From 33c49f7fa03cf7e3bf7bb3aa697dc567d910c661 Mon Sep 17 00:00:00 2001 From: Roberto Ierusalimschy Date: Thu, 22 Aug 2013 12:21:48 -0300 Subject: [PATCH] some details over new implementation of string table --- lstate.h | 8 ++++---- lstring.c | 34 ++++++++++++++++++---------------- ltests.c | 4 ++-- 3 files changed, 24 insertions(+), 22 deletions(-) diff --git a/lstate.h b/lstate.h index 1877b5d9..2c89aad6 100644 --- a/lstate.h +++ b/lstate.h @@ -1,5 +1,5 @@ /* -** $Id: lstate.h,v 2.86 2013/08/21 19:21:16 roberto Exp roberto $ +** $Id: lstate.h,v 2.87 2013/08/21 20:09:51 roberto Exp roberto $ ** Global State ** See Copyright Notice in lua.h */ @@ -59,9 +59,9 @@ struct lua_longjmp; /* defined in ldo.c */ typedef struct stringtable { TString **hash; - unsigned int nuse; /* number of elements */ - unsigned int empty; /* number of available empty slots */ - unsigned int size; + int nuse; /* number of elements */ + int empty; /* number of available empty slots */ + int size; } stringtable; diff --git a/lstring.c b/lstring.c index c8f10e96..e53c6375 100644 --- a/lstring.c +++ b/lstring.c @@ -1,5 +1,5 @@ /* -** $Id: lstring.c,v 2.28 2013/08/05 16:58:28 roberto Exp roberto $ +** $Id: lstring.c,v 2.29 2013/08/21 19:21:16 roberto Exp roberto $ ** String table (keeps all strings handled by Lua) ** See Copyright Notice in lua.h */ @@ -13,6 +13,7 @@ #include "lua.h" #include "ldebug.h" +#include "ldo.h" #include "lmem.h" #include "lobject.h" #include "lstate.h" @@ -24,7 +25,7 @@ /* second hash (for double hash) */ -#define h2(h1,hash,size) lmod(h1 + ((hash % 31) | 1), size) +#define h2(h1,hash,size) lmod(h1 + ((hash % 61) | 1), size) /* @@ -116,19 +117,18 @@ static TString *createstrobj (lua_State *L, const char *str, size_t l, static void rehash (lua_State *L, stringtable *tb) { - int newsize; - if (tb->nuse < tb->size / 2) { /* using less than half the size? */ - if (tb->nuse < tb->size / 4) /* using less than half of that? */ - newsize = tb->size / 2; /* shrink table */ - else - newsize = tb->size; /* keep size (but reorganize table) */ + int size = tb->size; + if (tb->nuse < size / 2) { /* using less than half the size? */ + if (tb->nuse < size / 4) /* using less than half of that? */ + size /= 2; /* shrink table */ + /* else keep size (but reorganize table) */ } else { /* table must grow */ - if (tb->size >= MAX_INT/2) - luaG_runerror(L, "string-table overflow: too many strings"); - newsize = tb->size * 2; + if (size >= MAX_INT/2) /* avoid arith. overflow */ + luaD_throw(L, LUA_ERRMEM); /* regular errors need new strings... */ + size *= 2; } - luaS_resize(L, newsize); + luaS_resize(L, size); } @@ -154,12 +154,10 @@ static TString *internshrstr (lua_State *L, const char *str, size_t l) { stringtable *tb = &G(L)->strt; int vacant = -1; int h1; - if (tb->empty <= 0) - rehash(L, tb); h1 = lmod(hash, tb->size); /* previous call can changed 'size' */ while ((ts = tb->hash[h1]) != NULL) { /* search the string in hash table */ if (ts == VACANTK) { - if (vacant < 0) vacant = h1; /* keep track of a vacant place */ + if (vacant < 0) vacant = h1; /* keep track of first vacant place */ } else if (l == ts->tsv.len && (memcmp(str, getstr(ts), l * sizeof(char)) == 0)) { @@ -174,12 +172,16 @@ static TString *internshrstr (lua_State *L, const char *str, size_t l) { } h1 = h2(h1, hash, tb->size); } + if (tb->empty <= 0) { /* no more empty spaces? */ + rehash(L, tb); + return internshrstr(L, str, l); /* recompute insertion with new size */ + } ts = createstrobj(L, str, l, LUA_TSHRSTR, hash); tb->nuse++; if (vacant < 0) /* found no vacant place? */ tb->empty--; /* will have to use the empty place */ else - h1 = vacant; /* insert string into vacant place */ + h1 = vacant; /* use vacant place */ tb->hash[h1] = ts; return ts; } diff --git a/ltests.c b/ltests.c index f6061213..d35bab5c 100644 --- a/ltests.c +++ b/ltests.c @@ -1,5 +1,5 @@ /* -** $Id: ltests.c,v 2.146 2013/08/20 17:46:34 roberto Exp roberto $ +** $Id: ltests.c,v 2.147 2013/08/21 19:21:16 roberto Exp roberto $ ** Internal Module for Debugging of the Lua Implementation ** See Copyright Notice in lua.h */ @@ -747,7 +747,7 @@ static int string_query (lua_State *L) { lua_pushinteger(L ,tb->size); return 2; } - else if ((unsigned int)s < tb->size) { + else if (s < tb->size) { TString *ts = tb->hash[s]; setsvalue2s(L, L->top, ts); api_incr_top(L);