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Utilities helping with reading writing and keeping various data
formats, including JSON, binary data and formatted text.
/*
* Copyright (c) 2016, Stein Eldar Johnsen
*
* 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 net.morimekta.util.io;
import java.io.CharArrayWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.util.Arrays;
/**
* IO Stream static utilities.
*/
public class IOUtils {
/**
* Skip all bytes in stream until (and including) given separator is found.
*
* @param in Input stream to read from.
* @param separator Separator bytes to skip until.
* @return True iff the separator was encountered.
* @throws IOException if unable to read from stream.
*/
public static boolean skipUntil(InputStream in, byte[] separator) throws IOException {
if (separator == null) {
throw new NullPointerException("Null separator given");
}
final int len = separator.length;
if(len > 0) {
if(len == 1) { return skipUntil(in, separator[0]); }
if(len > 4) { return skipUntilInternal(in, separator, new byte[len]); }
int mask = len == 2 ? 0xffff : len == 3 ? 0xffffff : 0xffffffff;
int sep = (separator[0] % 0x100) << 8 | ((int) separator[1] % 0x100);
if(len > 2) {
sep = sep << 8 | ((int) separator[2] % 0x100);
}
if(len > 3) {
sep = sep << 8 | ((int) separator[3] % 0x100);
}
int r, p = 0;
int tmp = 0;
while((r = in.read()) >= 0) {
++p;
tmp = tmp << 8 | r;
if(p >= len && (tmp & mask) == sep) {
return true;
}
}
return false;
}
return true;
}
/**
* Skip all bytes in stream until (and including) given byte is found.
*
* @param in Input stream to read from.
* @param separator Byte to skip until.
* @return True iff the separator was encountered.
* @throws IOException if unable to read from stream.
*/
public static boolean skipUntil(InputStream in, byte separator) throws IOException {
int r;
while((r = in.read()) >= 0) {
if(((byte) r) == separator) { return true; }
}
return false;
}
/**
* Copy all available data from one stream to another.
*
* @param in The stream to read fromn.
* @param out The stream to write to.
* @throws IOException If unable to read from or write to streams.
*/
public static void copy(InputStream in, OutputStream out) throws IOException {
byte[] buffer = new byte[BUF_SIZE];
int r;
while((r = in.read(buffer)) >= 0) {
out.write(buffer, 0, r);
}
}
/**
* Read next string from input stream.
*
* @param is The input stream to read.
* @return The resulting string.
* @throws IOException when unable to read from stream.
*/
public static String readString(InputStream is) throws IOException {
return readString(new Utf8StreamReader(is), '\0');
}
/**
* Read next string from input stream.
*
* @param is The input stream to read.
* @param term Terminator character.
* @return The string up until, but not including the terminator.
* @throws IOException when unable to read from stream.
*/
public static String readString(InputStream is, String term) throws IOException {
return readString(new Utf8StreamReader(is), term);
}
/**
* Read next string from input stream. The terminator is read but not
* included in the resulting string.
*
* @param is The input stream to read.
* @return The string up until, but not including the terminator.
* @throws IOException when unable to read from stream.
*/
public static String readString(Reader is) throws IOException {
return readString(is, '\0');
}
/**
* Read next string from input stream.
*
* @param is The reader to read characters from.
* @param term Terminator character.
* @return The string up until, but not including the terminator.
* @throws IOException when unable to read from stream.
*/
public static String readString(Reader is, char term) throws IOException {
CharArrayWriter baos = new CharArrayWriter();
int ch_int;
while ((ch_int = is.read()) >= 0) {
final char ch = (char) ch_int;
if (ch == term) {
break;
}
baos.write(ch);
}
return baos.toString();
}
/**
* Read next string from input stream.
*
* @param is The reader to read characters from.
* @param term Terminator character.
* @return The string up until, but not including the terminator.
* @throws IOException when unable to read from stream.
*/
public static String readString(Reader is, String term) throws IOException {
CharArrayWriter baos = new CharArrayWriter();
int ch_int;
char last = term.charAt(term.length() - 1);
while ((ch_int = is.read()) >= 0) {
final char ch = (char) ch_int;
baos.write(ch);
if (ch == last && baos.size() >= term.length()) {
String tmp = baos.toString();
if (tmp.substring(tmp.length() - term.length())
.equals(term)) {
return tmp.substring(0, tmp.length() - term.length());
}
}
}
return baos.toString();
}
/* -- PRIVATE METHODS -- */
private static final int BUF_SIZE = 4096;
private IOUtils() {}
private static boolean skipUntilInternal(InputStream in, byte[] separator, byte[] buffer) throws IOException {
int r;
int l = 0;
while((r = in.read()) >= 0) {
System.arraycopy(buffer, 1, buffer, 0, buffer.length - 1);
buffer[buffer.length - 1] = (byte) r;
++l;
if(l >= buffer.length && Arrays.equals(separator, buffer)) { return true; }
}
return false;
}
}
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