下面列出了java.nio.charset.CoderResult# isUnderflow ( ) 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。
String toString(byte[] ba, int length) {
CharsetDecoder cd = decoder().reset();
int len = (int)(length * cd.maxCharsPerByte());
char[] ca = new char[len];
if (len == 0)
return new String(ca);
ByteBuffer bb = ByteBuffer.wrap(ba, 0, length);
CharBuffer cb = CharBuffer.wrap(ca);
CoderResult cr = cd.decode(bb, cb, true);
if (!cr.isUnderflow())
throw new IllegalArgumentException(cr.toString());
cr = cd.flush(cb);
if (!cr.isUnderflow())
throw new IllegalArgumentException(cr.toString());
return new String(ca, 0, cb.position());
}
private void processInput(final boolean endOfInput) throws IOException {
// Prepare decoderIn for reading
decoderIn.flip();
CoderResult coderResult;
while (true) {
coderResult = decoder.decode(decoderIn, decoderOut, endOfInput);
if (coderResult.isOverflow()) {
flushOutput();
} else if (coderResult.isUnderflow()) {
break;
} else {
// The decoder is configured to replace malformed input and unmappable characters,
// so we should not get here.
throw new IOException("Unexpected coder result"); //NOI18N
}
}
// Discard the bytes that have been read
decoderIn.compact();
}
private static ByteBuffer encodeAsMuchAsPossible(final CharsetEncoder charsetEncoder, final CharBuffer charBuf,
final boolean endOfInput, final ByteBufferDestination destination, ByteBuffer temp) {
CoderResult result;
do {
result = charsetEncoder.encode(charBuf, temp, endOfInput);
temp = drainIfByteBufferFull(destination, temp, result);
} while (result.isOverflow()); // byte buffer has been drained: retry
if (!result.isUnderflow()) { // we should have fully read the char buffer contents
throwException(result);
}
return temp;
}
/**
* Write the given {@code CharSequence} using the given {@code Charset},
* starting at the current writing position.
* @param charSequence the char sequence to write into this buffer
* @param charset the charset to encode the char sequence with
* @return this buffer
* @since 5.1.4
*/
default DataBuffer write(CharSequence charSequence, Charset charset) {
Assert.notNull(charSequence, "CharSequence must not be null");
Assert.notNull(charset, "Charset must not be null");
if (charSequence.length() != 0) {
CharsetEncoder charsetEncoder = charset.newEncoder()
.onMalformedInput(CodingErrorAction.REPLACE)
.onUnmappableCharacter(CodingErrorAction.REPLACE);
CharBuffer inBuffer = CharBuffer.wrap(charSequence);
int estimatedSize = (int) (inBuffer.remaining() * charsetEncoder.averageBytesPerChar());
ByteBuffer outBuffer = ensureCapacity(estimatedSize)
.asByteBuffer(writePosition(), writableByteCount());
while (true) {
CoderResult cr = (inBuffer.hasRemaining() ?
charsetEncoder.encode(inBuffer, outBuffer, true) : CoderResult.UNDERFLOW);
if (cr.isUnderflow()) {
cr = charsetEncoder.flush(outBuffer);
}
if (cr.isUnderflow()) {
break;
}
if (cr.isOverflow()) {
writePosition(writePosition() + outBuffer.position());
int maximumSize = (int) (inBuffer.remaining() * charsetEncoder.maxBytesPerChar());
ensureCapacity(maximumSize);
outBuffer = asByteBuffer(writePosition(), writableByteCount());
}
}
writePosition(writePosition() + outBuffer.position());
}
return this;
}
byte[] encode(char[] ca, int off, int len) {
int en = scale(len, ce.maxBytesPerChar());
byte[] ba = new byte[en];
if (len == 0)
return ba;
if (ce instanceof ArrayEncoder) {
int blen = ((ArrayEncoder)ce).encode(ca, off, len, ba);
return safeTrim(ba, blen, cs, isTrusted);
} else {
ce.reset();
ByteBuffer bb = ByteBuffer.wrap(ba);
CharBuffer cb = CharBuffer.wrap(ca, off, len);
try {
CoderResult cr = ce.encode(cb, bb, true);
if (!cr.isUnderflow())
cr.throwException();
cr = ce.flush(bb);
if (!cr.isUnderflow())
cr.throwException();
} catch (CharacterCodingException x) {
// Substitution is always enabled,
// so this shouldn't happen
throw new Error(x);
}
return safeTrim(ba, bb.position(), cs, isTrusted);
}
}
byte[] encode(char[] ca, int off, int len) {
int en = scale(len, ce.maxBytesPerChar());
byte[] ba = new byte[en];
if (len == 0)
return ba;
if (ce instanceof ArrayEncoder) {
int blen = ((ArrayEncoder)ce).encode(ca, off, len, ba);
return safeTrim(ba, blen, cs, isTrusted);
} else {
ce.reset();
ByteBuffer bb = ByteBuffer.wrap(ba);
CharBuffer cb = CharBuffer.wrap(ca, off, len);
try {
CoderResult cr = ce.encode(cb, bb, true);
if (!cr.isUnderflow())
cr.throwException();
cr = ce.flush(bb);
if (!cr.isUnderflow())
cr.throwException();
} catch (CharacterCodingException x) {
// Substitution is always enabled,
// so this shouldn't happen
throw new Error(x);
}
return safeTrim(ba, bb.position(), cs, isTrusted);
}
}
byte[] encode(char[] ca, int off, int len) {
int en = scale(len, ce.maxBytesPerChar());
byte[] ba = new byte[en];
if (len == 0)
return ba;
if (ce instanceof ArrayEncoder) {
int blen = ((ArrayEncoder)ce).encode(ca, off, len, ba);
return safeTrim(ba, blen, cs, isTrusted);
} else {
ce.reset();
ByteBuffer bb = ByteBuffer.wrap(ba);
CharBuffer cb = CharBuffer.wrap(ca, off, len);
try {
CoderResult cr = ce.encode(cb, bb, true);
if (!cr.isUnderflow())
cr.throwException();
cr = ce.flush(bb);
if (!cr.isUnderflow())
cr.throwException();
} catch (CharacterCodingException x) {
// Substitution is always enabled,
// so this shouldn't happen
throw new Error(x);
}
return safeTrim(ba, bb.position(), cs, isTrusted);
}
}
static ByteBuf encodeString0(ByteBufAllocator alloc, boolean enforceHeap, CharBuffer src, Charset charset) {
final CharsetEncoder encoder = CharsetUtil.getEncoder(charset);
int length = (int) ((double) src.remaining() * encoder.maxBytesPerChar());
boolean release = true;
final ByteBuf dst;
if (enforceHeap) {
dst = alloc.heapBuffer(length);
} else {
dst = alloc.buffer(length);
}
try {
final ByteBuffer dstBuf = dst.internalNioBuffer(0, length);
final int pos = dstBuf.position();
CoderResult cr = encoder.encode(src, dstBuf, true);
if (!cr.isUnderflow()) {
cr.throwException();
}
cr = encoder.flush(dstBuf);
if (!cr.isUnderflow()) {
cr.throwException();
}
dst.writerIndex(dst.writerIndex() + dstBuf.position() - pos);
release = false;
return dst;
} catch (CharacterCodingException x) {
throw new IllegalStateException(x);
} finally {
if (release) {
dst.release();
}
}
}
static byte[] encode(Charset cs, char[] ca, int off, int len) {
CharsetEncoder ce = cs.newEncoder();
int en = scale(len, ce.maxBytesPerChar());
byte[] ba = new byte[en];
if (len == 0)
return ba;
boolean isTrusted = false;
if (System.getSecurityManager() != null) {
if (!(isTrusted = (cs.getClass().getClassLoader0() == null))) {
ca = Arrays.copyOfRange(ca, off, off + len);
off = 0;
}
}
ce.onMalformedInput(CodingErrorAction.REPLACE)
.onUnmappableCharacter(CodingErrorAction.REPLACE)
.reset();
if (ce instanceof ArrayEncoder) {
int blen = ((ArrayEncoder)ce).encode(ca, off, len, ba);
return safeTrim(ba, blen, cs, isTrusted);
} else {
ByteBuffer bb = ByteBuffer.wrap(ba);
CharBuffer cb = CharBuffer.wrap(ca, off, len);
try {
CoderResult cr = ce.encode(cb, bb, true);
if (!cr.isUnderflow())
cr.throwException();
cr = ce.flush(bb);
if (!cr.isUnderflow())
cr.throwException();
} catch (CharacterCodingException x) {
throw new Error(x);
}
return safeTrim(ba, bb.position(), cs, isTrusted);
}
}
private CharBuffer readStringFromComponents(CharsetDecoder decoder) throws CharacterCodingException {
int size = (int)(remaining() * decoder.averageCharsPerByte());
CharBuffer decoded = CharBuffer.allocate(size);
int arrayIndex = currentArrayIndex;
final int viewSpan = limit() - position();
int processed = Math.min(currentArray.length - currentOffset, viewSpan);
ByteBuffer wrapper = ByteBuffer.wrap(currentArray, currentOffset, processed);
CoderResult step = CoderResult.OVERFLOW;
do {
boolean endOfInput = processed == viewSpan;
step = decoder.decode(wrapper, decoded, endOfInput);
if (step.isUnderflow() && endOfInput) {
step = decoder.flush(decoded);
break;
}
if (step.isOverflow()) {
size = 2 * size + 1;
CharBuffer upsized = CharBuffer.allocate(size);
decoded.flip();
upsized.put(decoded);
decoded = upsized;
continue;
}
byte[] next = contents.get(++arrayIndex);
int wrapSize = Math.min(next.length, viewSpan - processed);
wrapper = ByteBuffer.wrap(next, 0, wrapSize);
processed += wrapSize;
} while (!step.isError());
if (step.isError()) {
step.throwException();
}
return (CharBuffer) decoded.flip();
}
char[] decode(byte[] ba, int off, int len) {
int en = scale(len, cd.maxCharsPerByte());
char[] ca = new char[en];
if (len == 0)
return ca;
if (cd instanceof ArrayDecoder) {
int clen = ((ArrayDecoder)cd).decode(ba, off, len, ca);
return safeTrim(ca, clen, cs, isTrusted);
} else {
cd.reset();
ByteBuffer bb = ByteBuffer.wrap(ba, off, len);
CharBuffer cb = CharBuffer.wrap(ca);
try {
CoderResult cr = cd.decode(bb, cb, true);
if (!cr.isUnderflow())
cr.throwException();
cr = cd.flush(cb);
if (!cr.isUnderflow())
cr.throwException();
} catch (CharacterCodingException x) {
// Substitution is always enabled,
// so this shouldn't happen
throw new Error(x);
}
return safeTrim(ca, cb.position(), cs, isTrusted);
}
}
/**
* Convert the given bytes to characters.
*
* @param bc byte input
* @param cc char output
* @param ic byte input channel
* @param endOfInput Is this all of the available data
*
* @throws IOException If the conversion can not be completed
*/
public void convert(ByteBuffer bc, CharBuffer cc, ByteChunk.ByteInputChannel ic, boolean endOfInput)
throws IOException {
if ((bb == null) || (bb.array() != bc.array())) {
// Create a new byte buffer if anything changed
bb = ByteBuffer.wrap(bc.array(), bc.arrayOffset() + bc.position(), bc.remaining());
} else {
// Initialize the byte buffer
bb.limit(bc.limit());
bb.position(bc.position());
}
if ((cb == null) || (cb.array() != cc.array())) {
// Create a new char buffer if anything changed
cb = CharBuffer.wrap(cc.array(), cc.limit(), cc.capacity() - cc.limit());
} else {
// Initialize the char buffer
cb.limit(cc.capacity());
cb.position(cc.limit());
}
CoderResult result = null;
// Parse leftover if any are present
if (leftovers.position() > 0) {
int pos = cb.position();
// Loop until one char is decoded or there is a decoder error
do {
byte chr;
if (bc.remaining() == 0) {
int n = ic.realReadBytes();
chr = n < 0 ? -1 : bc.get();
} else {
chr = bc.get();
}
leftovers.put(chr);
leftovers.flip();
result = decoder.decode(leftovers, cb, endOfInput);
leftovers.position(leftovers.limit());
leftovers.limit(leftovers.array().length);
} while (result.isUnderflow() && (cb.position() == pos));
if (result.isError() || result.isMalformed()) {
result.throwException();
}
bb.position(bc.position());
leftovers.position(0);
}
// Do the decoding and get the results into the byte chunk and the char
// chunk
result = decoder.decode(bb, cb, endOfInput);
if (result.isError() || result.isMalformed()) {
result.throwException();
} else if (result.isOverflow()) {
// Propagate current positions to the byte chunk and char chunk, if
// this continues the char buffer will get resized
bc.position(bb.position());
cc.limit(cb.position());
} else if (result.isUnderflow()) {
// Propagate current positions to the byte chunk and char chunk
bc.position(bb.position());
cc.limit(cb.position());
// Put leftovers in the leftovers byte buffer
if (bc.remaining() > 0) {
leftovers.limit(leftovers.array().length);
leftovers.position(bc.remaining());
bc.get(leftovers.array(), 0, bc.remaining());
}
}
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
// Obey InputStream contract.
checkPositionIndexes(off, off + len, b.length);
if (len == 0) {
return 0;
}
// The rest of this method implements the process described by the CharsetEncoder javadoc.
int totalBytesRead = 0;
boolean doneEncoding = endOfInput;
DRAINING:
while (true) {
// We stay in draining mode until there are no bytes left in the output buffer. Then we go
// back to encoding/flushing.
if (draining) {
totalBytesRead += drain(b, off + totalBytesRead, len - totalBytesRead);
if (totalBytesRead == len || doneFlushing) {
return (totalBytesRead > 0) ? totalBytesRead : -1;
}
draining = false;
byteBuffer.clear();
}
while (true) {
// We call encode until there is no more input. The last call to encode will have endOfInput
// == true. Then there is a final call to flush.
CoderResult result;
if (doneFlushing) {
result = CoderResult.UNDERFLOW;
} else if (doneEncoding) {
result = encoder.flush(byteBuffer);
} else {
result = encoder.encode(charBuffer, byteBuffer, endOfInput);
}
if (result.isOverflow()) {
// Not enough room in output buffer--drain it, creating a bigger buffer if necessary.
startDraining(true);
continue DRAINING;
} else if (result.isUnderflow()) {
// If encoder underflows, it means either:
// a) the final flush() succeeded; next drain (then done)
// b) we encoded all of the input; next flush
// c) we ran of out input to encode; next read more input
if (doneEncoding) { // (a)
doneFlushing = true;
startDraining(false);
continue DRAINING;
} else if (endOfInput) { // (b)
doneEncoding = true;
} else { // (c)
readMoreChars();
}
} else if (result.isError()) {
// Only reach here if a CharsetEncoder with non-REPLACE settings is used.
result.throwException();
return 0; // Not called.
}
}
}
}
static char[] decode(Charset cs, byte[] ba, int off, int len) {
// (1)We never cache the "external" cs, the only benefit of creating
// an additional StringDe/Encoder object to wrap it is to share the
// de/encode() method. These SD/E objects are short-lifed, the young-gen
// gc should be able to take care of them well. But the best approash
// is still not to generate them if not really necessary.
// (2)The defensive copy of the input byte/char[] has a big performance
// impact, as well as the outgoing result byte/char[]. Need to do the
// optimization check of (sm==null && classLoader0==null) for both.
// (3)getClass().getClassLoader0() is expensive
// (4)There might be a timing gap in isTrusted setting. getClassLoader0()
// is only chcked (and then isTrusted gets set) when (SM==null). It is
// possible that the SM==null for now but then SM is NOT null later
// when safeTrim() is invoked...the "safe" way to do is to redundant
// check (... && (isTrusted || SM == null || getClassLoader0())) in trim
// but it then can be argued that the SM is null when the opertaion
// is started...
CharsetDecoder cd = cs.newDecoder();
int en = scale(len, cd.maxCharsPerByte());
char[] ca = new char[en];
if (len == 0)
return ca;
boolean isTrusted = false;
if (System.getSecurityManager() != null) {
if (!(isTrusted = (cs.getClass().getClassLoader0() == null))) {
ba = Arrays.copyOfRange(ba, off, off + len);
off = 0;
}
}
cd.onMalformedInput(CodingErrorAction.REPLACE)
.onUnmappableCharacter(CodingErrorAction.REPLACE)
.reset();
if (cd instanceof ArrayDecoder) {
int clen = ((ArrayDecoder)cd).decode(ba, off, len, ca);
return safeTrim(ca, clen, cs, isTrusted);
} else {
ByteBuffer bb = ByteBuffer.wrap(ba, off, len);
CharBuffer cb = CharBuffer.wrap(ca);
try {
CoderResult cr = cd.decode(bb, cb, true);
if (!cr.isUnderflow())
cr.throwException();
cr = cd.flush(cb);
if (!cr.isUnderflow())
cr.throwException();
} catch (CharacterCodingException x) {
// Substitution is always enabled,
// so this shouldn't happen
throw new Error(x);
}
return safeTrim(ca, cb.position(), cs, isTrusted);
}
}
@Override
public void write(Bytes out, @NotNull CharSequence cs) {
// Write the actual cs length for accurate StringBuilder.ensureCapacity() while reading
out.writeStopBit(cs.length());
long encodedSizePos = out.writePosition();
out.writeSkip(4);
charsetEncoder.reset();
inputBuffer.clear();
outputBuffer.clear();
int csPos = 0;
boolean endOfInput = false;
// this loop inspired by the CharsetEncoder.encode(CharBuffer) implementation
while (true) {
if (!endOfInput) {
int nextCsPos = Math.min(csPos + inputBuffer.remaining(), cs.length());
append(inputBuffer, cs, csPos, nextCsPos);
inputBuffer.flip();
endOfInput = nextCsPos == cs.length();
csPos = nextCsPos;
}
CoderResult cr = inputBuffer.hasRemaining() ?
charsetEncoder.encode(inputBuffer, outputBuffer, endOfInput) :
CoderResult.UNDERFLOW;
if (cr.isUnderflow() && endOfInput)
cr = charsetEncoder.flush(outputBuffer);
if (cr.isUnderflow()) {
if (endOfInput) {
break;
} else {
inputBuffer.compact();
continue;
}
}
if (cr.isOverflow()) {
outputBuffer.flip();
writeOutputBuffer(out);
outputBuffer.clear();
continue;
}
try {
cr.throwException();
} catch (CharacterCodingException e) {
throw new IORuntimeException(e);
}
}
outputBuffer.flip();
writeOutputBuffer(out);
out.writeInt(encodedSizePos, (int) (out.writePosition() - encodedSizePos - 4));
}
static char[] decode(Charset cs, byte[] ba, int off, int len) {
// (1)We never cache the "external" cs, the only benefit of creating
// an additional StringDe/Encoder object to wrap it is to share the
// de/encode() method. These SD/E objects are short-lifed, the young-gen
// gc should be able to take care of them well. But the best approash
// is still not to generate them if not really necessary.
// (2)The defensive copy of the input byte/char[] has a big performance
// impact, as well as the outgoing result byte/char[]. Need to do the
// optimization check of (sm==null && classLoader0==null) for both.
// (3)getClass().getClassLoader0() is expensive
// (4)There might be a timing gap in isTrusted setting. getClassLoader0()
// is only chcked (and then isTrusted gets set) when (SM==null). It is
// possible that the SM==null for now but then SM is NOT null later
// when safeTrim() is invoked...the "safe" way to do is to redundant
// check (... && (isTrusted || SM == null || getClassLoader0())) in trim
// but it then can be argued that the SM is null when the opertaion
// is started...
CharsetDecoder cd = cs.newDecoder();
int en = scale(len, cd.maxCharsPerByte());
char[] ca = new char[en];
if (len == 0)
return ca;
boolean isTrusted = false;
if (System.getSecurityManager() != null) {
if (!(isTrusted = (cs.getClass().getClassLoader0() == null))) {
ba = Arrays.copyOfRange(ba, off, off + len);
off = 0;
}
}
cd.onMalformedInput(CodingErrorAction.REPLACE)
.onUnmappableCharacter(CodingErrorAction.REPLACE)
.reset();
if (cd instanceof ArrayDecoder) {
int clen = ((ArrayDecoder)cd).decode(ba, off, len, ca);
return safeTrim(ca, clen, cs, isTrusted);
} else {
ByteBuffer bb = ByteBuffer.wrap(ba, off, len);
CharBuffer cb = CharBuffer.wrap(ca);
try {
CoderResult cr = cd.decode(bb, cb, true);
if (!cr.isUnderflow())
cr.throwException();
cr = cd.flush(cb);
if (!cr.isUnderflow())
cr.throwException();
} catch (CharacterCodingException x) {
// Substitution is always enabled,
// so this shouldn't happen
throw new Error(x);
}
return safeTrim(ca, cb.position(), cs, isTrusted);
}
}
/**
* {@inheritDoc}
*/
@Override
public String getString(CharsetDecoder decoder) throws CharacterCodingException {
if (!hasRemaining()) {
return "";
}
boolean utf16 = decoder.charset().name().startsWith("UTF-16");
int oldPos = position();
int oldLimit = limit();
int end = -1;
int newPos;
if (!utf16) {
end = indexOf((byte) 0x00);
if (end < 0) {
newPos = end = oldLimit;
} else {
newPos = end + 1;
}
} else {
int i = oldPos;
for (;;) {
boolean wasZero = get(i) == 0;
i++;
if (i >= oldLimit) {
break;
}
if (get(i) != 0) {
i++;
if (i >= oldLimit) {
break;
}
continue;
}
if (wasZero) {
end = i - 1;
break;
}
}
if (end < 0) {
newPos = end = oldPos + (oldLimit - oldPos & 0xFFFFFFFE);
} else {
if (end + 2 <= oldLimit) {
newPos = end + 2;
} else {
newPos = end;
}
}
}
if (oldPos == end) {
position(newPos);
return "";
}
limit(end);
decoder.reset();
int expectedLength = (int) (remaining() * decoder.averageCharsPerByte()) + 1;
CharBuffer out = CharBuffer.allocate(expectedLength);
for (;;) {
CoderResult cr;
if (hasRemaining()) {
cr = decoder.decode(buf(), out, true);
} else {
cr = decoder.flush(out);
}
if (cr.isUnderflow()) {
break;
}
if (cr.isOverflow()) {
CharBuffer o = CharBuffer.allocate(out.capacity() + expectedLength);
out.flip();
o.put(out);
out = o;
continue;
}
if (cr.isError()) {
// Revert the buffer back to the previous state.
limit(oldLimit);
position(oldPos);
cr.throwException();
}
}
limit(oldLimit);
position(newPos);
return out.flip().toString();
}
static byte[] encode(Charset cs, byte coder, byte[] val) {
if (cs == UTF_8) {
return encodeUTF8(coder, val);
} else if (cs == ISO_8859_1) {
return encode8859_1(coder, val);
} else if (cs == US_ASCII) {
return encodeASCII(coder, val);
}
CharsetEncoder ce = cs.newEncoder();
// fastpath for ascii compatible
if (coder == LATIN1 && (((ce instanceof ArrayEncoder) &&
((ArrayEncoder)ce).isASCIICompatible() &&
!hasNegatives(val, 0, val.length)))) {
return Arrays.copyOf(val, val.length);
}
int len = val.length >> coder; // assume LATIN1=0/UTF16=1;
int en = scale(len, ce.maxBytesPerChar());
byte[] ba = new byte[en];
if (len == 0) {
return ba;
}
boolean isTrusted = System.getSecurityManager() == null ||
cs.getClass().getClassLoader0() == null;
ce.onMalformedInput(CodingErrorAction.REPLACE)
.onUnmappableCharacter(CodingErrorAction.REPLACE)
.reset();
if (ce instanceof ArrayEncoder) {
if (!isTrusted) {
val = Arrays.copyOf(val, val.length);
}
int blen = (coder == LATIN1 ) ? ((ArrayEncoder)ce).encodeFromLatin1(val, 0, len, ba)
: ((ArrayEncoder)ce).encodeFromUTF16(val, 0, len, ba);
if (blen != -1) {
return safeTrim(ba, blen, isTrusted);
}
}
char[] ca = (coder == LATIN1 ) ? StringLatin1.toChars(val)
: StringUTF16.toChars(val);
ByteBuffer bb = ByteBuffer.wrap(ba);
CharBuffer cb = CharBuffer.wrap(ca, 0, len);
try {
CoderResult cr = ce.encode(cb, bb, true);
if (!cr.isUnderflow())
cr.throwException();
cr = ce.flush(bb);
if (!cr.isUnderflow())
cr.throwException();
} catch (CharacterCodingException x) {
throw new Error(x);
}
return safeTrim(ba, bb.position(), isTrusted);
}
static char[] decode(Charset cs, byte[] ba, int off, int len) {
// (1)We never cache the "external" cs, the only benefit of creating
// an additional StringDe/Encoder object to wrap it is to share the
// de/encode() method. These SD/E objects are short-lifed, the young-gen
// gc should be able to take care of them well. But the best approash
// is still not to generate them if not really necessary.
// (2)The defensive copy of the input byte/char[] has a big performance
// impact, as well as the outgoing result byte/char[]. Need to do the
// optimization check of (sm==null && classLoader0==null) for both.
// (3)getClass().getClassLoader0() is expensive
// (4)There might be a timing gap in isTrusted setting. getClassLoader0()
// is only chcked (and then isTrusted gets set) when (SM==null). It is
// possible that the SM==null for now but then SM is NOT null later
// when safeTrim() is invoked...the "safe" way to do is to redundant
// check (... && (isTrusted || SM == null || getClassLoader0())) in trim
// but it then can be argued that the SM is null when the opertaion
// is started...
CharsetDecoder cd = cs.newDecoder();
int en = scale(len, cd.maxCharsPerByte());
char[] ca = new char[en];
if (len == 0)
return ca;
boolean isTrusted = false;
if (System.getSecurityManager() != null) {
if (!(isTrusted = (cs.getClass().getClassLoader0() == null))) {
ba = Arrays.copyOfRange(ba, off, off + len);
off = 0;
}
}
cd.onMalformedInput(CodingErrorAction.REPLACE)
.onUnmappableCharacter(CodingErrorAction.REPLACE)
.reset();
if (cd instanceof ArrayDecoder) {
int clen = ((ArrayDecoder)cd).decode(ba, off, len, ca);
return safeTrim(ca, clen, cs, isTrusted);
} else {
ByteBuffer bb = ByteBuffer.wrap(ba, off, len);
CharBuffer cb = CharBuffer.wrap(ca);
try {
CoderResult cr = cd.decode(bb, cb, true);
if (!cr.isUnderflow())
cr.throwException();
cr = cd.flush(cb);
if (!cr.isUnderflow())
cr.throwException();
} catch (CharacterCodingException x) {
// Substitution is always enabled,
// so this shouldn't happen
throw new Error(x);
}
return safeTrim(ca, cb.position(), cs, isTrusted);
}
}
/**
* Convert the given characters to bytes.
*
* @param cc char input
* @param bc byte output
*/
public void convert(CharChunk cc, ByteChunk bc)
throws IOException {
if ((bb == null) || (bb.array() != bc.getBuffer())) {
// Create a new byte buffer if anything changed
bb = ByteBuffer.wrap(bc.getBuffer(), bc.getEnd(),
bc.getBuffer().length - bc.getEnd());
} else {
// Initialize the byte buffer
bb.limit(bc.getBuffer().length);
bb.position(bc.getEnd());
}
if ((cb == null) || (cb.array() != cc.getBuffer())) {
// Create a new char buffer if anything changed
cb = CharBuffer.wrap(cc.getBuffer(), cc.getStart(),
cc.getLength());
} else {
// Initialize the char buffer
cb.limit(cc.getEnd());
cb.position(cc.getStart());
}
CoderResult result = null;
// Parse leftover if any are present
if (leftovers.position() > 0) {
int pos = bb.position();
// Loop until one char is encoded or there is a encoder error
do {
leftovers.put((char) cc.substract());
leftovers.flip();
result = encoder.encode(leftovers, bb, false);
leftovers.position(leftovers.limit());
leftovers.limit(leftovers.array().length);
} while (result.isUnderflow() && (bb.position() == pos));
if (result.isError() || result.isMalformed()) {
result.throwException();
}
cb.position(cc.getStart());
leftovers.position(0);
}
// Do the decoding and get the results into the byte chunk and the char
// chunk
result = encoder.encode(cb, bb, false);
if (result.isError() || result.isMalformed()) {
result.throwException();
} else if (result.isOverflow()) {
// Propagate current positions to the byte chunk and char chunk
bc.setEnd(bb.position());
cc.setOffset(cb.position());
} else if (result.isUnderflow()) {
// Propagate current positions to the byte chunk and char chunk
bc.setEnd(bb.position());
cc.setOffset(cb.position());
// Put leftovers in the leftovers char buffer
if (cc.getLength() > 0) {
leftovers.limit(leftovers.array().length);
leftovers.position(cc.getLength());
cc.substract(leftovers.array(), 0, cc.getLength());
}
}
}