commit a80cada9142f9e967c710e37934067a708224161
parent a00013c8d0d268616e004715da499e88e03b534c
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Wed, 4 Mar 2015 10:30:56 -0300
new cache for interning strings
Diffstat:
6 files changed, 61 insertions(+), 15 deletions(-)
diff --git a/lgc.c b/lgc.c
@@ -1,5 +1,5 @@
/*
-** $Id: lgc.c,v 2.201 2014/12/20 13:58:15 roberto Exp roberto $
+** $Id: lgc.c,v 2.202 2015/01/16 16:54:37 roberto Exp roberto $
** Garbage Collector
** See Copyright Notice in lua.h
*/
@@ -967,6 +967,19 @@ void luaC_freeallobjects (lua_State *L) {
}
+/*
+** Clear API string cache. (Entries cannot be empty, so fill them with
+** a non-collectable string.)
+*/
+static void clearapihash (global_State *g) {
+ int i;
+ for (i = 0; i < STRCACHE_SIZE; i++) {
+ if (iswhite(g->strcache[i])) /* will entry be collected? */
+ g->strcache[i] = g->memerrmsg; /* replace it with something fixed */
+ }
+}
+
+
static l_mem atomic (lua_State *L) {
global_State *g = G(L);
l_mem work;
@@ -1007,6 +1020,7 @@ static l_mem atomic (lua_State *L) {
/* clear values from resurrected weak tables */
clearvalues(g, g->weak, origweak);
clearvalues(g, g->allweak, origall);
+ clearapihash(g);
g->currentwhite = cast_byte(otherwhite(g)); /* flip current white */
work += g->GCmemtrav; /* complete counting */
return work; /* estimate of memory marked by 'atomic' */
diff --git a/llimits.h b/llimits.h
@@ -1,5 +1,5 @@
/*
-** $Id: llimits.h,v 1.131 2015/02/09 15:41:56 roberto Exp roberto $
+** $Id: llimits.h,v 1.132 2015/03/03 19:53:13 roberto Exp roberto $
** Limits, basic types, and some other 'installation-dependent' definitions
** See Copyright Notice in lua.h
*/
@@ -187,6 +187,14 @@ typedef unsigned long Instruction;
#endif
+/*
+** Size of cache for strings in the API (better be a prime)
+*/
+#if !defined(STRCACHE_SIZE)
+#define STRCACHE_SIZE 127
+#endif
+
+
/* minimum size for string buffer */
#if !defined(LUA_MINBUFFER)
#define LUA_MINBUFFER 32
diff --git a/lstate.c b/lstate.c
@@ -1,5 +1,5 @@
/*
-** $Id: lstate.c,v 2.126 2014/11/02 19:19:04 roberto Exp roberto $
+** $Id: lstate.c,v 2.127 2014/11/02 19:33:33 roberto Exp roberto $
** Global State
** See Copyright Notice in lua.h
*/
@@ -37,9 +37,6 @@
#endif
-#define MEMERRMSG "not enough memory"
-
-
/*
** a macro to help the creation of a unique random seed when a state is
** created; the seed is used to randomize hashes.
@@ -200,12 +197,9 @@ static void f_luaopen (lua_State *L, void *ud) {
UNUSED(ud);
stack_init(L, L); /* init stack */
init_registry(L, g);
- luaS_resize(L, MINSTRTABSIZE); /* initial size of string table */
+ luaS_init(L);
luaT_init(L);
luaX_init(L);
- /* pre-create memory-error message */
- g->memerrmsg = luaS_newliteral(L, MEMERRMSG);
- luaC_fix(L, obj2gco(g->memerrmsg)); /* it should never be collected */
g->gcrunning = 1; /* allow gc */
g->version = lua_version(NULL);
luai_userstateopen(L);
diff --git a/lstate.h b/lstate.h
@@ -1,5 +1,5 @@
/*
-** $Id: lstate.h,v 2.118 2014/10/25 11:50:46 roberto Exp roberto $
+** $Id: lstate.h,v 2.119 2014/10/30 18:53:28 roberto Exp roberto $
** Global State
** See Copyright Notice in lua.h
*/
@@ -140,6 +140,7 @@ typedef struct global_State {
TString *memerrmsg; /* memory-error message */
TString *tmname[TM_N]; /* array with tag-method names */
struct Table *mt[LUA_NUMTAGS]; /* metatables for basic types */
+ TString *strcache[STRCACHE_SIZE]; /* cache for strings in API */
} global_State;
diff --git a/lstring.c b/lstring.c
@@ -1,5 +1,5 @@
/*
-** $Id: lstring.c,v 2.45 2014/11/02 19:19:04 roberto Exp roberto $
+** $Id: lstring.c,v 2.46 2015/01/16 16:54:37 roberto Exp roberto $
** String table (keeps all strings handled by Lua)
** See Copyright Notice in lua.h
*/
@@ -22,6 +22,8 @@
#include "lstring.h"
+#define MEMERRMSG "not enough memory"
+
/*
** Lua will use at most ~(2^LUAI_HASHLIMIT) bytes from a string to
@@ -85,6 +87,21 @@ void luaS_resize (lua_State *L, int newsize) {
}
+/*
+** Initialize the string table and the string cache
+*/
+void luaS_init (lua_State *L) {
+ global_State *g = G(L);
+ int i;
+ luaS_resize(L, MINSTRTABSIZE); /* initial size of string table */
+ /* pre-create memory-error message */
+ g->memerrmsg = luaS_newliteral(L, MEMERRMSG);
+ luaC_fix(L, obj2gco(g->memerrmsg)); /* it should never be collected */
+ for (i = 0; i < STRCACHE_SIZE; i++)
+ g->strcache[i] = g->memerrmsg; /* fill cache with valid strings */
+}
+
+
/*
** creates a new string object
@@ -163,10 +180,21 @@ TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
/*
-** new zero-terminated string
+** Create or reuse a zero-terminated string, first checking in the
+** cache (using the string address as a key). The cache can contain
+** only zero-terminated strings, so it is safe to use 'strcmp' to
+** check hits.
*/
TString *luaS_new (lua_State *L, const char *str) {
- return luaS_newlstr(L, str, strlen(str));
+ unsigned int i = point2uint(str) % STRCACHE_SIZE; /* hash */
+ TString **p = &G(L)->strcache[i];
+ if (strcmp(str, getstr(*p)) == 0) /* hit? */
+ return *p; /* that it is */
+ else { /* normal route */
+ TString *s = luaS_newlstr(L, str, strlen(str));
+ *p = s;
+ return s;
+ }
}
diff --git a/lstring.h b/lstring.h
@@ -1,5 +1,5 @@
/*
-** $Id: lstring.h,v 1.56 2014/07/18 14:46:47 roberto Exp roberto $
+** $Id: lstring.h,v 1.57 2015/01/16 16:54:37 roberto Exp roberto $
** String table (keep all strings handled by Lua)
** See Copyright Notice in lua.h
*/
@@ -36,6 +36,7 @@
LUAI_FUNC unsigned int luaS_hash (const char *str, size_t l, unsigned int seed);
LUAI_FUNC int luaS_eqlngstr (TString *a, TString *b);
LUAI_FUNC void luaS_resize (lua_State *L, int newsize);
+LUAI_FUNC void luaS_init (lua_State *L);
LUAI_FUNC void luaS_remove (lua_State *L, TString *ts);
LUAI_FUNC Udata *luaS_newudata (lua_State *L, size_t s);
LUAI_FUNC TString *luaS_newlstr (lua_State *L, const char *str, size_t l);
