Some more small improvements to 'luaO_pushvfstring'
Details:
- counter 'pushed' moved to the struct 'BuffFS'
- new auxiliar function 'getbuff' to build strings directly on
the buffer.
diff --git a/lobject.c b/lobject.c
index 123f0e5..58eecd4 100644
--- a/lobject.c
+++ b/lobject.c
@@ -392,126 +392,144 @@
}
-/* size for buffer used by 'luaO_pushvfstring' */
+/* size for buffer space used by 'luaO_pushvfstring' */
#define BUFVFS 400
/* buffer used by 'luaO_pushvfstring' */
typedef struct BuffFS {
- int blen; /* length of partial string in 'buff' */
- char buff[BUFVFS]; /* holds last part of the result */
+ int pushed; /* number of string pieces already on the stack */
+ int blen; /* length of partial string in 'space' */
+ char space[BUFVFS]; /* holds last part of the result */
} BuffFS;
-static void pushstr (lua_State *L, const char *str, size_t l) {
+/*
+** Push given string to the stack, as part of the buffer. If the stack
+** is almost full, join all partial strings in the stack into one.
+*/
+static void pushstr (lua_State *L, BuffFS *buff, const char *str, size_t l) {
setsvalue2s(L, L->top, luaS_newlstr(L, str, l));
L->top++;
+ buff->pushed++;
+ if (buff->pushed > 1 && L->top + 2 > L->stack_last) {
+ luaV_concat(L, buff->pushed); /* join all partial results into one */
+ buff->pushed = 1;
+ }
}
/*
-** empty the buffer into the stack
+** empty the buffer space into the stack
*/
static void clearbuff (lua_State *L, BuffFS *buff) {
- pushstr(L, buff->buff, buff->blen); /* push buffer */
- buff->blen = 0; /* buffer now is empty */
+ pushstr(L, buff, buff->space, buff->blen); /* push buffer contents */
+ buff->blen = 0; /* space now is empty */
}
/*
-** Add 'str' to the buffer. It buffer has no enough space,
-** empty the buffer. If string is still larger than the buffer,
-** push the string directly to the stack. Return number of items
-** pushed.
+** Get a space of size 'sz' in the buffer. If buffer has not enough
+** space, empty it. 'sz' must fit in an empty space.
*/
-static int addstr2buff (lua_State *L, BuffFS *buff, const char *str,
- size_t slen) {
- int pushed = 0; /* number of items pushed to the stack */
- lua_assert(buff->blen <= BUFVFS);
- if (slen > BUFVFS - cast_sizet(buff->blen)) { /* string does not fit? */
+static char *getbuff (lua_State *L, BuffFS *buff, size_t sz) {
+ lua_assert(buff->blen <= BUFVFS); lua_assert(sz <= BUFVFS);
+ if (sz > BUFVFS - cast_sizet(buff->blen)) /* string does not fit? */
clearbuff(L, buff);
- pushed = 1;
- if (slen >= BUFVFS) { /* string still does not fit into buffer? */
- pushstr(L, str, slen); /* push string */
- return 2;
- }
- }
- memcpy(buff->buff + buff->blen, str, slen); /* add string to buffer */
- buff->blen += slen;
- return pushed;
+ return buff->space + buff->blen;
}
+#define addsize(b,sz) ((b)->blen += (sz))
+
+
/*
-** Add a number to the buffer; return number of strings pushed into
-** the stack. (At most one, to free buffer space.)
+** Add 'str' to the buffer. If string is larger than the buffer space,
+** push the string directly to the stack.
*/
-static int addnum2buff (lua_State *L, BuffFS *buff, TValue *num) {
- char numbuff[MAXNUMBER2STR];
- size_t len = tostringbuff(num, numbuff); /* format number into 'numbuff' */
- return addstr2buff(L, buff, numbuff, len);
+static void addstr2buff (lua_State *L, BuffFS *buff, const char *str,
+ size_t slen) {
+ if (slen <= BUFVFS) { /* does string fit into buffer? */
+ char *bf = getbuff(L, buff, slen);
+ memcpy(bf, str, slen); /* add string to buffer */
+ addsize(buff, slen);
+ }
+ else { /* string larger than buffer */
+ clearbuff(L, buff); /* string comes after buffer's content */
+ pushstr(L, buff, str, slen); /* push string */
+ }
}
/*
-** this function handles only '%d', '%c', '%f', '%p', and '%s'
+** Add a number to the buffer.
+*/
+static void addnum2buff (lua_State *L, BuffFS *buff, TValue *num) {
+ char *numbuff = getbuff(L, buff, MAXNUMBER2STR);
+ size_t len = tostringbuff(num, numbuff); /* format number into 'numbuff' */
+ addsize(buff, len);
+}
+
+
+/*
+** this function handles only '%d', '%c', '%f', '%p', '%s', and '%%'
conventional formats, plus Lua-specific '%I' and '%U'
*/
const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) {
BuffFS buff; /* holds last part of the result */
- int pushed = 0; /* number of strings in the stack to concatenate */
const char *e; /* points to next '%' */
- buff.blen = 0;
+ buff.pushed = buff.blen = 0;
while ((e = strchr(fmt, '%')) != NULL) {
- pushed += addstr2buff(L, &buff, fmt, e - fmt); /* add 'fmt' up to '%' */
+ addstr2buff(L, &buff, fmt, e - fmt); /* add 'fmt' up to '%' */
switch (*(e + 1)) { /* conversion specifier */
case 's': { /* zero-terminated string */
const char *s = va_arg(argp, char *);
if (s == NULL) s = "(null)";
- pushed += addstr2buff(L, &buff, s, strlen(s));
+ addstr2buff(L, &buff, s, strlen(s));
break;
}
case 'c': { /* an 'int' as a character */
/* if non-printable character, print its code */
- char bf[10];
+ char *bf = getbuff(L, &buff, 10);
int c = va_arg(argp, int);
- int l = (lisprint(c)) ? l_sprintf(bf, sizeof(bf), "%c", c)
- : l_sprintf(bf, sizeof(bf), "<\\%u>", c);
- pushed += addstr2buff(L, &buff, bf, l);
+ int len = (lisprint(c)) ? l_sprintf(bf, 10, "%c", c)
+ : l_sprintf(bf, 10, "<\\%u>", c);
+ addsize(&buff, len);
break;
}
case 'd': { /* an 'int' */
TValue num;
setivalue(&num, va_arg(argp, int));
- pushed += addnum2buff(L, &buff, &num);
+ addnum2buff(L, &buff, &num);
break;
}
case 'I': { /* a 'lua_Integer' */
TValue num;
setivalue(&num, cast(lua_Integer, va_arg(argp, l_uacInt)));
- pushed += addnum2buff(L, &buff, &num);
+ addnum2buff(L, &buff, &num);
break;
}
case 'f': { /* a 'lua_Number' */
TValue num;
setfltvalue(&num, cast_num(va_arg(argp, l_uacNumber)));
- pushed += addnum2buff(L, &buff, &num);
+ addnum2buff(L, &buff, &num);
break;
}
case 'p': { /* a pointer */
- char bf[3 * sizeof(void*) + 8]; /* should be enough space for '%p' */
+ const int sz = 3 * sizeof(void*) + 8; /* enough space for '%p' */
+ char *bf = getbuff(L, &buff, sz);
void *p = va_arg(argp, void *);
- int l = l_sprintf(bf, sizeof(bf), "%p", p);
- pushed += addstr2buff(L, &buff, bf, l);
+ int len = l_sprintf(bf, sz, "%p", p);
+ addsize(&buff, len);
break;
}
case 'U': { /* a 'long' as a UTF-8 sequence */
char bf[UTF8BUFFSZ];
- int l = luaO_utf8esc(bf, va_arg(argp, long));
- pushed += addstr2buff(L, &buff, bf + UTF8BUFFSZ - l, l);
+ int len = luaO_utf8esc(bf, va_arg(argp, long));
+ addstr2buff(L, &buff, bf + UTF8BUFFSZ - len, len);
break;
}
case '%': {
- pushed += addstr2buff(L, &buff, "%", 1);
+ addstr2buff(L, &buff, "%", 1);
break;
}
default: {
@@ -519,16 +537,12 @@
*(e + 1));
}
}
- if (pushed > 1 && L->top + 2 > L->stack_last) { /* no free stack space? */
- luaV_concat(L, pushed); /* join all partial results into one */
- pushed = 1;
- }
fmt = e + 2; /* skip '%' and the specifier */
}
- pushed += addstr2buff(L, &buff, fmt, strlen(fmt)); /* rest of 'fmt' */
+ addstr2buff(L, &buff, fmt, strlen(fmt)); /* rest of 'fmt' */
clearbuff(L, &buff); /* empty buffer into the stack */
- if (pushed > 0)
- luaV_concat(L, pushed + 1); /* join all partial results */
+ if (buff.pushed > 1)
+ luaV_concat(L, buff.pushed); /* join all partial results */
return svalue(s2v(L->top - 1));
}
diff --git a/testes/strings.lua b/testes/strings.lua
index 66c1176..bc123d1 100644
--- a/testes/strings.lua
+++ b/testes/strings.lua
@@ -458,6 +458,9 @@
str = string.rep("a", blen - 1) .. "%p" .. string.rep("cd", blen)
testpfs("P", str, {})
+
+ str = string.rep("%%", 3 * blen) .. "%p" .. string.rep("%%", 2 * blen)
+ testpfs("P", str, {})
end
