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/*
** tree.c
** TecCGraf - PUC-Rio
*/
char *rcs_tree="$Id: tree.c,v 1.27 1997/06/09 17:28:14 roberto Exp roberto $";
#include <string.h>
#include "luamem.h"
#include "lua.h"
#include "tree.h"
#include "lex.h"
#include "hash.h"
#include "table.h"
#include "fallback.h"
#define NUM_HASHS 64
typedef struct {
int size;
int nuse; /* number of elements (including EMPTYs) */
TaggedString **hash;
} stringtable;
static int initialized = 0;
static stringtable string_root[NUM_HASHS];
static TaggedString EMPTY = {LUA_T_STRING, NULL, {{NOT_USED, NOT_USED}},
0, 2, {0}};
static unsigned long hash (char *s, int tag)
{
unsigned long h;
if (tag != LUA_T_STRING)
h = (unsigned long)s;
else {
h = 0;
while (*s)
h = ((h<<5)-h)^(unsigned char)*(s++);
}
return h;
}
static void luaI_inittree (void)
{
int i;
for (i=0; i<NUM_HASHS; i++) {
string_root[i].size = 0;
string_root[i].nuse = 0;
string_root[i].hash = NULL;
}
}
static void initialize (void)
{
initialized = 1;
luaI_inittree();
luaI_addReserved();
luaI_initsymbol();
luaI_initconstant();
luaI_initfallbacks();
}
static void grow (stringtable *tb)
{
int newsize = luaI_redimension(tb->size);
TaggedString **newhash = newvector(newsize, TaggedString *);
int i;
for (i=0; i<newsize; i++)
newhash[i] = NULL;
/* rehash */
tb->nuse = 0;
for (i=0; i<tb->size; i++)
if (tb->hash[i] != NULL && tb->hash[i] != &EMPTY) {
int h = tb->hash[i]->hash%newsize;
while (newhash[h])
h = (h+1)%newsize;
newhash[h] = tb->hash[i];
tb->nuse++;
}
luaI_free(tb->hash);
tb->size = newsize;
tb->hash = newhash;
}
static TaggedString *newone(char *buff, int tag, unsigned long h)
{
TaggedString *ts;
if (tag == LUA_T_STRING) {
ts = (TaggedString *)luaI_malloc(sizeof(TaggedString)+strlen(buff));
strcpy(ts->str, buff);
ts->u.s.varindex = ts->u.s.constindex = NOT_USED;
ts->tag = LUA_T_STRING;
}
else {
ts = (TaggedString *)luaI_malloc(sizeof(TaggedString));
ts->u.v = buff;
ts->tag = tag == LUA_ANYTAG ? 0 : tag;
}
ts->marked = 0;
ts->hash = h;
return ts;
}
static TaggedString *insert (char *buff, int tag, stringtable *tb)
{
TaggedString *ts;
unsigned long h = hash(buff, tag);
int i;
int j = -1;
if ((Long)tb->nuse*3 >= (Long)tb->size*2)
{
if (!initialized)
initialize();
grow(tb);
}
i = h%tb->size;
while ((ts = tb->hash[i]) != NULL)
{
if (ts == &EMPTY)
j = i;
else if ((ts->tag == LUA_T_STRING) ?
(tag == LUA_T_STRING && (strcmp(buff, ts->str) == 0)) :
((tag == ts->tag || tag == LUA_ANYTAG) && buff == ts->u.v))
return ts;
i = (i+1)%tb->size;
}
/* not found */
lua_pack();
if (j != -1) /* is there an EMPTY space? */
i = j;
else
tb->nuse++;
ts = tb->hash[i] = newone(buff, tag, h);
return ts;
}
TaggedString *luaI_createudata (void *udata, int tag)
{
return insert(udata, tag, &string_root[(unsigned)udata%NUM_HASHS]);
}
TaggedString *lua_createstring (char *str)
{
return insert(str, LUA_T_STRING, &string_root[(unsigned)str[0]%NUM_HASHS]);
}
void luaI_strcallIM (TaggedString *l)
{
TObject o;
ttype(&o) = LUA_T_USERDATA;
for (; l; l=l->next) {
tsvalue(&o) = l;
luaI_gcIM(&o);
}
}
void luaI_strfree (TaggedString *l)
{
while (l) {
TaggedString *next = l->next;
luaI_free(l);
l = next;
}
}
/*
** Garbage collection function.
*/
TaggedString *luaI_strcollector (long *acum)
{
Long counter = 0;
TaggedString *frees = NULL;
int i;
for (i=0; i<NUM_HASHS; i++)
{
stringtable *tb = &string_root[i];
int j;
for (j=0; j<tb->size; j++)
{
TaggedString *t = tb->hash[j];
if (t != NULL && t->marked <= 1)
{
if (t->marked)
t->marked = 0;
else
{
t->next = frees;
frees = t;
tb->hash[j] = &EMPTY;
counter++;
}
}
}
}
*acum += counter;
return frees;
}
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