X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=hashtable.h;h=a337df41ea03f7856595ab1d9aa15579dce51f51;hb=0b9a8924695870c15bc39feb6ec96d525954eaba;hp=5d9e2d620045924a20db2b3bea491622bfe1ebd0;hpb=ac06a98f90fe5c333cd8628e72e11f532c0c6444;p=model-checker.git diff --git a/hashtable.h b/hashtable.h index 5d9e2d6..a337df4 100644 --- a/hashtable.h +++ b/hashtable.h @@ -7,12 +7,27 @@ #include #include - +#include "mymemory.h" + +/** + * Hashtable linked node class, for chained storage of hash table conflicts. By + * default it is snapshotting, but you can pass in your own allocation + * functions. + * + * @tparam _Key Type name for the key + * @tparam _Val Type name for the values to be stored + * @tparam _malloc Provide your own 'malloc' for the table, or default to + * snapshotting. + * @tparam _calloc Provide your own 'calloc' for the table, or default to + * snapshotting. + * @tparam _free Provide your own 'free' for the table, or default to + * snapshotting. + */ template - struct hashlistnode { - _Key key; - _Val val; - struct hashlistnode<_Key,_Val, _malloc, _calloc, _free> *next; +struct hashlistnode { + _Key key; + _Val val; + struct hashlistnode<_Key,_Val, _malloc, _calloc, _free> *next; void * operator new(size_t size) { return _malloc(size); @@ -29,14 +44,34 @@ template +/** + * Hashtable class. By default it is snapshotting, but you can pass in your own + * allocation functions. + * + * @tparam _Key Type name for the key + * @tparam _Val Type name for the values to be stored + * @tparam _KeyInt Integer type that is at least as large as _Key. Used for key + * manipulation and storage. + * @tparam _Shift Logical shift to apply to all keys. Default 0. + * @tparam _malloc Provide your own 'malloc' for the table, or default to + * snapshotting. + * @tparam _calloc Provide your own 'calloc' for the table, or default to + * snapshotting. + * @tparam _free Provide your own 'free' for the table, or default to + * snapshotting. + */ +template class HashTable { public: + /** + * Constructor + * @param initialcapacity Sets the initial capacity of the hash table. + * Default size 1024. + * @param factor Sets the percentage full before the hashtable is + * resized. Default ratio 0.5. + */ HashTable(unsigned int initialcapacity=1024, double factor=0.5) { // Allocate space for the hash table table = (struct hashlistnode<_Key,_Val, _malloc, _calloc,_free> **) _calloc(initialcapacity, sizeof(struct hashlistnode<_Key,_Val, _malloc, _calloc, _free> *)); @@ -47,6 +82,7 @@ template * bin = table[i]; @@ -59,25 +95,29 @@ template * bin = table[i]; while(bin!=NULL) { struct hashlistnode<_Key,_Val, _malloc, _calloc, _free> * next=bin->next; @@ -91,14 +131,10 @@ template threshold) { - //Resize - unsigned int newsize = capacity << 1; - resize(newsize); - } + if (size > threshold) + resize(capacity << 1); struct hashlistnode<_Key,_Val, _malloc, _calloc, _free> *ptr = table[(((_KeyInt)key) & mask)>>_Shift]; - size++; struct hashlistnode<_Key,_Val, _malloc, _calloc, _free> *search = ptr; while(search!=NULL) { @@ -114,18 +150,24 @@ templateval=val; newptr->next=ptr; table[(((_KeyInt)key)&mask)>>_Shift]=newptr; + size++; } - /** Put a key entry into the table. */ - _Val * ensureptr(_Key key) { - if(size > threshold) { - //Resize - unsigned int newsize = capacity << 1; - resize(newsize); - } + /** + * @brief Get a valid pointer to a value corresponding to a given key + * + * Ensure that key is present in the hash table, then return a pointer + * to its value bin. This may require either creating a new bin for + * this key (with a default-constructed value) or simply locating and + * returning a pointer to an existing value. + * @param key The key to check + * @return A pointer to the value in the table + */ + _Val * get_safe_ptr(_Key key) { + if (size > threshold) + resize(capacity << 1); - struct hashlistnode<_Key,_Val, _malloc, _calloc, _free> *ptr = table[(((_KeyInt)key) & mask)>>_Shift]; - size++; + struct hashlistnode<_Key,_Val, _malloc, _calloc, _free> *ptr = table[(((_KeyInt)key) & mask)>>_Shift]; struct hashlistnode<_Key,_Val, _malloc, _calloc, _free> *search = ptr; while(search!=NULL) { @@ -139,6 +181,7 @@ templatekey=key; newptr->next=ptr; table[(((_KeyInt)key)&mask)>>_Shift]=newptr; + size++; return &newptr->val; }