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nsHashSets.h
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00037 
00038 #ifndef __nsHashSets_h__
00039 #define __nsHashSets_h__
00040 
00041 #include "nsDoubleHashtable.h"
00042 
00043 /*
00044  * HASH SETS
00045  *
00046  * These hash classes describe hashtables that contain keys without values.
00047  * This is useful when you want to store things and then just test for their
00048  * existence later.  We have defined standard ones for string, int and void.
00049  *
00050  * nsStringHashSet:  nsAString&
00051  * nsCStringHashSet: nsACString&
00052  * nsInt32HashSet:   PRInt32
00053  * nsVoidHashSet:    void*
00054  *
00055  * USAGE:
00056  * Put(): put a thing of the given type into the set
00057  * Contains(): whether it contains a thing of the given type
00058  * To use, you just do: (for example)
00059  *
00060  * #include "nsDoubleHashtable.h"
00061  * nsInt32HashSet mySet;
00062  * mySet.Init(1);
00063  * mySet.Put(5);
00064  * if (mySet.Contains(5)) {
00065  *   printf("yay\n");
00066  * }
00067  *
00068  * There is a nice convenient macro for declaring empty map classes:
00069  * DECL_DHASH_SET(CLASSNAME, ENTRY_CLASS, KEY_TYPE)
00070  * - CLASSNAME: the name of the class
00071  * - ENTRY_CLASS: the name of the entry class with the key in it
00072  * - KEY_TYPE: the type of key for Put() and Contains()
00073  *
00074  * DHASH_SET(CLASSNAME, ENTRY_CLASS, KEY_TYPE) is the companion macro
00075  * you must put in the .cpp (implementation) code.
00076  */
00077 
00078 #define DECL_DHASH_SET(CLASSNAME,ENTRY_CLASS,KEY_TYPE)                        \
00079 DECL_DHASH_WRAPPER(CLASSNAME##Super,ENTRY_CLASS,KEY_TYPE)                     \
00080 class DHASH_EXPORT CLASSNAME : public CLASSNAME##Super {                      \
00081 public:                                                                       \
00082   CLASSNAME() : CLASSNAME##Super() { }                                        \
00083   ~CLASSNAME() { }                                                            \
00084   nsresult Put(const KEY_TYPE aKey) {                                         \
00085     return AddEntry(aKey) ? NS_OK : NS_ERROR_OUT_OF_MEMORY;                   \
00086   }                                                                           \
00087   PRBool Contains(const KEY_TYPE aKey) {                                      \
00088     return GetEntry(aKey) ? PR_TRUE : PR_FALSE;                               \
00089   }                                                                           \
00090 };
00091 
00092 #define DHASH_SET(CLASSNAME,ENTRY_CLASS,KEY_TYPE)                              \
00093 DHASH_WRAPPER(CLASSNAME##Super,ENTRY_CLASS,KEY_TYPE)
00094 
00095 #undef DHASH_EXPORT
00096 #define DHASH_EXPORT NS_COM
00097 
00098 DECL_DHASH_SET(nsStringHashSet, PLDHashStringEntry, nsAString&)
00099 DECL_DHASH_SET(nsCStringHashSet,PLDHashCStringEntry,nsACString&)
00100 DECL_DHASH_SET(nsInt32HashSet,  PLDHashInt32Entry,  PRInt32)
00101 DECL_DHASH_SET(nsVoidHashSet,   PLDHashVoidEntry,   void*)
00102 
00103 #undef DHASH_EXPORT
00104 #define DHASH_EXPORT
00105 
00106 
00107 #endif