| /* |
| * Copyright 2000-2013 JetBrains s.r.o. |
| * |
| * 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 com.intellij.vcs.log.impl; |
| |
| import com.intellij.vcs.log.Hash; |
| import org.jetbrains.annotations.NotNull; |
| |
| import java.util.Arrays; |
| |
| /** |
| * <p>The {@link Hash} implementation which stores a hash in a byte array thus saving some memory.</p> |
| */ |
| public class HashImpl implements Hash { |
| |
| private static final int SHORT_HASH_LENGTH = 7; |
| |
| @NotNull |
| private final byte[] myData; |
| private final int myHashCode; |
| |
| @NotNull |
| public static Hash build(@NotNull String inputStr) { |
| byte[] data = buildData(inputStr); |
| return new HashImpl(data); |
| } |
| |
| @NotNull |
| private static byte[] buildData(@NotNull String inputStr) { |
| // if length == 5, need 3 byte + 1 signal byte |
| int length = inputStr.length(); |
| byte even = (byte)(length % 2); |
| byte[] data = new byte[length / 2 + 1 + even]; |
| data[0] = even; |
| try { |
| for (int i = 0; i < length / 2; i++) { |
| int k = Integer.parseInt(inputStr.substring(2 * i, 2 * i + 2), 16); |
| data[i + 1] = (byte)(k - 128); |
| } |
| if (even == 1) { |
| int k = Integer.parseInt(inputStr.substring(length - 1), 16); |
| data[length / 2 + 1] = (byte)(k - 128); |
| } |
| } |
| catch (NumberFormatException e) { |
| throw new IllegalArgumentException("bad hash string: " + inputStr); |
| } |
| return data; |
| } |
| |
| private HashImpl(@NotNull byte[] hash) { |
| myData = hash; |
| myHashCode = Arrays.hashCode(hash); |
| } |
| |
| @NotNull |
| @Override |
| public String asString() { |
| assert myData.length > 0 : "bad length Hash.data"; |
| byte even = myData[0]; |
| StringBuilder sb = new StringBuilder(); |
| for (int i = 1; i < myData.length; i++) { |
| int k1 = (myData[i] + 128) / 16; |
| int k2 = (myData[i] + 128) % 16; |
| char c1 = Character.forDigit(k1, 16); |
| char c2 = Character.forDigit(k2, 16); |
| if (i == myData.length - 1 && even == 1) { |
| sb.append(c2); |
| } |
| else { |
| sb.append(c1).append(c2); |
| } |
| } |
| return sb.toString(); |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (this == o) return true; |
| if (o == null || getClass() != o.getClass()) return false; |
| HashImpl that = (HashImpl)o; |
| return myHashCode == that.myHashCode && Arrays.equals(myData, that.myData); |
| } |
| |
| @Override |
| public int hashCode() { |
| return myHashCode; |
| } |
| |
| @Override |
| public String toString() { |
| return asString(); |
| } |
| |
| @NotNull |
| @Override |
| public String toShortString() { |
| String s = asString(); |
| return s.substring(0, Math.min(s.length(), SHORT_HASH_LENGTH)); |
| } |
| } |