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The osx x86_64 swt jar as available in the Eclipse 4.6 (Neon) release for OSX. It is suitable for use with jface and other dependencies available from maven central in the org.eclipse.scout.sdk.deps group. The sources is copied from swt-4.6-cocoa-macosx-x86_64.zip from http://download.eclipse.org/eclipse/downloads/drops4/R-4.6-201606061100/ and javadoc is generated from sources.
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/*******************************************************************************
 * Copyright (c) 2000, 2011 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.internal.image;


import org.eclipse.swt.*;
import java.io.*;

class PngChunk extends Object {
	byte[] reference;

	static final int LENGTH_OFFSET = 0;
	static final int TYPE_OFFSET = 4;
	static final int DATA_OFFSET = 8;

	static final int TYPE_FIELD_LENGTH = 4;
	static final int LENGTH_FIELD_LENGTH = 4;
	static final int MIN_LENGTH = 12;

	static final int CHUNK_UNKNOWN = -1;
	// Critical chunks.
	static final int CHUNK_IHDR = 0;
	static final int CHUNK_PLTE = 1;
	static final int CHUNK_IDAT = 2;
	static final int CHUNK_IEND = 3;
	// Non-critical chunks.
	static final int CHUNK_tRNS = 5;

	static final byte[] TYPE_IHDR = {(byte) 'I', (byte) 'H', (byte) 'D', (byte) 'R'};
	static final byte[] TYPE_PLTE = {(byte) 'P', (byte) 'L', (byte) 'T', (byte) 'E'};
	static final byte[] TYPE_IDAT = {(byte) 'I', (byte) 'D', (byte) 'A', (byte) 'T'};
	static final byte[] TYPE_IEND = {(byte) 'I', (byte) 'E', (byte) 'N', (byte) 'D'};
	static final byte[] TYPE_tRNS = {(byte) 't', (byte) 'R', (byte) 'N', (byte) 'S'};

	static final int[] CRC_TABLE;
	static {
		CRC_TABLE = new int[256];
		for (int i = 0; i < 256; i++) {
			CRC_TABLE[i] = i;
			for (int j = 0; j < 8; j++) {
				if ((CRC_TABLE[i] & 0x1) == 0) {
					CRC_TABLE[i] = (CRC_TABLE[i] >> 1) & 0x7FFFFFFF;
				} else {
					CRC_TABLE[i] = 0xEDB88320 ^ ((CRC_TABLE[i] >> 1) & 0x7FFFFFFF);
				}
			}
		}
	}

	int length;

/**
 * Construct a PngChunk using the reference bytes
 * given.
 */
PngChunk(byte[] reference) {
	super();
	setReference(reference);
	if (reference.length < LENGTH_OFFSET + LENGTH_FIELD_LENGTH) SWT.error(SWT.ERROR_INVALID_IMAGE);
	length = getInt32(LENGTH_OFFSET);
}

/**
 * Construct a PngChunk with the specified number of
 * data bytes.
 */
PngChunk(int dataLength) {
	this(new byte[MIN_LENGTH + dataLength]);
	setLength(dataLength);
}

/**
 * Get the PngChunk's reference byteArray;
 */
byte[] getReference() {
	return reference;
}

/**
 * Set the PngChunk's reference byteArray;
 */
void setReference(byte[] reference) {
	this.reference = reference;
}

/**
 * Get the 16-bit integer from the reference byte
 * array at the given offset.
 */
int getInt16(int offset) {
	int answer = 0;
	answer |= (reference[offset] & 0xFF) << 8;
	answer |= (reference[offset + 1] & 0xFF);
	return answer;
}

/**
 * Set the 16-bit integer in the reference byte
 * array at the given offset.
 */
void setInt16(int offset, int value) {
	reference[offset] = (byte) ((value >> 8) & 0xFF);
	reference[offset + 1] = (byte) (value & 0xFF);
}

/**
 * Get the 32-bit integer from the reference byte
 * array at the given offset.
 */
int getInt32(int offset) {
	int answer = 0;
	answer |= (reference[offset] & 0xFF) << 24;
	answer |= (reference[offset + 1] & 0xFF) << 16;
	answer |= (reference[offset + 2] & 0xFF) << 8;
	answer |= (reference[offset + 3] & 0xFF);
	return answer;
}

/**
 * Set the 32-bit integer in the reference byte
 * array at the given offset.
 */
void setInt32(int offset, int value) {
	reference[offset] = (byte) ((value >> 24) & 0xFF);
	reference[offset + 1] = (byte) ((value >> 16) & 0xFF);
	reference[offset + 2] = (byte) ((value >> 8) & 0xFF);
	reference[offset + 3] = (byte) (value & 0xFF);
}

/**
 * Get the length of the data component of this chunk.
 * This is not the length of the entire chunk.
 */
int getLength() {
	return length;
}

/**
 * Set the length of the data component of this chunk.
 * This is not the length of the entire chunk.
 */
void setLength(int value) {
	setInt32(LENGTH_OFFSET, value);
	length = value;
}

/**
 * Get the chunk type. This is a four byte value.
 * Each byte should be an ASCII character.
 * The first byte is upper case if the chunk is critical.
 * The second byte is upper case if the chunk is publicly defined.
 * The third byte must be upper case.
 * The fourth byte is upper case if the chunk is unsafe to copy.
 * Public chunk types are defined by the PNG Development Group.
 */
byte[] getTypeBytes() {
	byte[] type = new byte[4];
	System.arraycopy(reference, TYPE_OFFSET, type, 0, TYPE_FIELD_LENGTH);
	return type;
}

/**
 * Set the chunk type. This is a four byte value.
 * Each byte should be an ASCII character.
 * The first byte is upper case if the chunk is critical.
 * The second byte is upper case if the chunk is publicly defined.
 * The third byte must be upper case.
 * The fourth byte is upper case if the chunk is unsafe to copy.
 * Public chunk types are defined by the PNG Development Group.
 */
void setType(byte[] value) {
	if (value.length != TYPE_FIELD_LENGTH) {
		SWT.error (SWT.ERROR_INVALID_ARGUMENT);
	}
	System.arraycopy(value, 0, reference, TYPE_OFFSET, TYPE_FIELD_LENGTH);
}

/**
 * Get the chunk's data.
 */
byte[] getData() {
	int dataLength = getLength();
	if (reference.length < MIN_LENGTH + dataLength) {
		SWT.error (SWT.ERROR_INVALID_RANGE);
	}
	byte[] data = new byte[dataLength];
	System.arraycopy(reference, DATA_OFFSET, data, 0, dataLength);
	return data;
}

/**
 * Set the chunk's data.
 * This method has two side-effects.
 * 1. It will set the length field to be the length
 *    of the data array given.
 * 2. It will set the CRC field to the computed CRC
 *    value of the data array given.
 */
void setData(byte[] data) {
	setLength(data.length);
	System.arraycopy(data, 0, reference, DATA_OFFSET, data.length);
	setCRC(computeCRC());
}

/**
 * Get the CRC value for the chunk's data.
 * Ensure that the length field has a good
 * value before making this call.
 */
int getCRC() {
	int crcOffset = DATA_OFFSET + getLength();
	return getInt32(crcOffset);
}

/**
 * Set the CRC value for the chunk's data.
 * Ensure that the length field has a good
 * value before making this call.
 */
void setCRC(int value) {
	int crcOffset = DATA_OFFSET + getLength();
	setInt32(crcOffset, value);
}

/**
 * Get the chunk's total size including the length, type, and crc fields.
 */
int getSize() {
	return MIN_LENGTH + getLength();
}

/**
 * Compute the CRC value for the chunk's data. Answer
 * whether this value matches the value stored in the
 * chunk.
 */
boolean checkCRC() {
	int crc = computeCRC();
	int storedCRC = getCRC();
	return crc == storedCRC;
}

/**
 * Answer the CRC value of chunk's data.
 */
int computeCRC() {
	int crc = 0xFFFFFFFF;
	int start = TYPE_OFFSET;
	int stop = DATA_OFFSET + getLength();
	for (int i = start; i < stop; i++) {
		int index = (crc ^ reference[i]) & 0xFF;
		crc =  CRC_TABLE[index] ^ ((crc >> 8) & 0x00FFFFFF);
	}
	return ~crc;
}

boolean typeMatchesArray(byte[] array) {
	for (int i = 0; i < TYPE_FIELD_LENGTH; i++) {
		if (reference[TYPE_OFFSET + i] != array[i]){
			return false;
		}
	}
	return true;
}

boolean isCritical() {
	char c = (char) getTypeBytes()[0];
	return 'A' <= c && c <= 'Z';
}

int getChunkType() {
	if (typeMatchesArray(TYPE_IHDR)) return CHUNK_IHDR;
	if (typeMatchesArray(TYPE_PLTE)) return CHUNK_PLTE;
	if (typeMatchesArray(TYPE_IDAT)) return CHUNK_IDAT;
	if (typeMatchesArray(TYPE_IEND)) return CHUNK_IEND;
	if (typeMatchesArray(TYPE_tRNS)) return CHUNK_tRNS;
	return CHUNK_UNKNOWN;
}

/**
 * Read the next PNG chunk from the input stream given.
 * If unable to read a chunk, return null.
 */
static PngChunk readNextFromStream(LEDataInputStream stream) {
	try {
		int headerLength = LENGTH_FIELD_LENGTH + TYPE_FIELD_LENGTH;
		byte[] headerBytes = new byte[headerLength];
		int result = stream.read(headerBytes, 0, headerLength);
		stream.unread(headerBytes);
		if (result != headerLength) return null;

		PngChunk tempChunk = new PngChunk(headerBytes);

		int chunkLength = tempChunk.getSize();
		byte[] chunk = new byte[chunkLength];
		result = stream.read(chunk, 0, chunkLength);
		if (result != chunkLength) return null;

		switch (tempChunk.getChunkType()) {
			case CHUNK_IHDR:
				return new PngIhdrChunk(chunk);
			case CHUNK_PLTE:
				return new PngPlteChunk(chunk);
			case CHUNK_IDAT:
				return new PngIdatChunk(chunk);
			case CHUNK_IEND:
				return new PngIendChunk(chunk);
			case CHUNK_tRNS:
				return new PngTrnsChunk(chunk);
			default:
				return new PngChunk(chunk);
		}
	} catch (IOException e) {
		return null;
	}
}

/**
 * Answer whether the chunk is a valid PNG chunk.
 */
void validate(PngFileReadState readState, PngIhdrChunk headerChunk) {
	if (reference.length < MIN_LENGTH) SWT.error(SWT.ERROR_INVALID_IMAGE);

	byte[] type = getTypeBytes();

	// The third character MUST be upper case.
	char c = (char) type[2];
	if (!('A' <= c && c <= 'Z')) SWT.error(SWT.ERROR_INVALID_IMAGE);

	// All characters must be letters.
	for (int i = 0; i < TYPE_FIELD_LENGTH; i++) {
		c = (char) type[i];
		if (!(('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z'))) {
			SWT.error(SWT.ERROR_INVALID_IMAGE);
		}
	}

	// The stored CRC must match the data's computed CRC.
	if (!checkCRC()) SWT.error(SWT.ERROR_INVALID_IMAGE);
}

/**
 * Provided so that subclasses can override and add
 * data to the toString() call.
 */
void contributeToString(StringBuffer buffer) {}

/**
 * Returns a string containing a concise, human-readable
 * description of the receiver.
 *
 * @return a string representation of the event
 */
@Override
public String toString() {
	StringBuffer buffer = new StringBuffer();
	buffer.append("{");
	buffer.append("\n\tLength: ");
	buffer.append(getLength());
	buffer.append("\n\tType: ");
	byte[] type = getTypeBytes();
	for(int i = 0; i < type.length; i++) {
		buffer.append((char) type[i]);
	}

	contributeToString(buffer);

	buffer.append("\n\tCRC: ");
	buffer.append(Integer.toHexString(getCRC()));
	buffer.append("\n}");
	return buffer.toString();
}

}