diff options
Diffstat (limited to 'src/main/java/com')
| -rw-r--r-- | src/main/java/com/amazon/carbonado/util/Converter.java | 84 |
1 files changed, 20 insertions, 64 deletions
diff --git a/src/main/java/com/amazon/carbonado/util/Converter.java b/src/main/java/com/amazon/carbonado/util/Converter.java index 41e29be..33278a4 100644 --- a/src/main/java/com/amazon/carbonado/util/Converter.java +++ b/src/main/java/com/amazon/carbonado/util/Converter.java @@ -21,8 +21,6 @@ package com.amazon.carbonado.util; import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
-import java.math.BigInteger;
-
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
@@ -293,16 +291,6 @@ public abstract class Converter { addConversionSwitch(b, fromType);
}
- /*
- * Generate big switch statements that operate on Classes.
- *
- * For switch case count, obtain a prime number, at least twice as
- * large as needed. This should minimize hash collisions. Since all
- * the hash keys are known up front, the capacity could be tweaked
- * until there are no collisions, but this technique is easier and
- * deterministic.
- */
-
private void addConversionSwitch(CodeBuilder b, Class fromType) {
Map<Class, Method> toMap;
Map<Class, ?> caseMap;
@@ -325,23 +313,28 @@ public abstract class Converter { caseMap = toMap;
}
- int caseCount = caseCount(caseMap.size());
+ Map<Integer, List<Class>> caseMatches = new HashMap<Integer, List<Class>>();
- int[] cases = new int[caseCount];
- for (int i=0; i<caseCount; i++) {
- cases[i] = i;
+ for (Class to : caseMap.keySet()) {
+ int caseValue = to.hashCode();
+ List<Class> matches = caseMatches.get(caseValue);
+ if (matches == null) {
+ matches = new ArrayList<Class>();
+ caseMatches.put(caseValue, matches);
+ }
+ matches.add(to);
}
- Label[] switchLabels = new Label[caseCount];
+ int[] cases = new int[caseMatches.size()];
+ Label[] switchLabels = new Label[caseMatches.size()];
Label noMatch = b.createLabel();
- List<Class>[] caseMatches = caseMatches(caseMap, caseCount);
- for (int i=0; i<caseCount; i++) {
- List<?> matches = caseMatches[i];
- if (matches == null || matches.size() == 0) {
- switchLabels[i] = noMatch;
- } else {
+ {
+ int i = 0;
+ for (Integer caseValue : caseMatches.keySet()) {
+ cases[i] = caseValue;
switchLabels[i] = b.createLabel();
+ i++;
}
}
@@ -359,24 +352,14 @@ public abstract class Converter { if (caseMap.size() > 1) {
b.loadLocal(caseVar);
-
b.invokeVirtual(Class.class.getName(), "hashCode", TypeDesc.INT, null);
- b.loadConstant(0x7fffffff);
- b.math(Opcode.IAND);
- b.loadConstant(caseCount);
- b.math(Opcode.IREM);
-
b.switchBranch(cases, switchLabels, noMatch);
}
TypeDesc fromTypeDesc = TypeDesc.forClass(fromType);
- for (int i=0; i<caseCount; i++) {
- List<Class> matches = caseMatches[i];
- if (matches == null || matches.size() == 0) {
- continue;
- }
-
+ int i = 0;
+ for (List<Class> matches : caseMatches.values()) {
switchLabels[i].setLocation();
int matchCount = matches.size();
@@ -445,6 +428,8 @@ public abstract class Converter { notEqual.setLocation();
}
}
+
+ i++;
}
noMatch.setLocation();
@@ -482,35 +467,6 @@ public abstract class Converter { b.throwObject();
}
- private int caseCount(int size) {
- BigInteger capacity = BigInteger.valueOf(size * 2 + 1);
- while (!capacity.isProbablePrime(100)) {
- capacity = capacity.add(BigInteger.valueOf(2));
- }
- return capacity.intValue();
- }
-
- /**
- * Returns the types that match on a given case. The array length is
- * the same as the case count. Each list represents the matches. The
- * lists themselves may be null if no matches for that case.
- */
- private List<Class>[] caseMatches(Map<Class, ?> caseMap, int caseCount) {
- List<Class>[] cases = new List[caseCount];
-
- for (Class to : caseMap.keySet()) {
- int hashCode = to.hashCode();
- int caseValue = (hashCode & 0x7fffffff) % caseCount;
- List matches = cases[caseValue];
- if (matches == null) {
- matches = cases[caseValue] = new ArrayList<Class>();
- }
- matches.add(to);
- }
-
- return cases;
- }
-
/**
* @return null if should not be defined
*/
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