Sorry for my mistake. After a more throughout dig in, this thing has already fixed several years ago, at year 2015. Issue close.
Xeno Amess <[email protected]> 于2022年2月4日周五 21:40写道： > Besides, is it worthy to develop a public float Math.ceil(float) function? > > Xeno Amess <[email protected]> 于2022年2月4日周五 21:39写道： > >> patch applied. >> >> Index: src/java.base/share/classes/java/lang/Module.java >> IDEA additional info: >> Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP >> <+>UTF-8 >> =================================================================== >> diff --git a/src/java.base/share/classes/java/lang/Module.java >> b/src/java.base/share/classes/java/lang/Module.java >> --- a/src/java.base/share/classes/java/lang/Module.java (revision >> 3d926dd66ef6551e91a4ebbbc59dcff58f5ede5a) >> +++ b/src/java.base/share/classes/java/lang/Module.java (revision >> deeba25d15398fea8bc971ac915e348878b2c27a) >> @@ -1133,7 +1133,7 @@ >> boolean isBootLayer = (ModuleLayer.boot() == null); >> >> int numModules = cf.modules().size(); >> - int cap = (int)(numModules / 0.75f + 1.0f); >> + int cap = (int)Math.ceil(numModules / 0.75f); >> Map<String, Module> nameToModule = new HashMap<>(cap); >> >> // to avoid repeated lookups and reduce iteration overhead, we >> create >> Index: src/java.base/share/classes/java/util/HashMap.java >> IDEA additional info: >> Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP >> <+>UTF-8 >> =================================================================== >> diff --git a/src/java.base/share/classes/java/util/HashMap.java >> b/src/java.base/share/classes/java/util/HashMap.java >> --- a/src/java.base/share/classes/java/util/HashMap.java (revision >> 3d926dd66ef6551e91a4ebbbc59dcff58f5ede5a) >> +++ b/src/java.base/share/classes/java/util/HashMap.java (revision >> deeba25d15398fea8bc971ac915e348878b2c27a) >> @@ -495,9 +495,9 @@ >> int s = m.size(); >> if (s > 0) { >> if (table == null) { // pre-size >> - float ft = ((float)s / loadFactor) + 1.0F; >> - int t = ((ft < (float)MAXIMUM_CAPACITY) ? >> - (int)ft : MAXIMUM_CAPACITY); >> + double dt = Math.ceil(s / loadFactor); >> + int t = ((dt < (double)MAXIMUM_CAPACITY) ? >> + (int)dt : MAXIMUM_CAPACITY); >> if (t > threshold) >> threshold = tableSizeFor(t); >> } else { >> @@ -1527,12 +1527,12 @@ >> } else if (mappings == 0) { >> // use defaults >> } else if (mappings > 0) { >> - float fc = (float)mappings / lf + 1.0f; >> - int cap = ((fc < DEFAULT_INITIAL_CAPACITY) ? >> + double dc = Math.ceil(mappings / lf); >> + int cap = ((dc < DEFAULT_INITIAL_CAPACITY) ? >> DEFAULT_INITIAL_CAPACITY : >> - (fc >= MAXIMUM_CAPACITY) ? >> + (dc >= MAXIMUM_CAPACITY) ? >> MAXIMUM_CAPACITY : >> - tableSizeFor((int)fc)); >> + tableSizeFor((int)dc)); >> float ft = (float)cap * lf; >> threshold = ((cap < MAXIMUM_CAPACITY && ft < >> MAXIMUM_CAPACITY) ? >> (int)ft : Integer.MAX_VALUE); >> Index: src/java.base/share/classes/java/util/WeakHashMap.java >> IDEA additional info: >> Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP >> <+>UTF-8 >> =================================================================== >> diff --git a/src/java.base/share/classes/java/util/WeakHashMap.java >> b/src/java.base/share/classes/java/util/WeakHashMap.java >> --- a/src/java.base/share/classes/java/util/WeakHashMap.java (revision >> 3d926dd66ef6551e91a4ebbbc59dcff58f5ede5a) >> +++ b/src/java.base/share/classes/java/util/WeakHashMap.java (revision >> deeba25d15398fea8bc971ac915e348878b2c27a) >> @@ -251,7 +251,7 @@ >> * @since 1.3 >> */ >> public WeakHashMap(Map<? extends K, ? extends V> m) { >> - this(Math.max((int) ((float)m.size() / DEFAULT_LOAD_FACTOR + >> 1.0F), >> + this(Math.max((int) Math.ceil(m.size() / DEFAULT_LOAD_FACTOR), >> DEFAULT_INITIAL_CAPACITY), >> DEFAULT_LOAD_FACTOR); >> putAll(m); >> >> Xeno Amess <[email protected]> 于2022年2月4日周五 18:45写道： >> >>> also find some other places have same problem. >>> If some of your already-in people aggree, I would create a pr, but >>> according to the rules seems I should wait for now. >>> >>> Xeno Amess <[email protected]> 于2022年2月4日周五 18:42写道： >>> >>>> import java.lang.reflect.Array; >>>> import java.lang.reflect.Field; >>>> import java.util.HashMap; >>>> import java.util.Map; >>>> >>>> public class TestMap { >>>> >>>> public static void main(String[] args) throws NoSuchFieldException, >>>> IllegalAccessException { >>>> HashMap<Object, Object> a = new HashMap<>(); >>>> fill12(a); >>>> HashMap<Object, Object> b = new HashMap<>(12); >>>> fill12(b); >>>> HashMap<Object, Object> c = new HashMap<>(a); >>>> HashMap<Object, Object> d = new HashMap<>(); >>>> d.putAll(a); >>>> System.out.println("a : " + getArrayLength(a)); >>>> System.out.println("b : " + getArrayLength(b)); >>>> System.out.println("c : " + getArrayLength(c)); >>>> System.out.println("d : " + getArrayLength(d)); >>>> } >>>> >>>> public static void fill12(Map<Object, Object> map) { >>>> for (int i = 0; i < 12; i++) { >>>> map.put(i, i); >>>> } >>>> } >>>> >>>> public static int getArrayLength(Map<Object, Object> map) throws >>>> NoSuchFieldException, IllegalAccessException { >>>> Field field = HashMap.class.getDeclaredField("table"); >>>> field.setAccessible(true); >>>> Object table = field.get(map); >>>> return Array.getLength(table); >>>> } >>>> >>>> } >>>> >>>> run this and we get the output: >>>> >>>> a : 16 >>>> b : 16 >>>> c : 32 >>>> d : 32 >>>> >>>> So I go see the codes. >>>> >>>> /** >>>> * Implements Map.putAll and Map constructor. >>>> * >>>> * @param m the map >>>> * @param evict false when initially constructing this map, else >>>> * true (relayed to method afterNodeInsertion). >>>> */ >>>> final void putMapEntries(Map<? extends K, ? extends V> m, boolean evict) { >>>> int s = m.size(); >>>> if (s > 0) { >>>> if (table == null) { // pre-size >>>> float ft = ((float)s / loadFactor) + 1.0F; >>>> int t = ((ft < (float)MAXIMUM_CAPACITY) ? >>>> (int)ft : MAXIMUM_CAPACITY); >>>> if (t > threshold) >>>> threshold = tableSizeFor(t); >>>> } else { >>>> // Because of linked-list bucket constraints, we cannot >>>> // expand all at once, but can reduce total resize >>>> // effort by repeated doubling now vs later >>>> while (s > threshold && table.length < MAXIMUM_CAPACITY) >>>> resize(); >>>> } >>>> >>>> for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) { >>>> K key = e.getKey(); >>>> V value = e.getValue(); >>>> putVal(hash(key), key, value, false, evict); >>>> } >>>> } >>>> } >>>> >>>> yep I do think *((float)s / loadFactor) + 1.0F* here is wrong. >>>> >>>> It should be *Math.ceil((float)s / loadFactor)* >>>> >>>> So I wish to generate a pull request. >>>> >>>> Anyone interested? >>>> >>>>
