hashtable.h

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/*  
 *      HashTable.h - HashTable class for MAXScript
 *
 *          Copyright (c) John Wainwright 1996
 *
 */

#pragma once

#include "..\kernel\value.h"

struct binding 
{
    void*   key;
    void*   value;
};

struct secondary                        /* secondary extent struct          */
{
    UINT    size;                     /* size of secondary extent   */  // SR NOTE64: was size_t
    binding*    bindings;           /* table of bindings                */
};
    
#define KEY_IS_OBJECT   0x0001      /* init flags that indicate whether keys & values are full MXS collectable objects */
#define VALUE_IS_OBJECT 0x0002

ScripterExport int  default_eq_fn(const void* key1, const void* key2);  /* default comparator & hash fns */
ScripterExport DWORD_PTR default_hash_fn(const void* key);

class HashTabMapper;

visible_class_debug_ok (HashTable)

class HashTable : public Value
{
public:
   // SR NOTE64: hash functions returned "INT_PTR" (and previously I suppose they
   // used to return 'int'; in Win64, the hash values can get pretty huge, and negative,
   // and then hash_value % size will give a negative value -- not good.  I'd change it
   // to a DWORD, but then the default hash function, which just returns the pointer
   // casted to an INT_PTR, would have to do more computations and this might slow
   // things down too much.  So I'll just change it to an unsigned value instead and
   // introduce a typedef for it.
   typedef DWORD_PTR (*hash_fn_type)(const void*);
   typedef int       (*eq_fn_type)(const void*, const void*);

private:
    secondary   **table;            /* primary extent: tbl of second's  */
    UINT        size;               /* table size                       */  // SR NOTE64: Was size_t
    int         n_entries;          /* no. entries in primary extent    */
    eq_fn_type  eq_fn;            /* key equivalence function       */
    hash_fn_type hash_fn;         /* key hgashing function          */
    int         cursor;             /* cursors used for sequencing...   */
    int         secondCursor;           
    short       flags;
    HashTable*  inner;              /* links to next & prev tables when */
    HashTable*  outer;              /* used as a lexical scope table    */
    int         level;              // scope nesting level

public:
    ScripterExport HashTable(UINT primary_size, eq_fn_type key_eq_fn, hash_fn_type key_hash_fn, int flags);
                HashTable() { init(17, default_eq_fn, default_hash_fn, KEY_IS_OBJECT + VALUE_IS_OBJECT); }
                HashTable(UINT primary_size) { init(primary_size, default_eq_fn, default_hash_fn, KEY_IS_OBJECT + VALUE_IS_OBJECT); }
    ScripterExport ~HashTable();
    ScripterExport void     init(UINT primary_size, eq_fn_type key_eq_fn, hash_fn_type key_hash_fn, int flags);
#   define      is_hashtable(v) ((DbgVerify(!is_sourcepositionwrapper(v)), (v))->tag == class_tag(HashTable))

    ScripterExport static CRITICAL_SECTION hash_update; // for syncing allocation hashtable updates

    static void setup();

                classof_methods (HashTable, Value);
    void        collect() { delete this;}
    ScripterExport void     gc_trace();

    ScripterExport Value*   get(const void* key);
    ScripterExport Value*   put(const void* key, const void* val);
    ScripterExport Value*   put_new(const void* key, const void* val);
    ScripterExport Value*   find_key(const void *val);
    ScripterExport Value*   set(const void* key, const void* val);
    ScripterExport void     remove(const void* key);
    ScripterExport void     map_keys_and_vals(void (*fn)(const void* key, const void* val, void* arg), void* arg);
    ScripterExport void     map_keys_and_vals(HashTabMapper* mapper);
    ScripterExport int      num_entries() { return n_entries; }


    HashTable*  enter_scope();
    HashTable*  leave_scope();
    HashTable*  next_scope();
    int         scope_level() { return level; }
};

class HashTabMapper 
{
public:
    virtual void map(const void* key, const void* val)=0;
};

#define SECONDARY_BUCKET    5