EncoderContext.java

/*
 * Copyright 2006-2007 Jeremias Maerki.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.zxing.datamatrix.encoder;

import com.google.zxing.Dimension;

import java.nio.charset.Charset;

final class EncoderContext {

	private final String msg;
	private SymbolShapeHint shape;
	private Dimension minSize;
	private Dimension maxSize;
	private final StringBuilder codewords;
	int pos;
	private int newEncoding;
	private SymbolInfo symbolInfo;
	private int skipAtEnd;

	EncoderContext(String msg) {
		// From this point on Strings are not Unicode anymore!
		byte[] msgBinary = msg.getBytes(Charset.forName("ISO-8859-1"));
		StringBuilder sb = new StringBuilder(msgBinary.length);
		for (int i = 0, c = msgBinary.length; i < c; i++) {
			char ch = (char) (msgBinary[i] & 0xff);
			if (ch == '?' && msg.charAt(i) != '?') {
				throw new IllegalArgumentException(
						"Message contains characters outside ISO-8859-1 encoding.");
			}
			sb.append(ch);
		}
		this.msg = sb.toString(); // Not Unicode here!
		shape = SymbolShapeHint.FORCE_NONE;
		this.codewords = new StringBuilder(msg.length());
		newEncoding = -1;
	}

	public void setSymbolShape(SymbolShapeHint shape) {
		this.shape = shape;
	}

	public void setSizeConstraints(Dimension minSize, Dimension maxSize) {
		this.minSize = minSize;
		this.maxSize = maxSize;
	}

	public String getMessage() {
		return this.msg;
	}

	public void setSkipAtEnd(int count) {
		this.skipAtEnd = count;
	}

	public char getCurrentChar() {
		return msg.charAt(pos);
	}

	public char getCurrent() {
		return msg.charAt(pos);
	}

	public StringBuilder getCodewords() {
		return codewords;
	}

	public void writeCodewords(String codewords) {
		this.codewords.append(codewords);
	}

	public void writeCodeword(char codeword) {
		this.codewords.append(codeword);
	}

	public int getCodewordCount() {
		return this.codewords.length();
	}

	public int getNewEncoding() {
		return newEncoding;
	}

	public void signalEncoderChange(int encoding) {
		this.newEncoding = encoding;
	}

	public void resetEncoderSignal() {
		this.newEncoding = -1;
	}

	public boolean hasMoreCharacters() {
		return pos < getTotalMessageCharCount();
	}

	private int getTotalMessageCharCount() {
		return msg.length() - skipAtEnd;
	}

	public int getRemainingCharacters() {
		return getTotalMessageCharCount() - pos;
	}

	public SymbolInfo getSymbolInfo() {
		return symbolInfo;
	}

	public void updateSymbolInfo() {
		updateSymbolInfo(getCodewordCount());
	}

	public void updateSymbolInfo(int len) {
		if (this.symbolInfo == null || len > this.symbolInfo.getDataCapacity()) {
			this.symbolInfo = SymbolInfo.lookup(len, shape, minSize, maxSize,
					true);
		}
	}

	public void resetSymbolInfo() {
		this.symbolInfo = null;
	}
}