import StringUtils from '../../common/StringUtils';
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import StringBuilder from '../../util/StringBuilder';
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import { EDIFACT_ENCODATION, ASCII_ENCODATION } from './constants';
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import HighLevelEncoder from './HighLevelEncoder';
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export class EdifactEncoder {
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getEncodingMode() {
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return EDIFACT_ENCODATION;
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}
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encode(context) {
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// step F
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const buffer = new StringBuilder();
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while (context.hasMoreCharacters()) {
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const c = context.getCurrentChar();
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this.encodeChar(c, buffer);
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context.pos++;
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const count = buffer.length();
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if (count >= 4) {
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context.writeCodewords(this.encodeToCodewords(buffer.toString()));
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const test = buffer.toString().substring(4);
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buffer.setLengthToZero();
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buffer.append(test);
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// buffer.delete(0, 4);
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// for (let i = 0; i < 4; i++) {
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// buffer.deleteCharAt(i);
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// }
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const newMode = HighLevelEncoder.lookAheadTest(context.getMessage(), context.pos, this.getEncodingMode());
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if (newMode !== this.getEncodingMode()) {
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// Return to ASCII encodation, which will actually handle latch to new mode
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context.signalEncoderChange(ASCII_ENCODATION);
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break;
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}
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}
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}
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buffer.append(StringUtils.getCharAt(31)); // Unlatch
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this.handleEOD(context, buffer);
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}
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/**
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* Handle "end of data" situations
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*
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* @param context the encoder context
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* @param buffer the buffer with the remaining encoded characters
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*/
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handleEOD(context, buffer) {
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try {
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const count = buffer.length();
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if (count === 0) {
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return; // Already finished
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}
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if (count === 1) {
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// Only an unlatch at the end
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context.updateSymbolInfo();
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let available = context.getSymbolInfo().getDataCapacity() -
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context.getCodewordCount();
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const remaining = context.getRemainingCharacters();
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// The following two lines are a hack inspired by the 'fix' from https://sourceforge.net/p/barcode4j/svn/221/
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if (remaining > available) {
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context.updateSymbolInfo(context.getCodewordCount() + 1);
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available =
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context.getSymbolInfo().getDataCapacity() -
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context.getCodewordCount();
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}
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if (remaining <= available && available <= 2) {
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return; // No unlatch
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}
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}
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if (count > 4) {
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throw new Error('Count must not exceed 4');
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}
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const restChars = count - 1;
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const encoded = this.encodeToCodewords(buffer.toString());
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const endOfSymbolReached = !context.hasMoreCharacters();
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let restInAscii = endOfSymbolReached && restChars <= 2;
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if (restChars <= 2) {
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context.updateSymbolInfo(context.getCodewordCount() + restChars);
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const available = context.getSymbolInfo().getDataCapacity() -
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context.getCodewordCount();
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if (available >= 3) {
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restInAscii = false;
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context.updateSymbolInfo(context.getCodewordCount() + encoded.length);
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// available = context.symbolInfo.dataCapacity - context.getCodewordCount();
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}
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}
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if (restInAscii) {
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context.resetSymbolInfo();
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context.pos -= restChars;
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}
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else {
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context.writeCodewords(encoded);
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}
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}
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finally {
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context.signalEncoderChange(ASCII_ENCODATION);
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}
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}
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encodeChar(c, sb) {
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if (c >= ' '.charCodeAt(0) && c <= '?'.charCodeAt(0)) {
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sb.append(c);
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}
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else if (c >= '@'.charCodeAt(0) && c <= '^'.charCodeAt(0)) {
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sb.append(StringUtils.getCharAt(c - 64));
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}
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else {
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HighLevelEncoder.illegalCharacter(StringUtils.getCharAt(c));
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}
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}
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encodeToCodewords(sb) {
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const len = sb.length;
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if (len === 0) {
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throw new Error('StringBuilder must not be empty');
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}
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const c1 = sb.charAt(0).charCodeAt(0);
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const c2 = len >= 2 ? sb.charAt(1).charCodeAt(0) : 0;
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const c3 = len >= 3 ? sb.charAt(2).charCodeAt(0) : 0;
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const c4 = len >= 4 ? sb.charAt(3).charCodeAt(0) : 0;
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const v = (c1 << 18) + (c2 << 12) + (c3 << 6) + c4;
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const cw1 = (v >> 16) & 255;
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const cw2 = (v >> 8) & 255;
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const cw3 = v & 255;
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const res = new StringBuilder();
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res.append(cw1);
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if (len >= 2) {
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res.append(cw2);
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}
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if (len >= 3) {
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res.append(cw3);
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}
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return res.toString();
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}
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}
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