diff options
Diffstat (limited to 'src/lstring.c')
-rw-r--r-- | src/lstring.c | 139 |
1 files changed, 62 insertions, 77 deletions
diff --git a/src/lstring.c b/src/lstring.c index fd7cc580..fa974ae9 100644 --- a/src/lstring.c +++ b/src/lstring.c @@ -1,5 +1,5 @@ /* -** $Id: lstring.c,v 1.13 1998/06/19 16:14:09 roberto Exp $ +** $Id: lstring.c,v 1.19 1999/02/26 15:49:53 roberto Exp $ ** String table (keeps all strings handled by Lua) ** See Copyright Notice in lua.h */ @@ -14,7 +14,9 @@ #include "lua.h" -#define NUM_HASHS 61 +#define NUM_HASHSTR 31 +#define NUM_HASHUDATA 31 +#define NUM_HASHS (NUM_HASHSTR+NUM_HASHUDATA) #define gcsizestring(l) (1+(l/64)) /* "weight" for a string with length 'l' */ @@ -25,8 +27,7 @@ static TaggedString EMPTY = {{NULL, 2}, 0L, 0, {{{LUA_T_NIL, {NULL}}, 0L}}, {0}}; -void luaS_init (void) -{ +void luaS_init (void) { int i; L->string_root = luaM_newvector(NUM_HASHS, stringtable); for (i=0; i<NUM_HASHS; i++) { @@ -37,16 +38,14 @@ void luaS_init (void) } -static unsigned long hash_s (char *s, long l) -{ - unsigned long h = 0; +static unsigned long hash_s (char *s, long l) { + unsigned long h = 0; /* seed */ while (l--) - h = ((h<<5)-h)^(unsigned char)*(s++); + h = h ^ ((h<<5)+(h>>2)+(unsigned char)*(s++)); return h; } -static int newsize (stringtable *tb) -{ +static int newsize (stringtable *tb) { int size = tb->size; int realuse = 0; int i; @@ -54,16 +53,11 @@ static int newsize (stringtable *tb) for (i=0; i<size; i++) if (tb->hash[i] != NULL && 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); + return luaO_redimension((realuse+1)*2); /* +1 is the new element */ } -static void grow (stringtable *tb) -{ - +static void grow (stringtable *tb) { int ns = newsize(tb); TaggedString **newhash = luaM_newvector(ns, TaggedString *); int i; @@ -73,10 +67,13 @@ static void grow (stringtable *tb) 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%ns; - while (newhash[h]) - h = (h+1)%ns; - newhash[h] = tb->hash[i]; + unsigned long h = tb->hash[i]->hash; + int h1 = h%ns; + while (newhash[h1]) { + h1 += (h&(ns-2)) + 1; /* double hashing */ + if (h1 >= ns) h1 -= ns; + } + newhash[h1] = tb->hash[i]; tb->nuse++; } } @@ -86,8 +83,7 @@ static void grow (stringtable *tb) } -static TaggedString *newone_s (char *str, long l, unsigned long h) -{ +static TaggedString *newone_s (char *str, long l, unsigned long h) { TaggedString *ts = (TaggedString *)luaM_malloc(sizeof(TaggedString)+l); memcpy(ts->str, str, l); ts->str[l] = 0; /* ending 0 */ @@ -101,8 +97,7 @@ static TaggedString *newone_s (char *str, long l, unsigned long h) return ts; } -static TaggedString *newone_u (char *buff, int tag, unsigned long h) -{ +static TaggedString *newone_u (char *buff, int tag, unsigned long h) { TaggedString *ts = luaM_new(TaggedString); ts->u.d.v = buff; ts->u.d.tag = (tag == LUA_ANYTAG) ? 0 : tag; @@ -114,82 +109,79 @@ static TaggedString *newone_u (char *buff, int tag, unsigned long h) return ts; } -static TaggedString *insert_s (char *str, long l, stringtable *tb) -{ +static TaggedString *insert_s (char *str, long l, stringtable *tb) { TaggedString *ts; unsigned long h = hash_s(str, l); int size = tb->size; - int i; int j = -1; + int h1; if ((long)tb->nuse*3 >= (long)size*2) { grow(tb); size = tb->size; } - for (i = h%size; (ts = tb->hash[i]) != NULL; ) { + h1 = h%size; + while ((ts = tb->hash[h1]) != NULL) { if (ts == &EMPTY) - j = i; - else if (ts->constindex >= 0 && - ts->u.s.len == l && - (memcmp(str, ts->str, l) == 0)) + j = h1; + else if (ts->u.s.len == l && (memcmp(str, ts->str, l) == 0)) return ts; - if (++i == size) i=0; + h1 += (h&(size-2)) + 1; /* double hashing */ + if (h1 >= size) h1 -= size; } /* not found */ if (j != -1) /* is there an EMPTY space? */ - i = j; + h1 = j; else tb->nuse++; - ts = tb->hash[i] = newone_s(str, l, h); + ts = tb->hash[h1] = newone_s(str, l, h); return ts; } -static TaggedString *insert_u (void *buff, int tag, stringtable *tb) -{ + +static TaggedString *insert_u (void *buff, int tag, stringtable *tb) { TaggedString *ts; unsigned long h = (unsigned long)buff; int size = tb->size; - int i; int j = -1; + int h1; if ((long)tb->nuse*3 >= (long)size*2) { grow(tb); size = tb->size; } - for (i = h%size; (ts = tb->hash[i]) != NULL; ) { + h1 = h%size; + while ((ts = tb->hash[h1]) != NULL) { if (ts == &EMPTY) - j = i; - else if (ts->constindex < 0 && /* is a udata? */ - (tag == ts->u.d.tag || tag == LUA_ANYTAG) && - buff == ts->u.d.v) + j = h1; + else if ((tag == ts->u.d.tag || tag == LUA_ANYTAG) && buff == ts->u.d.v) return ts; - if (++i == size) i=0; + h1 += (h&(size-2)) + 1; /* double hashing */ + if (h1 >= size) h1 -= size; } /* not found */ if (j != -1) /* is there an EMPTY space? */ - i = j; + h1 = j; else tb->nuse++; - ts = tb->hash[i] = newone_u(buff, tag, h); + ts = tb->hash[h1] = newone_u(buff, tag, h); return ts; } -TaggedString *luaS_createudata (void *udata, int tag) -{ - return insert_u(udata, tag, &L->string_root[(unsigned)udata%NUM_HASHS]); + +TaggedString *luaS_createudata (void *udata, int tag) { + int t = ((unsigned)udata%NUM_HASHUDATA)+NUM_HASHSTR; + return insert_u(udata, tag, &L->string_root[t]); } -TaggedString *luaS_newlstr (char *str, long l) -{ - int i = (l==0)?0:(unsigned char)str[0]; - return insert_s(str, l, &L->string_root[i%NUM_HASHS]); +TaggedString *luaS_newlstr (char *str, long l) { + int t = (l==0) ? 0 : ((int)((unsigned char)str[0]*l))%NUM_HASHSTR; + return insert_s(str, l, &L->string_root[t]); } -TaggedString *luaS_new (char *str) -{ +TaggedString *luaS_new (char *str) { return luaS_newlstr(str, strlen(str)); } -TaggedString *luaS_newfixedstring (char *str) -{ +TaggedString *luaS_newfixedstring (char *str) { TaggedString *ts = luaS_new(str); if (ts->head.marked == 0) ts->head.marked = 2; /* avoid GC */ @@ -197,8 +189,7 @@ TaggedString *luaS_newfixedstring (char *str) } -void luaS_free (TaggedString *l) -{ +void luaS_free (TaggedString *l) { while (l) { TaggedString *next = (TaggedString *)l->head.next; L->nblocks -= (l->constindex == -1) ? 1 : gcsizestring(l->u.s.len); @@ -212,8 +203,7 @@ void luaS_free (TaggedString *l) ** Garbage collection functions. */ -static void remove_from_list (GCnode *l) -{ +static void remove_from_list (GCnode *l) { while (l) { GCnode *next = l->next; while (next && !next->marked) @@ -223,8 +213,7 @@ static void remove_from_list (GCnode *l) } -TaggedString *luaS_collector (void) -{ +TaggedString *luaS_collector (void) { TaggedString *frees = NULL; int i; remove_from_list(&(L->rootglobal)); @@ -247,18 +236,18 @@ TaggedString *luaS_collector (void) } -TaggedString *luaS_collectudata (void) -{ +TaggedString *luaS_collectudata (void) { TaggedString *frees = NULL; int i; L->rootglobal.next = NULL; /* empty list of globals */ - for (i=0; i<NUM_HASHS; i++) { + for (i=NUM_HASHSTR; i<NUM_HASHS; i++) { stringtable *tb = &L->string_root[i]; int j; for (j=0; j<tb->size; j++) { TaggedString *t = tb->hash[j]; - if (t == NULL || t == &EMPTY || t->constindex != -1) - continue; /* get only user data */ + if (t == NULL || t == &EMPTY) + continue; + LUA_ASSERT(t->constindex == -1, "must be userdata"); t->head.next = (GCnode *)frees; frees = t; tb->hash[j] = &EMPTY; @@ -268,8 +257,7 @@ TaggedString *luaS_collectudata (void) } -void luaS_freeall (void) -{ +void luaS_freeall (void) { int i; for (i=0; i<NUM_HASHS; i++) { stringtable *tb = &L->string_root[i]; @@ -285,8 +273,7 @@ void luaS_freeall (void) } -void luaS_rawsetglobal (TaggedString *ts, TObject *newval) -{ +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; @@ -295,8 +282,7 @@ void luaS_rawsetglobal (TaggedString *ts, TObject *newval) } -char *luaS_travsymbol (int (*fn)(TObject *)) -{ +char *luaS_travsymbol (int (*fn)(TObject *)) { TaggedString *g; for (g=(TaggedString *)L->rootglobal.next; g; g=(TaggedString *)g->head.next) if (fn(&g->u.s.globalval)) @@ -305,8 +291,7 @@ char *luaS_travsymbol (int (*fn)(TObject *)) } -int luaS_globaldefined (char *name) -{ +int luaS_globaldefined (char *name) { TaggedString *ts = luaS_new(name); return ts->u.s.globalval.ttype != LUA_T_NIL; } |