Support for platforms where SJIS is unavailable (#1747)

* Add support for embedded JREs where SJIS isn't available

(cherry picked from commit 67896f97042f5a9772f0ebcfdbb91f275d86e087)

* Add support for embedded JREs where EUC_JP isn't available

(cherry picked from commit 979d3b648982b151b7a1e779e58d445086911b31)

core/src/main/java/com/google/zxing/common/StringUtils.java

@@ -32,7 +32,17 @@ import com.google.zxing.DecodeHintType;
 public final class StringUtils {
 
   private static final Charset PLATFORM_DEFAULT_ENCODING = Charset.defaultCharset();
-  public static final Charset SHIFT_JIS_CHARSET = Charset.forName("SJIS");
+  public static final Charset SHIFT_JIS_CHARSET;
+  static {
+    Charset sjisCharset;
+    try {
+      sjisCharset = Charset.forName("SJIS");
+    } catch (UnsupportedCharsetException ucee) {
+      // Can happen on JREs without lib/charsets.jar
+      sjisCharset = null;
+    }
+    SHIFT_JIS_CHARSET = sjisCharset;
+  }
   public static final Charset GB2312_CHARSET;
   static {
     Charset gb2312Charset;
@@ -44,10 +54,20 @@ public final class StringUtils {
     }
     GB2312_CHARSET = gb2312Charset;
   }
-  private static final Charset EUC_JP = Charset.forName("EUC_JP");
+  private static final Charset EUC_JP;
+  static {
+    Charset eucJpCharset;
+    try {
+      eucJpCharset = Charset.forName("EUC_JP");
+    } catch (UnsupportedCharsetException ucee) {
+      // Can happen on JREs without lib/charsets.jar
+      eucJpCharset = null;
+    }
+    EUC_JP = eucJpCharset;
+  }
   private static final boolean ASSUME_SHIFT_JIS =
-      SHIFT_JIS_CHARSET.equals(PLATFORM_DEFAULT_ENCODING) ||
+      (SHIFT_JIS_CHARSET != null && SHIFT_JIS_CHARSET.equals(PLATFORM_DEFAULT_ENCODING)) ||
-      EUC_JP.equals(PLATFORM_DEFAULT_ENCODING);
+      (EUC_JP != null && EUC_JP.equals(PLATFORM_DEFAULT_ENCODING));
 
   // Retained for ABI compatibility with earlier versions
   public static final String SHIFT_JIS = "SJIS";
@@ -101,7 +121,7 @@ public final class StringUtils {
     // which should be by far the most common encodings.
     int length = bytes.length;
     boolean canBeISO88591 = true;
-    boolean canBeShiftJIS = true;
+    boolean canBeShiftJIS = SHIFT_JIS_CHARSET != null;
     boolean canBeUTF8 = true;
     int utf8BytesLeft = 0;
     int utf2BytesChars = 0;

core/src/main/java/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java

@@ -211,6 +211,10 @@ final class DecodedBitStreamParser {
   private static void decodeKanjiSegment(BitSource bits,
                                          StringBuilder result,
                                          int count) throws FormatException {
+    if (StringUtils.SHIFT_JIS_CHARSET == null) {
+      // Not supported without charset support
+      throw FormatException.getFormatInstance();
+    }
     // Don't crash trying to read more bits than we have available.
     if (count * 13 > bits.available()) {
       throw FormatException.getFormatInstance();

core/src/main/java/com/google/zxing/qrcode/encoder/Encoder.java

@@ -29,6 +29,7 @@ import com.google.zxing.qrcode.decoder.Version;
 
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
+import java.nio.charset.UnsupportedCharsetException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Map;
@@ -91,7 +92,11 @@ public final class Encoder {
     Charset encoding = DEFAULT_BYTE_MODE_ENCODING;
     boolean hasEncodingHint = hints != null && hints.containsKey(EncodeHintType.CHARACTER_SET);
     if (hasEncodingHint) {
+      try {
         encoding = Charset.forName(hints.get(EncodeHintType.CHARACTER_SET).toString());
+      } catch (UnsupportedCharsetException ignore) {
+        //ignore the encodingHint and use the DEFAULT_BYTE_MODE_ENCODING
+      }
     }
 
     if (hasCompactionHint) {
@@ -244,7 +249,9 @@ public final class Encoder {
    * if it is Shift_JIS, and the input is only double-byte Kanji, then we return {@link Mode#KANJI}.
    */
   private static Mode chooseMode(String content, Charset encoding) {
-    if (StringUtils.SHIFT_JIS_CHARSET.equals(encoding) && isOnlyDoubleByteKanji(content)) {
+    if (StringUtils.SHIFT_JIS_CHARSET != null &&
+        StringUtils.SHIFT_JIS_CHARSET.equals(encoding) &&
+        isOnlyDoubleByteKanji(content)) {
       // Choose Kanji mode if all input are double-byte characters
       return Mode.KANJI;
     }
@@ -605,6 +612,10 @@ public final class Encoder {
   }
 
   static void appendKanjiBytes(String content, BitArray bits) throws WriterException {
+    if (StringUtils.SHIFT_JIS_CHARSET == null) {
+      // Not supported without charset support
+      throw new WriterException("SJIS Charset not supported on this platform");
+    }
     byte[] bytes = content.getBytes(StringUtils.SHIFT_JIS_CHARSET);
     if (bytes.length % 2 != 0) {
       throw new WriterException("Kanji byte size not even");