scummvm/engine/lua/lstring.cpp
Pawel Kolodziejski 94dbb1a1da formating code
2008-09-10 11:16:57 +00:00

283 lines
6.5 KiB
C++

/*
** $Id$
** String table (keeps all strings handled by Lua)
** See Copyright Notice in lua.h
*/
#include "common/util.h"
#include "engine/lua/lmem.h"
#include "engine/lua/lobject.h"
#include "engine/lua/lstate.h"
#include "engine/lua/lstring.h"
#include "engine/lua/lua.h"
#define gcsizestring(l) (1 + (l / 64)) // "weight" for a string with length 'l'
TaggedString EMPTY = {{NULL, 2}, 0L, 0, {{{LUA_T_NIL, {NULL}}, 0L}}, {0}};
void luaS_init() {
int32 i;
L->string_root = luaM_newvector(NUM_HASHS, stringtable);
for (i = 0; i < NUM_HASHS; i++) {
L->string_root[i].size = 0;
L->string_root[i].nuse = 0;
L->string_root[i].hash = NULL;
}
}
static uint32 hash_s(const char *s, int32 l) {
uint32 h = 0;
while (l--)
h = ((h << 5) - h) ^ (byte)*(s++);
return h;
}
static int32 newsize(stringtable *tb) {
int32 size = tb->size;
int32 realuse = 0;
int32 i;
// count how many entries are really in use
for (i = 0; i < size; i++)
if (tb->hash[i] && tb->hash[i] != &EMPTY)
realuse++;
if (2 * (realuse + 1) <= size) // +1 is the new element
return size; // don't need to grow, just rehash to clear EMPTYs
else
return luaO_redimension(size);
}
static void grow(stringtable *tb) {
int32 ns = newsize(tb);
TaggedString **newhash = luaM_newvector(ns, TaggedString *);
int32 i;
for (i = 0; i < ns; i++)
newhash[i] = NULL;
// rehash
tb->nuse = 0;
for (i = 0; i < tb->size; i++) {
if (tb->hash[i] && tb->hash[i] != &EMPTY) {
int32 h = tb->hash[i]->hash % ns;
while (newhash[h])
h = (h + 1) % ns;
newhash[h] = tb->hash[i];
tb->nuse++;
}
}
luaM_free(tb->hash);
tb->size = ns;
tb->hash = newhash;
}
static TaggedString *newone_s(const char *str, int32 l, uint32 h) {
TaggedString *ts = (TaggedString *)luaM_malloc(sizeof(TaggedString) + l);
memcpy(ts->str, str, l);
ts->str[l] = 0; // ending 0
ts->u.s.globalval.ttype = LUA_T_NIL; // initialize global value
ts->u.s.len = l;
ts->constindex = 0;
L->nblocks += gcsizestring(l);
ts->head.marked = 0;
ts->head.next = (GCnode *)ts; // signal it is in no list
ts->hash = h;
return ts;
}
static TaggedString *newone_u(char *buff, int32 tag, uint32 h) {
TaggedString *ts = luaM_new(TaggedString);
ts->u.d.v = buff;
ts->u.d.tag = (tag == LUA_ANYTAG) ? 0 : tag;
ts->constindex = -1; // tag -> this is a userdata
L->nblocks++;
ts->head.marked = 0;
ts->head.next = (GCnode *)ts; // signal it is in no list
ts->hash = h;
return ts;
}
static TaggedString *insert_s (const char *str, int32 l, stringtable *tb) {
TaggedString *ts;
uint32 h = hash_s(str, l);
int32 size = tb->size;
int32 i;
int32 j = -1;
if (tb->nuse * 3 >= size * 2) {
grow(tb);
size = tb->size;
}
for (i = h % size; (ts = tb->hash[i]); ) {
if (ts == &EMPTY)
j = i;
else if (ts->constindex >= 0 && ts->u.s.len == l && (memcmp(str, ts->str, MAX(l, ts->u.s.len)) == 0))
return ts;
if (++i == size)
i = 0;
}
// not found
if (j != -1) // is there an EMPTY space?
i = j;
else
tb->nuse++;
ts = tb->hash[i] = newone_s(str, l, h);
return ts;
}
static TaggedString *insert_u(void *buff, int32 tag, stringtable *tb) {
TaggedString *ts;
#ifdef TARGET_64BITS
uint32 h = (uint64)buff;
#else
uint32 h = (uint32)buff;
#endif
int32 size = tb->size;
int32 i;
int32 j = -1;
if (tb->nuse * 3 >= size * 2) {
grow(tb);
size = tb->size;
}
for (i = h % size; (ts = tb->hash[i]) != NULL; ) {
if (ts == &EMPTY)
j = i;
else if (ts->constindex < 0 && (tag == ts->u.d.tag || tag == LUA_ANYTAG) && buff == ts->u.d.v)
return ts;
if (++i == size)
i = 0;
}
// not found
if (j != -1) // is there an EMPTY space?
i = j;
else
tb->nuse++;
ts = tb->hash[i] = newone_u((char *)buff, tag, h);
return ts;
}
TaggedString *luaS_createudata(void *udata, int32 tag) {
#ifdef TARGET_64BITS
return insert_u(udata, tag, &L->string_root[(uint64)udata % NUM_HASHS]);
#else
return insert_u(udata, tag, &L->string_root[(uint32)udata % NUM_HASHS]);
#endif
}
TaggedString *luaS_newlstr(const char *str, int32 l) {
int32 i = (l == 0) ? 0 : (byte)str[0];
return insert_s(str, l, &L->string_root[i % NUM_HASHS]);
}
TaggedString *luaS_new(const char *str) {
return luaS_newlstr(str, strlen(str));
}
TaggedString *luaS_newfixedstring(const char *str) {
TaggedString *ts = luaS_new(str);
if (ts->head.marked == 0)
ts->head.marked = 2; // avoid GC
return ts;
}
void luaS_free(TaggedString *l) {
while (l) {
TaggedString *next = (TaggedString *)l->head.next;
L->nblocks -= (l->constindex == -1) ? 1 : gcsizestring(l->u.s.len);
luaM_free(l);
l = next;
}
}
/*
** Garbage collection functions.
*/
static void remove_from_list(GCnode *l) {
while (l) {
GCnode *next = l->next;
while (next && !next->marked)
next = l->next = next->next;
l = next;
}
}
TaggedString *luaS_collector() {
TaggedString *frees = NULL;
int32 i;
remove_from_list(&(L->rootglobal));
for (i = 0; i < NUM_HASHS; i++) {
stringtable *tb = &L->string_root[i];
int32 j;
for (j = 0; j < tb->size; j++) {
TaggedString *t = tb->hash[j];
if (!t)
continue;
if (t->head.marked == 1)
t->head.marked = 0;
else if (!t->head.marked) {
t->head.next = (GCnode *)frees;
frees = t;
tb->hash[j] = &EMPTY;
}
}
}
return frees;
}
TaggedString *luaS_collectudata() {
TaggedString *frees = NULL;
int32 i;
L->rootglobal.next = NULL; // empty list of globals
for (i = 0; i < NUM_HASHS; i++) {
stringtable *tb = &L->string_root[i];
int32 j;
for (j = 0; j < tb->size; j++) {
TaggedString *t = tb->hash[j];
if (!t || t == &EMPTY || t->constindex != -1)
continue; // get only user data
t->head.next = (GCnode *)frees;
frees = t;
tb->hash[j] = &EMPTY;
}
}
return frees;
}
void luaS_freeall() {
int32 i;
for (i = 0; i < NUM_HASHS; i++) {
stringtable *tb = &L->string_root[i];
int32 j;
for (j = 0; j < tb->size; j++) {
TaggedString *t = tb->hash[j];
if (t == &EMPTY)
continue;
luaM_free(t);
}
luaM_free(tb->hash);
}
luaM_free(L->string_root);
}
void luaS_rawsetglobal(TaggedString *ts, TObject *newval) {
ts->u.s.globalval = *newval;
if (ts->head.next == (GCnode *)ts) { // is not in list?
ts->head.next = L->rootglobal.next;
L->rootglobal.next = (GCnode *)ts;
}
}
char *luaS_travsymbol (int32 (*fn)(TObject *)) {
TaggedString *g;
for (g = (TaggedString *)L->rootglobal.next; g; g = (TaggedString *)g->head.next)
if (fn(&g->u.s.globalval))
return g->str;
return NULL;
}
int32 luaS_globaldefined(const char *name) {
TaggedString *ts = luaS_new(name);
return ts->u.s.globalval.ttype != LUA_T_NIL;
}