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-2.14.0-sources.jar). You can download it at Jackson Maven Website.

You can also browse Jackson Core Source Code below:

⏎ com/fasterxml/jackson/core/format/InputAccessor.java

package com.fasterxml.jackson.core.format;

import java.io.*;

import com.fasterxml.jackson.core.JsonFactory;

/**
 * Interface used to expose beginning of a data file to data format
 * detection code.
 */
public interface InputAccessor
{
    /**
     * Method to call to check if more input is available.
     * Since this may result in more content to be read (at least
     * one more byte), a {@link IOException} may get thrown.
     *
     * @return Whether there is at least one more input byte accessible
     *
     * @throws IOException If check for more content failed due to issue with
     *   underlying input abstraction
     */
    boolean hasMoreBytes() throws IOException;

    /**
     * Returns next byte available, if any; if no more bytes are
     * available, will throw {@link java.io.EOFException}.
     *
     * @return Next content byte, if available
     *
     * @throws IOException If called and there is no more content available
     */
    byte nextByte() throws IOException;

    /**
     * Method that can be called to reset accessor to read from beginning of input.
     */
    void reset();

    /*
    /**********************************************************
    /* Standard implementation
    /**********************************************************
     */

    /**
     * Basic implementation that reads data from given
     * {@link InputStream} and buffers it as necessary.
     */
    class Std implements InputAccessor
    {
        protected final InputStream _in;

        protected final byte[] _buffer;

        protected final int _bufferedStart;

        /**
         * End of valid bytes in the buffer (points to one past last valid)
         */
        protected int _bufferedEnd;
        
        /**
         * Pointer to next available buffered byte in {@link #_buffer}.
         */
        protected int _ptr;

        // Constructor used when content to check is available via
        // input stream and must be read.
        public Std(InputStream in, byte[] buffer)
        {
            _in = in;
            _buffer = buffer;
            _bufferedStart = 0;
            _ptr = 0;
            _bufferedEnd = 0;
        }

        // Constructor used when the full input (or at least enough leading bytes
        // of full input) is available.
        public Std(byte[] inputDocument) {
            this(inputDocument, 0, inputDocument.length);
        }

        // Constructor used when the full input (or at least enough leading bytes
        // of full input) is available.
        public Std(byte[] inputDocument, int start, int len)
        {
            _in = null;
            _buffer = inputDocument;
            _ptr = start;
            _bufferedStart = start;
            _bufferedEnd = start+len;
        }
        
        @Override
        public boolean hasMoreBytes() throws IOException
        {
            if (_ptr < _bufferedEnd) { // already got more
                return true;
            }
            if (_in == null) { // nowhere to read from
                return false;
            }
            int amount = _buffer.length - _ptr;
            if (amount < 1) { // can not load any more
                return false;
            }
            int count = _in.read(_buffer, _ptr, amount);
            if (count <= 0) { // EOF
                return false;
            }
            _bufferedEnd += count;
            return true;
        }

        @Override
        public byte nextByte() throws IOException
        {
            // should we just try loading more automatically?
            if (_ptr >= _bufferedEnd) {
                if (!hasMoreBytes()) {
                    throw new EOFException("Failed auto-detect: could not read more than "+_ptr+" bytes (max buffer size: "+_buffer.length+")");
                }
            }
            return _buffer[_ptr++];
        }

        @Override
        public void reset() {
            _ptr = _bufferedStart;
        }

        /*
        /**********************************************************
        /* Extended API for DataFormatDetector/Matcher
        /**********************************************************
         */

        public DataFormatMatcher createMatcher(JsonFactory match, MatchStrength matchStrength)
        {
            return new DataFormatMatcher(_in, _buffer, _bufferedStart, (_bufferedEnd - _bufferedStart),
                    match, matchStrength);
        }
    }
}

⏎ com/fasterxml/jackson/core/format/InputAccessor.java

Or download all of them as a single archive file:

File name: jackson-core-2.14.0-sources.jar
File size: 497693 bytes
Release date: 2022-11-05
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