com.fitbur.jackson.dataformat.yaml.UTF8Reader Maven / Gradle / Ivy
package com.fitbur.jackson.dataformat.yaml;
import java.io.*;
import java.lang.ref.SoftReference;
/**
* Optimized Reader that reads UTF-8 encoded content from an input stream.
* In addition to doing (hopefully) optimal conversion, it can also take
* array of "pre-read" (leftover) bytes; this is necessary when preliminary
* stream/reader is trying to figure out underlying character encoding.
*/
public final class UTF8Reader
extends Reader
{
private final static int DEFAULT_BUFFER_SIZE = 8000;
/**
* This ThreadLocal contains a {@link java.lang.ref.SoftRerefence}
* to a byte array used for holding content to decode
*/
final protected static ThreadLocal> _bufferRecycler
= new ThreadLocal>();
protected final byte[][] _bufferHolder;
private InputStream _inputSource;
private final boolean _autoClose;
protected byte[] _inputBuffer;
/**
* Pointer to the next available byte (if any), iff less than
* mByteBufferEnd
*/
protected int _inputPtr;
/**
* Pointed to the end marker, that is, position one after the last
* valid available byte.
*/
protected int _inputEnd;
/**
* Decoded first character of a surrogate pair, if one needs to be buffered
*/
protected int _surrogate = -1;
/**
* Total read character count; used for error reporting purposes
*/
int _charCount = 0;
/**
* Total read byte count; used for error reporting purposes
*/
int _byteCount = 0;
/*
/**********************************************************************
/* Life-cycle
/**********************************************************************
*/
public UTF8Reader(InputStream in, boolean autoClose)
{
super((in == null) ? new Object() : in);
_inputSource = in;
_bufferHolder = _findBufferHolder();
byte[] buffer = _bufferHolder[0];
if (buffer == null) {
_bufferHolder[0] = buffer = new byte[DEFAULT_BUFFER_SIZE];
}
_inputBuffer = buffer;
_inputPtr = 0;
_inputEnd = 0;
_autoClose = autoClose;
}
public UTF8Reader(byte[] buf, int ptr, int len, boolean autoClose)
{
super(new Object());
_inputSource = null;
_inputBuffer = buf;
_inputPtr = ptr;
_inputEnd = ptr+len;
_autoClose = autoClose;
_bufferHolder = null;
}
private static byte[][] _findBufferHolder()
{
byte[][] bufs = null;
SoftReference ref = _bufferRecycler.get();
if (ref != null) {
bufs = ref.get();
}
if (bufs == null) {
bufs = new byte[1][];
_bufferRecycler.set(new SoftReference(bufs));
}
return bufs;
}
/*
/**********************************************************************
/* Reader API
/**********************************************************************
*/
@Override
public void close()
throws IOException
{
InputStream in = _inputSource;
if (in != null) {
_inputSource = null;
if (_autoClose) {
in.close();
}
}
freeBuffers();
}
private char[] _tmpBuffer = null;
/**
* Although this method is implemented by the base class, AND it should
* never be called by Woodstox code, let's still implement it bit more
* efficiently just in case
*/
@Override
public int read()
throws IOException
{
if (_tmpBuffer == null) {
_tmpBuffer = new char[1];
}
if (read(_tmpBuffer, 0, 1) < 1) {
return -1;
}
return _tmpBuffer[0];
}
@Override
public int read(char[] cbuf) throws IOException {
return read(cbuf, 0, cbuf.length);
}
@Override
public int read(char[] cbuf, int start, int len)
throws IOException
{
// Already EOF?
if (_inputBuffer == null) {
return -1;
}
len += start;
int outPtr = start;
// Ok, first; do we have a surrogate from last round?
if (_surrogate >= 0) {
cbuf[outPtr++] = (char) _surrogate;
_surrogate = -1;
// No need to load more, already got one char
} else {
/* To prevent unnecessary blocking (esp. with network streams),
* we'll only require decoding of a single char
*/
int left = (_inputEnd - _inputPtr);
/* So; only need to load more if we can't provide at least
* one more character. We need not do thorough check here,
* but let's check the common cases here: either completely
* empty buffer (left == 0), or one with less than max. byte
* count for a single char, and starting of a multi-byte
* encoding (this leaves possibility of a 2/3-byte char
* that is still fully accessible... but that can be checked
* by the load method)
*/
if (left < 4) {
// Need to load more?
if (left < 1 || _inputBuffer[_inputPtr] < 0) {
if (!loadMore(left)) { // (legal) EOF?
return -1;
}
}
}
}
final byte[] buf = _inputBuffer;
int inPtr = _inputPtr;
final int inBufLen = _inputEnd;
main_loop:
while (outPtr < len) {
// At this point we have at least one byte available
int c = (int) buf[inPtr++];
// Let's first do the quickie loop for common case; 7-bit ASCII
if (c >= 0) { // ASCII? can probably loop, then
cbuf[outPtr++] = (char) c; // ok since MSB is never on
// Ok, how many such chars could we safely process without overruns?
// (will combine 2 in-loop comparisons into just one)
int outMax = (len - outPtr); // max output
int inMax = (inBufLen - inPtr); // max input
int inEnd = inPtr + ((inMax < outMax) ? inMax : outMax);
ascii_loop:
while (true) {
if (inPtr >= inEnd) {
break main_loop;
}
c = buf[inPtr++];
if (c < 0) { // or multi-byte
break ascii_loop;
}
cbuf[outPtr++] = (char) c;
}
}
int needed;
// Ok; if we end here, we got multi-byte combination
if ((c & 0xE0) == 0xC0) { // 2 bytes (0x0080 - 0x07FF)
c = (c & 0x1F);
needed = 1;
} else if ((c & 0xF0) == 0xE0) { // 3 bytes (0x0800 - 0xFFFF)
c = (c & 0x0F);
needed = 2;
} else if ((c & 0xF8) == 0xF0) {
// 4 bytes; double-char BS, with surrogates and all...
c = (c & 0x0F);
needed = 3;
} else {
reportInvalidInitial(c & 0xFF, outPtr-start);
// never gets here...
needed = 1;
}
/* Do we have enough bytes? If not, let's just push back the
* byte and leave, since we have already gotten at least one
* char decoded. This way we will only block (with read from
* input stream) when absolutely necessary.
*/
if ((inBufLen - inPtr) < needed) {
--inPtr;
break main_loop;
}
int d = (int) buf[inPtr++];
if ((d & 0xC0) != 0x080) {
reportInvalidOther(d & 0xFF, outPtr-start);
}
c = (c << 6) | (d & 0x3F);
if (needed > 1) { // needed == 1 means 2 bytes total
d = buf[inPtr++]; // 3rd byte
if ((d & 0xC0) != 0x080) {
reportInvalidOther(d & 0xFF, outPtr-start);
}
c = (c << 6) | (d & 0x3F);
if (needed > 2) { // 4 bytes? (need surrogates)
d = buf[inPtr++];
if ((d & 0xC0) != 0x080) {
reportInvalidOther(d & 0xFF, outPtr-start);
}
c = (c << 6) | (d & 0x3F);
/* Ugh. Need to mess with surrogates. Ok; let's inline them
* there, then, if there's room: if only room for one,
* need to save the surrogate for the rainy day...
*/
c -= 0x10000; // to normalize it starting with 0x0
cbuf[outPtr++] = (char) (0xD800 + (c >> 10));
// hmmh. can this ever be 0? (not legal, at least?)
c = (0xDC00 | (c & 0x03FF));
// Room for second part?
if (outPtr >= len) { // nope
_surrogate = c;
break main_loop;
}
// sure, let's fall back to normal processing:
}
// Otherwise, should we check that 3-byte chars are
// legal ones (should not expand to surrogates?
// For now, let's not...
/*
else {
if (c >= 0xD800 && c < 0xE000) {
reportInvalid(c, outPtr-start, "(a surrogate character) ");
}
}
*/
}
cbuf[outPtr++] = (char) c;
if (inPtr >= inBufLen) {
break main_loop;
}
}
_inputPtr = inPtr;
len = outPtr - start;
_charCount += len;
return len;
}
/*
/**********************************************************************
/* Internal/package methods:
/**********************************************************************
*/
protected final InputStream getStream() { return _inputSource; }
/**
* Method for reading as many bytes from the underlying stream as possible
* (that fit in the buffer), to the beginning of the buffer.
*
* @return Number of bytes read, if any; -1 for end-of-input.
*/
protected final int readBytes()
throws IOException
{
_inputPtr = 0;
_inputEnd = 0;
if (_inputSource != null) {
int count = _inputSource.read(_inputBuffer, 0, _inputBuffer.length);
if (count > 0) {
_inputEnd = count;
}
return count;
}
return -1;
}
/**
* Method for reading as many bytes from the underlying stream as possible
* (that fit in the buffer considering offset), to the specified offset.
*
* @return Number of bytes read, if any; -1 to indicate none available
* (that is, end of input)
*/
protected final int readBytesAt(int offset)
throws IOException
{
// shouldn't modify mBytePtr, assumed to be 'offset'
if (_inputSource != null) {
int count = _inputSource.read(_inputBuffer, offset, _inputBuffer.length - offset);
if (count > 0) {
_inputEnd += count;
}
return count;
}
return -1;
}
/**
* This method should be called along with (or instead of) normal
* close. After calling this method, no further reads should be tried.
* Method will try to recycle read buffers (if any).
*/
public final void freeBuffers()
{
if (_bufferHolder != null) {
byte[] buf = _inputBuffer;
if (buf != null) {
_inputBuffer = null;
_bufferHolder[0] = buf;
}
}
}
/*
/**********************************************************************
/* Internal methods
/**********************************************************************
*/
private void reportInvalidInitial(int mask, int offset)
throws IOException
{
// input (byte) ptr has been advanced by one, by now:
int bytePos = _byteCount + _inputPtr - 1;
int charPos = _charCount + offset + 1;
throw new CharConversionException("Invalid UTF-8 start byte 0x"+Integer.toHexString(mask)
+" (at char #"+charPos+", byte #"+bytePos+")");
}
private void reportInvalidOther(int mask, int offset)
throws IOException
{
int bytePos = _byteCount + _inputPtr - 1;
int charPos = _charCount + offset;
throw new CharConversionException("Invalid UTF-8 middle byte 0x"+Integer.toHexString(mask)
+" (at char #"+charPos+", byte #"+bytePos+")");
}
private void reportUnexpectedEOF(int gotBytes, int needed)
throws IOException
{
int bytePos = _byteCount + gotBytes;
int charPos = _charCount;
throw new CharConversionException("Unexpected EOF in the middle of a multi-byte char: got "
+gotBytes+", needed "+needed +", at char #"+charPos+", byte #"+bytePos+")");
}
/*
private void reportInvalid(int value, int offset, String msg) throws IOException
{
int bytePos = _byteCount + _inputPtr - 1;
int charPos = _charCount + offset;
throw new CharConversionException("Invalid UTF-8 character 0x"+Integer.toHexString(value)+msg
+" at char #"+charPos+", byte #"+bytePos+")");
}
*/
/**
* @param available Number of "unused" bytes in the input buffer
*
* @return True, if enough bytes were read to allow decoding of at least
* one full character; false if EOF was encountered instead.
*/
private boolean loadMore(int available)
throws IOException
{
_byteCount += (_inputEnd - available);
// Bytes that need to be moved to the beginning of buffer?
if (available > 0) {
if (_inputPtr > 0) {
// sanity check: can only move if we "own" buffers
if (_bufferHolder == null) {
throw new IllegalStateException("Internal error: need to move partially decoded character; buffer not modifiable");
}
for (int i = 0; i < available; ++i) {
_inputBuffer[i] = _inputBuffer[_inputPtr+i];
}
_inputPtr = 0;
_inputEnd = available;
}
} else {
/* Ok; here we can actually reasonably expect an EOF,
* so let's do a separate read right away:
*/
int count = readBytes();
if (count < 1) {
freeBuffers(); // to help GC?
if (count < 0) { // -1
return false;
}
// 0 count is no good; let's err out
reportStrangeStream();
}
}
/* We now have at least one byte... and that allows us to
* calculate exactly how many bytes we need!
*/
@SuppressWarnings("cast")
int c = (int) _inputBuffer[_inputPtr];
if (c >= 0) { // single byte (ascii) char... cool, can return
return true;
}
// Ok, a multi-byte char, let's check how many bytes we'll need:
int needed;
if ((c & 0xE0) == 0xC0) { // 2 bytes (0x0080 - 0x07FF)
needed = 2;
} else if ((c & 0xF0) == 0xE0) { // 3 bytes (0x0800 - 0xFFFF)
needed = 3;
} else if ((c & 0xF8) == 0xF0) {
// 4 bytes; double-char BS, with surrogates and all...
needed = 4;
} else {
reportInvalidInitial(c & 0xFF, 0);
// never gets here... but compiler whines without this:
needed = 1;
}
/* And then we'll just need to load up to that many bytes;
* if an EOF is hit, that'll be an error. But we need not do
* actual decoding here, just load enough bytes.
*/
while ((_inputPtr + needed) > _inputEnd) {
int count = readBytesAt(_inputEnd);
if (count < 1) {
if (count < 0) { // -1, EOF... no good!
freeBuffers();
reportUnexpectedEOF(_inputEnd, needed);
}
// 0 count is no good; let's err out
reportStrangeStream();
}
}
return true;
}
protected void reportBounds(char[] cbuf, int start, int len) throws IOException {
throw new ArrayIndexOutOfBoundsException("read(buf,"+start+","+len+"), cbuf["+cbuf.length+"]");
}
protected void reportStrangeStream() throws IOException {
throw new IOException("Strange I/O stream, returned 0 bytes on read");
}
}
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