/**
* Maps blah file with a random offset and checks to see if read from the ByteBuffer gets the
* right line number
*/
private static void testRead() throws Exception {
StringBuilder sb = new StringBuilder();
sb.setLength(4);
for (int x = 0; x < 1000; x++) {
try (FileInputStream fis = new FileInputStream(blah)) {
FileChannel fc = fis.getChannel();
long offset = generator.nextInt(10000);
long expectedResult = offset / CHARS_PER_LINE;
offset = expectedResult * CHARS_PER_LINE;
MappedByteBuffer b = fc.map(MapMode.READ_ONLY, offset, 100);
for (int i = 0; i < 4; i++) {
byte aByte = b.get(i);
sb.setCharAt(i, (char) aByte);
}
int result = Integer.parseInt(sb.toString());
if (result != expectedResult) {
err.println("I expected " + expectedResult);
err.println("I got " + result);
throw new Exception("Read test failed");
}
}
}
}
/**
* Maps blah file with a random offset and checks to see if data written out to the file can be
* read back in
*/
private static void testWrite() throws Exception {
StringBuilder sb = new StringBuilder();
sb.setLength(4);
for (int x = 0; x < 1000; x++) {
try (RandomAccessFile raf = new RandomAccessFile(blah, "rw")) {
FileChannel fc = raf.getChannel();
long offset = generator.nextInt(1000);
MappedByteBuffer b = fc.map(MapMode.READ_WRITE, offset, 100);
for (int i = 0; i < 4; i++) {
b.put(i, (byte) ('0' + i));
}
for (int i = 0; i < 4; i++) {
byte aByte = b.get(i);
sb.setCharAt(i, (char) aByte);
}
if (!sb.toString().equals("0123")) throw new Exception("Write test failed");
}
}
}
public static void main(String args[]) throws Exception {
String inputFile = "samplein.txt";
String outputFile = "sampleout.txt";
RandomAccessFile inf = new RandomAccessFile(inputFile, "r");
RandomAccessFile outf = new RandomAccessFile(outputFile, "rw");
long inputLength = new File(inputFile).length();
FileChannel inc = inf.getChannel();
FileChannel outc = outf.getChannel();
MappedByteBuffer inputData = inc.map(FileChannel.MapMode.READ_ONLY, 0, inputLength);
Charset latin1 = Charset.forName("ISO-8859-1");
CharsetDecoder decoder = latin1.newDecoder();
CharsetEncoder encoder = latin1.newEncoder();
CharBuffer cb = decoder.decode(inputData);
// Process char data here
ByteBuffer outputData = encoder.encode(cb);
outc.write(outputData);
inf.close();
outf.close();
}
/**
* Checks that FileChannel map throws one of the expected exceptions when invoked with the given
* inputs.
*/
private static void checkException(
FileChannel fc, MapMode mode, long position, long size, Class<?>... expected)
throws IOException {
Exception exc = null;
try {
fc.map(mode, position, size);
} catch (Exception actual) {
exc = actual;
}
if (exc != null) {
for (Class<?> clazz : expected) {
if (clazz.isInstance(exc)) {
return;
}
}
}
System.err.println("Expected one of");
for (Class<?> clazz : expected) {
System.out.println(clazz);
}
if (exc == null) {
throw new RuntimeException("No expection thrown");
} else {
throw new RuntimeException("Unexpected exception thrown", exc);
}
}
public static void main(String[] args) throws Exception {
fc = new RandomAccessFile("test.dat", "rw").getChannel();
MappedByteBuffer out = fc.map(FileChannel.MapMode.READ_WRITE, 0, LENGTH);
for (int i = 0; i < LENGTH; i++) out.put((byte) 'x');
new LockAndModify(out, 0, 0 + LENGTH / 3);
new LockAndModify(out, LENGTH / 2, LENGTH / 2 + LENGTH / 4);
}
/**
* Creates and initializes an SPV block store. Will create the given file if it's missing. This
* operation will block on disk.
*/
public SPVBlockStore(NetworkParameters params, File file) throws BlockStoreException {
checkNotNull(file);
this.params = checkNotNull(params);
try {
this.numHeaders = DEFAULT_NUM_HEADERS;
boolean exists = file.exists();
// Set up the backing file.
randomAccessFile = new RandomAccessFile(file, "rw");
long fileSize = getFileSize();
if (!exists) {
log.info("Creating new SPV block chain file " + file);
randomAccessFile.setLength(fileSize);
} else if (randomAccessFile.length() != fileSize) {
throw new BlockStoreException(
"File size on disk does not match expected size: "
+ randomAccessFile.length()
+ " vs "
+ fileSize);
}
FileChannel channel = randomAccessFile.getChannel();
fileLock = channel.tryLock();
if (fileLock == null)
throw new BlockStoreException("Store file is already locked by another process");
// Map it into memory read/write. The kernel will take care of flushing writes to disk at the
// most
// efficient times, which may mean that until the map is deallocated the data on disk is
// randomly
// inconsistent. However the only process accessing it is us, via this mapping, so our own
// view will
// always be correct. Once we establish the mmap the underlying file and channel can go away.
// Note that
// the details of mmapping vary between platforms.
buffer = channel.map(FileChannel.MapMode.READ_WRITE, 0, fileSize);
// Check or initialize the header bytes to ensure we don't try to open some random file.
byte[] header;
if (exists) {
header = new byte[4];
buffer.get(header);
if (!new String(header, "US-ASCII").equals(HEADER_MAGIC))
throw new BlockStoreException("Header bytes do not equal " + HEADER_MAGIC);
} else {
initNewStore(params);
}
} catch (Exception e) {
try {
if (randomAccessFile != null) randomAccessFile.close();
} catch (IOException e2) {
throw new BlockStoreException(e2);
}
throw new BlockStoreException(e);
}
}
private static void testHighOffset() throws Exception {
StringBuilder sb = new StringBuilder();
sb.setLength(4);
for (int x = 0; x < 1000; x++) {
try (RandomAccessFile raf = new RandomAccessFile(blah, "rw")) {
FileChannel fc = raf.getChannel();
long offset = 66000;
MappedByteBuffer b = fc.map(MapMode.READ_WRITE, offset, 100);
}
}
}
/**
* Read the contents of a text file using a memory-mapped byte buffer.
*
* <p>A MappedByteBuffer, is simply a special ByteBuffer. MappedByteBuffer maps a region of a file
* directly in memory. Typically, that region comprises the entire file, although it could map a
* portion. You must, therefore, specify what part of the file to map. Moreover, as with the other
* Buffer objects, no constructor exists; you must ask the java.nio.channels.FileChannel for its
* map() method to get a MappedByteBuffer.
*
* <p>Direct buffers allocate their data directly in the runtime environment memory, bypassing the
* JVM|OS boundary, usually doubling file copy speed. However, they generally cost more to
* allocate.
*/
private static String fastStreamCopy(String filename) {
String s = "";
FileChannel fc = null;
try {
fc = new FileInputStream(filename).getChannel();
// int length = (int)fc.size();
MappedByteBuffer byteBuffer = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());
// CharBuffer charBuffer =
// Charset.forName("ISO-8859-1").newDecoder().decode(byteBuffer);
// ByteBuffer byteBuffer = ByteBuffer.allocate(length);
// ByteBuffer byteBuffer = ByteBuffer.allocateDirect(length);
// CharBuffer charBuffer = byteBuffer.asCharBuffer();
// CharBuffer charBuffer =
// ByteBuffer.allocateDirect(length).asCharBuffer();
/*
* int size = charBuffer.length(); if (size > 0) { StringBuffer sb =
* new StringBuffer(size); for (int count=0; count<size; count++)
* sb.append(charBuffer.get()); s = sb.toString(); }
*
* if (length > 0) { StringBuffer sb = new StringBuffer(length); for
* (int count=0; count<length; count++) {
* sb.append(byteBuffer.get()); } s = sb.toString(); }
*/
int size = byteBuffer.capacity();
if (size > 0) {
// Retrieve all bytes in the buffer
byteBuffer.clear();
byte[] bytes = new byte[size];
byteBuffer.get(bytes, 0, bytes.length);
s = new String(bytes);
}
fc.close();
} catch (FileNotFoundException fnfx) {
System.err.println("File not found: " + fnfx);
} catch (IOException iox) {
System.err.println("I/O problems: " + iox);
} finally {
if (fc != null) {
try {
fc.close();
} catch (IOException ignore) {
// ignore
}
}
}
return s;
}
public static long checksumMappedFile(Path filename) throws IOException {
try (FileChannel channel = FileChannel.open(filename)) {
CRC32 crc = new CRC32();
int length = (int) channel.size();
MappedByteBuffer buffer = channel.map(FileChannel.MapMode.READ_ONLY, 0, length);
for (int p = 0; p < length; p++) {
int c = buffer.get(p);
crc.update(c);
}
return crc.getValue();
}
}
private void readFromFile(File file) throws IOException {
fis = new FileInputStream(file);
chan = fis.getChannel();
ByteBuffer buf = chan.map(FileChannel.MapMode.READ_ONLY, 0, (int) file.length());
readFromBuffer(buf);
}
/** Tests zero size file mapping */
private static void testZero() throws Exception {
try (FileInputStream fis = new FileInputStream(blah)) {
FileChannel fc = fis.getChannel();
MappedByteBuffer b = fc.map(MapMode.READ_ONLY, 0, 0);
}
}
