X12Encoder.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;

final class X12Encoder extends C40Encoder {

	@Override
	public int getEncodingMode() {
		return HighLevelEncoder.X12_ENCODATION;
	}

	@Override
	public void encode(EncoderContext context) {
		// step C
		StringBuilder buffer = new StringBuilder();
		while (context.hasMoreCharacters()) {
			char c = context.getCurrentChar();
			context.pos++;

			encodeChar(c, buffer);

			int count = buffer.length();
			if ((count % 3) == 0) {
				writeNextTriplet(context, buffer);

				int newMode = HighLevelEncoder.lookAheadTest(
						context.getMessage(), context.pos, getEncodingMode());
				if (newMode != getEncodingMode()) {
					context.signalEncoderChange(newMode);
					break;
				}
			}
		}
		handleEOD(context, buffer);
	}

	@Override
	int encodeChar(char c, StringBuilder sb) {
		if (c == '\r') {
			sb.append('\0');
		} else if (c == '*') {
			sb.append('\1');
		} else if (c == '>') {
			sb.append('\2');
		} else if (c == ' ') {
			sb.append('\3');
		} else if (c >= '0' && c <= '9') {
			sb.append((char) (c - 48 + 4));
		} else if (c >= 'A' && c <= 'Z') {
			sb.append((char) (c - 65 + 14));
		} else {
			HighLevelEncoder.illegalCharacter(c);
		}
		return 1;
	}

	@Override
	void handleEOD(EncoderContext context, StringBuilder buffer) {
		context.updateSymbolInfo();
		int available = context.getSymbolInfo().getDataCapacity()
				- context.getCodewordCount();
		int count = buffer.length();
		if (count == 2) {
			context.writeCodeword(HighLevelEncoder.X12_UNLATCH);
			context.pos -= 2;
			context.signalEncoderChange(HighLevelEncoder.ASCII_ENCODATION);
		} else if (count == 1) {
			context.pos--;
			if (available > 1) {
				context.writeCodeword(HighLevelEncoder.X12_UNLATCH);
			}
			// NOP - No unlatch necessary
			context.signalEncoderChange(HighLevelEncoder.ASCII_ENCODATION);
		}
	}
}