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[log] HashImpl: remove the caching map

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* HashImpl objects creation doesn't affect performance significantly.
* The map is not enough for big projects anyway.
This commit is contained in:
Kirill Likhodedov
2014-03-11 15:11:33 +04:00
parent 0affa6a6f9
commit 5bd2cdd0f3
1 changed files with 15 additions and 41 deletions
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platform/vcs-log/impl/src/com/intellij/vcs/log/impl/HashImpl.java
+15 -41
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@@ -19,50 +19,22 @@ import com.intellij.vcs.log.Hash;
import org.jetbrains.annotations.NotNull;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
/**
* <p>The {@link Hash} implementation which stores a hash in a byte array thus saving some memory.</p>
* <p>
* In addition to that, it hash a static cache which lets avoid creating multiple HashImpl objects for the same hash value:
* <code>
* if (inputStr_1 == inputStr_2) {
* Hash.build(inputStr_1) == Hash.build(inputStr_2)
* }
* </code>
* </p>
*
* @author erokhins
*/
public class HashImpl implements Hash {
private static final int SHORT_HASH_LENGTH = 7;
private static final int CAPABILITY = 5000;
private static final Map<Hash, Hash> ourCache = new HashMap<Hash, Hash>(CAPABILITY);
@NotNull
private final byte[] data;
private final int hashCode;
private static void clearMap() {
if (ourCache.size() >= CAPABILITY - 5) {
ourCache.clear();
}
}
private final byte[] myData;
private final int myHashCode;
@NotNull
public static Hash build(@NotNull String inputStr) {
clearMap();
byte[] data = buildData(inputStr);
Hash newHash = new HashImpl(data);
if (ourCache.containsKey(newHash)) {
return ourCache.get(newHash);
}
else {
ourCache.put(newHash, newHash);
}
return newHash;
return new HashImpl(data);
}
@NotNull
@@ -89,22 +61,22 @@ public class HashImpl implements Hash {
}
private HashImpl(@NotNull byte[] hash) {
this.data = hash;
this.hashCode = Arrays.hashCode(hash);
myData = hash;
myHashCode = Arrays.hashCode(hash);
}
@NotNull
@Override
public String asString() {
assert data.length > 0 : "bad length Hash.data";
byte even = data[0];
assert myData.length > 0 : "bad length Hash.data";
byte even = myData[0];
StringBuilder sb = new StringBuilder();
for (int i = 1; i < data.length; i++) {
int k1 = (data[i] + 128) / 16;
int k2 = (data[i] + 128) % 16;
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 == data.length - 1 && even == 1) {
if (i == myData.length - 1 && even == 1) {
sb.append(c2);
}
else {
@@ -119,13 +91,15 @@ public class HashImpl implements Hash {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
HashImpl that = (HashImpl)o;
return (hashCode == that.hashCode && asString().equals(that.asString()));
return (myHashCode == that.myHashCode && asString().equals(that.asString()));
}
@Override
public int hashCode() {
return hashCode;
return myHashCode;
}
@Override
public String toString() {
return asString();
}