Jackson Core Source Code

Jackson is "the Java JSON library" or "the best JSON parser for Java". Or simply as "JSON for Java".

Jackson Core Source Code files are provided in the source packge (jackson-core-2.12.4-sources.jar). You can download it at Jackson Maven Website.

You can also browse Jackson Core Source Code below:

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com/fasterxml/jackson/core/json/UTF8JsonGenerator.java

package com.fasterxml.jackson.core.json;

import java.io.*;
import java.math.BigDecimal;
import java.math.BigInteger;

import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.core.io.CharTypes;
import com.fasterxml.jackson.core.io.CharacterEscapes;
import com.fasterxml.jackson.core.io.IOContext;
import com.fasterxml.jackson.core.io.NumberOutput;

public class UTF8JsonGenerator
    extends JsonGeneratorImpl
{
    private final static byte BYTE_u = (byte) 'u';

    private final static byte BYTE_0 = (byte) '0';

    private final static byte BYTE_LBRACKET = (byte) '[';
    private final static byte BYTE_RBRACKET = (byte) ']';
    private final static byte BYTE_LCURLY = (byte) '{';
    private final static byte BYTE_RCURLY = (byte) '}';

    private final static byte BYTE_BACKSLASH = (byte) '\\';
    private final static byte BYTE_COMMA = (byte) ',';
    private final static byte BYTE_COLON = (byte) ':';

    // intermediate copies only made up to certain length...
    private final static int MAX_BYTES_TO_BUFFER = 512;

    private final static byte[] HEX_CHARS = CharTypes.copyHexBytes();

    private final static byte[] NULL_BYTES = { 'n', 'u', 'l', 'l' };
    private final static byte[] TRUE_BYTES = { 't', 'r', 'u', 'e' };
    private final static byte[] FALSE_BYTES = { 'f', 'a', 'l', 's', 'e' };

    /*
    /**********************************************************
    /* Configuration
    /**********************************************************
     */

    /**
     * Underlying output stream used for writing JSON content.
     */
    final protected OutputStream _outputStream;

    /**
     * Character used for quoting JSON Object property names
     * and String values.
     *
     * @since 2.8
     */
    protected byte _quoteChar;

    /*
    /**********************************************************
    /* Output buffering
    /**********************************************************
     */

    /**
     * Intermediate buffer in which contents are buffered before
     * being written using {@link #_outputStream}.
     */
    protected byte[] _outputBuffer;

    /**
     * Pointer to the position right beyond the last character to output
     * (end marker; may be past the buffer)
     */
    protected int _outputTail;

    /**
     * End marker of the output buffer; one past the last valid position
     * within the buffer.
     */
    protected final int _outputEnd;

    /**
     * Maximum number of <code>char</code>s that we know will always fit
     * in the output buffer after escaping
     */
    protected final int _outputMaxContiguous;

    /**
     * Intermediate buffer in which characters of a String are copied
     * before being encoded.
     */
    protected char[] _charBuffer;

    /**
     * Length of <code>_charBuffer</code>
     */
    protected final int _charBufferLength;

    /**
     * 6 character temporary buffer allocated if needed, for constructing
     * escape sequences
     */
    protected byte[] _entityBuffer;

    /**
     * Flag that indicates whether the output buffer is recycable (and
     * needs to be returned to recycler once we are done) or not.
     */
    protected boolean _bufferRecyclable;

    /*
    /**********************************************************
    /* Life-cycle
    /**********************************************************
     */

    /**
     * @since 2.10
     */
    @SuppressWarnings("deprecation")
    public UTF8JsonGenerator(IOContext ctxt, int features, ObjectCodec codec,
            OutputStream out, char quoteChar)
    {
        super(ctxt, features, codec);
        _outputStream = out;
        _quoteChar = (byte) quoteChar;
        if (quoteChar != '"') { // since 2.10
            _outputEscapes = CharTypes.get7BitOutputEscapes(quoteChar);
        }

        _bufferRecyclable = true;
        _outputBuffer = ctxt.allocWriteEncodingBuffer();
        _outputEnd = _outputBuffer.length;

        /* To be exact, each char can take up to 6 bytes when escaped (Unicode
         * escape with backslash, 'u' and 4 hex digits); but to avoid fluctuation,
         * we will actually round down to only do up to 1/8 number of chars
         */
        _outputMaxContiguous = _outputEnd >> 3;
        _charBuffer = ctxt.allocConcatBuffer();
        _charBufferLength = _charBuffer.length;

        // By default we use this feature to determine additional quoting
        if (isEnabled(Feature.ESCAPE_NON_ASCII)) {
            setHighestNonEscapedChar(127);
        }
    }

    /**
     * @since 2.10
     */
    public UTF8JsonGenerator(IOContext ctxt, int features, ObjectCodec codec,
            OutputStream out, char quoteChar,
            byte[] outputBuffer, int outputOffset, boolean bufferRecyclable)
    {
        
        super(ctxt, features, codec);
        _outputStream = out;
        _quoteChar = (byte) quoteChar;
        if (quoteChar != '"') { // since 2.10
            _outputEscapes = CharTypes.get7BitOutputEscapes(quoteChar);
        }

        _bufferRecyclable = bufferRecyclable;
        _outputTail = outputOffset;
        _outputBuffer = outputBuffer;
        _outputEnd = _outputBuffer.length;
        // up to 6 bytes per char (see above), rounded up to 1/8
        _outputMaxContiguous = (_outputEnd >> 3);
        _charBuffer = ctxt.allocConcatBuffer();
        _charBufferLength = _charBuffer.length;
    }

    @Deprecated // since 2.10
    public UTF8JsonGenerator(IOContext ctxt, int features, ObjectCodec codec,
            OutputStream out) {
        this(ctxt, features, codec, out, JsonFactory.DEFAULT_QUOTE_CHAR);
    }

    @Deprecated // since 2.10
    public UTF8JsonGenerator(IOContext ctxt, int features, ObjectCodec codec,
            OutputStream out,
            byte[] outputBuffer, int outputOffset, boolean bufferRecyclable)
    {
        this(ctxt, features, codec, out, JsonFactory.DEFAULT_QUOTE_CHAR,
                outputBuffer, outputOffset, bufferRecyclable);
    }

    /*
    /**********************************************************
    /* Overridden configuration methods
    /**********************************************************
     */

    @Override
    public Object getOutputTarget() {
        return _outputStream;
    }

    @Override
    public int getOutputBuffered() {
        // Assuming tail is always valid, set to 0 on close
        return _outputTail;
    }

    /*
    /**********************************************************
    /* Overridden methods
    /**********************************************************
     */

    @Override
    public void writeFieldName(String name)  throws IOException
    {
        if (_cfgPrettyPrinter != null) {
            _writePPFieldName(name);
            return;
        }
        final int status = _writeContext.writeFieldName(name);
        if (status == JsonWriteContext.STATUS_EXPECT_VALUE) {
            _reportError("Can not write a field name, expecting a value");
        }
        if (status == JsonWriteContext.STATUS_OK_AFTER_COMMA) { // need comma
            if (_outputTail >= _outputEnd) {
                _flushBuffer();
            }
            _outputBuffer[_outputTail++] = BYTE_COMMA;
        }
        /* To support [JACKSON-46], we'll do this:
         * (Question: should quoting of spaces (etc) still be enabled?)
         */
        if (_cfgUnqNames) {
            _writeStringSegments(name, false);
            return;
        }
        final int len = name.length();
        // Does it fit in buffer?
        if (len > _charBufferLength) { // no, offline
            _writeStringSegments(name, true);
            return;
        }
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        // But as one segment, or multiple?
        if (len <= _outputMaxContiguous) {
            if ((_outputTail + len) > _outputEnd) { // caller must ensure enough space
                _flushBuffer();
            }
            _writeStringSegment(name, 0, len);
        } else {
            _writeStringSegments(name, 0, len);
        }
        // and closing quotes; need room for one more char:
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
    }
    
    @Override
    public void writeFieldName(SerializableString name) throws IOException
    {
        if (_cfgPrettyPrinter != null) {
            _writePPFieldName(name);
            return;
        }
        final int status = _writeContext.writeFieldName(name.getValue());
        if (status == JsonWriteContext.STATUS_EXPECT_VALUE) {
            _reportError("Can not write a field name, expecting a value");
        }
        if (status == JsonWriteContext.STATUS_OK_AFTER_COMMA) {
            if (_outputTail >= _outputEnd) {
                _flushBuffer();
            }
            _outputBuffer[_outputTail++] = BYTE_COMMA;
        }
        if (_cfgUnqNames) {
            _writeUnq(name);
            return;
        }
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        int len = name.appendQuotedUTF8(_outputBuffer, _outputTail);
        if (len < 0) { // couldn't append, bit longer processing
            _writeBytes(name.asQuotedUTF8());
        } else {
            _outputTail += len;
        }
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
    }    

    private final void _writeUnq(SerializableString name) throws IOException {
        int len = name.appendQuotedUTF8(_outputBuffer, _outputTail);
        if (len < 0) {
            _writeBytes(name.asQuotedUTF8());
        } else {
            _outputTail += len;
        }
    }
    
    /*
    /**********************************************************
    /* Output method implementations, structural
    /**********************************************************
     */

    @Override
    public final void writeStartArray() throws IOException
    {
        _verifyValueWrite("start an array");
        _writeContext = _writeContext.createChildArrayContext();
        if (_cfgPrettyPrinter != null) {
            _cfgPrettyPrinter.writeStartArray(this);
        } else {
            if (_outputTail >= _outputEnd) {
                _flushBuffer();
            }
            _outputBuffer[_outputTail++] = BYTE_LBRACKET;
        }
    }

    @Override // since 2.12
    public final void writeStartArray(Object currentValue) throws IOException
    {
        _verifyValueWrite("start an array");
        _writeContext = _writeContext.createChildArrayContext(currentValue);
        if (_cfgPrettyPrinter != null) {
            _cfgPrettyPrinter.writeStartArray(this);
        } else {
            if (_outputTail >= _outputEnd) {
                _flushBuffer();
            }
            _outputBuffer[_outputTail++] = BYTE_LBRACKET;
        }
    }

    @Override // since 2.12
    public void writeStartArray(Object currentValue, int size) throws IOException
    {
        _verifyValueWrite("start an array");
        _writeContext = _writeContext.createChildArrayContext(currentValue);
        if (_cfgPrettyPrinter != null) {
            _cfgPrettyPrinter.writeStartArray(this);
        } else {
            if (_outputTail >= _outputEnd) {
                _flushBuffer();
            }
            _outputBuffer[_outputTail++] = BYTE_LBRACKET;
        }
    }

    @Override
    public final void writeEndArray() throws IOException
    {
        if (!_writeContext.inArray()) {
            _reportError("Current context not Array but "+_writeContext.typeDesc());
        }
        if (_cfgPrettyPrinter != null) {
            _cfgPrettyPrinter.writeEndArray(this, _writeContext.getEntryCount());
        } else {
            if (_outputTail >= _outputEnd) {
                _flushBuffer();
            }
            _outputBuffer[_outputTail++] = BYTE_RBRACKET;
        }
        _writeContext = _writeContext.clearAndGetParent();
    }

    @Override
    public final void writeStartObject() throws IOException
    {
        _verifyValueWrite("start an object");
        _writeContext = _writeContext.createChildObjectContext();
        if (_cfgPrettyPrinter != null) {
            _cfgPrettyPrinter.writeStartObject(this);
        } else {
            if (_outputTail >= _outputEnd) {
                _flushBuffer();
            }
            _outputBuffer[_outputTail++] = BYTE_LCURLY;
        }
    }

    @Override // since 2.8
    public void writeStartObject(Object forValue) throws IOException
    {
        _verifyValueWrite("start an object");
        JsonWriteContext ctxt = _writeContext.createChildObjectContext(forValue);
        _writeContext = ctxt;
        if (_cfgPrettyPrinter != null) {
            _cfgPrettyPrinter.writeStartObject(this);
        } else {
            if (_outputTail >= _outputEnd) {
                _flushBuffer();
            }
            _outputBuffer[_outputTail++] = '{';
        }
    }

    @Override
    public final void writeEndObject() throws IOException
    {
        if (!_writeContext.inObject()) {
            _reportError("Current context not Object but "+_writeContext.typeDesc());
        }
        if (_cfgPrettyPrinter != null) {
            _cfgPrettyPrinter.writeEndObject(this, _writeContext.getEntryCount());
        } else {
            if (_outputTail >= _outputEnd) {
                _flushBuffer();
            }
            _outputBuffer[_outputTail++] = BYTE_RCURLY;
        }
        _writeContext = _writeContext.clearAndGetParent();
    }

    /**
     * Specialized version of <code>_writeFieldName</code>, off-lined
     * to keep the "fast path" as simple (and hopefully fast) as possible.
     */
    protected final void _writePPFieldName(String name) throws IOException
    {
        int status = _writeContext.writeFieldName(name);
        if (status == JsonWriteContext.STATUS_EXPECT_VALUE) {
            _reportError("Can not write a field name, expecting a value");
        }
        if ((status == JsonWriteContext.STATUS_OK_AFTER_COMMA)) {
            _cfgPrettyPrinter.writeObjectEntrySeparator(this);
        } else {
            _cfgPrettyPrinter.beforeObjectEntries(this);
        }
        if (_cfgUnqNames) {
            _writeStringSegments(name, false);
            return;
        }
        final int len = name.length();
        if (len > _charBufferLength) {
            _writeStringSegments(name, true);
            return;
        }
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        name.getChars(0, len, _charBuffer, 0);
        // But as one segment, or multiple?
        if (len <= _outputMaxContiguous) {
            if ((_outputTail + len) > _outputEnd) { // caller must ensure enough space
                _flushBuffer();
            }
            _writeStringSegment(_charBuffer, 0, len);
        } else {
            _writeStringSegments(_charBuffer, 0, len);
        }
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
    }

    protected final void _writePPFieldName(SerializableString name) throws IOException
    {
        final int status = _writeContext.writeFieldName(name.getValue());
        if (status == JsonWriteContext.STATUS_EXPECT_VALUE) {
            _reportError("Can not write a field name, expecting a value");
        }
        if (status == JsonWriteContext.STATUS_OK_AFTER_COMMA) {
            _cfgPrettyPrinter.writeObjectEntrySeparator(this);
        } else {
            _cfgPrettyPrinter.beforeObjectEntries(this);
        }

        final boolean addQuotes = !_cfgUnqNames; // standard
        if (addQuotes) {
            if (_outputTail >= _outputEnd) {
                _flushBuffer();
            }
            _outputBuffer[_outputTail++] = _quoteChar;
        }
        int len = name.appendQuotedUTF8(_outputBuffer, _outputTail);
        if (len < 0) {
            _writeBytes(name.asQuotedUTF8());
        } else {
            _outputTail += len;
        }
        if (addQuotes) {
            if (_outputTail >= _outputEnd) {
                _flushBuffer();
            }
            _outputBuffer[_outputTail++] = _quoteChar;
        }
    }
    
    /*
    /**********************************************************
    /* Output method implementations, textual
    /**********************************************************
     */

    @Override
    public void writeString(String text) throws IOException
    {
        _verifyValueWrite(WRITE_STRING);
        if (text == null) {
            _writeNull();
            return;
        }
        // First: if we can't guarantee it all fits, quoted, within output, offline
        final int len = text.length();
        if (len > _outputMaxContiguous) { // nope: off-line handling
            _writeStringSegments(text, true);
            return;
        }
        if ((_outputTail + len) >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        _writeStringSegment(text, 0, len); // we checked space already above
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
    }

    @Override
    public void writeString(Reader reader, int len) throws IOException {
        _verifyValueWrite(WRITE_STRING);
        if (reader == null) {
            _reportError("null reader");
            return; // just to block warnings by lgtm.com
        }

        int toRead = (len >= 0) ? len : Integer.MAX_VALUE;
        final char[] buf = _charBuffer;

        // Add leading quote
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;

        // read
        while (toRead > 0){
            int toReadNow = Math.min(toRead, buf.length);
            int numRead = reader.read(buf, 0, toReadNow);
            if(numRead <= 0){
                break;
            }
            if ((_outputTail + len) >= _outputEnd) {
                _flushBuffer();
            }
            _writeStringSegments(buf, 0, numRead);
            //decrease tracker
            toRead -= numRead;
        }

        // Add trailing quote
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;

        if (toRead > 0 && len >= 0){
            _reportError("Didn't read enough from reader");
        }
    }

    @Override
    public void writeString(char[] text, int offset, int len) throws IOException
    {
        _verifyValueWrite(WRITE_STRING);
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        // One or multiple segments?
        if (len <= _outputMaxContiguous) {
            if ((_outputTail + len) > _outputEnd) { // caller must ensure enough space
                _flushBuffer();
            }
            _writeStringSegment(text, offset, len);
        } else {
            _writeStringSegments(text, offset, len);
        }
        // And finally, closing quotes
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
    }

    @Override
    public final void writeString(SerializableString text) throws IOException
    {
        _verifyValueWrite(WRITE_STRING);
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        int len = text.appendQuotedUTF8(_outputBuffer, _outputTail);
        if (len < 0) {
            _writeBytes(text.asQuotedUTF8());
        } else {
            _outputTail += len;
        }
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
    }
    
    @Override
    public void writeRawUTF8String(byte[] text, int offset, int length) throws IOException
    {
        _verifyValueWrite(WRITE_STRING);
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        _writeBytes(text, offset, length);
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
    }

    @Override
    public void writeUTF8String(byte[] text, int offset, int len) throws IOException
    {
        _verifyValueWrite(WRITE_STRING);
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        // One or multiple segments?
        if (len <= _outputMaxContiguous) {
            _writeUTF8Segment(text, offset, len);
        } else {
            _writeUTF8Segments(text, offset, len);
        }
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
    }

    /*
    /**********************************************************
    /* Output method implementations, unprocessed ("raw")
    /**********************************************************
     */

    @Override
    public void writeRaw(String text) throws IOException {
        final int len = text.length();
        final char[] buf = _charBuffer;
        if (len <= buf.length) {
            text.getChars(0, len, buf, 0);
            writeRaw(buf, 0, len);
        } else {
            writeRaw(text, 0, len);
        }
    }

    @Override
    public void writeRaw(String text, int offset, int len) throws IOException
    {
        final char[] buf = _charBuffer;
        final int cbufLen = buf.length;

        // minor optimization: see if we can just get and copy
        if (len <= cbufLen) {
            text.getChars(offset, offset+len, buf, 0);
            writeRaw(buf, 0, len);
            return;
        }

        // If not, need segmented approach. For speed, let's also use input buffer
        // size that is guaranteed to fit in output buffer; each char can expand to
        // at most 3 bytes, so at most 1/3 of buffer size.
        final int maxChunk = Math.min(cbufLen,
                (_outputEnd >> 2) + (_outputEnd >> 4)); // == (1/4 + 1/16) == 5/16
        final int maxBytes = maxChunk * 3;

        while (len > 0) {
            int len2 = Math.min(maxChunk, len);
            text.getChars(offset, offset+len2, buf, 0);
            if ((_outputTail + maxBytes) > _outputEnd) {
                _flushBuffer();
            }
            // If this is NOT the last segment and if the last character looks like
            // split surrogate second half, drop it
            // 21-Mar-2017, tatu: Note that we could check for either `len` or `len2`;
            //    point here is really that we only "punt" surrogate if it is NOT the
            //    only character left; otherwise we'd end up with a poison pill if the
            //    very last character was unpaired first-surrogate
            if (len2 > 1) {
                char ch = buf[len2-1];
                if ((ch >= SURR1_FIRST) && (ch <= SURR1_LAST)) {
                    --len2;
                }
            }
            _writeRawSegment(buf, 0, len2);
            offset += len2;
            len -= len2;
        }
    }

    @Override
    public void writeRaw(SerializableString text) throws IOException
    {
        int len = text.appendUnquotedUTF8(_outputBuffer, _outputTail);
        if (len < 0) {
            _writeBytes(text.asUnquotedUTF8());
        } else {
            _outputTail += len;
        }
    }

    // since 2.5
    @Override
    public void writeRawValue(SerializableString text) throws IOException {
        _verifyValueWrite(WRITE_RAW);
        int len = text.appendUnquotedUTF8(_outputBuffer, _outputTail);
        if (len < 0) {
            _writeBytes(text.asUnquotedUTF8());
        } else {
            _outputTail += len;
        }
    }

    // @TODO: rewrite for speed...
    @Override
    public final void writeRaw(char[] cbuf, int offset, int len) throws IOException
    {
        // First: if we have 3 x charCount spaces, we know it'll fit just fine
        {
            int len3 = len+len+len;
            if ((_outputTail + len3) > _outputEnd) {
                // maybe we could flush?
                if (_outputEnd < len3) { // wouldn't be enough...
                    _writeSegmentedRaw(cbuf, offset, len);
                    return;
                }
                // yes, flushing brings enough space
                _flushBuffer();
            }
        }
        len += offset; // now marks the end

        // Note: here we know there is enough room, hence no output boundary checks
        main_loop:
        while (offset < len) {
            inner_loop:
            while (true) {
                int ch = (int) cbuf[offset];
                if (ch > 0x7F) {
                    break inner_loop;
                }
                _outputBuffer[_outputTail++] = (byte) ch;
                if (++offset >= len) {
                    break main_loop;
                }
            }
            char ch = cbuf[offset++];
            if (ch < 0x800) { // 2-byte?
                _outputBuffer[_outputTail++] = (byte) (0xc0 | (ch >> 6));
                _outputBuffer[_outputTail++] = (byte) (0x80 | (ch & 0x3f));
            } else {
                offset = _outputRawMultiByteChar(ch, cbuf, offset, len);
            }
        }
    }

    @Override
    public void writeRaw(char ch) throws IOException
    {
        if ((_outputTail + 3) >= _outputEnd) {
            _flushBuffer();
        }
        final byte[] bbuf = _outputBuffer;
        if (ch <= 0x7F) {
            bbuf[_outputTail++] = (byte) ch;
        } else  if (ch < 0x800) { // 2-byte?
            bbuf[_outputTail++] = (byte) (0xc0 | (ch >> 6));
            bbuf[_outputTail++] = (byte) (0x80 | (ch & 0x3f));
        } else {
            /*offset =*/ _outputRawMultiByteChar(ch, null, 0, 0);
        }
    }

    /**
     * Helper method called when it is possible that output of raw section
     * to output may cross buffer boundary
     */
    private final void _writeSegmentedRaw(char[] cbuf, int offset, int len) throws IOException
    {
        final int end = _outputEnd;
        final byte[] bbuf = _outputBuffer;
        final int inputEnd = offset + len;
        
        main_loop:
        while (offset < inputEnd) {
            inner_loop:
            while (true) {
                int ch = (int) cbuf[offset];
                if (ch >= 0x80) {
                    break inner_loop;
                }
                // !!! TODO: fast(er) writes (roll input, output checks in one)
                if (_outputTail >= end) {
                    _flushBuffer();
                }
                bbuf[_outputTail++] = (byte) ch;
                if (++offset >= inputEnd) {
                    break main_loop;
                }
            }
            if ((_outputTail + 3) >= _outputEnd) {
                _flushBuffer();
            }
            char ch = cbuf[offset++];
            if (ch < 0x800) { // 2-byte?
                bbuf[_outputTail++] = (byte) (0xc0 | (ch >> 6));
                bbuf[_outputTail++] = (byte) (0x80 | (ch & 0x3f));
            } else {
                offset = _outputRawMultiByteChar(ch, cbuf, offset, inputEnd);
            }
        }
    }

    /**
     * Helper method that is called for segmented write of raw content
     * when explicitly outputting a segment of longer thing.
     * Caller has to take care of ensuring there's no split surrogate
     * pair at the end (that is, last char can not be first part of a
     * surrogate char pair).
     *
     * @since 2.8.2
     */
    private void _writeRawSegment(char[] cbuf, int offset, int end) throws IOException
    {
        main_loop:
        while (offset < end) {
            inner_loop:
            while (true) {
                int ch = (int) cbuf[offset];
                if (ch > 0x7F) {
                    break inner_loop;
                }
                _outputBuffer[_outputTail++] = (byte) ch;
                if (++offset >= end) {
                    break main_loop;
                }
            }
            char ch = cbuf[offset++];
            if (ch < 0x800) { // 2-byte?
                _outputBuffer[_outputTail++] = (byte) (0xc0 | (ch >> 6));
                _outputBuffer[_outputTail++] = (byte) (0x80 | (ch & 0x3f));
            } else {
                offset = _outputRawMultiByteChar(ch, cbuf, offset, end);
            }
        }
    }

    /*
    /**********************************************************
    /* Output method implementations, base64-encoded binary
    /**********************************************************
     */

    @Override
    public void writeBinary(Base64Variant b64variant,
            byte[] data, int offset, int len)
        throws IOException, JsonGenerationException
    {
        _verifyValueWrite(WRITE_BINARY);
        // Starting quotes
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        _writeBinary(b64variant, data, offset, offset+len);
        // and closing quotes
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
    }

    @Override
    public int writeBinary(Base64Variant b64variant,
            InputStream data, int dataLength)
        throws IOException, JsonGenerationException
    {
        _verifyValueWrite(WRITE_BINARY);
        // Starting quotes
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        byte[] encodingBuffer = _ioContext.allocBase64Buffer();
        int bytes;
        try {
            if (dataLength < 0) { // length unknown
                bytes = _writeBinary(b64variant, data, encodingBuffer);
            } else {
                int missing = _writeBinary(b64variant, data, encodingBuffer, dataLength);
                if (missing > 0) {
                    _reportError("Too few bytes available: missing "+missing+" bytes (out of "+dataLength+")");
                }
                bytes = dataLength;
            }
        } finally {
            _ioContext.releaseBase64Buffer(encodingBuffer);
        }
        // and closing quotes
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        return bytes;
    }
    
    /*
    /**********************************************************
    /* Output method implementations, primitive
    /**********************************************************
     */

    @Override
    public void writeNumber(short s) throws IOException
    {
        _verifyValueWrite(WRITE_NUMBER);
        // up to 5 digits and possible minus sign
        if ((_outputTail + 6) >= _outputEnd) {
            _flushBuffer();
        }
        if (_cfgNumbersAsStrings) {
            _writeQuotedShort(s);
            return;
        }
        _outputTail = NumberOutput.outputInt(s, _outputBuffer, _outputTail);
    }
    
    private final void _writeQuotedShort(short s) throws IOException {
        if ((_outputTail + 8) >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        _outputTail = NumberOutput.outputInt(s, _outputBuffer, _outputTail);
        _outputBuffer[_outputTail++] = _quoteChar;
    } 
    
    @Override
    public void writeNumber(int i) throws IOException
    {
        _verifyValueWrite(WRITE_NUMBER);
        // up to 10 digits and possible minus sign
        if ((_outputTail + 11) >= _outputEnd) {
            _flushBuffer();
        }
        if (_cfgNumbersAsStrings) {
            _writeQuotedInt(i);
            return;
        }
        _outputTail = NumberOutput.outputInt(i, _outputBuffer, _outputTail);
    }

    private final void _writeQuotedInt(int i) throws IOException
    {
        if ((_outputTail + 13) >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        _outputTail = NumberOutput.outputInt(i, _outputBuffer, _outputTail);
        _outputBuffer[_outputTail++] = _quoteChar;
    }    

    @Override
    public void writeNumber(long l) throws IOException
    {
        _verifyValueWrite(WRITE_NUMBER);
        if (_cfgNumbersAsStrings) {
            _writeQuotedLong(l);
            return;
        }
        if ((_outputTail + 21) >= _outputEnd) {
            // up to 20 digits, minus sign
            _flushBuffer();
        }
        _outputTail = NumberOutput.outputLong(l, _outputBuffer, _outputTail);
    }

    private final void _writeQuotedLong(long l) throws IOException
    {
        if ((_outputTail + 23) >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        _outputTail = NumberOutput.outputLong(l, _outputBuffer, _outputTail);
        _outputBuffer[_outputTail++] = _quoteChar;
    }

    @Override
    public void writeNumber(BigInteger value) throws IOException
    {
        _verifyValueWrite(WRITE_NUMBER);
        if (value == null) {
            _writeNull();
        } else if (_cfgNumbersAsStrings) {
            _writeQuotedRaw(value.toString());
        } else {
            writeRaw(value.toString());
        }
    }

    @SuppressWarnings("deprecation")
    @Override
    public void writeNumber(double d) throws IOException
    {
        if (_cfgNumbersAsStrings ||
            (NumberOutput.notFinite(d)
                && Feature.QUOTE_NON_NUMERIC_NUMBERS.enabledIn(_features))) {
            writeString(String.valueOf(d));
            return;
        }
        // What is the max length for doubles? 40 chars?
        _verifyValueWrite(WRITE_NUMBER);
        writeRaw(String.valueOf(d));
    }

    @SuppressWarnings("deprecation")
    @Override
    public void writeNumber(float f) throws IOException
    {
        if (_cfgNumbersAsStrings ||
            (NumberOutput.notFinite(f)
                && Feature.QUOTE_NON_NUMERIC_NUMBERS.enabledIn(_features))) {
            writeString(String.valueOf(f));
            return;
        }
        // What is the max length for floats?
        _verifyValueWrite(WRITE_NUMBER);
        writeRaw(String.valueOf(f));
    }

    @Override
    public void writeNumber(BigDecimal value) throws IOException
    {
        // Don't really know max length for big decimal, no point checking
        _verifyValueWrite(WRITE_NUMBER);
        if (value == null) {
            _writeNull();
        } else  if (_cfgNumbersAsStrings) {
            _writeQuotedRaw(_asString(value));
        } else {
            writeRaw(_asString(value));
        }
    }

    @Override
    public void writeNumber(String encodedValue) throws IOException
    {
        _verifyValueWrite(WRITE_NUMBER);
        if (encodedValue == null) {
            _writeNull();
        } else if (_cfgNumbersAsStrings) {
            _writeQuotedRaw(encodedValue);            
        } else {
            writeRaw(encodedValue);
        }
    }

    @Override
    public void writeNumber(char[] encodedValueBuffer, int offset, int length) throws IOException {
        _verifyValueWrite(WRITE_NUMBER);
        if (_cfgNumbersAsStrings) {
            _writeQuotedRaw(encodedValueBuffer, offset, length);
        } else {
            writeRaw(encodedValueBuffer, offset, length);
        }
    }

    private final void _writeQuotedRaw(String value) throws IOException
    {
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        writeRaw(value);
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
    }

    private void _writeQuotedRaw(char[] text, int offset, int length) throws IOException
    {
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
        writeRaw(text, offset, length);
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = _quoteChar;
    }

    @Override
    public void writeBoolean(boolean state) throws IOException
    {
        _verifyValueWrite(WRITE_BOOLEAN);
        if ((_outputTail + 5) >= _outputEnd) {
            _flushBuffer();
        }
        byte[] keyword = state ? TRUE_BYTES : FALSE_BYTES;
        int len = keyword.length;
        System.arraycopy(keyword, 0, _outputBuffer, _outputTail, len);
        _outputTail += len;
    }

    @Override
    public void writeNull() throws IOException
    {
        _verifyValueWrite(WRITE_NULL);
        _writeNull();
    }

    /*
    /**********************************************************
    /* Implementations for other methods
    /**********************************************************
     */

    @Override
    protected final void _verifyValueWrite(String typeMsg) throws IOException
    {
        final int status = _writeContext.writeValue();
        if (_cfgPrettyPrinter != null) {
            // Otherwise, pretty printer knows what to do...
            _verifyPrettyValueWrite(typeMsg, status);
            return;
        }
        byte b;
        switch (status) {
        case JsonWriteContext.STATUS_OK_AS_IS:
        default:
            return;
        case JsonWriteContext.STATUS_OK_AFTER_COMMA:
            b = BYTE_COMMA;
            break;
        case JsonWriteContext.STATUS_OK_AFTER_COLON:
            b = BYTE_COLON;
            break;
        case JsonWriteContext.STATUS_OK_AFTER_SPACE: // root-value separator
            if (_rootValueSeparator != null) {
                byte[] raw = _rootValueSeparator.asUnquotedUTF8();
                if (raw.length > 0) {
                    _writeBytes(raw);
                }
            }
            return;
        case JsonWriteContext.STATUS_EXPECT_NAME:
            _reportCantWriteValueExpectName(typeMsg);
            return;
        }
        if (_outputTail >= _outputEnd) {
            _flushBuffer();
        }
        _outputBuffer[_outputTail++] = b;
    }

    /*
    /**********************************************************
    /* Low-level output handling
    /**********************************************************
     */

    @Override
    public void flush() throws IOException
    {
        _flushBuffer();
        if (_outputStream != null) {
            if (isEnabled(Feature.FLUSH_PASSED_TO_STREAM)) {
                _outputStream.flush();
            }
        }
    }

    @Override
    public void close() throws IOException
    {
        super.close();

        /* 05-Dec-2008, tatu: To add [JACKSON-27], need to close open
         *   scopes.
         */
        // First: let's see that we still have buffers...
        if ((_outputBuffer != null)
            && isEnabled(Feature.AUTO_CLOSE_JSON_CONTENT)) {
            while (true) {
                JsonStreamContext ctxt = getOutputContext();
                if (ctxt.inArray()) {
                    writeEndArray();
                } else if (ctxt.inObject()) {
                    writeEndObject();
                } else {
                    break;
                }
            }
        }
        _flushBuffer();
        _outputTail = 0; // just to ensure we don't think there's anything buffered

        /* 25-Nov-2008, tatus: As per [JACKSON-16] we are not to call close()
         *   on the underlying Reader, unless we "own" it, or auto-closing
         *   feature is enabled.
         *   One downside: when using UTF8Writer, underlying buffer(s)
         *   may not be properly recycled if we don't close the writer.
         */
        if (_outputStream != null) {
            if (_ioContext.isResourceManaged() || isEnabled(Feature.AUTO_CLOSE_TARGET)) {
                _outputStream.close();
            } else if (isEnabled(Feature.FLUSH_PASSED_TO_STREAM)) {
                // If we can't close it, we should at least flush
                _outputStream.flush();
            }
        }
        // Internal buffer(s) generator has can now be released as well
        _releaseBuffers();
    }

    @Override
    protected void _releaseBuffers()
    {
        byte[] buf = _outputBuffer;
        if (buf != null && _bufferRecyclable) {
            _outputBuffer = null;
            _ioContext.releaseWriteEncodingBuffer(buf);
        }
        char[] cbuf = _charBuffer;
        if (cbuf != null) {
            _charBuffer = null;
            _ioContext.releaseConcatBuffer(cbuf);
        }
    }

    /*
    /**********************************************************
    /* Internal methods, low-level writing, raw bytes
    /**********************************************************
     */

    private final void _writeBytes(byte[] bytes) throws IOException
    {
        final int len = bytes.length;
        if ((_outputTail + len) > _outputEnd) {
            _flushBuffer();
            // still not enough?
            if (len > MAX_BYTES_TO_BUFFER) {
                _outputStream.write(bytes, 0, len);
                return;
            }
        }
        System.arraycopy(bytes, 0, _outputBuffer, _outputTail, len);
        _outputTail += len;
    }

    private final void _writeBytes(byte[] bytes, int offset, int len) throws IOException
    {
        if ((_outputTail + len) > _outputEnd) {
            _flushBuffer();
            // still not enough?
            if (len > MAX_BYTES_TO_BUFFER) {
                _outputStream.write(bytes, offset, len);
                return;
            }
        }
        System.arraycopy(bytes, offset, _outputBuffer, _outputTail, len);
        _outputTail += len;
    }

    /*
    /**********************************************************
    /* Internal methods, mid-level writing, String segments
    /**********************************************************
     */
    
    /**
     * Method called when String to write is long enough not to fit
     * completely in temporary copy buffer. If so, we will actually
     * copy it in small enough chunks so it can be directly fed
     * to single-segment writes (instead of maximum slices that
     * would fit in copy buffer)
     */
    private final void _writeStringSegments(String text, boolean addQuotes) throws IOException
    {
        if (addQuotes) {
            if (_outputTail >= _outputEnd) {
                _flushBuffer();
            }
            _outputBuffer[_outputTail++] = _quoteChar;        
        }

        int left = text.length();
        int offset = 0;

        while (left > 0) {
            int len = Math.min(_outputMaxContiguous, left);
            if ((_outputTail + len) > _outputEnd) { // caller must ensure enough space
                _flushBuffer();
            }
            _writeStringSegment(text, offset, len);
            offset += len;
            left -= len;
        }

        if (addQuotes) {
            if (_outputTail >= _outputEnd) {
                _flushBuffer();
            }
            _outputBuffer[_outputTail++] = _quoteChar;
        }
    }

    /**
     * Method called when character sequence to write is long enough that
     * its maximum encoded and escaped form is not guaranteed to fit in
     * the output buffer. If so, we will need to choose smaller output
     * chunks to write at a time.
     */
    private final void _writeStringSegments(char[] cbuf, int offset, int totalLen) throws IOException
    {
        do {
            int len = Math.min(_outputMaxContiguous, totalLen);
            if ((_outputTail + len) > _outputEnd) { // caller must ensure enough space
                _flushBuffer();
            }
            _writeStringSegment(cbuf, offset, len);
            offset += len;
            totalLen -= len;
        } while (totalLen > 0);
    }

    private final void _writeStringSegments(String text, int offset, int totalLen) throws IOException
    {
        do {
            int len = Math.min(_outputMaxContiguous, totalLen);
            if ((_outputTail + len) > _outputEnd) { // caller must ensure enough space
                _flushBuffer();
            }
            _writeStringSegment(text, offset, len);
            offset += len;
            totalLen -= len;
        } while (totalLen > 0);
    }

    /*
    /**********************************************************
    /* Internal methods, low-level writing, text segments
    /**********************************************************
     */

    /**
     * This method called when the string content is already in
     * a char buffer, and its maximum total encoded and escaped length
     * can not exceed size of the output buffer.
     * Caller must ensure that there is enough space in output buffer,
     * assuming case of all non-escaped ASCII characters, as well as
     * potentially enough space for other cases (but not necessarily flushed)
     */
    private final void _writeStringSegment(char[] cbuf, int offset, int len)
        throws IOException
    {
        // note: caller MUST ensure (via flushing) there's room for ASCII only
        
        // Fast+tight loop for ASCII-only, no-escaping-needed output
        len += offset; // becomes end marker, then

        int outputPtr = _outputTail;
        final byte[] outputBuffer = _outputBuffer;
        final int[] escCodes = _outputEscapes;

        while (offset < len) {
            int ch = cbuf[offset];
            // note: here we know that (ch > 0x7F) will cover case of escaping non-ASCII too:
            if (ch > 0x7F || escCodes[ch] != 0) {
                break;
            }
            outputBuffer[outputPtr++] = (byte) ch;
            ++offset;
        }
        _outputTail = outputPtr;
        if (offset < len) {
            if (_characterEscapes != null) {
                _writeCustomStringSegment2(cbuf, offset, len);
            } else if (_maximumNonEscapedChar == 0) {
                _writeStringSegment2(cbuf, offset, len);
            } else {
                _writeStringSegmentASCII2(cbuf, offset, len);
            }

        }
    }

    private final void _writeStringSegment(String text, int offset, int len) throws IOException
    {
        // note: caller MUST ensure (via flushing) there's room for ASCII only
        // Fast+tight loop for ASCII-only, no-escaping-needed output
        len += offset; // becomes end marker, then

        int outputPtr = _outputTail;
        final byte[] outputBuffer = _outputBuffer;
        final int[] escCodes = _outputEscapes;

        while (offset < len) {
            int ch = text.charAt(offset);
            // note: here we know that (ch > 0x7F) will cover case of escaping non-ASCII too:
            if (ch > 0x7F || escCodes[ch] != 0) {
                break;
            }
            outputBuffer[outputPtr++] = (byte) ch;
            ++offset;
        }
        _outputTail = outputPtr;
        if (offset < len) {
            if (_characterEscapes != null) {
                _writeCustomStringSegment2(text, offset, len);
            } else if (_maximumNonEscapedChar == 0) {
                _writeStringSegment2(text, offset, len);
            } else {
                _writeStringSegmentASCII2(text, offset, len);
            }
        }
    }

    /**
     * Secondary method called when content contains characters to escape,
     * and/or multi-byte UTF-8 characters.
     */
    private final void _writeStringSegment2(final char[] cbuf, int offset, final int end) throws IOException
    {
        // Ok: caller guarantees buffer can have room; but that may require flushing:
        if ((_outputTail +  6 * (end - offset)) > _outputEnd) {
            _flushBuffer();
        }

        int outputPtr = _outputTail;

        final byte[] outputBuffer = _outputBuffer;
        final int[] escCodes = _outputEscapes;
        
        while (offset < end) {
            int ch = cbuf[offset++];
            if (ch <= 0x7F) {
                 if (escCodes[ch] == 0) {
                     outputBuffer[outputPtr++] = (byte) ch;
                     continue;
                 }
                 int escape = escCodes[ch];
                 if (escape > 0) { // 2-char escape, fine
                     outputBuffer[outputPtr++] = BYTE_BACKSLASH;
                     outputBuffer[outputPtr++] = (byte) escape;
                 } else {
                     // ctrl-char, 6-byte escape...
                     outputPtr = _writeGenericEscape(ch, outputPtr);
                }
                continue;
            }
            if (ch <= 0x7FF) { // fine, just needs 2 byte output
                outputBuffer[outputPtr++] = (byte) (0xc0 | (ch >> 6));
                outputBuffer[outputPtr++] = (byte) (0x80 | (ch & 0x3f));
            } else {
                outputPtr = _outputMultiByteChar(ch, outputPtr);
            }
        }
        _outputTail = outputPtr;
    }

    private final void _writeStringSegment2(final String text, int offset, final int end) throws IOException
    {
        if ((_outputTail +  6 * (end - offset)) > _outputEnd) {
            _flushBuffer();
        }

        int outputPtr = _outputTail;

        final byte[] outputBuffer = _outputBuffer;
        final int[] escCodes = _outputEscapes;
        
        while (offset < end) {
            int ch = text.charAt(offset++);
            if (ch <= 0x7F) {
                 if (escCodes[ch] == 0) {
                     outputBuffer[outputPtr++] = (byte) ch;
                     continue;
                 }
                 int escape = escCodes[ch];
                 if (escape > 0) { // 2-char escape, fine
                     outputBuffer[outputPtr++] = BYTE_BACKSLASH;
                     outputBuffer[outputPtr++] = (byte) escape;
                 } else {
                     // ctrl-char, 6-byte escape...
                     outputPtr = _writeGenericEscape(ch, outputPtr);
                }
                continue;
            }
            if (ch <= 0x7FF) { // fine, just needs 2 byte output
                outputBuffer[outputPtr++] = (byte) (0xc0 | (ch >> 6));
                outputBuffer[outputPtr++] = (byte) (0x80 | (ch & 0x3f));
            } else {
                outputPtr = _outputMultiByteChar(ch, outputPtr);
            }
        }
        _outputTail = outputPtr;
    }
    
    /*
    /**********************************************************
    /* Internal methods, low-level writing, text segment
    /* with additional escaping (ASCII or such)
    /**********************************************************
     */

    /**
     * Same as <code>_writeStringSegment2(char[], ...)</code., but with
     * additional escaping for high-range code points
     */
    private final void _writeStringSegmentASCII2(final char[] cbuf, int offset, final int end) throws IOException
    {
        // Ok: caller guarantees buffer can have room; but that may require flushing:
        if ((_outputTail +  6 * (end - offset)) > _outputEnd) {
            _flushBuffer();
        }
        int outputPtr = _outputTail;
    
        final byte[] outputBuffer = _outputBuffer;
        final int[] escCodes = _outputEscapes;
        final int maxUnescaped = _maximumNonEscapedChar;
        
        while (offset < end) {
            int ch = cbuf[offset++];
            if (ch <= 0x7F) {
                 if (escCodes[ch] == 0) {
                     outputBuffer[outputPtr++] = (byte) ch;
                     continue;
                 }
                 int escape = escCodes[ch];
                 if (escape > 0) { // 2-char escape, fine
                     outputBuffer[outputPtr++] = BYTE_BACKSLASH;
                     outputBuffer[outputPtr++] = (byte) escape;
                 } else {
                     // ctrl-char, 6-byte escape...
                     outputPtr = _writeGenericEscape(ch, outputPtr);
                 }
                 continue;
            }
            if (ch > maxUnescaped) { // [JACKSON-102] Allow forced escaping if non-ASCII (etc) chars:
                outputPtr = _writeGenericEscape(ch, outputPtr);
                continue;
            }
            if (ch <= 0x7FF) { // fine, just needs 2 byte output
                outputBuffer[outputPtr++] = (byte) (0xc0 | (ch >> 6));
                outputBuffer[outputPtr++] = (byte) (0x80 | (ch & 0x3f));
            } else {
                outputPtr = _outputMultiByteChar(ch, outputPtr);
            }
        }
        _outputTail = outputPtr;
    }

    private final void _writeStringSegmentASCII2(final String text, int offset, final int end) throws IOException
    {
        // Ok: caller guarantees buffer can have room; but that may require flushing:
        if ((_outputTail +  6 * (end - offset)) > _outputEnd) {
            _flushBuffer();
        }
    
        int outputPtr = _outputTail;
    
        final byte[] outputBuffer = _outputBuffer;
        final int[] escCodes = _outputEscapes;
        final int maxUnescaped = _maximumNonEscapedChar;
        
        while (offset < end) {
            int ch = text.charAt(offset++);
            if (ch <= 0x7F) {
                 if (escCodes[ch] == 0) {
                     outputBuffer[outputPtr++] = (byte) ch;
                     continue;
                 }
                 int escape = escCodes[ch];
                 if (escape > 0) { // 2-char escape, fine
                     outputBuffer[outputPtr++] = BYTE_BACKSLASH;
                     outputBuffer[outputPtr++] = (byte) escape;
                 } else {
                     // ctrl-char, 6-byte escape...
                     outputPtr = _writeGenericEscape(ch, outputPtr);
                 }
                 continue;
            }
            if (ch > maxUnescaped) { // [JACKSON-102] Allow forced escaping if non-ASCII (etc) chars:
                outputPtr = _writeGenericEscape(ch, outputPtr);
                continue;
            }
            if (ch <= 0x7FF) { // fine, just needs 2 byte output
                outputBuffer[outputPtr++] = (byte) (0xc0 | (ch >> 6));
                outputBuffer[outputPtr++] = (byte) (0x80 | (ch & 0x3f));
            } else {
                outputPtr = _outputMultiByteChar(ch, outputPtr);
            }
        }
        _outputTail = outputPtr;
    }
    
    /*
    /**********************************************************
    /* Internal methods, low-level writing, text segment
    /* with fully custom escaping (and possibly escaping of non-ASCII
    /**********************************************************
     */

    /**
     * Same as <code>_writeStringSegmentASCII2(char[], ...)</code., but with
     * additional checking for completely custom escapes
     */
    private final void _writeCustomStringSegment2(final char[] cbuf, int offset, final int end) throws IOException
    {
        // Ok: caller guarantees buffer can have room; but that may require flushing:
        if ((_outputTail +  6 * (end - offset)) > _outputEnd) {
            _flushBuffer();
        }
        int outputPtr = _outputTail;
    
        final byte[] outputBuffer = _outputBuffer;
        final int[] escCodes = _outputEscapes;
        // may or may not have this limit
        final int maxUnescaped = (_maximumNonEscapedChar <= 0) ? 0xFFFF : _maximumNonEscapedChar;
        final CharacterEscapes customEscapes = _characterEscapes; // non-null
        
        while (offset < end) {
            int ch = cbuf[offset++];
            if (ch <= 0x7F) {
                 if (escCodes[ch] == 0) {
                     outputBuffer[outputPtr++] = (byte) ch;
                     continue;
                 }
                 int escape = escCodes[ch];
                 if (escape > 0) { // 2-char escape, fine
                     outputBuffer[outputPtr++] = BYTE_BACKSLASH;
                     outputBuffer[outputPtr++] = (byte) escape;
                 } else if (escape == CharacterEscapes.ESCAPE_CUSTOM) {
                     SerializableString esc = customEscapes.getEscapeSequence(ch);
                     if (esc == null) {
                         _reportError("Invalid custom escape definitions; custom escape not found for character code 0x"
                                 +Integer.toHexString(ch)+", although was supposed to have one");
                     }
                     outputPtr = _writeCustomEscape(outputBuffer, outputPtr, esc, end-offset);
                 } else {
                     // ctrl-char, 6-byte escape...
                     outputPtr = _writeGenericEscape(ch, outputPtr);
                 }
                 continue;
            }
            if (ch > maxUnescaped) { // [JACKSON-102] Allow forced escaping if non-ASCII (etc) chars:
                outputPtr = _writeGenericEscape(ch, outputPtr);
                continue;
            }
            SerializableString esc = customEscapes.getEscapeSequence(ch);
            if (esc != null) {
                outputPtr = _writeCustomEscape(outputBuffer, outputPtr, esc, end-offset);
                continue;
            }
            if (ch <= 0x7FF) { // fine, just needs 2 byte output
                outputBuffer[outputPtr++] = (byte) (0xc0 | (ch >> 6));
                outputBuffer[outputPtr++] = (byte) (0x80 | (ch & 0x3f));
            } else {
                outputPtr = _outputMultiByteChar(ch, outputPtr);
            }
        }
        _outputTail = outputPtr;
    }

    private final void _writeCustomStringSegment2(final String text, int offset, final int end) throws IOException
    {
        // Ok: caller guarantees buffer can have room; but that may require flushing:
        if ((_outputTail +  6 * (end - offset)) > _outputEnd) {
            _flushBuffer();
        }
        int outputPtr = _outputTail;
    
        final byte[] outputBuffer = _outputBuffer;
        final int[] escCodes = _outputEscapes;
        // may or may not have this limit
        final int maxUnescaped = (_maximumNonEscapedChar <= 0) ? 0xFFFF : _maximumNonEscapedChar;
        final CharacterEscapes customEscapes = _characterEscapes; // non-null
        
        while (offset < end) {
            int ch = text.charAt(offset++);
            if (ch <= 0x7F) {
                 if (escCodes[ch] == 0) {
                     outputBuffer[outputPtr++] = (byte) ch;
                     continue;
                 }
                 int escape = escCodes[ch];
                 if (escape > 0) { // 2-char escape, fine
                     outputBuffer[outputPtr++] = BYTE_BACKSLASH;
                     outputBuffer[outputPtr++] = (byte) escape;
                 } else if (escape == CharacterEscapes.ESCAPE_CUSTOM) {
                     SerializableString esc = customEscapes.getEscapeSequence(ch);
                     if (esc == null) {
                         _reportError("Invalid custom escape definitions; custom escape not found for character code 0x"
                                 +Integer.toHexString(ch)+", although was supposed to have one");
                     }
                     outputPtr = _writeCustomEscape(outputBuffer, outputPtr, esc, end-offset);
                 } else {
                     // ctrl-char, 6-byte escape...
                     outputPtr = _writeGenericEscape(ch, outputPtr);
                 }
                 continue;
            }
            if (ch > maxUnescaped) { // [JACKSON-102] Allow forced escaping if non-ASCII (etc) chars:
                outputPtr = _writeGenericEscape(ch, outputPtr);
                continue;
            }
            SerializableString esc = customEscapes.getEscapeSequence(ch);
            if (esc != null) {
                outputPtr = _writeCustomEscape(outputBuffer, outputPtr, esc, end-offset);
                continue;
            }
            if (ch <= 0x7FF) { // fine, just needs 2 byte output
                outputBuffer[outputPtr++] = (byte) (0xc0 | (ch >> 6));
                outputBuffer[outputPtr++] = (byte) (0x80 | (ch & 0x3f));
            } else {
                outputPtr = _outputMultiByteChar(ch, outputPtr);
            }
        }
        _outputTail = outputPtr;
    }

    private final int _writeCustomEscape(byte[] outputBuffer, int outputPtr, SerializableString esc, int remainingChars)
        throws IOException, JsonGenerationException
    {
        byte[] raw = esc.asUnquotedUTF8(); // must be escaped at this point, shouldn't double-quote
        int len = raw.length;
        if (len > 6) { // may violate constraints we have, do offline
            return _handleLongCustomEscape(outputBuffer, outputPtr, _outputEnd, raw, remainingChars);
        }
        // otherwise will fit without issues, so:
        System.arraycopy(raw, 0, outputBuffer, outputPtr, len);
        return (outputPtr + len);
    }
    
    private final int _handleLongCustomEscape(byte[] outputBuffer, int outputPtr, int outputEnd,
            byte[] raw, int remainingChars)
        throws IOException, JsonGenerationException
    {
        final int len = raw.length;
        if ((outputPtr + len) > outputEnd) {
            _outputTail = outputPtr;
            _flushBuffer();
            outputPtr = _outputTail;
            if (len > outputBuffer.length) { // very unlikely, but possible...
                _outputStream.write(raw, 0, len);
                return outputPtr;
            }
        }
        System.arraycopy(raw, 0, outputBuffer, outputPtr, len);
        outputPtr += len;
        // but is the invariant still obeyed? If not, flush once more
        if ((outputPtr +  6 * remainingChars) > outputEnd) {
            _outputTail = outputPtr;
            _flushBuffer();
            return _outputTail;
        }
        return outputPtr;
    }

    /*
    /**********************************************************
    /* Internal methods, low-level writing, "raw UTF-8" segments
    /**********************************************************
     */
    
    /**
     * Method called when UTF-8 encoded (but NOT yet escaped!) content is not guaranteed
     * to fit in the output buffer after escaping; as such, we just need to
     * chunk writes.
     */
    private final void _writeUTF8Segments(byte[] utf8, int offset, int totalLen)
        throws IOException, JsonGenerationException
    {
        do {
            int len = Math.min(_outputMaxContiguous, totalLen);
            _writeUTF8Segment(utf8, offset, len);
            offset += len;
            totalLen -= len;
        } while (totalLen > 0);
    }
    
    private final void _writeUTF8Segment(byte[] utf8, final int offset, final int len)
        throws IOException, JsonGenerationException
    {
        // fast loop to see if escaping is needed; don't copy, just look
        final int[] escCodes = _outputEscapes;

        for (int ptr = offset, end = offset + len; ptr < end; ) {
            // 28-Feb-2011, tatu: escape codes just cover 7-bit range, so:
            int ch = utf8[ptr++];
            if ((ch >= 0) && escCodes[ch] != 0) {
                _writeUTF8Segment2(utf8, offset, len);
                return;
            }
        }
        
        // yes, fine, just copy the sucker
        if ((_outputTail + len) > _outputEnd) { // enough room or need to flush?
            _flushBuffer(); // but yes once we flush (caller guarantees length restriction)
        }
        System.arraycopy(utf8, offset, _outputBuffer, _outputTail, len);
        _outputTail += len;
    }

    private final void _writeUTF8Segment2(final byte[] utf8, int offset, int len)
        throws IOException, JsonGenerationException
    {
        int outputPtr = _outputTail;

        // Ok: caller guarantees buffer can have room; but that may require flushing:
        if ((outputPtr + (len * 6)) > _outputEnd) {
            _flushBuffer();
            outputPtr = _outputTail;
        }
        
        final byte[] outputBuffer = _outputBuffer;
        final int[] escCodes = _outputEscapes;
        len += offset; // so 'len' becomes 'end'
        
        while (offset < len) {
            byte b = utf8[offset++];
            int ch = b;
            if (ch < 0 || escCodes[ch] == 0) {
                outputBuffer[outputPtr++] = b;
                continue;
            }
            int escape = escCodes[ch];
            if (escape > 0) { // 2-char escape, fine
                outputBuffer[outputPtr++] = BYTE_BACKSLASH;
                outputBuffer[outputPtr++] = (byte) escape;
            } else {
                // ctrl-char, 6-byte escape...
                outputPtr = _writeGenericEscape(ch, outputPtr);
            }
        }
        _outputTail = outputPtr;
    }
    
    /*
    /**********************************************************
    /* Internal methods, low-level writing, base64 encoded
    /**********************************************************
     */
    
    protected final void _writeBinary(Base64Variant b64variant,
            byte[] input, int inputPtr, final int inputEnd)
        throws IOException, JsonGenerationException
    {
        // Encoding is by chunks of 3 input, 4 output chars, so:
        int safeInputEnd = inputEnd - 3;
        // Let's also reserve room for possible (and quoted) lf char each round
        int safeOutputEnd = _outputEnd - 6;
        int chunksBeforeLF = b64variant.getMaxLineLength() >> 2;

        // Ok, first we loop through all full triplets of data:
        while (inputPtr <= safeInputEnd) {
            if (_outputTail > safeOutputEnd) { // need to flush
                _flushBuffer();
            }
            // First, mash 3 bytes into lsb of 32-bit int
            int b24 = ((int) input[inputPtr++]) << 8;
            b24 |= ((int) input[inputPtr++]) & 0xFF;
            b24 = (b24 << 8) | (((int) input[inputPtr++]) & 0xFF);
            _outputTail = b64variant.encodeBase64Chunk(b24, _outputBuffer, _outputTail);
            if (--chunksBeforeLF <= 0) {
                // note: must quote in JSON value
                _outputBuffer[_outputTail++] = '\\';
                _outputBuffer[_outputTail++] = 'n';
                chunksBeforeLF = b64variant.getMaxLineLength() >> 2;
            }
        }

        // And then we may have 1 or 2 leftover bytes to encode
        int inputLeft = inputEnd - inputPtr; // 0, 1 or 2
        if (inputLeft > 0) { // yes, but do we have room for output?
            if (_outputTail > safeOutputEnd) { // don't really need 6 bytes but...
                _flushBuffer();
            }
            int b24 = ((int) input[inputPtr++]) << 16;
            if (inputLeft == 2) {
                b24 |= (((int) input[inputPtr++]) & 0xFF) << 8;
            }
            _outputTail = b64variant.encodeBase64Partial(b24, inputLeft, _outputBuffer, _outputTail);
        }
    }

    // write-method called when length is definitely known
    protected final int _writeBinary(Base64Variant b64variant,
            InputStream data, byte[] readBuffer, int bytesLeft)
        throws IOException, JsonGenerationException
    {
        int inputPtr = 0;
        int inputEnd = 0;
        int lastFullOffset = -3;       
        
        // Let's also reserve room for possible (and quoted) LF char each round
        int safeOutputEnd = _outputEnd - 6;
        int chunksBeforeLF = b64variant.getMaxLineLength() >> 2;

        while (bytesLeft > 2) { // main loop for full triplets
            if (inputPtr > lastFullOffset) {
                inputEnd = _readMore(data, readBuffer, inputPtr, inputEnd, bytesLeft);
                inputPtr = 0;
                if (inputEnd < 3) { // required to try to read to have at least 3 bytes
                    break;
                }
                lastFullOffset = inputEnd-3;
            }
            if (_outputTail > safeOutputEnd) { // need to flush
                _flushBuffer();
            }
            int b24 = ((int) readBuffer[inputPtr++]) << 8;
            b24 |= ((int) readBuffer[inputPtr++]) & 0xFF;
            b24 = (b24 << 8) | (((int) readBuffer[inputPtr++]) & 0xFF);
            bytesLeft -= 3;
            _outputTail = b64variant.encodeBase64Chunk(b24, _outputBuffer, _outputTail);
            if (--chunksBeforeLF <= 0) {
                _outputBuffer[_outputTail++] = '\\';
                _outputBuffer[_outputTail++] = 'n';
                chunksBeforeLF = b64variant.getMaxLineLength() >> 2;
            }
        }
        
        // And then we may have 1 or 2 leftover bytes to encode
        if (bytesLeft > 0) {
            inputEnd = _readMore(data, readBuffer, inputPtr, inputEnd, bytesLeft);
            inputPtr = 0;
            if (inputEnd > 0) { // yes, but do we have room for output?
                if (_outputTail > safeOutputEnd) { // don't really need 6 bytes but...
                    _flushBuffer();
                }
                int b24 = ((int) readBuffer[inputPtr++]) << 16;
                int amount;
                if (inputPtr < inputEnd) {
                    b24 |= (((int) readBuffer[inputPtr]) & 0xFF) << 8;
                    amount = 2;
                } else {
                    amount = 1;
                }
                _outputTail = b64variant.encodeBase64Partial(b24, amount, _outputBuffer, _outputTail);
                bytesLeft -= amount;
            }
        }
        return bytesLeft;
    }

    // write method when length is unknown
    protected final int _writeBinary(Base64Variant b64variant,
            InputStream data, byte[] readBuffer)
        throws IOException, JsonGenerationException
    {
        int inputPtr = 0;
        int inputEnd = 0;
        int lastFullOffset = -3;
        int bytesDone = 0;
        
        // Let's also reserve room for possible (and quoted) LF char each round
        int safeOutputEnd = _outputEnd - 6;
        int chunksBeforeLF = b64variant.getMaxLineLength() >> 2;

        // Ok, first we loop through all full triplets of data:
        while (true) {
            if (inputPtr > lastFullOffset) { // need to load more
                inputEnd = _readMore(data, readBuffer, inputPtr, inputEnd, readBuffer.length);
                inputPtr = 0;
                if (inputEnd < 3) { // required to try to read to have at least 3 bytes
                    break;
                }
                lastFullOffset = inputEnd-3;
            }
            if (_outputTail > safeOutputEnd) { // need to flush
                _flushBuffer();
            }
            // First, mash 3 bytes into lsb of 32-bit int
            int b24 = ((int) readBuffer[inputPtr++]) << 8;
            b24 |= ((int) readBuffer[inputPtr++]) & 0xFF;
            b24 = (b24 << 8) | (((int) readBuffer[inputPtr++]) & 0xFF);
            bytesDone += 3;
            _outputTail = b64variant.encodeBase64Chunk(b24, _outputBuffer, _outputTail);
            if (--chunksBeforeLF <= 0) {
                _outputBuffer[_outputTail++] = '\\';
                _outputBuffer[_outputTail++] = 'n';
                chunksBeforeLF = b64variant.getMaxLineLength() >> 2;
            }
        }

        // And then we may have 1 or 2 leftover bytes to encode
        if (inputPtr < inputEnd) { // yes, but do we have room for output?
            if (_outputTail > safeOutputEnd) { // don't really need 6 bytes but...
                _flushBuffer();
            }
            int b24 = ((int) readBuffer[inputPtr++]) << 16;
            int amount = 1;
            if (inputPtr < inputEnd) {
                b24 |= (((int) readBuffer[inputPtr]) & 0xFF) << 8;
                amount = 2;
            }
            bytesDone += amount;
            _outputTail = b64variant.encodeBase64Partial(b24, amount, _outputBuffer, _outputTail);
        }
        return bytesDone;
    }
    
    private final int _readMore(InputStream in,
            byte[] readBuffer, int inputPtr, int inputEnd,
            int maxRead) throws IOException
    {
        // anything to shift to front?
        int i = 0;
        while (inputPtr < inputEnd) {
            readBuffer[i++]  = readBuffer[inputPtr++];
        }
        inputPtr = 0;
        inputEnd = i;
        maxRead = Math.min(maxRead, readBuffer.length);
        
        do {
            int length = maxRead - inputEnd;
            if (length == 0) {
                break;
            }
            int count = in.read(readBuffer, inputEnd, length);            
            if (count < 0) {
                return inputEnd;
            }
            inputEnd += count;
        } while (inputEnd < 3);
        return inputEnd;
    }
    
    /*
    /**********************************************************
    /* Internal methods, character escapes/encoding
    /**********************************************************
     */
    
    /**
     * Method called to output a character that is beyond range of
     * 1- and 2-byte UTF-8 encodings, when outputting "raw" 
     * text (meaning it is not to be escaped or quoted)
     */
    private final int _outputRawMultiByteChar(int ch, char[] cbuf, int inputOffset, int inputEnd)
        throws IOException
    {
        // Let's handle surrogates gracefully (as 4 byte output):
        if (ch >= SURR1_FIRST) {
            if (ch <= SURR2_LAST) { // yes, outside of BMP
                // Do we have second part?
                if (inputOffset >= inputEnd || cbuf == null) { // nope... have to note down
                    _reportError(String.format(
"Split surrogate on writeRaw() input (last character): first character 0x%4x", ch));
                } else {
                    _outputSurrogates(ch, cbuf[inputOffset]);
                }
                return inputOffset+1;
            }
        }
        final byte[] bbuf = _outputBuffer;
        bbuf[_outputTail++] = (byte) (0xe0 | (ch >> 12));
        bbuf[_outputTail++] = (byte) (0x80 | ((ch >> 6) & 0x3f));
        bbuf[_outputTail++] = (byte) (0x80 | (ch & 0x3f));
        return inputOffset;
    }

    protected final void _outputSurrogates(int surr1, int surr2) throws IOException
    {
        int c = _decodeSurrogate(surr1, surr2);
        if ((_outputTail + 4) > _outputEnd) {
            _flushBuffer();
        }
        final byte[] bbuf = _outputBuffer;
        bbuf[_outputTail++] = (byte) (0xf0 | (c >> 18));
        bbuf[_outputTail++] = (byte) (0x80 | ((c >> 12) & 0x3f));
        bbuf[_outputTail++] = (byte) (0x80 | ((c >> 6) & 0x3f));
        bbuf[_outputTail++] = (byte) (0x80 | (c & 0x3f));
    }
    
    /**
     * 
     * @param ch
     * @param outputPtr Position within output buffer to append multi-byte in
     * 
     * @return New output position after appending
     * 
     * @throws IOException
     */
    private final int _outputMultiByteChar(int ch, int outputPtr) throws IOException
    {
        byte[] bbuf = _outputBuffer;
        if (ch >= SURR1_FIRST && ch <= SURR2_LAST) { // yes, outside of BMP; add an escape
            // 23-Nov-2015, tatu: As per [core#223], may or may not want escapes;
            //   it would be added here... but as things are, we do not have proper
            //   access yet...
//            if (Feature.ESCAPE_UTF8_SURROGATES.enabledIn(_features)) {
                bbuf[outputPtr++] = BYTE_BACKSLASH;
                bbuf[outputPtr++] = BYTE_u;
                
                bbuf[outputPtr++] = HEX_CHARS[(ch >> 12) & 0xF];
                bbuf[outputPtr++] = HEX_CHARS[(ch >> 8) & 0xF];
                bbuf[outputPtr++] = HEX_CHARS[(ch >> 4) & 0xF];
                bbuf[outputPtr++] = HEX_CHARS[ch & 0xF];
//            } else { ... }
        } else {
            bbuf[outputPtr++] = (byte) (0xe0 | (ch >> 12));
            bbuf[outputPtr++] = (byte) (0x80 | ((ch >> 6) & 0x3f));
            bbuf[outputPtr++] = (byte) (0x80 | (ch & 0x3f));
        }
        return outputPtr;
    }

    private final void _writeNull() throws IOException
    {
        if ((_outputTail + 4) >= _outputEnd) {
            _flushBuffer();
        }
        System.arraycopy(NULL_BYTES, 0, _outputBuffer, _outputTail, 4);
        _outputTail += 4;
    }
        
    /**
     * Method called to write a generic Unicode escape for given character.
     * 
     * @param charToEscape Character to escape using escape sequence (\\uXXXX)
     */
    private int _writeGenericEscape(int charToEscape, int outputPtr) throws IOException
    {
        final byte[] bbuf = _outputBuffer;
        bbuf[outputPtr++] = BYTE_BACKSLASH;
        bbuf[outputPtr++] = BYTE_u;
        if (charToEscape > 0xFF) {
            int hi = (charToEscape >> 8) & 0xFF;
            bbuf[outputPtr++] = HEX_CHARS[hi >> 4];
            bbuf[outputPtr++] = HEX_CHARS[hi & 0xF];
            charToEscape &= 0xFF;
        } else {
            bbuf[outputPtr++] = BYTE_0;
            bbuf[outputPtr++] = BYTE_0;
        }
        // We know it's a control char, so only the last 2 chars are non-0
        bbuf[outputPtr++] = HEX_CHARS[charToEscape >> 4];
        bbuf[outputPtr++] = HEX_CHARS[charToEscape & 0xF];
        return outputPtr;
    }

    protected final void _flushBuffer() throws IOException
    {
        int len = _outputTail;
        if (len > 0) {
            _outputTail = 0;
            _outputStream.write(_outputBuffer, 0, len);
        }
    }
}

com/fasterxml/jackson/core/json/UTF8JsonGenerator.java

 

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