/*
*
* * Copyright 2015. Appsi Mobile
* *
* * 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.larvalabs.svgandroid;
import java.lang.reflect.Field;
/**
* Parses numbers from SVG text. Based on the Batik Number Parser (Apache 2 License).
*
* @author Apache Software Foundation, Larva Labs LLC
*/
public class ParserHelper {
private static final Field STRING_CHARS;
/**
* 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 {
try {
STRING_CHARS = String.class.getDeclaredField("value");
STRING_CHARS.setAccessible(true);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
static {
for (int i = 0; i < pow10.length; i++) {
pow10[i] = Math.pow(10, i);
}
}
private final char[] s;
private final int n;
public int pos;
private char current;
public ParserHelper(String str, int pos) {
try {
this.s = (char[]) STRING_CHARS.get(str);
} catch (Exception e) {
throw new RuntimeException(e);
}
this.pos = pos;
n = s.length;
current = s[pos];
}
/**
* 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]);
}
private char read() {
if (pos < n) {
pos++;
}
if (pos == n) {
return '\0';
} else {
return s[pos];
}
}
public void skipWhitespace() {
while (pos < n) {
if (Character.isWhitespace(s[pos])) {
advance();
} else {
break;
}
}
}
public void skipNumberSeparator() {
while (pos < n) {
char c = s[pos];
switch (c) {
case ' ':
case ',':
case '\n':
case '\t':
advance();
break;
default:
return;
}
}
}
public void advance() {
current = read();
}
/**
* Parses the content of the buffer and converts it to a float.
*/
public float parseFloat() {
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 = read();
}
m1:
switch (current) {
default:
return Float.NaN;
case '.':
break;
case '0':
mantRead = true;
l:
for (; ; ) {
current = 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 = 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 = 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 = 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 = 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 = read();
switch (current) {
default:
reportUnexpectedCharacterError(current);
return 0f;
case '-':
expPos = false;
case '+':
current = 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 = 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 = 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);
}
private void reportUnexpectedCharacterError(char c) {
throw new RuntimeException("Unexpected char '" + c + "'.");
}
public float nextFloat() {
skipWhitespace();
float f = parseFloat();
skipNumberSeparator();
return f;
}
public int nextFlag() {
skipWhitespace();
int flag = current - '0';
current = read();
skipNumberSeparator();
return flag;
}
}