(pos) == 'P')
: (data.charAt(pos) == 'e' || data.charAt(pos) == 'E'))) {
// @formatter:on
hasExponent = true;
pos++;
if (pos + 1 < data.length() && (data.charAt(pos) == '-' || data.charAt(pos) == '+')) {
pos++;
}
for (; pos < data.length(); pos++) {
char ch = data.charAt(pos);
if (!isNumericASCII(ch)) {
break;
}
}
}
if (isBinary) {
String signed = hasSigned ? data.charAt(start) + "" : "";
int begin = start + (hasSigned ? 3 : 2);
return Long.parseLong(signed + new StringView(data, begin, pos).toString(), 2);
} else if (isDouble || hasExponent) {
return Double.valueOf(new StringView(data, start, pos).toString());
} else if (isHex) {
String signed = hasSigned ? data.charAt(start) + "" : "";
int begin = start + (hasSigned ? 3 : 2);
return Long.parseLong(signed + new StringView(data, begin, pos), 16);
} else {
return Long.parseLong(new StringView(data, start, pos).toString());
}
}
public String stringLiteral() throws SQLException {
return stringView().toString();
}
public StringView stringView() throws SQLException {
skipAnyWhitespace();
Validate.isTrue(isCharacter('\''));
return stringLiteralWithQuoted('\'');
}
public boolean eof() {
skipAnyWhitespace();
return pos >= data.length();
}
public boolean isCharacter(char ch) {
return !eof() && data.charAt(pos) == ch;
}
public StringView bareWord() throws SQLException {
skipAnyWhitespace();
// @formatter:off
if (isCharacter('`')) {
return stringLiteralWithQuoted('`');
} else if (isCharacter('"')) {
return stringLiteralWithQuoted('"');
} else if (data.charAt(pos) == '_'
|| (data.charAt(pos) >= 'a' && data.charAt(pos) <= 'z')
|| (data.charAt(pos) >= 'A' && data.charAt(pos) <= 'Z')) {
int start = pos;
for (pos++; pos < data.length(); pos++) {
if (!('_' == data.charAt(pos)
|| (data.charAt(pos) >= 'a' && data.charAt(pos) <= 'z')
|| (data.charAt(pos) >= 'A' && data.charAt(pos) <= 'Z')
|| (data.charAt(pos) >= '0' && data.charAt(pos) <= '9'))) {
break;
}
}
return new StringView(data, start, pos);
}
// @formatter:on
throw new SQLException("Expect Bare Token.");
}
public boolean isWhitespace() {
return data.charAt(pos++) == ' ';
}
private boolean isNumericASCII(char c) {
return c >= '0' && c <= '9';
}
private boolean isHexDigit(char c) {
return isNumericASCII(c) || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F');
}
private void skipAnyWhitespace() {
for (; pos < data.length(); pos++) {
// @formatter:off
if (data.charAt(pos) != ' '
&& data.charAt(pos) != '\t'
&& data.charAt(pos) != '\n'
&& data.charAt(pos) != '\r'
&& data.charAt(pos) != '\f') {
return;
}
// @formatter:on
}
}
private StringView stringLiteralWithQuoted(char quoted) throws SQLException {
int start = pos;
Validate.isTrue(data.charAt(pos) == quoted);
for (pos++; pos < data.length(); pos++) {
if (data.charAt(pos) == '\\')
pos++;
else if (data.charAt(pos) == quoted)
return new StringView(data, start + 1, pos++);
}
throw new SQLException("The String Literal is no Closed.");
}
}