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/* $Header: d:/cvsroot/tads/html/htmlhash.h,v 1.2 1999/05/17 02:52:21 MJRoberts Exp $ */
/*
* Copyright (c) 1997 by Michael J. Roberts. All Rights Reserved.
*
* Please see the accompanying license file, LICENSE.TXT, for information
* on using and copying this software.
*/
/*
Name
htmlhash.h - hash table implementation
Function
Notes
Modified
10/25/97 MJRoberts - Creation
*/
#ifndef HTMLHASH_H
#define HTMLHASH_H
#ifndef TADSHTML_H
#include "tadshtml.h"
#endif
/* ------------------------------------------------------------------------ */
/*
* Hash function interface class. Hash table clients must implement an
* appropriate hash function to use with the hash table; this abstract
* class provides the necessary interface.
*/
class CHtmlHashFunc
{
public:
virtual ~CHtmlHashFunc() { }
virtual unsigned int compute_hash(const textchar_t *str, size_t len) = 0;
};
/* ------------------------------------------------------------------------ */
/*
* Hash table symbol entry. This is an abstract class; subclasses must
* provide a symbol-matching method.
*/
class CHtmlHashEntry
{
public:
/*
* Construct the hash entry. 'copy' indicates whether we should
* make a private copy of the value; if not, the caller must keep
* the original string around as long as this hash entry is around.
* If 'copy' is true, we'll make a private copy of the string
* immediately, so the caller need not keep it around after
* constructing the entry.
*/
CHtmlHashEntry(const textchar_t *str, size_t len, int copy);
virtual ~CHtmlHashEntry();
/* determine if this entry matches a given string */
virtual int matches(const textchar_t *str, size_t len) = 0;
/* list link */
CHtmlHashEntry *nxt_;
/* get the string pointer and length */
const textchar_t *getstr() const { return str_; }
size_t getlen() const { return len_; }
protected:
const textchar_t *str_;
size_t len_;
int copy_ : 1;
};
/* ------------------------------------------------------------------------ */
/*
* Hash table
*/
class CHtmlHashTable
{
public:
/*
* Construct a hash table. IMPORTANT: the hash table object takes
* ownership of the hash function object, so the hash table object
* will delete the hash function object when the table is deleted.
*/
CHtmlHashTable(int hash_table_size, CHtmlHashFunc *hash_function);
/* delete the hash table */
~CHtmlHashTable();
/*
* Add a symbol. If 'copy' is true, it means that we need to make
* a private copy of the string; otherwise, the caller must ensure
* that the string remains valid as long as the hash table entry
* remains valid, since we'll just store a pointer to the original
* string. IMPORTANT: the hash table takes over ownership of the
* hash table entry; the hash table will delete this object when the
* hash table is deleted, so the client must not delete the entry
* once it's been added to the table.
*/
void add(CHtmlHashEntry *entry);
/*
* Remove an object from the cache. This routine does not delete
* the object.
*/
void remove(CHtmlHashEntry *entry);
/*
* Delete all entries in the table
*/
void delete_all_entries();
/*
* Find an entry in the table matching the given string
*/
CHtmlHashEntry *find(const textchar_t *str, size_t len);
/*
* find an entry that matches the longest leading substring of the
* given string
*/
CHtmlHashEntry *find_leading_substr(const textchar_t *str, size_t len);
/*
* Enumerate all entries, invoking a callback for each entry in the
* table
*/
void enum_entries(void (*func)(void *ctx, class CHtmlHashEntry *entry),
void *ctx);
private:
/* internal service routine for checking hash table sizes for validity */
int is_power_of_two(int n);
/* compute the hash value for an entry/a string */
unsigned int compute_hash(CHtmlHashEntry *entry);
unsigned int compute_hash(const textchar_t *str, size_t len);
/* the table of hash entries */
CHtmlHashEntry **table_;
size_t table_size_;
/* hash function */
CHtmlHashFunc *hash_function_;
};
/* ------------------------------------------------------------------------ */
/*
* Simple case-insensitive hash function
*/
class CHtmlHashFuncCI: public CHtmlHashFunc
{
public:
unsigned int compute_hash(const textchar_t *str, size_t len);
};
/* ------------------------------------------------------------------------ */
/*
* Simple case-sensitive hash function implementation
*/
class CHtmlHashFuncCS: public CHtmlHashFunc
{
public:
unsigned int compute_hash(const textchar_t *str, size_t len);
};
/* ------------------------------------------------------------------------ */
/*
* Concrete subclass of CHtmlHashEntry providing a case-insensitive
* symbol match implementation
*/
class CHtmlHashEntryCI: public CHtmlHashEntry
{
public:
CHtmlHashEntryCI(const textchar_t *str, size_t len, int copy)
: CHtmlHashEntry(str, len, copy) { }
virtual int matches(const textchar_t *str, size_t len);
};
/* ------------------------------------------------------------------------ */
/*
* Concrete subclass of CHtmlHashEntry providing a case-sensitive symbol
* match implementation
*/
class CHtmlHashEntryCS: public CHtmlHashEntry
{
public:
CHtmlHashEntryCS(const textchar_t *str, size_t len, int copy)
: CHtmlHashEntry(str, len, copy) { }
virtual int matches(const textchar_t *str, size_t len);
};
/* ------------------------------------------------------------------------ */
/*
* Simple hash function that hashes an (unsigned int) as its key
*/
class CHtmlHashFuncUInt: public CHtmlHashFuncCS
{
};
/*
* Hash entry that maps an integer key to a void* value
*/
class CHtmlHashEntryUInt: public CHtmlHashEntryCS
{
public:
CHtmlHashEntryUInt(unsigned int key, void *val)
: CHtmlHashEntryCS((const textchar_t *)&key, sizeof(key), FALSE)
{
key_ = key;
str_ = (const textchar_t *)&key_;
val_ = val;
}
/* the key vlaue */
unsigned int key_;
/* the value associated with the key */
void *val_;
};
#endif /* HTMLHASH_H */
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