| /* |
| * Copyright (C) 2010 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 libcore.io; |
| |
| import java.io.ByteArrayOutputStream; |
| import java.io.EOFException; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.OutputStream; |
| import java.io.Reader; |
| import java.io.StringWriter; |
| import java.util.Arrays; |
| import java.util.concurrent.atomic.AtomicReference; |
| |
| public final class Streams { |
| private static AtomicReference<byte[]> skipBuffer = new AtomicReference<byte[]>(); |
| |
| private Streams() {} |
| |
| /** |
| * Implements InputStream.read(int) in terms of InputStream.read(byte[], int, int). |
| * InputStream assumes that you implement InputStream.read(int) and provides default |
| * implementations of the others, but often the opposite is more efficient. |
| */ |
| public static int readSingleByte(InputStream in) throws IOException { |
| byte[] buffer = new byte[1]; |
| int result = in.read(buffer, 0, 1); |
| return (result != -1) ? buffer[0] & 0xff : -1; |
| } |
| |
| /** |
| * Implements OutputStream.write(int) in terms of OutputStream.write(byte[], int, int). |
| * OutputStream assumes that you implement OutputStream.write(int) and provides default |
| * implementations of the others, but often the opposite is more efficient. |
| */ |
| public static void writeSingleByte(OutputStream out, int b) throws IOException { |
| byte[] buffer = new byte[1]; |
| buffer[0] = (byte) (b & 0xff); |
| out.write(buffer); |
| } |
| |
| /** |
| * Fills 'dst' with bytes from 'in', throwing EOFException if insufficient bytes are available. |
| */ |
| public static void readFully(InputStream in, byte[] dst) throws IOException { |
| readFully(in, dst, 0, dst.length); |
| } |
| |
| /** |
| * Reads exactly 'byteCount' bytes from 'in' (into 'dst' at offset 'offset'), and throws |
| * EOFException if insufficient bytes are available. |
| * |
| * Used to implement {@link java.io.DataInputStream#readFully(byte[], int, int)}. |
| */ |
| public static void readFully(InputStream in, byte[] dst, int offset, int byteCount) throws IOException { |
| if (byteCount == 0) { |
| return; |
| } |
| if (in == null) { |
| throw new NullPointerException("in == null"); |
| } |
| if (dst == null) { |
| throw new NullPointerException("dst == null"); |
| } |
| Arrays.checkOffsetAndCount(dst.length, offset, byteCount); |
| while (byteCount > 0) { |
| int bytesRead = in.read(dst, offset, byteCount); |
| if (bytesRead < 0) { |
| throw new EOFException(); |
| } |
| offset += bytesRead; |
| byteCount -= bytesRead; |
| } |
| } |
| |
| /** |
| * Returns a byte[] containing the remainder of 'in', closing it when done. |
| */ |
| public static byte[] readFully(InputStream in) throws IOException { |
| try { |
| return readFullyNoClose(in); |
| } finally { |
| in.close(); |
| } |
| } |
| |
| /** |
| * Returns a byte[] containing the remainder of 'in'. |
| */ |
| public static byte[] readFullyNoClose(InputStream in) throws IOException { |
| ByteArrayOutputStream bytes = new ByteArrayOutputStream(); |
| byte[] buffer = new byte[1024]; |
| int count; |
| while ((count = in.read(buffer)) != -1) { |
| bytes.write(buffer, 0, count); |
| } |
| return bytes.toByteArray(); |
| } |
| |
| /** |
| * Returns the remainder of 'reader' as a string, closing it when done. |
| */ |
| public static String readFully(Reader reader) throws IOException { |
| try { |
| StringWriter writer = new StringWriter(); |
| char[] buffer = new char[1024]; |
| int count; |
| while ((count = reader.read(buffer)) != -1) { |
| writer.write(buffer, 0, count); |
| } |
| return writer.toString(); |
| } finally { |
| reader.close(); |
| } |
| } |
| |
| public static void skipAll(InputStream in) throws IOException { |
| do { |
| in.skip(Long.MAX_VALUE); |
| } while (in.read() != -1); |
| } |
| |
| /** |
| * Skip <b>at most</b> {@code byteCount} bytes from {@code in} by calling read |
| * repeatedly until either the stream is exhausted or we read fewer bytes than |
| * we ask for. |
| * |
| * <p>This method reuses the skip buffer but is careful to never use it at |
| * the same time that another stream is using it. Otherwise streams that use |
| * the caller's buffer for consistency checks like CRC could be clobbered by |
| * other threads. A thread-local buffer is also insufficient because some |
| * streams may call other streams in their skip() method, also clobbering the |
| * buffer. |
| */ |
| public static long skipByReading(InputStream in, long byteCount) throws IOException { |
| // acquire the shared skip buffer. |
| byte[] buffer = skipBuffer.getAndSet(null); |
| if (buffer == null) { |
| buffer = new byte[4096]; |
| } |
| |
| long skipped = 0; |
| while (skipped < byteCount) { |
| int toRead = (int) Math.min(byteCount - skipped, buffer.length); |
| int read = in.read(buffer, 0, toRead); |
| if (read == -1) { |
| break; |
| } |
| skipped += read; |
| if (read < toRead) { |
| break; |
| } |
| } |
| |
| // release the shared skip buffer. |
| skipBuffer.set(buffer); |
| |
| return skipped; |
| } |
| |
| /** |
| * Copies all of the bytes from {@code in} to {@code out}. Neither stream is closed. |
| * Returns the total number of bytes transferred. |
| */ |
| public static int copy(InputStream in, OutputStream out) throws IOException { |
| int total = 0; |
| byte[] buffer = new byte[8192]; |
| int c; |
| while ((c = in.read(buffer)) != -1) { |
| total += c; |
| out.write(buffer, 0, c); |
| } |
| return total; |
| } |
| |
| /** |
| * Returns the ASCII characters up to but not including the next "\r\n", or |
| * "\n". |
| * |
| * @throws java.io.EOFException if the stream is exhausted before the next newline |
| * character. |
| */ |
| public static String readAsciiLine(InputStream in) throws IOException { |
| // TODO: support UTF-8 here instead |
| |
| StringBuilder result = new StringBuilder(80); |
| while (true) { |
| int c = in.read(); |
| if (c == -1) { |
| throw new EOFException(); |
| } else if (c == '\n') { |
| break; |
| } |
| |
| result.append((char) c); |
| } |
| int length = result.length(); |
| if (length > 0 && result.charAt(length - 1) == '\r') { |
| result.setLength(length - 1); |
| } |
| return result.toString(); |
| } |
| } |