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Add unicity of enum instances for a given value
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,86 @@ | ||
| package org.bytedeco.javacpp; | ||
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| import org.bytedeco.javacpp.tools.Logger; | ||
| import sun.misc.Unsafe; | ||
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| import java.lang.reflect.Field; | ||
| import java.util.EnumSet; | ||
| import java.util.concurrent.ConcurrentHashMap; | ||
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| public class EnumValueMap<E extends Enum<E>> extends ConcurrentHashMap<Long, E> { | ||
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| private static final Logger logger = Logger.create(Loader.class); | ||
| private static final ConcurrentHashMap<Class<? extends Enum<?>>, EnumValueMap<?>> maps = new ConcurrentHashMap<>(); | ||
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| static public <E extends Enum<E>> E getEnum(long v, Class<E> c) { | ||
| EnumValueMap<E> evm = (EnumValueMap<E>) maps.get(c); | ||
| if (evm == null) { | ||
| evm = new EnumValueMap<>(); | ||
| try { | ||
| Field valueField = c.getDeclaredField("value"); | ||
| if (valueField.getType() == boolean.class) | ||
| for (E e : EnumSet.allOf(c)) | ||
| evm.put(valueField.getBoolean(e) ? 1L : 0, e); | ||
| else | ||
| for (E e : EnumSet.allOf(c)) | ||
| evm.put(valueField.getLong(e), e); | ||
| maps.put(c, evm); | ||
| } catch (NoSuchFieldException | IllegalAccessException e) { | ||
| logger.warn("Enum class " + c + " doesn't have an accessible value field"); | ||
| } | ||
| } | ||
| E e = evm.get(v); | ||
| if (e == null) | ||
| e = evm.instantiate(v, c); | ||
| return e; | ||
| } | ||
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| private static Unsafe UNSAFE; | ||
| static { | ||
| try { | ||
| Class<?> c = Class.forName("sun.misc.Unsafe"); | ||
| Field f = c.getDeclaredField("theUnsafe"); | ||
| f.setAccessible(true); | ||
| UNSAFE = (Unsafe) f.get(null); | ||
| } catch (ClassNotFoundException | NoSuchFieldException | IllegalAccessException e) { | ||
| logger.warn("Unsafe not available"); | ||
| } | ||
| } | ||
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| private synchronized E instantiate(long l, Class<E> c) { | ||
| if (UNSAFE == null) return null; | ||
| try { | ||
| E e = (E) UNSAFE.allocateInstance(c); | ||
| Field ordinalField = Enum.class.getDeclaredField("ordinal"); | ||
| ordinalField.setAccessible(true); | ||
| ordinalField.setInt(e, size()); | ||
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| Field nameField = Enum.class.getDeclaredField("name"); | ||
| nameField.setAccessible(true); | ||
| nameField.set(e, "DYN_"+l); | ||
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| Field valueField = c.getDeclaredField("value"); | ||
| valueField.setAccessible(true); | ||
| Class<?> type = valueField.getType(); | ||
| if (type == boolean.class) | ||
| valueField.setBoolean(e, l != 0); | ||
| else if (type == byte.class) | ||
| valueField.setByte(e, (byte) l); | ||
| else if (type == short.class) | ||
| valueField.setShort(e, (short) l); | ||
| else if (type == int.class) | ||
| valueField.setInt(e, (int) l); | ||
| else if (type == long.class) | ||
| valueField.setLong(e, l); | ||
| else { | ||
| logger.warn("Value type of " + c +" is not a boolean or an integral type"); | ||
| return null; | ||
| } | ||
| put(l, e); | ||
| return e; | ||
| } catch (InstantiationException | NoSuchFieldException | IllegalAccessException exc) { | ||
| logger.warn("Cannot dynamically instantiate " + c + ": " + exc); | ||
| return null; | ||
| } | ||
| } | ||
| } |
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