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)

3 files changed, 50 insertions, 15 deletions

diff --git a/core/src/main/java/com/google/zxing/common/StringUtils.java b/core/src/main/java/com/google/zxing/common/StringUtils.java
index b749d838b..0a773715f 100644
--- a/core/src/main/java/com/google/zxing/common/StringUtils.java
+++ b/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) ||
-      EUC_JP.equals(PLATFORM_DEFAULT_ENCODING);
+      (SHIFT_JIS_CHARSET != null && SHIFT_JIS_CHARSET.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;
diff --git a/core/src/main/java/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java b/core/src/main/java/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java
index 6aa955333..e23ca545b 100644
--- a/core/src/main/java/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java
+++ b/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();
diff --git a/core/src/main/java/com/google/zxing/qrcode/encoder/Encoder.java b/core/src/main/java/com/google/zxing/qrcode/encoder/Encoder.java
index cc093205e..97f316ddd 100644
--- a/core/src/main/java/com/google/zxing/qrcode/encoder/Encoder.java
+++ b/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) {
-      encoding = Charset.forName(hints.get(EncodeHintType.CHARACTER_SET).toString());
+      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) {
@@ -105,15 +110,15 @@ public final class Encoder {
       version = rn.getVersion();
 
     } else {
-    
+
       // Pick an encoding mode appropriate for the content. Note that this will not attempt to use
       // multiple modes / segments even if that were more efficient.
       mode = chooseMode(content, encoding);
-  
+
       // This will store the header information, like mode and
       // length, as well as "header" segments like an ECI segment.
       BitArray headerBits = new BitArray();
-  
+
       // Append ECI segment if applicable
       if (mode == Mode.BYTE && hasEncodingHint) {
         CharacterSetECI eci = CharacterSetECI.getCharacterSetECI(encoding);
@@ -121,21 +126,21 @@ public final class Encoder {
           appendECI(eci, headerBits);
         }
       }
-  
+
       // Append the FNC1 mode header for GS1 formatted data if applicable
       if (hasGS1FormatHint) {
         // GS1 formatted codes are prefixed with a FNC1 in first position mode header
         appendModeInfo(Mode.FNC1_FIRST_POSITION, headerBits);
       }
-    
+
       // (With ECI in place,) Write the mode marker
       appendModeInfo(mode, headerBits);
-  
+
       // Collect data within the main segment, separately, to count its size if needed. Don't add it to
       // main payload yet.
       BitArray dataBits = new BitArray();
       appendBytes(content, mode, dataBits, encoding);
-  
+
       if (hints != null && hints.containsKey(EncodeHintType.QR_VERSION)) {
         int versionNumber = Integer.parseInt(hints.get(EncodeHintType.QR_VERSION).toString());
         version = Version.getVersionForNumber(versionNumber);
@@ -146,7 +151,7 @@ public final class Encoder {
       } else {
         version = recommendVersion(ecLevel, mode, headerBits, dataBits);
       }
-    
+
       headerAndDataBits = new BitArray();
       headerAndDataBits.appendBitArray(headerBits);
       // Find "length" of main segment and write it
@@ -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");