X-Git-Url: http://plrg.eecs.uci.edu/git/?p=model-checker.git;a=blobdiff_plain;f=hashtable.h;h=2802eabead5af4f48ec49196a21ad34edfe1fa1a;hp=a15265bafbe7f1b7658c4ddbcb8bcb8b6175a124;hb=HEAD;hpb=360053ccc0b524d1a902a6e0a4f91fb4889311f9

diff --git a/hashtable.h b/hashtable.h
index a15265b..2802eab 100644
--- a/hashtable.h
+++ b/hashtable.h
@@ -2,8 +2,8 @@
  *  @brief Hashtable.  Standard chained bucket variety.
  */
 
-#ifndef HASHTABLE_H
-#define HASHTABLE_H
+#ifndef __HASHTABLE_H__
+#define __HASHTABLE_H__
 
 #include <stdlib.h>
 #include <stdio.h>
@@ -12,29 +12,24 @@
 #include "common.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.
+ * @brief HashTable node
  *
  * @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<typename _Key, typename _Val>
-
 struct hashlistnode {
 	_Key key;
 	_Val val;
 };
 
 /**
- * Hashtable class. By default it is snapshotting, but you can pass in your own
- * allocation functions.
+ * @brief A simple, custom hash table
+ *
+ * By default it is snapshotting, but you can pass in your own allocation
+ * functions. Note that this table does not support the value 0 (NULL) used as
+ * a key and is designed primarily with pointer-based keys in mind. Other
+ * primitive key types are supported only for non-zero values.
  *
  * @tparam _Key    Type name for the key
  * @tparam _Val    Type name for the values to be stored
@@ -49,10 +44,10 @@ struct hashlistnode {
  *                 snapshotting.
  */
 template<typename _Key, typename _Val, typename _KeyInt, int _Shift = 0, void * (* _malloc)(size_t) = snapshot_malloc, void * (* _calloc)(size_t, size_t) = snapshot_calloc, void (*_free)(void *) = snapshot_free>
-	class HashTable {
+class HashTable {
  public:
 	/**
-	 * Constructor
+	 * @brief Hash table constructor
 	 * @param initialcapacity Sets the initial capacity of the hash table.
 	 * Default size 1024.
 	 * @param factor Sets the percentage full before the hashtable is
@@ -69,7 +64,7 @@ template<typename _Key, typename _Val, typename _KeyInt, int _Shift = 0, void *
 		size = 0; // Initial number of elements in the hash
 	}
 
-	/** Destructor */
+	/** @brief Hash table destructor */
 	~HashTable() {
 		_free(table);
 	}
@@ -94,14 +89,21 @@ template<typename _Key, typename _Val, typename _KeyInt, int _Shift = 0, void *
 		_free(p);
 	}
 
-	/** Reset the table to its initial state. */
+	/** @brief Reset the table to its initial state. */
 	void reset() {
 		memset(table, 0, capacity * sizeof(struct hashlistnode<_Key, _Val>));
 		size = 0;
 	}
 
-	/** Put a key value pair into the table. */
+	/**
+	 * @brief Put a key/value pair into the table
+	 * @param key The key for the new value; must not be 0 or NULL
+	 * @param val The value to store in the table
+	 */
 	void put(_Key key, _Val val) {
+		/* HashTable cannot handle 0 as a key */
+		ASSERT(key);
+
 		if (size > threshold)
 			resize(capacity << 1);
 
@@ -123,10 +125,17 @@ template<typename _Key, typename _Val, typename _KeyInt, int _Shift = 0, void *
 		size++;
 	}
 
-	/** Lookup the corresponding value for the given key. */
+	/**
+	 * @brief Lookup the corresponding value for the given key
+	 * @param key The key for finding the value; must not be 0 or NULL
+	 * @return The value in the table, if the key is found; otherwise 0
+	 */
 	_Val get(_Key key) const {
 		struct hashlistnode<_Key, _Val> *search;
 
+		/* HashTable cannot handle 0 as a key */
+		ASSERT(key);
+
 		unsigned int index = ((_KeyInt)key) >> _Shift;
 		do {
 			index &= capacitymask;
@@ -135,13 +144,20 @@ template<typename _Key, typename _Val, typename _KeyInt, int _Shift = 0, void *
 				return search->val;
 			index++;
 		} while (search->key);
-		return (_Val) 0;
+		return (_Val)0;
 	}
 
-	/** Check whether the table contains a value for the given key. */
+	/**
+	 * @brief Check whether the table contains a value for the given key
+	 * @param key The key for finding the value; must not be 0 or NULL
+	 * @return True, if the key is found; false otherwise
+	 */
 	bool contains(_Key key) const {
 		struct hashlistnode<_Key, _Val> *search;
 
+		/* HashTable cannot handle 0 as a key */
+		ASSERT(key);
+
 		unsigned int index = ((_KeyInt)key) >> _Shift;
 		do {
 			index &= capacitymask;
@@ -153,22 +169,25 @@ template<typename _Key, typename _Val, typename _KeyInt, int _Shift = 0, void *
 		return false;
 	}
 
-	/** Resize the table. */
+	/**
+	 * @brief Resize the table
+	 * @param newsize The new size of the table
+	 */
 	void resize(unsigned int newsize) {
 		struct hashlistnode<_Key, _Val> *oldtable = table;
 		struct hashlistnode<_Key, _Val> *newtable;
 		unsigned int oldcapacity = capacity;
 
-		if ((newtable = (struct hashlistnode<_Key, _Val> *) _calloc(newsize, sizeof(struct hashlistnode<_Key, _Val>))) == NULL) {
+		if ((newtable = (struct hashlistnode<_Key, _Val> *)_calloc(newsize, sizeof(struct hashlistnode<_Key, _Val>))) == NULL) {
 			model_print("calloc error %s %d\n", __FILE__, __LINE__);
 			exit(EXIT_FAILURE);
 		}
 
-		table = newtable;          //Update the global hashtable upon resize()
+		table = newtable;          // Update the global hashtable upon resize()
 		capacity = newsize;
 		capacitymask = newsize - 1;
 
-		threshold = (unsigned int) (newsize * loadfactor);
+		threshold = (unsigned int)(newsize * loadfactor);
 
 		struct hashlistnode<_Key, _Val> *bin = &oldtable[0];
 		struct hashlistnode<_Key, _Val> *lastbin = &oldtable[oldcapacity];
@@ -188,7 +207,7 @@ template<typename _Key, typename _Val, typename _KeyInt, int _Shift = 0, void *
 			search->val = bin->val;
 		}
 
-		_free(oldtable);            //Free the memory of the old hash table
+		_free(oldtable);            // Free the memory of the old hash table
 	}
 
  private:
@@ -199,4 +218,5 @@ template<typename _Key, typename _Val, typename _KeyInt, int _Shift = 0, void *
 	unsigned int threshold;
 	double loadfactor;
 };
-#endif
+
+#endif /* __HASHTABLE_H__ */