下面列出了java.util.Objects#checkFromIndexSize ( ) 实例代码，或者点击链接到github查看源代码，也可以在右侧发表评论。
/**
* Reads bytes from the socket into the given byte array.
* @return the number of bytes read or -1 at EOF
* @throws IndexOutOfBoundsException if the bound checks fail
* @throws SocketException if the socket is closed or a socket I/O error occurs
* @throws SocketTimeoutException if the read timeout elapses
*/
private int read(byte[] b, int off, int len) throws IOException {
Objects.checkFromIndexSize(off, len, b.length);
if (len == 0) {
return 0;
} else {
readLock.lock();
try {
// emulate legacy behavior to return -1, even if socket is closed
if (readEOF)
return -1;
// read up to MAX_BUFFER_SIZE bytes
int size = Math.min(len, MAX_BUFFER_SIZE);
int n = implRead(b, off, size);
if (n == -1)
readEOF = true;
return n;
} finally {
readLock.unlock();
}
}
}
@Override
public BigInteger getBigInteger(byte[] b, int offset, int size, boolean signed) {
Objects.checkFromIndexSize(offset, size, b.length);
int msbIndex = 0;
if (!signed) {
// prepend 0 byte
++size;
msbIndex = 1;
}
int bIndex = 0;
byte[] bytes = new byte[size];
for (int i = size - 1; i >= msbIndex; i--) {
bytes[i] = b[offset + bIndex++];
}
return new BigInteger(bytes);
}
@Override
public void putBigInteger(byte[] b, int offset, int size, BigInteger value) {
Objects.checkFromIndexSize(offset, size, b.length);
int fillIndex = offset + size - 1; // start fill from MSB
int srcIndex;
byte[] valBytes = value.toByteArray();
if (valBytes.length >= size) {
srcIndex = valBytes.length - size;
}
else {
srcIndex = 0;
byte signbits = (value.signum() < 0) ? (byte) 0xff : 0;
for (int i = valBytes.length; i < size; i++) {
b[fillIndex--] = signbits;
}
}
for (int i = srcIndex; i < valBytes.length; i++) {
b[fillIndex--] = valBytes[i];
}
}
public synchronized int read(byte[] bs, int off, int len)
throws IOException
{
Objects.checkFromIndexSize(off, len, bs.length);
if (len == 0)
return 0;
ByteBuffer bb = ((this.bs == bs)
? this.bb
: ByteBuffer.wrap(bs));
bb.limit(Math.min(off + len, bb.capacity()));
bb.position(off);
this.bb = bb;
this.bs = bs;
return read(bb);
}
@Override
public int getInt(byte[] b, int offset) {
Objects.checkFromIndexSize(offset, Integer.BYTES, b.length);
int v = b[offset];
for (int i = 1; i < 4; i++) {
v = (v << 8) | (b[offset + i] & 0xff);
}
return v;
}
@Override
public long getLong(byte[] b, int offset) {
Objects.checkFromIndexSize(offset, Long.BYTES, b.length);
long v = b[offset];
for (int i = 1; i < 8; i++) {
v = (v << 8) | (b[offset + i] & 0xff);
}
return v;
}
@Override
public long getValue(byte[] b, int offset, int size) {
Objects.checkFromIndexSize(offset, size, b.length);
Objects.checkIndex(size, Long.BYTES + 1);
long val = 0;
for (int i = 0; i < size; i++) {
val = (val << 8) | (b[offset + i] & 0xff);
}
return val;
}
/**
* Update the MAC with bytes from an array.
*
* @param input the input bytes.
* @param offset the starting index from which to update the MAC.
* @param len the number of bytes to process.
*/
void engineUpdate(byte[] input, int offset, int len) {
Objects.checkFromIndexSize(offset, len, input.length);
if (blockOffset > 0) {
// We have some left-over data from previous updates
int blockSpaceLeft = BLOCK_LENGTH - blockOffset;
if (len < blockSpaceLeft) {
System.arraycopy(input, offset, block, blockOffset, len);
blockOffset += len;
return; // block wasn't filled
} else {
System.arraycopy(input, offset, block, blockOffset,
blockSpaceLeft);
offset += blockSpaceLeft;
len -= blockSpaceLeft;
processBlock(block, 0, BLOCK_LENGTH);
blockOffset = 0;
}
}
while (len >= BLOCK_LENGTH) {
processBlock(input, offset, BLOCK_LENGTH);
offset += BLOCK_LENGTH;
len -= BLOCK_LENGTH;
}
if (len > 0) { // and len < BLOCK_LENGTH
System.arraycopy(input, offset, block, 0, len);
blockOffset = len;
}
}
@Override
public void putInt(byte[] b, int offset, int value) {
Objects.checkFromIndexSize(offset, Integer.BYTES, b.length);
b[offset + 3] = (byte) (value);
for (int i = 2; i >= 0; i--) {
value >>= 8;
b[offset + i] = (byte) (value);
}
}
/**
* Encrypt exactly one block of plaintext.
*/
void encryptBlock(byte[] in, int inOffset,
byte[] out, int outOffset) {
Objects.checkFromIndexSize(inOffset, AES_BLOCK_SIZE, in.length);
Objects.checkFromIndexSize(outOffset, AES_BLOCK_SIZE, out.length);
implEncryptBlock(in, inOffset, out, outOffset);
}
@Override
public int getInt(byte[] b, int offset) {
Objects.checkFromIndexSize(offset, Integer.BYTES, b.length);
int v = b[offset + 3];
for (int i = 2; i >= 0; i--) {
v = (v << 8) | (b[offset + i] & 0xff);
}
return v;
}
@Override
public long write(ByteBuffer[] srcs, int offset, int length)
throws IOException
{
Objects.checkFromIndexSize(offset, length, srcs.length);
writeLock.lock();
try {
boolean blocking = isBlocking();
long n = 0;
try {
beginWrite(blocking);
n = IOUtil.write(fd, srcs, offset, length, nd);
if (blocking) {
while (IOStatus.okayToRetry(n) && isOpen()) {
park(Net.POLLOUT);
n = IOUtil.write(fd, srcs, offset, length, nd);
}
}
} finally {
endWrite(blocking, n > 0);
if (n <= 0 && isOutputClosed)
throw new AsynchronousCloseException();
}
return IOStatus.normalize(n);
} finally {
writeLock.unlock();
}
}
@Override
public void putValue(long value, int size, byte[] b, int offset) {
Objects.checkFromIndexSize(offset, size, b.length);
Objects.checkIndex(size, Long.BYTES + 1);
for (int i = 0; i < size; i++) {
b[offset + i] = (byte) value;
value >>= 8;
}
}
@Override
public short getShort(byte[] b, int offset) {
Objects.checkFromIndexSize(offset, Short.BYTES, b.length);
return (short) (((b[offset] & 0xff) << 8) | (b[offset + 1] & 0xff));
}
@Override
public short getShort(byte[] b, int offset) {
Objects.checkFromIndexSize(offset, Short.BYTES, b.length);
return (short) (((b[offset + 1] & 0xff) << 8) | (b[offset] & 0xff));
}
/**
* Reads up to {@code len} bytes of data into an array of bytes from this
* input stream. If {@code pos} equals {@code count}, then {@code -1} is
* returned to indicate end of file. Otherwise, the number {@code k} of
* bytes read is equal to the smaller of {@code len} and {@code count-pos}.
* If {@code k} is positive, then bytes {@code buf[pos]} through
* {@code buf[pos+k-1]} are copied into {@code b[off]} through
* {@code b[off+k-1]} in the manner performed by {@code System.arraycopy}.
* The value {@code k} is added into {@code pos} and {@code k} is returned.
* <p>
* This {@code read} method cannot block.
*
* @param b the buffer into which the data is read.
* @param off the start offset in the destination array {@code b}
* @param len the maximum number of bytes read.
* @return the total number of bytes read into the buffer, or
* {@code -1} if there is no more data because the end of
* the stream has been reached.
* @throws NullPointerException If {@code b} is {@code null}.
* @throws IndexOutOfBoundsException If {@code off} is negative,
* {@code len} is negative, or {@code len} is greater than
* {@code b.length - off}
*/
public synchronized int read(byte b[], int off, int len) {
Objects.checkFromIndexSize(off, len, b.length);
if (pos >= count) {
return -1;
}
int avail = count - pos;
if (len > avail) {
len = avail;
}
if (len <= 0) {
return 0;
}
System.arraycopy(buf, pos, b, off, len);
pos += len;
return len;
}
/**
* Reads up to {@code len} bytes of data from the input stream into
* an array of bytes. An attempt is made to read as many as
* {@code len} bytes, but a smaller number may be read.
* The number of bytes actually read is returned as an integer.
*
* <p> This method blocks until input data is available, end of file is
* detected, or an exception is thrown.
*
* <p> If {@code len} is zero, then no bytes are read and
* {@code 0} is returned; otherwise, there is an attempt to read at
* least one byte. If no byte is available because the stream is at end of
* file, the value {@code -1} is returned; otherwise, at least one
* byte is read and stored into {@code b}.
*
* <p> The first byte read is stored into element {@code b[off]}, the
* next one into {@code b[off+1]}, and so on. The number of bytes read
* is, at most, equal to {@code len}. Let <i>k</i> be the number of
* bytes actually read; these bytes will be stored in elements
* {@code b[off]} through {@code b[off+}<i>k</i>{@code -1]},
* leaving elements {@code b[off+}<i>k</i>{@code ]} through
* {@code b[off+len-1]} unaffected.
*
* <p> In every case, elements {@code b[0]} through
* {@code b[off-1]} and elements {@code b[off+len]} through
* {@code b[b.length-1]} are unaffected.
*
* <p> The {@code read(b, off, len)} method
* for class {@code InputStream} simply calls the method
* {@code read()} repeatedly. If the first such call results in an
* {@code IOException}, that exception is returned from the call to
* the {@code read(b,} {@code off,} {@code len)} method. If
* any subsequent call to {@code read()} results in a
* {@code IOException}, the exception is caught and treated as if it
* were end of file; the bytes read up to that point are stored into
* {@code b} and the number of bytes read before the exception
* occurred is returned. The default implementation of this method blocks
* until the requested amount of input data {@code len} has been read,
* end of file is detected, or an exception is thrown. Subclasses are
* encouraged to provide a more efficient implementation of this method.
*
* @param b the buffer into which the data is read.
* @param off the start offset in array {@code b}
* at which the data is written.
* @param len the maximum number of bytes to read.
* @return the total number of bytes read into the buffer, or
* {@code -1} if there is no more data because the end of
* the stream has been reached.
* @throws IOException If the first byte cannot be read for any reason
* other than end of file, or if the input stream has been closed,
* or if some other I/O error occurs.
* @throws NullPointerException If {@code b} is {@code null}.
* @throws IndexOutOfBoundsException If {@code off} is negative,
* {@code len} is negative, or {@code len} is greater than
* {@code b.length - off}
* @see java.io.InputStream#read()
*/
public int read(byte b[], int off, int len) throws IOException {
Objects.checkFromIndexSize(off, len, b.length);
if (len == 0) {
return 0;
}
int c = read();
if (c == -1) {
return -1;
}
b[off] = (byte)c;
int i = 1;
try {
for (; i < len ; i++) {
c = read();
if (c == -1) {
break;
}
b[off + i] = (byte)c;
}
} catch (IOException ee) {
}
return i;
}
@Override
public final CharTermAttribute setLength(int length) {
Objects.checkFromIndexSize(0, length, termBuffer.length);
termLength = length;
return this;
}
/**
* Returns a new {@code Reader} that reads no characters. The returned
* stream is initially open. The stream is closed by calling the
* {@code close()} method. Subsequent calls to {@code close()} have no
* effect.
*
* <p> While the stream is open, the {@code read()}, {@code read(char[])},
* {@code read(char[], int, int)}, {@code read(Charbuffer)}, {@code
* ready()}, {@code skip(long)}, and {@code transferTo()} methods all
* behave as if end of stream has been reached. After the stream has been
* closed, these methods all throw {@code IOException}.
*
* <p> The {@code markSupported()} method returns {@code false}. The
* {@code mark()} and {@code reset()} methods throw an {@code IOException}.
*
* <p> The {@link #lock object} used to synchronize operations on the
* returned {@code Reader} is not specified.
*
* @return a {@code Reader} which reads no characters
*
* @since 11
*/
public static Reader nullReader() {
return new Reader() {
private volatile boolean closed;
private void ensureOpen() throws IOException {
if (closed) {
throw new IOException("Stream closed");
}
}
@Override
public int read() throws IOException {
ensureOpen();
return -1;
}
@Override
public int read(char[] cbuf, int off, int len) throws IOException {
Objects.checkFromIndexSize(off, len, cbuf.length);
ensureOpen();
if (len == 0) {
return 0;
}
return -1;
}
@Override
public int read(CharBuffer target) throws IOException {
Objects.requireNonNull(target);
ensureOpen();
if (target.hasRemaining()) {
return -1;
}
return 0;
}
@Override
public boolean ready() throws IOException {
ensureOpen();
return false;
}
@Override
public long skip(long n) throws IOException {
ensureOpen();
return 0L;
}
@Override
public long transferTo(Writer out) throws IOException {
Objects.requireNonNull(out);
ensureOpen();
return 0L;
}
@Override
public void close() {
closed = true;
}
};
}
/**
* Translates the sign-magnitude representation of a BigInteger into a
* BigInteger. The sign is represented as an integer signum value: -1 for
* negative, 0 for zero, or 1 for positive. The magnitude is a sub-array of
* a byte array in <i>big-endian</i> byte-order: the most significant byte
* is the element at index {@code off}. A zero value of the length
* {@code len} is permissible, and will result in a BigInteger value of 0,
* whether signum is -1, 0 or 1. The {@code magnitude} array is assumed to
* be unchanged for the duration of the constructor call.
*
* An {@code IndexOutOfBoundsException} is thrown if the length of the array
* {@code magnitude} is non-zero and either {@code off} is negative,
* {@code len} is negative, or {@code off+len} is greater than the length of
* {@code magnitude}.
*
* @param signum signum of the number (-1 for negative, 0 for zero, 1
* for positive).
* @param magnitude big-endian binary representation of the magnitude of
* the number.
* @param off the start offset of the binary representation.
* @param len the number of bytes to use.
* @throws NumberFormatException {@code signum} is not one of the three
* legal values (-1, 0, and 1), or {@code signum} is 0 and
* {@code magnitude} contains one or more non-zero bytes.
* @throws IndexOutOfBoundsException if the provided array offset and
* length would cause an index into the byte array to be
* negative or greater than or equal to the array length.
* @since 9
*/
public BigInteger(int signum, byte[] magnitude, int off, int len) {
if (signum < -1 || signum > 1) {
throw(new NumberFormatException("Invalid signum value"));
}
Objects.checkFromIndexSize(off, len, magnitude.length);
// stripLeadingZeroBytes() returns a zero length array if len == 0
this.mag = stripLeadingZeroBytes(magnitude, off, len);
if (this.mag.length == 0) {
this.signum = 0;
} else {
if (signum == 0)
throw(new NumberFormatException("signum-magnitude mismatch"));
this.signum = signum;
}
if (mag.length >= MAX_MAG_LENGTH) {
checkRange();
}
}