commit ea445708839d48f03d32817071e5fce1e08c3927
parent e091a254dfe4521d837469d3ae7cc329e2df3376
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Wed, 29 Apr 2009 14:09:17 -0300
hash table for strings is rehashed in place
Diffstat:
M | lstring.c | | | 34 | ++++++++++++++++++---------------- |
1 file changed, 18 insertions(+), 16 deletions(-)
diff --git a/lstring.c b/lstring.c
@@ -1,5 +1,5 @@
/*
-** $Id: lstring.c,v 2.11 2008/02/19 18:55:09 roberto Exp roberto $
+** $Id: lstring.c,v 2.12 2009/04/17 14:40:13 roberto Exp roberto $
** String table (keeps all strings handled by Lua)
** See Copyright Notice in lua.h
*/
@@ -20,30 +20,32 @@
void luaS_resize (lua_State *L, int newsize) {
- GCObject **newhash;
- stringtable *tb;
int i;
+ stringtable *tb = &G(L)->strt;
if (G(L)->gcstate == GCSsweepstring)
return; /* cannot resize during GC traverse */
- newhash = luaM_newvector(L, newsize, GCObject *);
- tb = &G(L)->strt;
- for (i=0; i<newsize; i++) newhash[i] = NULL;
+ if (newsize > tb->size) {
+ luaM_reallocvector(L, tb->hash, tb->size, newsize, GCObject *);
+ for (i = tb->size; i < newsize; i++) tb->hash[i] = NULL;
+ }
/* rehash */
for (i=0; i<tb->size; i++) {
GCObject *p = tb->hash[i];
+ tb->hash[i] = NULL;
while (p) { /* for each node in the list */
GCObject *next = gch(p)->next; /* save next */
- unsigned int h = gco2ts(p)->hash;
- int h1 = lmod(h, newsize); /* new position */
- lua_assert(cast_int(h%newsize) == lmod(h, newsize));
- gch(p)->next = newhash[h1]; /* chain it */
- newhash[h1] = p;
+ unsigned int h = lmod(gco2ts(p)->hash, newsize); /* new position */
+ gch(p)->next = tb->hash[h]; /* chain it */
+ tb->hash[h] = p;
p = next;
}
}
- luaM_freearray(L, tb->hash, tb->size);
+ if (newsize < tb->size) {
+ /* shrinking slice must be empty */
+ lua_assert(tb->hash[newsize] == NULL && tb->hash[tb->size - 1] == NULL);
+ luaM_reallocvector(L, tb->hash, tb->size, newsize, GCObject *);
+ }
tb->size = newsize;
- tb->hash = newhash;
}
@@ -84,12 +86,12 @@ TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
TString *ts = rawgco2ts(o);
if (h == ts->tsv.hash && ts->tsv.len == l &&
(memcmp(str, getstr(ts), l) == 0)) {
- /* string may be dead */
- if (isdead(G(L), o)) changewhite(o);
+ if (isdead(G(L), o)) /* string is dead (but was not collected yet)? */
+ changewhite(o); /* resurrect it */
return ts;
}
}
- return newlstr(L, str, l, h); /* not found */
+ return newlstr(L, str, l, h); /* not found; create a new string */
}