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size of short strings stored in a single byte, to reduce the size

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of struct 'TString'
This commit is contained in:
Roberto Ierusalimschy
2015-01-16 14:54:37 -02:00
parent 5b01cb39b5
commit 7e2015a46d
9 changed files with 69 additions and 45 deletions
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32
lvm.c
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@@ -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 */