qse/qse/lib/stx/dic.c

300 lines
7.7 KiB
C

/*
* $Id$
*/
#include "stx.h"
#include <qse/cmn/str.h>
/* NOTE:
* The code here implements SystemDictionary whose key is always a symbol.
* Dictionary, on the contrary, can accept any object as a key.
*/
struct qse_stx_association_t
{
qse_stx_objhdr_t h;
qse_word_t key;
qse_word_t value;
};
typedef struct qse_stx_association_t qse_stx_association_t;
struct qse_stx_systemdictionary_t
{
qse_stx_objhdr_t h;
qse_word_t tally;
/* variable part begins here */
qse_word_t slot[1];
};
typedef struct qse_stx_systemdictionary_t qse_stx_systemdictionary_t;
static qse_word_t new_association (
qse_stx_t* stx, qse_word_t key, qse_word_t value)
{
#if 0
qse_word_t x;
x = qse_stx_allocwordobj (
stx, QSE_NULL, QSE_STX_ASSOCIATION_SIZE, QSE_NULL, 0);
if (ISNIL(stx,x)) return stx->ref.nil;
OBJCLASS(stx,x) = stx->ref.class_association;
WORDAT(stx,x,QSE_STX_ASSOCIATION_KEY) = key;
WORDAT(stx,x,QSE_STX_ASSOCIATION_VALUE) = value;
return x;
#endif
qse_word_t x;
QSE_ASSERT (REFISIDX(stx,stx->ref.class_association));
QSE_ASSERT (!ISNIL(stx,stx->ref.class_association));
x = qse_stx_instantiate (
stx, stx->ref.class_association, QSE_NULL, QSE_NULL, 0);
if (!ISNIL(stx,x))
{
WORDAT(stx,x,QSE_STX_ASSOCIATION_KEY) = key;
WORDAT(stx,x,QSE_STX_ASSOCIATION_VALUE) = value;
}
return x;
}
static qse_word_t expand (qse_stx_t* stx, qse_word_t dic)
{
qse_word_t oldcapa, newdic, newcapa;
qse_stx_systemdictionary_t* oldptr, * newptr;
QSE_ASSERT (REFISIDX(stx,stx->ref.class_systemdictionary));
QSE_ASSERT (!ISNIL(stx,stx->ref.class_systemdictionary));
QSE_ASSERTX (
REFISIDX(stx,dic),
"The reference is not an object index"
);
/* WARNING:
* if this assertion fails, adjust the initial size of the
* system dicionary. i don't want this function to be called
* during the bootstrapping.
*/
QSE_ASSERT (OBJCLASS(stx,dic) == stx->ref.class_systemdictionary);
/* get the current capacity excluding the tally field */
oldcapa = OBJSIZE(stx,dic) - 1;
/* instantiate a new dictionary with its capacity doubled.
* 1 fixed slot for the tally field is encoded is the class part.
* so 'newcapa' specifies the number of slots to hold associations */
newcapa = oldcapa * 2;
newdic = qse_stx_instantiate (
stx, OBJCLASS(stx,dic),
QSE_NULL, QSE_NULL, newcapa
);
if (ISNIL(stx,newdic)) return stx->ref.nil;
/* get object pointers for easier access without using macros */
oldptr = (qse_stx_systemdictionary_t*)PTRBYREF(stx,dic);
newptr = (qse_stx_systemdictionary_t*)PTRBYREF(stx,newdic);
newptr->tally = INTTOREF(stx,0);
QSE_ASSERT (newcapa == OBJSIZE(stx,newdic)-1);
/* reorganize the dictionary */
while (oldcapa > 0)
{
qse_word_t assoc;
assoc = oldptr->slot[--oldcapa];
if (!ISNIL(stx,assoc))
{
qse_word_t index;
index = qse_stx_hashobj (stx, WORDAT(stx,assoc,QSE_STX_ASSOCIATION_KEY)) % newcapa;
while (!ISNIL(stx,newptr->slot[index]))
index = (index + 1) % newcapa;
newptr->slot[index] = assoc;
}
}
newptr->tally = oldptr->tally;
/* TODO: explore if dic can be immediately destroyed. */
qse_stx_swapmem (stx, REFTOIDX(stx,dic), REFTOIDX(stx,newdic));
return dic;
}
static qse_word_t find_basic_index (
qse_stx_t* stx, qse_word_t dic, qse_word_t key)
{
qse_word_t capa, index;
qse_stx_systemdictionary_t* dicptr;
/* ensure that dic is a system dictionary */
QSE_ASSERT (REFISIDX(stx,dic));
QSE_ASSERT (OBJTYPE(stx,dic) == WORDOBJ);
QSE_ASSERT (dic == stx->ref.sysdic ||
OBJCLASS(stx,dic) == stx->ref.class_systemdictionary);
/* ensure that the key is a symbol */
QSE_ASSERT (REFISIDX(stx,key));
QSE_ASSERT (OBJCLASS(stx,key) == stx->ref.class_symbol);
QSE_ASSERT (OBJTYPE(stx,key) == CHAROBJ);
capa = OBJSIZE(stx,dic) - 1; /* exclude the tally field */
index = qse_stx_hashobj (stx, key) % capa;
dicptr = (qse_stx_systemdictionary_t*)PTRBYREF(stx,dic);
do
{
qse_word_t assoc, sym;
assoc = dicptr->slot[index];
if (ISNIL(stx,assoc)) break; /* not found */
sym = WORDAT (stx, assoc, QSE_STX_ASSOCIATION_KEY);
/* make sure that the key is a symbol */
QSE_ASSERT (REFISIDX(stx,sym));
QSE_ASSERT (OBJCLASS(stx,sym) == stx->ref.class_symbol);
QSE_ASSERT (OBJTYPE(stx,sym) == CHAROBJ);
/* check if the key matches */
if (qse_strxncmp(
&CHARAT(stx,key,0), OBJSIZE(stx,key),
&CHARAT(stx,sym,0), OBJSIZE(stx,sym)) == 0) break;
index = (index + 1) % capa;
}
while (1);
/* Include the tally back when returning the association index.
* you can access the association with WORDAT() by using this index. */
return index + 1;
}
/* look up a system dictionary by a null-terminated string */
qse_word_t qse_stx_lookupdic (
qse_stx_t* stx, qse_word_t dic, const qse_char_t* skey)
{
qse_word_t capa, index;
qse_stx_systemdictionary_t* dicptr;
QSE_ASSERT (REFISIDX(stx,dic));
QSE_ASSERT (OBJTYPE(stx,dic) == WORDOBJ);
QSE_ASSERT (dic == stx->ref.sysdic ||
OBJCLASS(stx,dic) == stx->ref.class_systemdictionary);
capa = OBJSIZE(stx,dic) - 1; /* exclude the tally field */
index = qse_stx_hashstr (stx, skey) % capa;
dicptr = (qse_stx_systemdictionary_t*)PTRBYREF(stx,dic);
do
{
qse_word_t assoc, keyref;
assoc = dicptr->slot[index];
if (ISNIL(stx,assoc)) break; /* not found */
keyref = WORDAT(stx,assoc,QSE_STX_ASSOCIATION_KEY);
QSE_ASSERT (REFISIDX(stx,keyref));
QSE_ASSERT (OBJCLASS(stx,keyref) == stx->ref.class_symbol);
QSE_ASSERT (OBJTYPE(stx,keyref) == CHAROBJ);
if (qse_strxcmp (
&CHARAT(stx,keyref,0), OBJSIZE(stx,keyref),
skey) == 0) break;
index = (index + 1) % capa;
}
while (1);
return dicptr->slot[index];
}
qse_word_t qse_stx_getdic (qse_stx_t* stx, qse_word_t dic, qse_word_t key)
{
/* returns the association for the key. nil if it is not found */
return WORDAT (stx, dic, find_basic_index (stx, dic, key));
}
qse_word_t qse_stx_putdic (
qse_stx_t* stx, qse_word_t dic, qse_word_t key, qse_word_t value)
{
qse_word_t index, capa, tally, assoc;
qse_stx_systemdictionary_t* dicptr;
/* the dicionary must have at least one slot excluding tally */
QSE_ASSERT (OBJSIZE(stx,dic) > 1);
capa = OBJSIZE(stx,dic) - 1;
dicptr = (qse_stx_systemdictionary_t*)PTRBYREF(stx,dic);
tally = REFTOINT(stx,dicptr->tally);
index = find_basic_index (stx, dic, key) - 1;
assoc = dicptr->slot[index];
/*assoc = WORDAT(stx,dic,slot);*/
if (ISNIL(stx,assoc))
{
/* the key is not found */
if (tally + 1 >= capa)
{
/* Enlarge the dictionary if there is one free slot left.
* The last free slot left is always maintained to be nil.
* The nil slot plays multiple roles.
* - make sure that lookup never enters a infinite loop.
* - the slot's index can be returned when no key is found.
*/
if (ISNIL(stx, expand (stx, dic))) return stx->ref.nil;
capa = OBJSIZE(stx,dic) - 1;
dicptr = (qse_stx_systemdictionary_t*)PTRBYREF(stx,dic);
/* tally must remain the same after expansion */
QSE_ASSERT (tally == REFTOINT(stx,dicptr->tally));
/* find the key in the expanded dictionary again */
index = find_basic_index (stx, dic, key) - 1;
/* the basic index returned must point to nil meaning
* the key is not found */
QSE_ASSERT (ISNIL(stx,dicptr->slot[index]));
}
assoc = new_association (stx, key, value);
if (ISNIL(stx,assoc)) return stx->ref.nil;
dicptr->slot[index] = assoc;
dicptr->tally = INTTOREF(stx,tally+1);
}
else
{
/* found the key. change the value */
WORDAT(stx,assoc,QSE_STX_ASSOCIATION_VALUE) = value;
}
return assoc;
}
#if 0
void qse_stx_walkdic (
qse_stx_t* stx, qse_word_t dic,
void (*func) (qse_stx_t*,qse_word_t,void*), void* data)
{
qse_word_t index, assoc;
qse_word_t size = OBJSIZE(stx,dic);
for (index = 1; index < size; index++)
{
assoc = WORDAT (stx, dic, index);
if (assoc == stx->nil) continue;
func (stx, assoc, data);
}
}
#endif