/*
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You 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 org.apache.batik.parser;
import java.io.IOException;
This class represents a parser with support for numbers.
Author: Stephane Hillion Version: $Id: NumberParser.java 1733416 2016-03-03 07:07:13Z gadams $
/**
* This class represents a parser with support for numbers.
*
* @author <a href="mailto:stephane@hillion.org">Stephane Hillion</a>
* @version $Id: NumberParser.java 1733416 2016-03-03 07:07:13Z gadams $
*/
public abstract class NumberParser extends AbstractParser {
Parses the content of the buffer and converts it to a float.
/**
* Parses the content of the buffer and converts it to a float.
*/
protected float parseFloat() throws ParseException, IOException {
int mant = 0;
int mantDig = 0;
boolean mantPos = true;
boolean mantRead = false;
int exp = 0;
int expDig = 0;
int expAdj = 0;
boolean expPos = true;
switch (current) {
case '-':
mantPos = false;
// fallthrough
case '+':
current = reader.read();
}
m1: switch (current) {
default:
reportUnexpectedCharacterError( current );
return 0.0f;
case '.':
break;
case '0':
mantRead = true;
l: for (;;) {
current = reader.read();
switch (current) {
case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
break l;
case '.': case 'e': case 'E':
break m1;
default:
return 0.0f;
case '0':
}
}
case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
mantRead = true;
l: for (;;) {
if (mantDig < 9) {
mantDig++;
mant = mant * 10 + (current - '0');
} else {
expAdj++;
}
current = reader.read();
switch (current) {
default:
break l;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
}
}
}
if (current == '.') {
current = reader.read();
m2: switch (current) {
default:
case 'e': case 'E':
if (!mantRead) {
reportUnexpectedCharacterError( current );
return 0.0f;
}
break;
case '0':
if (mantDig == 0) {
l: for (;;) {
current = reader.read();
expAdj--;
switch (current) {
case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
break l;
default:
if (!mantRead) {
return 0.0f;
}
break m2;
case '0':
}
}
}
case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
l: for (;;) {
if (mantDig < 9) {
mantDig++;
mant = mant * 10 + (current - '0');
expAdj--;
}
current = reader.read();
switch (current) {
default:
break l;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
}
}
}
}
switch (current) {
case 'e': case 'E':
current = reader.read();
switch (current) {
default:
reportUnexpectedCharacterError( current );
return 0f;
case '-':
expPos = false;
case '+':
current = reader.read();
switch (current) {
default:
reportUnexpectedCharacterError( current );
return 0f;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
}
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
}
en: switch (current) {
case '0':
l: for (;;) {
current = reader.read();
switch (current) {
case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
break l;
default:
break en;
case '0':
}
}
case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
l: for (;;) {
if (expDig < 3) {
expDig++;
exp = exp * 10 + (current - '0');
}
current = reader.read();
switch (current) {
default:
break l;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
}
}
}
default:
}
if (!expPos) {
exp = -exp;
}
exp += expAdj;
if (!mantPos) {
mant = -mant;
}
return buildFloat(mant, exp);
}
Computes a float from mantissa and exponent.
/**
* Computes a float from mantissa and exponent.
*/
public static float buildFloat(int mant, int exp) {
if (exp < -125 || mant == 0) {
return 0.0f;
}
if (exp >= 128) {
return (mant > 0)
? Float.POSITIVE_INFINITY
: Float.NEGATIVE_INFINITY;
}
if (exp == 0) {
return mant;
}
if (mant >= (1 << 26)) {
mant++; // round up trailing bits if they will be dropped.
}
return (float) ((exp > 0) ? mant * pow10[exp] : mant / pow10[-exp]);
}
Array of powers of ten. Using double instead of float gives a tiny bit more precision.
/**
* Array of powers of ten. Using double instead of float gives a tiny bit more precision.
*/
private static final double[] pow10 = new double[128];
static {
for (int i = 0; i < pow10.length; i++) {
pow10[i] = Math.pow(10, i);
}
}
}