/*
    * Copyright 2015 The Netty Project
    *
    * The Netty Project licenses this file to you under the Apache License,
    * version 2.0 (the "License"); you may not use this file except in compliance
    * with the License. You may obtain a copy of the License at:
    *
    *   https://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   * License for the specific language governing permissions and limitations
   * under the License.
   */
  package io.netty.buffer;
  
  import io.netty.util.internal.PlatformDependent;
  
  import java.lang.invoke.VarHandle;
  
  /**
   * Utility class for heap buffers.
   */
  final class HeapByteBufUtil {
  
      static byte getByte(byte[] memory, int index) {
          return memory[index];
      }
  
      static short getShort(byte[] memory, int index) {
          VarHandle shortBeArrayView = PlatformDependent.shortBeArrayView();
          if (shortBeArrayView != null) {
              return (short) shortBeArrayView.get(memory, index);
          }
          return getShort0(memory, index);
      }
  
      private static short getShort0(byte[] memory, int index) {
          return (short) (memory[index] << 8 | memory[index + 1] & 0xFF);
      }
  
      static short getShortLE(byte[] memory, int index) {
          VarHandle shortLeArrayView = PlatformDependent.shortLeArrayView();
          if (shortLeArrayView != null) {
              return (short) shortLeArrayView.get(memory, index);
          }
          return (short) (memory[index] & 0xff | memory[index + 1] << 8);
      }
  
      static int getUnsignedMedium(byte[] memory, int index) {
          return  (memory[index]     & 0xff) << 16 |
                  (memory[index + 1] & 0xff) <<  8 |
                  memory[index + 2] & 0xff;
      }
  
      static int getUnsignedMediumLE(byte[] memory, int index) {
          return  memory[index]     & 0xff         |
                  (memory[index + 1] & 0xff) <<  8 |
                  (memory[index + 2] & 0xff) << 16;
      }
  
      static int getInt(byte[] memory, int index) {
          VarHandle intBeArrayView  = PlatformDependent.intBeArrayView();
          if (intBeArrayView != null) {
              return (int) intBeArrayView.get(memory, index);
          }
          return getInt0(memory, index);
      }
  
      private static int getInt0(byte[] memory, int index) {
          return (memory[index] & 0xFF) << 24 |
                 (memory[index + 1] & 0xFF) << 16 |
                 (memory[index + 2] & 0xFF) << 8 |
                 (memory[index + 3] & 0xFF);
      }
  
      static int getIntLE(byte[] memory, int index) {
          VarHandle intLeArrayView = PlatformDependent.intLeArrayView();
          if (intLeArrayView != null) {
              return (int) intLeArrayView.get(memory, index);
          }
          return getIntLE0(memory, index);
      }
  
      private static int getIntLE0(byte[] memory, int index) {
          return (memory[index] & 0xFF) |
                 (memory[index + 1] & 0xFF) << 8 |
                 (memory[index + 2] & 0xFF) << 16 |
                 (memory[index + 3] & 0xFF) << 24;
      }
  
      static long getLong(byte[] memory, int index) {
          VarHandle longBeArrayView = PlatformDependent.longBeArrayView();
          if (longBeArrayView != null) {
              return (long) longBeArrayView.get(memory, index);
          }
          return getLong0(memory, index);
      }
 
     private static long getLong0(byte[] memory, int index) {
         return ((long) memory[index] & 0xFF) << 56 |
                ((long) memory[index + 1] & 0xFF) << 48 |
                ((long) memory[index + 2] & 0xFF) << 40 |
                ((long) memory[index + 3] & 0xFF) << 32 |
                ((long) memory[index + 4] & 0xFF) << 24 |
                ((long) memory[index + 5] & 0xFF) << 16 |
                ((long) memory[index + 6] & 0xFF) << 8 |
                ((long) memory[index + 7] & 0xFF);
     }
 
     static long getLongLE(byte[] memory, int index) {
         VarHandle longLeArrayView = PlatformDependent.longLeArrayView();
         if (longLeArrayView != null) {
             return (long) longLeArrayView.get(memory, index);
         }
         return getLongLE0(memory, index);
     }
 
     private static long getLongLE0(byte[] memory, int index) {
         return ((long) memory[index] & 0xFF) |
                ((long) memory[index + 1] & 0xFF) << 8 |
                ((long) memory[index + 2] & 0xFF) << 16 |
                ((long) memory[index + 3] & 0xFF) << 24 |
                ((long) memory[index + 4] & 0xFF) << 32 |
                ((long) memory[index + 5] & 0xFF) << 40 |
                ((long) memory[index + 6] & 0xFF) << 48 |
                ((long) memory[index + 7] & 0xFF) << 56;
     }
 
     static void setByte(byte[] memory, int index, int value) {
         memory[index] = (byte) value;
     }
 
     static void setShort(byte[] memory, int index, int value) {
         VarHandle shortBeArrayView = PlatformDependent.shortBeArrayView();
         if (shortBeArrayView != null) {
             shortBeArrayView.set(memory, index, (short) value);
             return;
         }
         memory[index]     = (byte) (value >>> 8);
         memory[index + 1] = (byte) value;
     }
 
     static void setShortLE(byte[] memory, int index, int value) {
         VarHandle shortLeArrayView = PlatformDependent.shortLeArrayView();
         if (shortLeArrayView != null) {
             shortLeArrayView.set(memory, index, (short) value);
             return;
         }
         memory[index]     = (byte) value;
         memory[index + 1] = (byte) (value >>> 8);
     }
 
     static void setMedium(byte[] memory, int index, int value) {
         memory[index]     = (byte) (value >>> 16);
         memory[index + 1] = (byte) (value >>> 8);
         memory[index + 2] = (byte) value;
     }
 
     static void setMediumLE(byte[] memory, int index, int value) {
         memory[index]     = (byte) value;
         memory[index + 1] = (byte) (value >>> 8);
         memory[index + 2] = (byte) (value >>> 16);
     }
 
     static void setInt(byte[] memory, int index, int value) {
         VarHandle intBeArrayView = PlatformDependent.intBeArrayView();
         if (intBeArrayView != null) {
             intBeArrayView.set(memory, index, value);
             return;
         }
         setInt0(memory, index, value);
     }
 
     private static void setInt0(byte[] memory, int index, int value) {
         memory[index]     = (byte) (value >>> 24);
         memory[index + 1] = (byte) (value >>> 16);
         memory[index + 2] = (byte) (value >>> 8);
         memory[index + 3] = (byte) value;
     }
 
     static void setIntLE(byte[] memory, int index, int value) {
         VarHandle intLeArrayView = PlatformDependent.intLeArrayView();
         if (intLeArrayView != null) {
             intLeArrayView.set(memory, index, value);
             return;
         }
         setIntLE0(memory, index, value);
     }
 
     private static void setIntLE0(byte[] memory, int index, int value) {
         memory[index]     = (byte) value;
         memory[index + 1] = (byte) (value >>> 8);
         memory[index + 2] = (byte) (value >>> 16);
         memory[index + 3] = (byte) (value >>> 24);
     }
 
     static void setLong(byte[] memory, int index, long value) {
         VarHandle longBeArrayView = PlatformDependent.longBeArrayView();
         if (longBeArrayView != null) {
             longBeArrayView.set(memory, index, value);
             return;
         }
         setLong0(memory, index, value);
     }
 
     private static void setLong0(byte[] memory, int index, long value) {
         memory[index]     = (byte) (value >>> 56);
         memory[index + 1] = (byte) (value >>> 48);
         memory[index + 2] = (byte) (value >>> 40);
         memory[index + 3] = (byte) (value >>> 32);
         memory[index + 4] = (byte) (value >>> 24);
         memory[index + 5] = (byte) (value >>> 16);
         memory[index + 6] = (byte) (value >>> 8);
         memory[index + 7] = (byte) value;
     }
 
     static void setLongLE(byte[] memory, int index, long value) {
         VarHandle longLeArrayView = PlatformDependent.longLeArrayView();
         if (longLeArrayView != null) {
             longLeArrayView.set(memory, index, value);
             return;
         }
         setLongLE0(memory, index, value);
     }
 
     private static void setLongLE0(byte[] memory, int index, long value) {
         memory[index]     = (byte) value;
         memory[index + 1] = (byte) (value >>> 8);
         memory[index + 2] = (byte) (value >>> 16);
         memory[index + 3] = (byte) (value >>> 24);
         memory[index + 4] = (byte) (value >>> 32);
         memory[index + 5] = (byte) (value >>> 40);
         memory[index + 6] = (byte) (value >>> 48);
         memory[index + 7] = (byte) (value >>> 56);
     }
 
     private HeapByteBufUtil() { }
 }