Re: Problem with string.format in lua 5.0 & 5.1
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- Subject: Re: Problem with string.format in lua 5.0 & 5.1
- From: Roberto Ierusalimschy <roberto@...>
- Date: 2005年12月15日 17:02:54 -0200
> Is this will be available in 5.0?
No... This is not a bug, but an improvement.
> And where I can get the code from?
Follows the significant part from lstrlib.c (for 5.1). (luaconf.h should
change according to previous message.)
-- Roberto
/* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */
#define MAX_ITEM 512
/* valid flags in a format specification */
#define FLAGS "-+ #0"
/*
** maximum size of each format specification (such as '%-099.99d')
** (+10 accounts for %99.99x plus margin of error)
*/
#define MAX_FORMAT (sizeof(FLAGS) + sizeof(LUA_INTFRMLEN) + 10)
static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {
size_t l;
const char *s = luaL_checklstring(L, arg, &l);
luaL_addchar(b, '"');
while (l--) {
switch (*s) {
case '"': case '\\': case '\n': {
luaL_addchar(b, '\\');
luaL_addchar(b, *s);
break;
}
case '0円': {
luaL_addlstring(b, "\000円", 4);
break;
}
default: {
luaL_addchar(b, *s);
break;
}
}
s++;
}
luaL_addchar(b, '"');
}
static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {
const char *p = strfrmt;
while (strchr(FLAGS, *p)) p++; /* skip flags */
if ((size_t)(p - strfrmt) >= sizeof(FLAGS))
luaL_error(L, "invalid format (repeated flags)");
if (isdigit(uchar(*p))) p++; /* skip width */
if (isdigit(uchar(*p))) p++; /* (2 digits at most) */
if (*p == '.') {
p++;
if (isdigit(uchar(*p))) p++; /* skip precision */
if (isdigit(uchar(*p))) p++; /* (2 digits at most) */
}
if (isdigit(uchar(*p)))
luaL_error(L, "invalid format (width or precision too long)");
*(form++) = '%';
strncpy(form, strfrmt, p - strfrmt + 1);
form += p - strfrmt + 1;
*form = '0円';
return p;
}
static void addintlen (char *form) {
int l = strlen(form);
char spec = form[l - 1];
strcpy(form + l - 1, LUA_INTFRMLEN);
form[l + sizeof(LUA_INTFRMLEN) - 2] = spec;
form[l + sizeof(LUA_INTFRMLEN) - 1] = '0円';
}
static int str_format (lua_State *L) {
int arg = 1;
size_t sfl;
const char *strfrmt = luaL_checklstring(L, arg, &sfl);
const char *strfrmt_end = strfrmt+sfl;
luaL_Buffer b;
luaL_buffinit(L, &b);
while (strfrmt < strfrmt_end) {
if (*strfrmt != L_ESC)
luaL_addchar(&b, *strfrmt++);
else if (*++strfrmt == L_ESC)
luaL_addchar(&b, *strfrmt++); /* %% */
else { /* format item */
char form[MAX_FORMAT]; /* to store the format (`%...') */
char buff[MAX_ITEM]; /* to store the formatted item */
arg++;
strfrmt = scanformat(L, strfrmt, form);
switch (*strfrmt++) {
case 'c': {
sprintf(buff, form, (int)luaL_checknumber(L, arg));
break;
}
case 'd': case 'i': {
addintlen(form);
sprintf(buff, form, (LUA_INTFRM_T)luaL_checknumber(L, arg));
break;
}
case 'o': case 'u': case 'x': case 'X': {
addintlen(form);
sprintf(buff, form, (unsigned LUA_INTFRM_T)luaL_checknumber(L, arg));
break;
}
case 'e': case 'E': case 'f':
case 'g': case 'G': {
sprintf(buff, form, (double)luaL_checknumber(L, arg));
break;
}
case 'q': {
addquoted(L, &b, arg);
continue; /* skip the 'addsize' at the end */
}
case 's': {
size_t l;
const char *s = luaL_checklstring(L, arg, &l);
if (!strchr(form, '.') && l >= 100) {
/* no precision and string is too long to be formatted;
keep original string */
lua_pushvalue(L, arg);
luaL_addvalue(&b);
continue; /* skip the `addsize' at the end */
}
else {
sprintf(buff, form, s);
break;
}
}
default: { /* also treat cases `pnLlh' */
return luaL_error(L, "invalid option to " LUA_QL("format"));
}
}
luaL_addlstring(&b, buff, strlen(buff));
}
}
luaL_pushresult(&b);
return 1;
}