| /* |
| * Copyright (C) 2011 The Android Open Source Project |
| * |
| * Licensed 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 |
| * |
| * http://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 java.nio; |
| |
| import java.io.FileDescriptor; |
| import java.io.IOException; |
| import libcore.io.Libcore; |
| import libcore.io.ErrnoException; |
| |
| /** |
| * Used to implement java.nio read(ByteBuffer[])/write(ByteBuffer[]) operations as POSIX readv(2) |
| * and writev(2) calls. |
| */ |
| final class IoVec { |
| enum Direction { READV, WRITEV }; |
| |
| private final ByteBuffer[] byteBuffers; |
| private final int offset; |
| private final int bufferCount; |
| |
| private final Object[] ioBuffers; |
| private final int[] offsets; |
| private final int[] byteCounts; |
| |
| private final Direction direction; |
| |
| IoVec(ByteBuffer[] byteBuffers, int offset, int bufferCount, Direction direction) { |
| this.byteBuffers = byteBuffers; |
| this.offset = offset; |
| this.bufferCount = bufferCount; |
| this.direction = direction; |
| this.ioBuffers = new Object[bufferCount]; |
| this.offsets = new int[bufferCount]; |
| this.byteCounts = new int[bufferCount]; |
| } |
| |
| int init() { |
| int totalRemaining = 0; |
| for (int i = 0; i < bufferCount; ++i) { |
| ByteBuffer b = byteBuffers[i + offset]; |
| if (direction == Direction.READV) { |
| b.checkWritable(); |
| } |
| int remaining = b.remaining(); |
| if (b.isDirect()) { |
| ioBuffers[i] = b; |
| offsets[i] = b.position(); |
| } else { |
| ioBuffers[i] = NioUtils.unsafeArray(b); |
| offsets[i] = NioUtils.unsafeArrayOffset(b) + b.position(); |
| } |
| byteCounts[i] = remaining; |
| totalRemaining += remaining; |
| } |
| return totalRemaining; |
| } |
| |
| int doTransfer(FileDescriptor fd) throws IOException { |
| try { |
| if (direction == Direction.READV) { |
| int result = Libcore.os.readv(fd, ioBuffers, offsets, byteCounts); |
| if (result == 0) { |
| result = -1; |
| } |
| return result; |
| } else { |
| return Libcore.os.writev(fd, ioBuffers, offsets, byteCounts); |
| } |
| } catch (ErrnoException errnoException) { |
| throw errnoException.rethrowAsIOException(); |
| } |
| } |
| |
| void didTransfer(int byteCount) { |
| for (int i = 0; byteCount > 0 && i < bufferCount; ++i) { |
| ByteBuffer b = byteBuffers[i + offset]; |
| if (byteCounts[i] < byteCount) { |
| b.position(b.limit()); |
| byteCount -= byteCounts[i]; |
| } else { |
| b.position((direction == Direction.WRITEV ? b.position() : 0) + byteCount); |
| byteCount = 0; |
| } |
| } |
| } |
| } |