Remake

java/com/google/flatbuffers/FlatBufferBuilder.java

@@ -367,6 +367,39 @@ public class FlatBufferBuilder {
     }
     /// @endcond
 
+   /**
+     * Create a vector of tables.
+     *
+     * @param offsets Offsets of the tables.
+     * @return Returns offset of the vector.
+     */
+    public int createVectorOfTables(int[] offsets) {
+        notNested();
+        startVector(4, offsets.length, 4);
+        for(int i = offsets.length - 1; i >= 0; i--) addOffset(offsets[i]);
+        return endVector();
+    }
+
+    /**
+     * Create a vector of sorted by the key tables.
+     *
+     * @param type Type of the tables.
+     * @param offsets Offsets of the tables.
+     * @return Returns offset of the sorted vector.
+     */
+    public <T> int createSortedTableVector(Class<T> type, int[] offsets) {
+        try{
+            return (int)type.getMethod("createMySortedTableVector", FlatBufferBuilder.class, ByteBuffer.class, int[].class).invoke(null, this, bb, offsets);
+        } catch (NoSuchMethodException e) {
+            e.printStackTrace();
+        } catch (SecurityException e) {
+            e.printStackTrace();
+        } catch (Exception e){
+            e.printStackTrace();
+        }
+        return 0;
+    }
+	
    /**
     * Encode the string `s` in the buffer using UTF-8.  If {@code s} is
     * already a {@link CharBuffer}, this method is allocation free.

java/com/google/flatbuffers/Table.java

@@ -56,9 +56,11 @@ public class Table {
    * @param vtable_offset An `int` offset to the vtable in the Table's ByteBuffer.
    * @return Returns an offset into the object, or `0` if the field is not present.
    */
-  protected int __offset(int vtable_offset) {
-    int vtable = bb_pos - bb.getInt(bb_pos);
-    return vtable_offset < bb.getShort(vtable) ? bb.getShort(vtable + vtable_offset) : 0;
+  protected int __offset(int vtable_offset) { return __offset(vtable_offset, bb_pos - bb.getInt(bb_pos), bb, false); }
+
+  protected static int __offset(int vtable_offset, int vtable, ByteBuffer _bb, boolean invoked_static) {
+    if (!invoked_static) return vtable_offset < _bb.getShort(vtable) ? _bb.getShort(vtable + vtable_offset) : 0;
+    else return _bb.getShort(vtable + vtable_offset - _bb.getInt(vtable)) + vtable;
   }
 
   /**
@@ -83,11 +85,15 @@ public class Table {
    * @return Returns a `String` from the data stored inside the FlatBuffer at `offset`.
    */
   protected String __string(int offset) {
+    return __string(offset, bb);
+  }
+
+  protected static String __string(int offset, ByteBuffer _bb) {
     CharsetDecoder decoder = UTF8_DECODER.get();
     decoder.reset();
 
-    offset += bb.getInt(offset);
-    ByteBuffer src = bb.duplicate().order(ByteOrder.LITTLE_ENDIAN);
+    offset += _bb.getInt(offset);
+    ByteBuffer src = _bb.duplicate().order(ByteOrder.LITTLE_ENDIAN);
     int length = src.getInt(offset);
     src.position(offset + SIZEOF_INT);
     src.limit(offset + SIZEOF_INT + length);

net/FlatBuffers/FlatBufferBuilder.cs

@@ -295,6 +295,18 @@ namespace FlatBuffers
             PutInt(_vectorNumElems);
             return new VectorOffset(Offset);
         }
+		
+        /// <summary>
+        /// Creates a vector of tables.
+        /// </summary>
+        /// <param name="offsets">Offsets of the tables.</param>
+        public VectorOffset CreateVectorOfTables<T>(Offset<T>[] offsets) where T : class
+        {
+            NotNested();
+            StartVector(sizeof(int), offsets.Length, sizeof(int));
+            for (int i = offsets.Length - 1; i >= 0; i--) AddOffset(offsets[i].Value);
+            return EndVector();
+        }
 
         /// @cond FLATBUFFERS_INTENRAL
         public void Nested(int obj)

net/FlatBuffers/Table.cs

@@ -31,10 +31,12 @@ namespace FlatBuffers
 
         // Look up a field in the vtable, return an offset into the object, or 0 if the field is not
         // present.
-        protected int __offset(int vtableOffset)
+        protected int __offset(int vtableOffset) { return __offset(vtableOffset, bb_pos - bb.GetInt(bb_pos), bb, false); }
+
+        protected static int __offset(int vtableOffset, int vtable, ByteBuffer _bb, bool invoked_static)
         {
-            int vtable = bb_pos - bb.GetInt(bb_pos);
-            return vtableOffset < bb.GetShort(vtable) ? (int)bb.GetShort(vtable + vtableOffset) : 0;
+            if (!invoked_static) return vtableOffset < _bb.GetShort(vtable) ? (int)_bb.GetShort(vtable + vtableOffset) : 0;
+            else return (int)_bb.GetShort(vtable + vtableOffset - _bb.GetInt(vtable)) + vtable;
         }
 
         // Retrieve the relative offset stored at "offset"
@@ -44,12 +46,14 @@ namespace FlatBuffers
         }
 
         // Create a .NET String from UTF-8 data stored inside the flatbuffer.
-        protected string __string(int offset)
+        protected string __string(int offset) { return __string(offset, bb); }
+
+        protected static string __string(int offset, ByteBuffer _bb)
         {
-            offset += bb.GetInt(offset);
-            var len = bb.GetInt(offset);
+            offset += _bb.GetInt(offset);
+            var len = _bb.GetInt(offset);
             var startPos = offset + sizeof(int);
-            return Encoding.UTF8.GetString(bb.Data, startPos , len);
+            return Encoding.UTF8.GetString(_bb.Data, startPos, len);
         }
 
         // Get the length of a vector whose offset is stored at "offset" in this object.

src/idl_gen_general.cpp

@@ -960,6 +960,7 @@ void GenStruct(StructDef &struct_def, std::string *code_ptr) {
     }
   }
   code += "\n";
+  flatbuffers::FieldDef *key_field = nullptr;
   if (struct_def.fixed) {
     // create a struct constructor function
     code += "  public static " + GenOffsetType(struct_def) + " ";
@@ -1048,6 +1049,7 @@ void GenStruct(StructDef &struct_def, std::string *code_ptr) {
          it != struct_def.fields.vec.end(); ++it) {
       auto &field = **it;
       if (field.deprecated) continue;
+      if (field.key) key_field = &field;
       code += "  public static void " + FunctionStart('A') + "dd";
       code += MakeCamel(field.name);
       code += "(FlatBufferBuilder builder, ";
@@ -1130,6 +1132,71 @@ void GenStruct(StructDef &struct_def, std::string *code_ptr) {
       code += "); }\n";
     }
   }
+  if (struct_def.has_key) {
+    bool is_string = key_field->value.type.base_type == BASE_TYPE_STRING;
+    std::string key_name = lang_.language == IDLOptions::kCSharp ? MakeCamel(key_field->name) : key_field->name + "()";
+    std::string key_type = GenTypeGet(key_field->value.type);
+    std::string key_offset = NumToString(key_field->value.offset);
+    std::string key_getter = is_string ? GenGetter(key_field->value.type) : GenGetter(key_field->value.type).substr(2);
+    std::string data_buffer = lang_.language == IDLOptions::kCSharp ? "builder.DataBuffer" : "bb";
+
+    code += "\n  public static int " + FunctionStart('K') + "eysCompare(" + key_type + " o1, " + key_type + " o2) ";
+    if (lang_.language == IDLOptions::kJava && !is_string) {
+      code += "{\n    if (o1 < o2) return -1;\n";
+      code += "    else if (o1 == o2) return 0;\n";
+      code += "    else return 1;\n  }\n";
+    }
+    else {
+      code += "{ return o1." + FunctionStart('C') + "ompareTo(o2); }\n";
+    }
+
+    code += "\n  public int " + FunctionStart('K') + "eyCompareWithValue(" + key_type + " val) ";
+    if (lang_.language == IDLOptions::kJava && !is_string) {
+      code += "{\n    if (" + key_name + " < val) return -1;\n";
+      code += "    else if (" + key_name + " == val) return 0;\n";
+      code += "    else return 1;\n  }\n";
+    }
+    else {
+      code += "{ return " + key_name + "." + FunctionStart('C') + "ompareTo(val); }\n";
+    }
+
+    code += "\n  public static ";
+    code += (lang_.language == IDLOptions::kCSharp ? "VectorOffset " : "int ") + FunctionStart('C') + "reateMySortedTableVector(FlatBufferBuilder builder, ";
+    code += (lang_.language == IDLOptions::kCSharp ? " Offset<" + struct_def.name + ">" : "ByteBuffer bb, int") + "[] off" + (lang_.language == IDLOptions::kCSharp ? "sets" : "") + ") {\n";
+    if (lang_.language == IDLOptions::kJava) {
+      code += "    Integer[] offsets = new Integer[off.length];\n";
+      code += "    for (int i = 0; i < off.length; i++) offsets[i] = off[i];\n";
+    }
+    code += "    Array";
+    code += (lang_.language == IDLOptions::kCSharp ? ".S" : "s.s");
+    code += "ort(offsets, (";
+    code += (lang_.language == IDLOptions::kCSharp ? "Offset<" + struct_def.name + "> o1, Offset<" + struct_def.name + "> o2) => " : "Integer o1, Integer o2) -> ");
+    code += FunctionStart('K') + "eysCompare(";
+    code += (is_string ? key_getter : data_buffer + key_getter) + "(__offset(" + key_offset + ", " + data_buffer + (lang_.language == IDLOptions::kCSharp ? ".Length - o1.Value" : ".array().length - o1");
+    code += ", " + data_buffer + ", true)" + (is_string ? ", " + data_buffer : "") + "),\n      ";
+    code += (is_string ? key_getter : data_buffer + key_getter) + "(__offset(" + key_offset + ", " + data_buffer + (lang_.language == IDLOptions::kCSharp ? ".Length - o2.Value" : ".array().length - o2");
+    code += ", " + data_buffer + ", true)" + (is_string ? ", " + data_buffer : "") + ")));\n";
+    if (lang_.language == IDLOptions::kJava) code += "    for (int i = 0; i < off.length; i++) off[i] = offsets[i];\n";
+    code += "    return builder." + FunctionStart('C') + "reateVectorOfTables(off" + (lang_.language == IDLOptions::kCSharp ? "sets" : "") + ");\n  }\n";
+
+    code += "\n  public static " + struct_def.name + " " + FunctionStart('L') + "ookupByKey(" + struct_def.name;
+    code += "[] tables, " + key_type + " key) {\n";
+    code += "    int span = tables." + FunctionStart('L') + "ength, start = 0;\n";
+    code += "    while (span != 0) {\n";
+    code += "      int middle = span / 2;\n";
+    code += "      " + struct_def.name + " table = tables[start + middle];\n";
+    code += "      int comp = table." + FunctionStart('K') + "eyCompareWithValue(key);\n";
+    code += "      if (comp > 0) span = middle;\n";
+    code += "      else if (comp < 0) {\n";
+    code += "        middle++;\n";
+    code += "        start += middle;\n";
+    code += "        span -= middle;\n";
+    code += "      }\n";
+    code += "      else return table;\n";
+    code += "    }\n";
+    code += "    return null;\n";
+    code += "  }\n";
+  }
   code += "}";
   // Java does not need the closing semi-colon on class definitions.
   code += (lang_.language != IDLOptions::kJava) ? ";" : "";

tests/FlatBuffers.Test/FlatBuffersExampleTests.cs

@@ -39,6 +39,19 @@ namespace FlatBuffers.Test
             // better for performance.
             var fbb = new FlatBufferBuilder(1);
 
+            StringOffset[] names = { fbb.CreateString("Frodo"), fbb.CreateString("Barney"), fbb.CreateString("Wilma") };
+            Offset<Monster>[] off = new Offset<Monster>[3];
+            Monster.StartMonster(fbb);
+            Monster.AddName(fbb, names[0]);
+            off[0] = Monster.EndMonster(fbb);
+            Monster.StartMonster(fbb);
+            Monster.AddName(fbb, names[1]);
+            off[1] = Monster.EndMonster(fbb);
+            Monster.StartMonster(fbb);
+            Monster.AddName(fbb, names[2]);
+            off[2] = Monster.EndMonster(fbb);
+            var sortMons = Monster.CreateMySortedTableVector(fbb, off);
+			
             // We set up the same values as monsterdata.json:
 
             var str = fbb.CreateString("MyMonster");
@@ -79,6 +92,7 @@ namespace FlatBuffers.Test
             Monster.AddTest4(fbb, test4);
             Monster.AddTestarrayofstring(fbb, testArrayOfString);
             Monster.AddTestbool(fbb, false);
+            Monster.AddTestarrayoftables(fbb, sortMons);
             var mon = Monster.EndMonster(fbb);
 
             Monster.FinishMonsterBuffer(fbb, mon);
@@ -102,6 +116,17 @@ namespace FlatBuffers.Test
             // the mana field should retain its default value
             Assert.AreEqual(monster.MutateMana((short)10), false);
             Assert.AreEqual(monster.Mana, (short)150);
+			
+            // Accessing a vector of sorted by the key tables
+            Monster[] monsters = { monster.GetTestarrayoftables(0), monster.GetTestarrayoftables(1), monster.GetTestarrayoftables(2) };
+            Assert.AreEqual(monster.GetTestarrayoftables(0).Name, "Barney");
+            Assert.AreEqual(monster.GetTestarrayoftables(1).Name, "Frodo");
+            Assert.AreEqual(monster.GetTestarrayoftables(2).Name, "Wilma");
+			
+            // Example of searching for a table by the key
+            Assert.IsTrue(Monster.LookupByKey(monsters, "Frodo") != null);
+            Assert.IsTrue(Monster.LookupByKey(monsters, "Barney") != null);
+            Assert.IsTrue(Monster.LookupByKey(monsters, "Wilma") != null);
 
             // testType is an existing field and mutating it should succeed
             Assert.AreEqual(monster.TestType, Any.Monster);

tests/JavaTest.java

@@ -51,6 +51,19 @@ class JavaTest {
         // better for performance.
         FlatBufferBuilder fbb = new FlatBufferBuilder(1);
 
+        int[] names = {fbb.createString("Frodo"), fbb.createString("Barney"), fbb.createString("Wilma")};
+        int[] off = new int[3];
+        Monster.startMonster(fbb);
+        Monster.addName(fbb, names[0]);
+        off[0] = Monster.endMonster(fbb);
+        Monster.startMonster(fbb);
+        Monster.addName(fbb, names[1]);
+        off[1] = Monster.endMonster(fbb);
+        Monster.startMonster(fbb);
+        Monster.addName(fbb, names[2]);
+        off[2] = Monster.endMonster(fbb);
+        int sortMons = fbb.createSortedTableVector(Monster.class, off);
+		
         // We set up the same values as monsterdata.json:
 
         int str = fbb.createString("MyMonster");
@@ -84,6 +97,7 @@ class JavaTest {
         Monster.addTestarrayofstring(fbb, testArrayOfString);
         Monster.addTestbool(fbb, false);
         Monster.addTesthashu32Fnv1(fbb, Integer.MAX_VALUE + 1L);
+        Monster.addTestarrayoftables(fbb, sortMons);
         int mon = Monster.endMonster(fbb);
 
         Monster.finishMonsterBuffer(fbb, mon);
@@ -121,6 +135,17 @@ class JavaTest {
         // the mana field should retain its default value
         TestEq(monster.mutateMana((short)10), false);
         TestEq(monster.mana(), (short)150);
+		
+		// Accessing a vector of sorted by the key tables
+        Monster[] monsters = { monster.testarrayoftables(0), monster.testarrayoftables(1), monster.testarrayoftables(2) };
+        TestEq(monster.testarrayoftables(0).name(), "Barney");
+        TestEq(monster.testarrayoftables(1).name(), "Frodo");
+        TestEq(monster.testarrayoftables(2).name(), "Wilma");
+		
+		// Example of searching for a table by the key
+        TestEq(Monster.lookupByKey(monsters, "Frodo").name(), "Frodo");
+        TestEq(Monster.lookupByKey(monsters, "Barney").name(), "Barney");
+        TestEq(Monster.lookupByKey(monsters, "Wilma").name(), "Wilma");
 
         // testType is an existing field and mutating it should succeed
         TestEq(monster.testType(), (byte)Any.Monster);

tests/MyGame/Example/Monster.cs

@@ -129,6 +129,33 @@ public sealed class Monster : Table {
     return new Offset<Monster>(o);
   }
   public static void FinishMonsterBuffer(FlatBufferBuilder builder, Offset<Monster> offset) { builder.Finish(offset.Value, "MONS"); }
+  
+  public static int KeysCompare(string o1, string o2) { return o1.CompareTo(o2); }
+
+  public int KeyCompareWithValue(string val) { return Name.CompareTo(val); }
+
+  public static VectorOffset CreateMySortedTableVector(FlatBufferBuilder builder,  Offset<Monster>[] offsets) {
+    Array.Sort(offsets, (Offset<Monster> o1, Offset<Monster> o2) => KeysCompare(__string(__offset(10, builder.DataBuffer.Length - o1.Value, builder.DataBuffer, true), builder.DataBuffer),
+      __string(__offset(10, builder.DataBuffer.Length - o2.Value, builder.DataBuffer, true), builder.DataBuffer)));
+    return builder.CreateVectorOfTables(offsets);
+  }
+
+  public static Monster LookupByKey(Monster[] tables, string key) {
+    int span = tables.Length, start = 0;
+    while (span != 0) {
+      int middle = span / 2;
+      Monster table = tables[start + middle];
+      int comp = table.KeyCompareWithValue(key);
+      if (comp > 0) span = middle;
+      else if (comp < 0) {
+        middle++;
+        start += middle;
+        span -= middle;
+      }
+      else return table;
+    }
+    return null;
+  }
 };
 
 

tests/MyGame/Example/Monster.java

@@ -135,5 +135,35 @@ public final class Monster extends Table {
     return o;
   }
   public static void finishMonsterBuffer(FlatBufferBuilder builder, int offset) { builder.finish(offset, "MONS"); }
+  
+  public static int keysCompare(String o1, String o2) { return o1.compareTo(o2); }
+
+  public int keyCompareWithValue(String val) { return name().compareTo(val); }
+
+  public static int createMySortedTableVector(FlatBufferBuilder builder, ByteBuffer bb, int[] off) {
+    Integer[] offsets = new Integer[off.length];
+    for (int i = 0; i < off.length; i++) offsets[i] = off[i];
+    Arrays.sort(offsets, (Integer o1, Integer o2) -> keysCompare(__string(__offset(10, bb.array().length - o1, bb, true), bb),
+      __string(__offset(10, bb.array().length - o2, bb, true), bb)));
+    for (int i = 0; i < off.length; i++) off[i] = offsets[i];
+    return builder.createVectorOfTables(off);
+  }
+
+  public static Monster lookupByKey(Monster[] tables, String key) {
+    int span = tables.length, start = 0;
+    while (span != 0) {
+      int middle = span / 2;
+      Monster table = tables[start + middle];
+      int comp = table.keyCompareWithValue(key);
+      if (comp > 0) span = middle;
+      else if (comp < 0) {
+        middle++;
+        start += middle;
+        span -= middle;
+      }
+      else return table;
+    }
+    return null;
+  }
 }