/*
* Copyright (C) 2014 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 android.hardware.camera2.marshal.impl;
import android.hardware.camera2.marshal.Marshaler;
import android.hardware.camera2.marshal.MarshalQueryable;
import android.hardware.camera2.utils.TypeReference;
import android.util.Log;
import java.nio.ByteBuffer;
import java.util.HashMap;
import static android.hardware.camera2.impl.CameraMetadataNative.*;
import static android.hardware.camera2.marshal.MarshalHelpers.*;
/**
* Marshal any simple enum (0-arg constructors only) into/from either
* {@code TYPE_BYTE} or {@code TYPE_INT32}.
*
* <p>Default values of the enum are mapped to its ordinal; this can be overridden
* by providing a manual value with {@link #registerEnumValues}.</p>
* @param <T> the type of {@code Enum}
*/
public class MarshalQueryableEnum<T extends Enum<T>> implements MarshalQueryable<T> {
private static final String TAG = MarshalQueryableEnum.class.getSimpleName();
private static final boolean VERBOSE = Log.isLoggable(TAG, Log.VERBOSE);
private static final int UINT8_MIN = 0x0;
private static final int UINT8_MAX = (1 << Byte.SIZE) - 1;
private static final int UINT8_MASK = UINT8_MAX;
private class MarshalerEnum extends Marshaler<T> {
private final Class<T> mClass;
@SuppressWarnings("unchecked")
protected MarshalerEnum(TypeReference<T> typeReference, int nativeType) {
super(MarshalQueryableEnum.this, typeReference, nativeType);
mClass = (Class<T>)typeReference.getRawType();
}
@Override
public void marshal(T value, ByteBuffer buffer) {
int enumValue = getEnumValue(value);
if (mNativeType == TYPE_INT32) {
buffer.putInt(enumValue);
} else if (mNativeType == TYPE_BYTE) {
if (enumValue < UINT8_MIN || enumValue > UINT8_MAX) {
throw new UnsupportedOperationException(String.format(
"Enum value %x too large to fit into unsigned byte", enumValue));
}
buffer.put((byte)enumValue);
} else {
throw new AssertionError();
}
}
@Override
public T unmarshal(ByteBuffer buffer) {
int enumValue;
switch (mNativeType) {
case TYPE_INT32:
enumValue = buffer.getInt();
break;
case TYPE_BYTE:
// get the unsigned byte value; avoid sign extension
enumValue = buffer.get() & UINT8_MASK;
break;
default:
throw new AssertionError(
"Unexpected native type; impossible since its not supported");
}
return getEnumFromValue(mClass, enumValue);
}
@Override
public int getNativeSize() {
return getPrimitiveTypeSize(mNativeType);
}
}
@Override
public Marshaler<T> createMarshaler(TypeReference<T> managedType, int nativeType) {
return new MarshalerEnum(managedType, nativeType);
}
@Override
public boolean isTypeMappingSupported(TypeReference<T> managedType, int nativeType) {
if (nativeType == TYPE_INT32 || nativeType == TYPE_BYTE) {
if (managedType.getType() instanceof Class<?>) {
Class<?> typeClass = (Class<?>)managedType.getType();
if (typeClass.isEnum()) {
if (VERBOSE) {
Log.v(TAG, "possible enum detected for " + typeClass);
}
// The enum must not take extra arguments
try {
// match a class like: "public enum Fruits { Apple, Orange; }"
typeClass.getDeclaredConstructor(String.class, int.class);
return true;
} catch (NoSuchMethodException e) {
// Skip: custom enum with a special constructor e.g. Foo(T), but need Foo()
Log.e(TAG, "Can't marshal class " + typeClass + "; no default constructor");
} catch (SecurityException e) {
// Skip: wouldn't be able to touch the enum anyway
Log.e(TAG, "Can't marshal class " + typeClass + "; not accessible");
}
}
}
}
return false;
}
@SuppressWarnings("rawtypes")
private static final HashMap<Class<? extends Enum>, int[]> sEnumValues =
new HashMap<Class<? extends Enum>, int[]>();
/**
* Register a non-sequential set of values to be used with the marshal/unmarshal functions.
*
* <p>This enables get/set to correctly marshal the enum into a value that is C-compatible.</p>
*
* @param enumType The class for an enum
* @param values A list of values mapping to the ordinals of the enum
*/
public static <T extends Enum<T>> void registerEnumValues(Class<T> enumType, int[] values) {
if (enumType.getEnumConstants().length != values.length) {
throw new IllegalArgumentException(
"Expected values array to be the same size as the enumTypes values "
+ values.length + " for type " + enumType);
}
if (VERBOSE) {
Log.v(TAG, "Registered enum values for type " + enumType + " values");
}
sEnumValues.put(enumType, values);
}
/**
* Get the numeric value from an enum.
*
* <p>This is usually the same as the ordinal value for
* enums that have fully sequential values, although for C-style enums the range of values
* may not map 1:1.</p>
*
* @param enumValue Enum instance
* @return Int guaranteed to be ABI-compatible with the C enum equivalent
*/
private static <T extends Enum<T>> int getEnumValue(T enumValue) {
int[] values;
values = sEnumValues.get(enumValue.getClass());
int ordinal = enumValue.ordinal();
if (values != null) {
return values[ordinal];
}
return ordinal;
}
/**
* Finds the enum corresponding to it's numeric value. Opposite of {@link #getEnumValue} method.
*
* @param enumType Class of the enum we want to find
* @param value The numeric value of the enum
* @return An instance of the enum
*/
private static <T extends Enum<T>> T getEnumFromValue(Class<T> enumType, int value) {
int ordinal;
int[] registeredValues = sEnumValues.get(enumType);
if (registeredValues != null) {
ordinal = -1;
for (int i = 0; i < registeredValues.length; ++i) {
if (registeredValues[i] == value) {
ordinal = i;
break;
}
}
} else {
ordinal = value;
}
T[] values = enumType.getEnumConstants();
if (ordinal < 0 || ordinal >= values.length) {
throw new IllegalArgumentException(
String.format(
"Argument 'value' (%d) was not a valid enum value for type %s "
+ "(registered? %b)",
value,
enumType, (registeredValues != null)));
}
return values[ordinal];
}
}
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