commit 7e2015a46df7976bddee313b994742e49e420714
parent 5b01cb39b5ec36c544152351c35c43149d9bbfec
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Fri, 16 Jan 2015 14:54:12 -0200
size of short strings stored in a single byte, to reduce the size
of struct 'TString'
Diffstat:
9 files changed, 69 insertions(+), 45 deletions(-)
diff --git a/lapi.c b/lapi.c
@@ -1,5 +1,5 @@
/*
-** $Id: lapi.c,v 2.243 2014/11/12 13:28:54 roberto Exp roberto $
+** $Id: lapi.c,v 2.244 2014/12/26 14:43:45 roberto Exp roberto $
** Lua API
** See Copyright Notice in lua.h
*/
@@ -382,15 +382,17 @@ LUA_API const char *lua_tolstring (lua_State *L, int idx, size_t *len) {
luaO_tostring(L, o);
lua_unlock(L);
}
- if (len != NULL) *len = tsvalue(o)->len;
+ if (len != NULL)
+ *len = vslen(o);
return svalue(o);
}
LUA_API size_t lua_rawlen (lua_State *L, int idx) {
StkId o = index2addr(L, idx);
- switch (ttnov(o)) {
- case LUA_TSTRING: return tsvalue(o)->len;
+ switch (ttype(o)) {
+ case LUA_TSHRSTR: return tsvalue(o)->shrlen;
+ case LUA_TLNGSTR: return tsvalue(o)->u.lnglen;
case LUA_TUSERDATA: return uvalue(o)->len;
case LUA_TTABLE: return luaH_getn(hvalue(o));
default: return 0;
diff --git a/ldump.c b/ldump.c
@@ -1,5 +1,5 @@
/*
-** $Id: ldump.c,v 2.33 2014/07/18 13:36:14 roberto Exp roberto $
+** $Id: ldump.c,v 2.34 2014/11/02 19:19:04 roberto Exp roberto $
** save precompiled Lua chunks
** See Copyright Notice in lua.h
*/
@@ -74,7 +74,7 @@ static void DumpString (const TString *s, DumpState *D) {
if (s == NULL)
DumpByte(0, D);
else {
- size_t size = s->len + 1; /* include trailing '\0' */
+ size_t size = tsslen(s) + 1; /* include trailing '\0' */
if (size < 0xFF)
DumpByte(cast_int(size), D);
else {
diff --git a/lgc.c b/lgc.c
@@ -1,5 +1,5 @@
/*
-** $Id: lgc.c,v 2.200 2014/11/02 19:19:04 roberto Exp roberto $
+** $Id: lgc.c,v 2.201 2014/12/20 13:58:15 roberto Exp roberto $
** Garbage Collector
** See Copyright Notice in lua.h
*/
@@ -226,10 +226,14 @@ static void reallymarkobject (global_State *g, GCObject *o) {
reentry:
white2gray(o);
switch (o->tt) {
- case LUA_TSHRSTR:
+ case LUA_TSHRSTR: {
+ gray2black(o);
+ g->GCmemtrav += sizelstring(gco2ts(o)->shrlen);
+ break;
+ }
case LUA_TLNGSTR: {
gray2black(o);
- g->GCmemtrav += sizestring(gco2ts(o));
+ g->GCmemtrav += sizelstring(gco2ts(o)->u.lnglen);
break;
}
case LUA_TUSERDATA: {
@@ -689,9 +693,10 @@ static void freeobj (lua_State *L, GCObject *o) {
case LUA_TUSERDATA: luaM_freemem(L, o, sizeudata(gco2u(o))); break;
case LUA_TSHRSTR:
luaS_remove(L, gco2ts(o)); /* remove it from hash table */
- /* go through */
+ luaM_freemem(L, o, sizelstring(gco2ts(o)->shrlen));
+ break;
case LUA_TLNGSTR: {
- luaM_freemem(L, o, sizestring(gco2ts(o)));
+ luaM_freemem(L, o, sizelstring(gco2ts(o)->u.lnglen));
break;
}
default: lua_assert(0);
diff --git a/lobject.h b/lobject.h
@@ -1,5 +1,5 @@
/*
-** $Id: lobject.h,v 2.105 2014/12/19 13:36:32 roberto Exp roberto $
+** $Id: lobject.h,v 2.106 2015/01/05 13:52:37 roberto Exp roberto $
** Type definitions for Lua objects
** See Copyright Notice in lua.h
*/
@@ -303,9 +303,12 @@ typedef TValue *StkId; /* index to stack elements */
typedef struct TString {
CommonHeader;
lu_byte extra; /* reserved words for short strings; "has hash" for longs */
+ lu_byte shrlen; /* length for short strings */
unsigned int hash;
- size_t len; /* number of characters in string */
- struct TString *hnext; /* linked list for hash table */
+ union {
+ size_t lnglen; /* length for long strings */
+ struct TString *hnext; /* linked list for hash table */
+ } u;
} TString;
@@ -329,6 +332,12 @@ typedef union UTString {
/* get the actual string (array of bytes) from a Lua value */
#define svalue(o) getstr(tsvalue(o))
+/* get string length from 'TString *s' */
+#define tsslen(s) ((s)->tt == LUA_TSHRSTR ? (s)->shrlen : (s)->u.lnglen)
+
+/* get string length from 'TValue *o' */
+#define vslen(o) tsslen(tsvalue(o))
+
/*
** Header for userdata; memory area follows the end of this structure
diff --git a/lstring.c b/lstring.c
@@ -1,5 +1,5 @@
/*
-** $Id: lstring.c,v 2.44 2014/07/21 16:02:10 roberto Exp roberto $
+** $Id: lstring.c,v 2.45 2014/11/02 19:19:04 roberto Exp roberto $
** String table (keeps all strings handled by Lua)
** See Copyright Notice in lua.h
*/
@@ -36,10 +36,10 @@
** equality for long strings
*/
int luaS_eqlngstr (TString *a, TString *b) {
- size_t len = a->len;
+ size_t len = a->u.lnglen;
lua_assert(a->tt == LUA_TLNGSTR && b->tt == LUA_TLNGSTR);
return (a == b) || /* same instance or... */
- ((len == b->len) && /* equal length and ... */
+ ((len == b->u.lnglen) && /* equal length and ... */
(memcmp(getstr(a), getstr(b), len) == 0)); /* equal contents */
}
@@ -69,9 +69,9 @@ void luaS_resize (lua_State *L, int newsize) {
TString *p = tb->hash[i];
tb->hash[i] = NULL;
while (p) { /* for each node in the list */
- TString *hnext = p->hnext; /* save next */
+ TString *hnext = p->u.hnext; /* save next */
unsigned int h = lmod(p->hash, newsize); /* new position */
- p->hnext = tb->hash[h]; /* chain it */
+ p->u.hnext = tb->hash[h]; /* chain it */
tb->hash[h] = p;
p = hnext;
}
@@ -97,7 +97,6 @@ static TString *createstrobj (lua_State *L, const char *str, size_t l,
totalsize = sizelstring(l);
o = luaC_newobj(L, tag, totalsize);
ts = gco2ts(o);
- ts->len = l;
ts->hash = h;
ts->extra = 0;
memcpy(getaddrstr(ts), str, l * sizeof(char));
@@ -110,8 +109,8 @@ void luaS_remove (lua_State *L, TString *ts) {
stringtable *tb = &G(L)->strt;
TString **p = &tb->hash[lmod(ts->hash, tb->size)];
while (*p != ts) /* find previous element */
- p = &(*p)->hnext;
- *p = (*p)->hnext; /* remove element from its list */
+ p = &(*p)->u.hnext;
+ *p = (*p)->u.hnext; /* remove element from its list */
tb->nuse--;
}
@@ -124,8 +123,8 @@ static TString *internshrstr (lua_State *L, const char *str, size_t l) {
global_State *g = G(L);
unsigned int h = luaS_hash(str, l, g->seed);
TString **list = &g->strt.hash[lmod(h, g->strt.size)];
- for (ts = *list; ts != NULL; ts = ts->hnext) {
- if (l == ts->len &&
+ for (ts = *list; ts != NULL; ts = ts->u.hnext) {
+ if (l == ts->shrlen &&
(memcmp(str, getstr(ts), l * sizeof(char)) == 0)) {
/* found! */
if (isdead(g, ts)) /* dead (but not collected yet)? */
@@ -138,7 +137,8 @@ static TString *internshrstr (lua_State *L, const char *str, size_t l) {
list = &g->strt.hash[lmod(h, g->strt.size)]; /* recompute with new size */
}
ts = createstrobj(L, str, l, LUA_TSHRSTR, h);
- ts->hnext = *list;
+ ts->shrlen = cast_byte(l);
+ ts->u.hnext = *list;
*list = ts;
g->strt.nuse++;
return ts;
@@ -152,9 +152,12 @@ TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
if (l <= LUAI_MAXSHORTLEN) /* short string? */
return internshrstr(L, str, l);
else {
+ TString *ts;
if (l + 1 > (MAX_SIZE - sizeof(TString))/sizeof(char))
luaM_toobig(L);
- return createstrobj(L, str, l, LUA_TLNGSTR, G(L)->seed);
+ ts = createstrobj(L, str, l, LUA_TLNGSTR, G(L)->seed);
+ ts->u.lnglen = l;
+ return ts;
}
}
diff --git a/lstring.h b/lstring.h
@@ -1,5 +1,5 @@
/*
-** $Id: lstring.h,v 1.54 2014/03/19 18:51:42 roberto Exp roberto $
+** $Id: lstring.h,v 1.56 2014/07/18 14:46:47 roberto Exp roberto $
** String table (keep all strings handled by Lua)
** See Copyright Notice in lua.h
*/
@@ -13,7 +13,6 @@
#define sizelstring(l) (sizeof(union UTString) + ((l) + 1) * sizeof(char))
-#define sizestring(s) sizelstring((s)->len)
#define sizeludata(l) (sizeof(union UUdata) + (l))
#define sizeudata(u) sizeludata((u)->len)
diff --git a/ltable.c b/ltable.c
@@ -1,5 +1,5 @@
/*
-** $Id: ltable.c,v 2.99 2014/11/02 19:19:04 roberto Exp roberto $
+** $Id: ltable.c,v 2.100 2015/01/05 13:52:37 roberto Exp roberto $
** Lua tables (hash)
** See Copyright Notice in lua.h
*/
@@ -127,7 +127,7 @@ static Node *mainposition (const Table *t, const TValue *key) {
case LUA_TLNGSTR: {
TString *s = tsvalue(key);
if (s->extra == 0) { /* no hash? */
- s->hash = luaS_hash(getstr(s), s->len, s->hash);
+ s->hash = luaS_hash(getstr(s), s->u.lnglen, s->hash);
s->extra = 1; /* now it has its hash */
}
return hashstr(t, tsvalue(key));
diff --git a/ltests.c b/ltests.c
@@ -1,5 +1,5 @@
/*
-** $Id: ltests.c,v 2.200 2014/12/10 11:30:51 roberto Exp roberto $
+** $Id: ltests.c,v 2.201 2014/12/18 12:13:42 roberto Exp roberto $
** Internal Module for Debugging of the Lua Implementation
** See Copyright Notice in lua.h
*/
@@ -724,7 +724,7 @@ static int string_query (lua_State *L) {
else if (s < tb->size) {
TString *ts;
int n = 0;
- for (ts = tb->hash[s]; ts != NULL; ts = ts->hnext) {
+ for (ts = tb->hash[s]; ts != NULL; ts = ts->u.hnext) {
setsvalue2s(L, L->top, ts);
api_incr_top(L);
n++;
diff --git a/lvm.c b/lvm.c
@@ -1,5 +1,5 @@
/*
-** $Id: lvm.c,v 2.231 2014/12/19 13:36:32 roberto Exp roberto $
+** $Id: lvm.c,v 2.232 2014/12/27 20:30:38 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@@ -73,7 +73,7 @@ int luaV_tonumber_ (const TValue *obj, lua_Number *n) {
return 1;
}
else if (cvt2num(obj) && /* string convertible to number? */
- luaO_str2num(svalue(obj), &v) == tsvalue(obj)->len + 1) {
+ luaO_str2num(svalue(obj), &v) == vslen(obj) + 1) {
*n = nvalue(&v); /* convert result of 'luaO_str2num' to a float */
return 1;
}
@@ -106,7 +106,7 @@ static int tointeger_aux (const TValue *obj, lua_Integer *p, int mode) {
return 1;
}
else if (cvt2num(obj) &&
- luaO_str2num(svalue(obj), &v) == tsvalue(obj)->len + 1) {
+ luaO_str2num(svalue(obj), &v) == vslen(obj) + 1) {
obj = &v;
goto again; /* convert result from 'luaO_str2num' to an integer */
}
@@ -239,9 +239,9 @@ void luaV_settable (lua_State *L, const TValue *t, TValue *key, StkId val) {
*/
static int l_strcmp (const TString *ls, const TString *rs) {
const char *l = getstr(ls);
- size_t ll = ls->len;
+ size_t ll = tsslen(ls);
const char *r = getstr(rs);
- size_t lr = rs->len;
+ size_t lr = tsslen(rs);
for (;;) { /* for each segment */
int temp = strcoll(l, r);
if (temp != 0) /* not equal? */
@@ -354,6 +354,8 @@ int luaV_equalobj (lua_State *L, const TValue *t1, const TValue *t2) {
#define tostring(L,o) \
(ttisstring(o) || (cvt2str(o) && (luaO_tostring(L, o), 1)))
+#define isemptystr(o) (ttisshrstring(o) && tsvalue(o)->shrlen == 0)
+
/*
** Main operation for concatenation: concat 'total' values in the stack,
** from 'L->top - total' up to 'L->top - 1'.
@@ -365,19 +367,19 @@ void luaV_concat (lua_State *L, int total) {
int n = 2; /* number of elements handled in this pass (at least 2) */
if (!(ttisstring(top-2) || cvt2str(top-2)) || !tostring(L, top-1))
luaT_trybinTM(L, top-2, top-1, top-2, TM_CONCAT);
- else if (tsvalue(top-1)->len == 0) /* second operand is empty? */
+ else if (isemptystr(top - 1)) /* second operand is empty? */
cast_void(tostring(L, top - 2)); /* result is first operand */
- else if (ttisstring(top-2) && tsvalue(top-2)->len == 0) {
+ else if (isemptystr(top - 2)) { /* first operand is an empty string? */
setobjs2s(L, top - 2, top - 1); /* result is second op. */
}
else {
/* at least two non-empty string values; get as many as possible */
- size_t tl = tsvalue(top-1)->len;
+ size_t tl = vslen(top - 1);
char *buffer;
int i;
/* collect total length */
for (i = 1; i < total && tostring(L, top-i-1); i++) {
- size_t l = tsvalue(top-i-1)->len;
+ size_t l = vslen(top - i - 1);
if (l >= (MAX_SIZE/sizeof(char)) - tl)
luaG_runerror(L, "string length overflow");
tl += l;
@@ -386,7 +388,7 @@ void luaV_concat (lua_State *L, int total) {
tl = 0;
n = i;
do { /* copy all strings to buffer */
- size_t l = tsvalue(top-i)->len;
+ size_t l = vslen(top - i);
memcpy(buffer+tl, svalue(top-i), l * sizeof(char));
tl += l;
} while (--i > 0);
@@ -403,7 +405,7 @@ void luaV_concat (lua_State *L, int total) {
*/
void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
const TValue *tm;
- switch (ttnov(rb)) {
+ switch (ttype(rb)) {
case LUA_TTABLE: {
Table *h = hvalue(rb);
tm = fasttm(L, h->metatable, TM_LEN);
@@ -411,8 +413,12 @@ void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
setivalue(ra, luaH_getn(h)); /* else primitive len */
return;
}
- case LUA_TSTRING: {
- setivalue(ra, tsvalue(rb)->len);
+ case LUA_TSHRSTR: {
+ setivalue(ra, tsvalue(rb)->shrlen);
+ return;
+ }
+ case LUA_TLNGSTR: {
+ setivalue(ra, tsvalue(rb)->u.lnglen);
return;
}
default: { /* try metamethod */
