PDF417: Automated structured append

Resolves #92

src/main/java/uk/org/okapibarcode/backend/Pdf417.java

@@ -68,6 +68,7 @@ private enum EncodingMode {
     private boolean structuredAppendIncludeSegmentCount;
 
     private static final int MAX_NUMERIC_COMPACTION_BLOCK_SIZE = 44;
+    protected static final int MAX_STRUCTURED_APPEND_TOTAL = 99_999;
 
     private static final int[] COEFRS = {
         /* k = 2 */
@@ -613,7 +614,7 @@ public void setVariant(int variant) {
      * @param position the position of this PDF417 symbol in the structured append series
      */
     public void setStructuredAppendPosition(int position) {
-        if (position < 1 || position > 99_999) {
+        if (position < 1 || position > MAX_STRUCTURED_APPEND_TOTAL) {
             throw new IllegalArgumentException("Invalid PDF417 structured append position: " + position);
         }
         this.structuredAppendPosition = position;
@@ -638,7 +639,7 @@ public int getStructuredAppendPosition() {
      * @param total the total number of PDF417 symbols in the structured append series
      */
     public void setStructuredAppendTotal(int total) {
-        if (total < 1 || total > 99_999) {
+        if (total < 1 || total > MAX_STRUCTURED_APPEND_TOTAL) {
             throw new IllegalArgumentException("Invalid PDF417 structured append total: " + total);
         }
         this.structuredAppendTotal = total;

src/main/java/uk/org/okapibarcode/backend/Pdf417AutoStructuredAppend.java

@@ -0,0 +1,179 @@
+/*
+ * Copyright 2024 Daniel Gredler
+ *
+ * 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 uk.org.okapibarcode.backend;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static java.nio.charset.StandardCharsets.ISO_8859_1;
+import static uk.org.okapibarcode.backend.Pdf417.MAX_STRUCTURED_APPEND_TOTAL;
+
+/**
+ * @author Urs Wolfer
+ */
+public class Pdf417AutoStructuredAppend {
+
+    /**
+     * Splits up the data into a series of structured append PDF417 symbols which include
+     * segment macro data <code>total</code> and <code>position</code>.
+     * Input data will be assumed to be of the type set by {@link Pdf417#setDataType(Symbol.DataType)}.
+     *
+     * @param data     the data to encode
+     * @param template the PDF417 symbol template which will be used for all created
+     *                 symbols. The following properties will be ignored from the template:
+     *                 <ul>
+     *                      <li>{@link Pdf417#setContent(String)}</li>
+     *                      <li>{@link Pdf417#setContent(byte[])}</li>
+     *                      <li>{@link Pdf417#setStructuredAppendTotal(int)}</li>
+     *                      <li>{@link Pdf417#setStructuredAppendPosition(int)}</li>
+     *                 </ul>
+     * @throws OkapiException if no data or data is invalid
+     */
+    public static List<Pdf417> createStructuredAppendSymbols(String data, Pdf417 template) {
+        return createStructuredAppendSymbols(data, template, false);
+    }
+
+    /**
+     * Overloaded method of {@link #createStructuredAppendSymbols(String, Pdf417)} which
+     * accepts binary data and passes it to {@link Pdf417#setContent(byte[])}.
+     *
+     * <p><b>NOTE:</b>See linked method above for details.
+     */
+    public static List<Pdf417> createStructuredAppendSymbols(byte[] data, Pdf417 template) {
+        return createStructuredAppendSymbols(new String(data, ISO_8859_1), template, true);
+    }
+
+    private static List<Pdf417> createStructuredAppendSymbols(String data, Pdf417 template, boolean forceByteCompaction) {
+        List<String> contentList = calculateStructuredAppendContent(data, template, forceByteCompaction);
+        return plotStructuredAppendSymbols(contentList, template, forceByteCompaction);
+    }
+
+    private static List<String> calculateStructuredAppendContent(String content, Pdf417 template, boolean forceByteCompaction) {
+        List<String> contentList = new ArrayList<>();
+        String remainingContent = content;
+        while (!remainingContent.isEmpty()) {
+            Pdf417 symbol = new Pdf417() {
+                @Override
+                protected void plotSymbol() {
+                    // expensive plotting is not required in this case
+                }
+            };
+            clone(template, symbol);
+
+            symbol.setStructuredAppendPosition(contentList.size() + 1);
+            symbol.setStructuredAppendTotal(MAX_STRUCTURED_APPEND_TOTAL);
+
+            String currentContent = remainingContent;
+            remainingContent = setContentAndGetRemainingWithBinarySearch(currentContent, symbol, forceByteCompaction);
+            contentList.add(currentContent.replace(remainingContent, ""));
+        }
+        return contentList;
+    }
+
+    private static List<Pdf417> plotStructuredAppendSymbols(List<String> contentList, Pdf417 template, boolean forceByteCompaction) {
+        int structuredAppendTotal = contentList.size();
+        List<Pdf417> symbols = new ArrayList<>(structuredAppendTotal);
+        for (int i = 0; i < structuredAppendTotal; i++) {
+            String content = contentList.get(i);
+            Pdf417 symbol = new Pdf417();
+            symbols.add(symbol);
+            clone(template, symbol);
+
+            symbol.setStructuredAppendPosition(i + 1);
+            symbol.setStructuredAppendTotal(structuredAppendTotal);
+
+            setContent(symbol, content, forceByteCompaction);
+        }
+        return symbols;
+    }
+
+    private static void clone(Pdf417 template, Pdf417 target) {
+        target.setFontName(template.getFontName());
+        target.setFontSize(template.getFontSize());
+        target.setDataType(template.getDataType());
+        target.setEmptyContentAllowed(template.getEmptyContentAllowed());
+        target.setHumanReadableAlignment(template.getHumanReadableAlignment());
+        target.setHumanReadableLocation(template.getHumanReadableLocation());
+        target.setModuleWidth(template.getModuleWidth());
+        target.setQuietZoneHorizontal(template.getQuietZoneHorizontal());
+        target.setQuietZoneVertical(template.getQuietZoneVertical());
+        target.setReaderInit(template.getReaderInit());
+        target.setDataColumns(template.getDataColumns());
+        target.setRows(template.getRows());
+        target.setPreferredEccLevel(template.getPreferredEccLevel());
+        target.setStructuredAppendFileId(template.getStructuredAppendFileId());
+        target.setStructuredAppendFileName(template.getStructuredAppendFileName());
+        target.setBarHeight(template.getBarHeight());
+        target.setMode(template.getMode());
+        target.setStructuredAppendIncludeSegmentCount(template.getStructuredAppendIncludeSegmentCount());
+    }
+
+    private static String setContentAndGetRemainingWithBinarySearch(String remainingContent, Pdf417 symbol, boolean forceByteCompaction) {
+        int low = 0;
+        int high = remainingContent.length();
+
+        while (low <= high) {
+            int mid = low + high >>> 1;
+            SetContentStatus result = trySetContent(remainingContent, symbol, mid, forceByteCompaction);
+            if (result == SetContentStatus.TRY_MORE) {
+                low = mid + 1;
+            } else {
+                if (result == SetContentStatus.MAX_REACHED) {
+                    return remainingContent.substring(mid);
+                }
+                high = mid - 1;
+            }
+        }
+
+        throw new RuntimeException("Failed to set content, this is a bug.");
+    }
+
+    private static SetContentStatus trySetContent(String remainingContent, Pdf417 symbol, int lengthToTry, boolean forceByteCompaction) {
+        int remainingContentLength = remainingContent.length();
+        int currentLength = Math.min(lengthToTry, remainingContentLength);
+        String currentContent = remainingContent.substring(0, currentLength);
+        try {
+            setContent(symbol, currentContent, forceByteCompaction);
+            if (currentLength == remainingContentLength) {
+                return SetContentStatus.MAX_REACHED;
+            }
+            currentContent = remainingContent.substring(0, currentLength + 1);
+            try {
+                setContent(symbol, currentContent, forceByteCompaction);
+                return SetContentStatus.TRY_MORE;
+            } catch (OkapiInputException e) {
+                return SetContentStatus.MAX_REACHED;
+            }
+        } catch (OkapiInputException e) {
+            return SetContentStatus.TOO_BIG;
+        }
+    }
+
+    private static void setContent(Pdf417 symbol, String currentContent, boolean forceByteCompaction) {
+        if (forceByteCompaction) {
+            symbol.setContent(currentContent.getBytes(ISO_8859_1));
+        } else {
+            symbol.setContent(currentContent);
+        }
+    }
+
+    private enum SetContentStatus {
+        TOO_BIG,
+        TRY_MORE,
+        MAX_REACHED
+    }
+}

src/test/java/uk/org/okapibarcode/backend/Pdf417AutoStructuredAppendTest.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2024 Daniel Gredler
+ *
+ * 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 uk.org.okapibarcode.backend;
+
+import com.google.zxing.BinaryBitmap;
+import com.google.zxing.ChecksumException;
+import com.google.zxing.FormatException;
+import com.google.zxing.LuminanceSource;
+import com.google.zxing.NotFoundException;
+import com.google.zxing.Result;
+import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
+import com.google.zxing.common.HybridBinarizer;
+import com.google.zxing.pdf417.PDF417Reader;
+import org.junit.jupiter.api.Test;
+import uk.org.okapibarcode.output.Java2DRenderer;
+
+import java.awt.Graphics2D;
+import java.awt.image.BufferedImage;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.List;
+
+import static java.awt.image.BufferedImage.TYPE_BYTE_BINARY;
+import static java.nio.charset.StandardCharsets.ISO_8859_1;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static uk.org.okapibarcode.graphics.Color.BLACK;
+import static uk.org.okapibarcode.graphics.Color.WHITE;
+
+/**
+ * @author Urs Wolfer
+ */
+class Pdf417AutoStructuredAppendTest {
+
+    @Test
+    public void testCreateStructuredAppendSymbols() throws Exception {
+        byte[] bytes = new byte[256];
+        for (int i = 0; i < bytes.length; i++) {
+            bytes[i] = (byte) i; // all possible byte values
+        }
+
+        Pdf417 symbolTemplate = new Pdf417();
+        symbolTemplate.setPreferredEccLevel(4);
+        symbolTemplate.setBarHeight(1);
+        symbolTemplate.setRows(12);
+        symbolTemplate.setDataColumns(13);
+        symbolTemplate.setStructuredAppendIncludeSegmentCount(true);
+
+        List<Pdf417> symbols = Pdf417AutoStructuredAppend.createStructuredAppendSymbols(new String(bytes, ISO_8859_1), symbolTemplate);
+        assertions(symbols, bytes);
+
+        List<Pdf417> symbolsByteEncoded = Pdf417AutoStructuredAppend.createStructuredAppendSymbols(bytes, symbolTemplate);
+        assertions(symbolsByteEncoded, bytes);
+    }
+
+    private static void assertions(List<Pdf417> symbols, byte[] bytes) throws IOException, NotFoundException, FormatException, ChecksumException {
+        assertEquals(2, symbols.size());
+
+        try (ByteArrayOutputStream outputStream = new ByteArrayOutputStream()) {
+            for (Pdf417 barcode : symbols) {
+                assertEquals(4, barcode.getPreferredEccLevel());
+                assertEquals(1, barcode.getBarHeight());
+                assertEquals(12, barcode.getRows());
+                assertEquals(13, barcode.getDataColumns());
+
+                BufferedImage img = new BufferedImage(barcode.getWidth(), barcode.getHeight(), TYPE_BYTE_BINARY);
+                Graphics2D g2d = img.createGraphics();
+                Java2DRenderer renderer = new Java2DRenderer(g2d, 1, WHITE, BLACK);
+                renderer.render(barcode);
+                g2d.dispose();
+
+                LuminanceSource source = new BufferedImageLuminanceSource(img);
+                BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
+                PDF417Reader reader = new PDF417Reader();
+                Result result = reader.decode(bitmap);
+
+                byte[] output = result.getText().getBytes(ISO_8859_1);
+                outputStream.write(output);
+
+            }
+            assertArrayEquals(bytes, outputStream.toByteArray());
+        }
+    }
+}