src/org/redkale/util/ByteBufferWriter.java

@@ -22,6 +22,8 @@ public class ByteBufferWriter {
 
     private ByteBuffer[] buffers;
 
+    private int position;
+
     protected ByteBufferWriter(Supplier<ByteBuffer> supplier) {
         this.supplier = supplier;
     }
@@ -51,33 +53,99 @@ public class ByteBufferWriter {
         return this.buffers;
     }
 
+    public int position() {
+        return position;
+    }
+
     public ByteBufferWriter put(byte b) {
         getLastBuffer(1).put(b);
+        position++;
         return this;
     }
 
-    public ByteBufferWriter put(short value) {
+    public ByteBufferWriter putShort(short value) {
         getLastBuffer(2).putShort(value);
+        position += 2;
         return this;
     }
 
     public ByteBufferWriter putInt(int value) {
         getLastBuffer(4).putInt(value);
+        position += 4;
         return this;
     }
 
+    //重新设置指定位置的值
+    public ByteBufferWriter putInt(final int index, int value) {
+        int start = 0;
+        ByteBuffer[] buffs = this.buffers;
+        for (int i = 0; i < buffs.length; i++) {
+            int pos = buffs[i].position();
+            if (pos + start > index) {
+                int r = pos + start - index;
+                if (r >= 4) {
+                    buffs[i].putInt(index - start, value);
+                    return this;
+                } else if (r == 3) {
+                    buffs[i].put(index - start, (byte) ((value >> 24) & 0xFF));
+                    buffs[i].put(index - start + 1, (byte) ((value >> 16) & 0xFF));
+                    buffs[i].put(index - start + 2, (byte) ((value >> 8) & 0xFF));
+                    buffs[i + 1].put(0, (byte) (value & 0xFF));
+                    return this;
+                } else if (r == 2) {
+                    buffs[i].put(index - start, (byte) ((value >> 24) & 0xFF));
+                    buffs[i].put(index - start + 1, (byte) ((value >> 16) & 0xFF));
+                    buffs[i + 1].put(0, (byte) ((value >> 8) & 0xFF));
+                    buffs[i + 1].put(1, (byte) (value & 0xFF));
+                    return this;
+                } else if (r == 1) {
+                    buffs[i].put(index - start, (byte) ((value >> 24) & 0xFF));
+                    buffs[i + 1].put(0, (byte) ((value >> 16) & 0xFF));
+                    buffs[i + 1].put(1, (byte) ((value >> 8) & 0xFF));
+                    buffs[i + 1].put(2, (byte) (value & 0xFF));
+                    return this;
+                }
+            } else {
+                start += pos;
+            }
+        }
+        throw new ArrayIndexOutOfBoundsException(index);
+    }
+
+//    public static void main(String[] args) throws Throwable {
+//        ObjectPool<ByteBuffer> pool = new ObjectPool<>(20, (p) -> ByteBuffer.allocate(10), (ByteBuffer t) -> t.clear(), (ByteBuffer t) -> false);
+//        ByteBufferWriter writer = ByteBufferWriter.create(pool);
+//        for (int i = 1; i <= 18; i++) {
+//            writer.put((byte) i);
+//        }
+//        System.out.println(Arrays.toString(toBytes(writer.toBuffers())));
+//
+//        writer = ByteBufferWriter.create(pool);
+//        for (int i = 1; i <= 18; i++) {
+//            writer.put((byte) i);
+//        }
+//        int value = 0x223344;
+//        byte[] b4 = new byte[]{(byte) ((value >> 24) & 0xFF), (byte) ((value >> 16) & 0xFF), (byte) ((value >> 8) & 0xFF), (byte) (value & 0xFF)};
+//        writer.putInt(9, value);
+//        System.out.println(Arrays.toString(b4));
+//        System.out.println(Arrays.toString(toBytes(writer.toBuffers())));
+//    }
+
     public ByteBufferWriter putFloat(float value) {
         getLastBuffer(4).putFloat(value);
+        position += 4;
         return this;
     }
 
     public ByteBufferWriter putLong(long value) {
         getLastBuffer(8).putLong(value);
+        position += 8;
         return this;
     }
 
     public ByteBufferWriter putDouble(double value) {
         getLastBuffer(8).putDouble(value);
+        position += 8;
         return this;
     }
 
@@ -90,11 +158,28 @@ public class ByteBufferWriter {
         int remain = buf.remaining();
         if (remain >= length) {
             buf.put(src, offset, length);
+            position += length;
         } else {
             buf.put(src, offset, remain);
+            position += remain;
             put(src, offset + remain, length - remain);
         }
         return this;
     }
 
+    public static byte[] toBytes(ByteBuffer[] buffers) {
+        if (buffers == null) return null;
+        int size = 0;
+        for (ByteBuffer buffer : buffers) {
+            size += buffer.remaining();
+        }
+        byte[] bs = new byte[size];
+        int index = 0;
+        for (ByteBuffer buffer : buffers) {
+            int remain = buffer.remaining();
+            buffer.get(bs, index, remain);
+            index += remain;
+        }
+        return bs;
+    }
 }