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/*
* This software is part of the SBCL system. See the README file for
* more information.
*
* This software is derived from the CMU CL system, which was
* written at Carnegie Mellon University and released into the
* public domain. The software is in the public domain and is
* provided with absolutely no warranty. See the COPYING and CREDITS
* files for more information.
*/
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <stdlib.h>
#include "sbcl.h"
#include "runtime.h"
#include "vars.h"
#include "os.h"
#define NAME_BUCKETS 31
#define OBJ_BUCKETS 31
static struct var *NameHash[NAME_BUCKETS], *ObjHash[OBJ_BUCKETS];
static int tempcntr = 1;
struct var {
lispobj obj;
lispobj (*update_fn)(struct var *var);
char *name;
long clock;
boolean map_back, permanent;
struct var *nnext; /* Next in name list */
struct var *onext; /* Next in object list */
};
static int hash_name(char *name)
{
unsigned long value = 0;
while (*name != '\0') {
value = (value << 1) ^ *(unsigned char *)(name++);
value = (value & (1-(1<<24))) ^ (value >> 24);
}
return value % NAME_BUCKETS;
}
static int hash_obj(lispobj obj)
{
return (unsigned long)obj % OBJ_BUCKETS;
}
void flush_vars()
{
int index;
struct var *var, *next, *perm = NULL;
/* Note: all vars in the object hash table also appear in the name hash
* table, so if we free everything in the name hash table, we free
* everything in the object hash table. */
for (index = 0; index < NAME_BUCKETS; index++)
for (var = NameHash[index]; var != NULL; var = next) {
next = var->nnext;
if (var->permanent) {
var->nnext = perm;
perm = var;
}
else {
free(var->name);
free(var);
}
}
memset(NameHash, 0, sizeof(NameHash));
memset(ObjHash, 0, sizeof(ObjHash));
tempcntr = 1;
for (var = perm; var != NULL; var = next) {
next = var->nnext;
index = hash_name(var->name);
var->nnext = NameHash[index];
NameHash[index] = var;
if (var->map_back) {
index = hash_obj(var->obj);
var->onext = ObjHash[index];
ObjHash[index] = var;
}
}
}
struct var *lookup_by_name(name)
char *name;
{
struct var *var;
for (var = NameHash[hash_name(name)]; var != NULL; var = var->nnext)
if (strcmp(var->name, name) == 0)
return var;
return NULL;
}
struct var *lookup_by_obj(obj)
lispobj obj;
{
struct var *var;
for (var = ObjHash[hash_obj(obj)]; var != NULL; var = var->onext)
if (var->obj == obj)
return var;
return NULL;
}
static struct var *make_var(char *name, boolean perm)
{
struct var *var = (struct var *)malloc(sizeof(struct var));
char buffer[256];
int index;
if (name == NULL) {
sprintf(buffer, "%d", tempcntr++);
name = buffer;
}
var->name = (char *)malloc(strlen(name)+1);
strcpy(var->name, name);
var->clock = 0;
var->permanent = perm;
var->map_back = 0;
index = hash_name(name);
var->nnext = NameHash[index];
NameHash[index] = var;
return var;
}
struct var *define_var(char *name, lispobj obj, boolean perm)
{
struct var *var = make_var(name, perm);
int index;
var->obj = obj;
var->update_fn = NULL;
if (lookup_by_obj(obj) == NULL) {
var->map_back = 1;
index = hash_obj(obj);
var->onext = ObjHash[index];
ObjHash[index] = var;
}
return var;
}
struct var *define_dynamic_var(char *name, lispobj updatefn(struct var *),
boolean perm)
{
struct var *var = make_var(name, perm);
var->update_fn = updatefn;
return var;
}
char *var_name(struct var *var)
{
return var->name;
}
lispobj var_value(struct var *var)
{
if (var->update_fn != NULL)
var->obj = (*var->update_fn)(var);
return var->obj;
}
long var_clock(struct var *var)
{
return var->clock;
}
void var_setclock(struct var *var, long val)
{
var->clock = val;
}
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