gistfile1.diff

diff -r 9126dde66e63 src/main/java/org/yaml/snakeyaml/emitter/Emitter.java
--- a/src/main/java/org/yaml/snakeyaml/emitter/Emitter.java	Wed Sep 05 20:14:52 2012 +0200
+++ b/src/main/java/org/yaml/snakeyaml/emitter/Emitter.java	Sat Sep 29 10:19:20 2012 -0500
@@ -46,6 +46,7 @@
 import org.yaml.snakeyaml.events.StreamEndEvent;
 import org.yaml.snakeyaml.events.StreamStartEvent;
 import org.yaml.snakeyaml.nodes.Tag;
+import org.yaml.snakeyaml.reader.StreamReader;
 import org.yaml.snakeyaml.scanner.Constant;
 import org.yaml.snakeyaml.util.ArrayStack;
 
@@ -1225,12 +1226,20 @@
                     String data;
                     if (ESCAPE_REPLACEMENTS.containsKey(ch)) {
                         data = "\\" + ESCAPE_REPLACEMENTS.get(ch);
-                    } else if (!this.allowUnicode) {
-                        // this is different from PyYAML which escapes all
-                        // non-ASCII characters
+                    } else if (!this.allowUnicode || !StreamReader.isPrintable(ch)) {
+                        // if !allowUnicode or the character is not printable, we must encode it
                         if (ch <= '\u00FF') {
                             String s = "0" + Integer.toString(ch, 16);
                             data = "\\x" + s.substring(s.length() - 2);
+                        } else if (ch >= '\uD800' && ch <= '\uDBFF') {
+                            if (end + 1 < text.length()) {
+                                Character ch2 = text.charAt(++end);
+                                String s = "000" + Long.toHexString(Character.toCodePoint(ch, ch2));
+                                data = "\\U" + s.substring(s.length() - 8) ;
+                            } else {
+                                String s = "000" + Integer.toString(ch, 16);
+                                data = "\\u" + s.substring(s.length() - 4);
+                            }
                         } else {
                             String s = "000" + Integer.toString(ch, 16);
                             data = "\\u" + s.substring(s.length() - 4);
diff -r 9126dde66e63 src/main/java/org/yaml/snakeyaml/reader/StreamReader.java
--- a/src/main/java/org/yaml/snakeyaml/reader/StreamReader.java	Wed Sep 05 20:14:52 2012 +0200
+++ b/src/main/java/org/yaml/snakeyaml/reader/StreamReader.java	Sat Sep 29 10:19:20 2012 -0500
@@ -85,9 +85,7 @@
         for (int i = begin; i < end; i++) {
             final char c = chars[i];
 
-            if ((c >= '\u0020' && c <= '\u007E') || c == '\n' || c == '\r' || c == '\t'
-                    || c == '\u0085' || (c >= '\u00A0' && c <= '\uD7FF')
-                    || (c >= '\uE000' && c <= '\uFFFD')) {
+            if (isPrintable(c)) {
                 continue;
             }
 
@@ -96,6 +94,12 @@
         }
     }
 
+    public static boolean isPrintable(final char c) {
+        return (c >= '\u0020' && c <= '\u007E') || c == '\n' || c == '\r' || c == '\t'
+                || c == '\u0085' || (c >= '\u00A0' && c <= '\uD7FF')
+                || (c >= '\uE000' && c <= '\uFFFD');
+    }
+
     public Mark getMark() {
         return new Mark(name, this.index, this.line, this.column, this.buffer, this.pointer);
     }
diff -r 9126dde66e63 src/test/java/org/yaml/snakeyaml/emitter/EmitterTest.java
--- a/src/test/java/org/yaml/snakeyaml/emitter/EmitterTest.java	Wed Sep 05 20:14:52 2012 +0200
+++ b/src/test/java/org/yaml/snakeyaml/emitter/EmitterTest.java	Sat Sep 29 10:19:20 2012 -0500
@@ -15,6 +15,8 @@
  */
 package org.yaml.snakeyaml.emitter;
 
+import java.io.IOException;
+import java.io.StringWriter;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
@@ -23,6 +25,10 @@
 import org.yaml.snakeyaml.DumperOptions;
 import org.yaml.snakeyaml.DumperOptions.ScalarStyle;
 import org.yaml.snakeyaml.Yaml;
+import org.yaml.snakeyaml.events.DocumentStartEvent;
+import org.yaml.snakeyaml.events.ImplicitTuple;
+import org.yaml.snakeyaml.events.ScalarEvent;
+import org.yaml.snakeyaml.events.StreamStartEvent;
 
 public class EmitterTest extends TestCase {
 
@@ -106,4 +112,19 @@
         String etalon = "\"aaa\": \"0123456789 0123456789\\n0123456789 0123456789\"\n\"bbb\": \"\\nbla-bla\"\n";
         assertEquals(etalon, output);
     }
+
+    // Issue #158
+    public void testWriteSupplementaryUnicode() throws IOException {
+        DumperOptions options = new DumperOptions();
+        String burger = new String(Character.toChars(0x1f354));
+        String halfBurger = "\uD83C";
+        StringWriter output = new StringWriter();
+        Emitter emitter = new Emitter(output, options);
+
+        emitter.emit(new StreamStartEvent(null, null));
+        emitter.emit(new DocumentStartEvent(null, null, false, null, null));
+        emitter.emit(new ScalarEvent(null, null, new ImplicitTuple(true, false), burger + halfBurger, null, null, '"'));
+        String expected = "! \"\\U0001f354\\ud83c\"";
+        assertEquals(expected, output.toString());
+    }
 }