1 /* 2 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"). 5 * You may not use this file except in compliance with the License. 6 * A copy of the License is located at 7 * 8 * http://aws.amazon.com/apache2.0 9 * 10 * or in the "license" file accompanying this file. This file is distributed 11 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either 12 * express or implied. See the License for the specific language governing 13 * permissions and limitations under the License. 14 */ 15 16 package software.amazon.awssdk.core.checksums; 17 18 import java.nio.ByteBuffer; 19 import java.util.zip.Checksum; 20 import software.amazon.awssdk.annotations.SdkPublicApi; 21 22 /** 23 * Extension of {@link Checksum} to support checksums and checksum validations used by the SDK that 24 * are not provided by the JDK. 25 */ 26 @SdkPublicApi 27 public interface SdkChecksum extends Checksum { 28 29 /** 30 * Returns the computed checksum in a byte array rather than the long provided by 31 * {@link #getValue()}. 32 * 33 * @return byte[] containing the checksum 34 */ getChecksumBytes()35 byte[] getChecksumBytes(); 36 37 /** 38 * Allows marking a checksum for checksums that support the ability to mark and reset. 39 * 40 * @param readLimit the maximum limit of bytes that can be read before the mark position becomes invalid. 41 */ mark(int readLimit)42 void mark(int readLimit); 43 44 45 46 /** 47 * Gets the Checksum based on the required Algorithm. 48 * Instances for CRC32C, CRC32 Algorithm will be added from CRT Java library once they are available in release. 49 * @param algorithm Algorithm for calculating the checksum 50 * @return Optional Checksum instances. 51 */ forAlgorithm(Algorithm algorithm)52 static SdkChecksum forAlgorithm(Algorithm algorithm) { 53 54 switch (algorithm) { 55 case SHA256: 56 return new Sha256Checksum(); 57 case SHA1: 58 return new Sha1Checksum(); 59 case CRC32: 60 return new Crc32Checksum(); 61 case CRC32C: 62 return new Crc32CChecksum(); 63 default: 64 throw new UnsupportedOperationException("Checksum not supported for " + algorithm); 65 } 66 } 67 68 /** 69 * Updates the current checksum with the specified array of bytes. 70 * 71 * @param b the array of bytes to update the checksum with 72 * 73 * @throws NullPointerException 74 * if {@code b} is {@code null} 75 */ update(byte[] b)76 default void update(byte[] b) { 77 update(b, 0, b.length); 78 } 79 80 81 /** 82 * Updates the current checksum with the bytes from the specified buffer. 83 * 84 * The checksum is updated with the remaining bytes in the buffer, starting 85 * at the buffer's position. Upon return, the buffer's position will be 86 * updated to its limit; its limit will not have been changed. 87 * 88 * @apiNote For best performance with DirectByteBuffer and other ByteBuffer 89 * implementations without a backing array implementers of this interface 90 * should override this method. 91 * 92 * @implSpec The default implementation has the following behavior.<br> 93 * For ByteBuffers backed by an accessible byte array. 94 * <pre>{@code 95 * update(buffer.array(), 96 * buffer.position() + buffer.arrayOffset(), 97 * buffer.remaining()); 98 * }</pre> 99 * For ByteBuffers not backed by an accessible byte array. 100 * <pre>{@code 101 * byte[] b = new byte[Math.min(buffer.remaining(), 4096)]; 102 * while (buffer.hasRemaining()) { 103 * int length = Math.min(buffer.remaining(), b.length); 104 * buffer.get(b, 0, length); 105 * update(b, 0, length); 106 * } 107 * }</pre> 108 * 109 * @param buffer the ByteBuffer to update the checksum with 110 * 111 * @throws NullPointerException 112 * if {@code buffer} is {@code null} 113 * 114 */ update(ByteBuffer buffer)115 default void update(ByteBuffer buffer) { 116 int pos = buffer.position(); 117 int limit = buffer.limit(); 118 int rem = limit - pos; 119 if (rem <= 0) { 120 return; 121 } 122 if (buffer.hasArray()) { 123 update(buffer.array(), pos + buffer.arrayOffset(), rem); 124 } else { 125 byte[] b = new byte[Math.min(buffer.remaining(), 4096)]; 126 while (buffer.hasRemaining()) { 127 int length = Math.min(buffer.remaining(), b.length); 128 buffer.get(b, 0, length); 129 update(b, 0, length); 130 } 131 } 132 buffer.position(limit); 133 } 134 135 } 136