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nodemcu-firmware/app/lua53/lstrlib.c

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Squashed updates do get Lua51 and Lua53 working (#3075) - Lots of minor but nasty bugfixes to get all tests to run clean - core lua and test suite fixes to allow luac -F to run cleanly against test suite - next tranch to get LFS working - luac.cross -a options plus fixes from feedback - UART fixes and lua.c merge - commit of wip prior to rebaselining against current dev - more tweaks
2020-04-27 02:13:38 +02:00
/*
** $Id: lstrlib.c,v 1.254.1.1 2017/04/19 17:29:57 roberto Exp $
** Standard library for string operations and pattern-matching
** See Copyright Notice in lua.h
*/
#define lstrlib_c
#define LUA_LIB
#include "lprefix.h"
#include <ctype.h>
#include <float.h>
#include <limits.h>
#include <locale.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"
#include "lnodemcu.h"
/*
** maximum number of captures that a pattern can do during
** pattern-matching. This limit is arbitrary, but must fit in
** an unsigned char.
*/
#if !defined(LUA_MAXCAPTURES)
#define LUA_MAXCAPTURES 32
#endif
/* macro to 'unsign' a character */
#define uchar(c) ((unsigned char)(c))
/*
** Some sizes are better limited to fit in 'int', but must also fit in
** 'size_t'. (We assume that 'lua_Integer' cannot be smaller than 'int'.)
*/
#define MAX_SIZET ((size_t)(~(size_t)0))
#define MAXSIZE \
(sizeof(size_t) < sizeof(int) ? MAX_SIZET : (size_t)(INT_MAX))
static int str_len (lua_State *L) {
size_t l;
luaL_checklstring(L, 1, &l);
lua_pushinteger(L, (lua_Integer)l);
return 1;
}
/* translate a relative string position: negative means back from end */
static lua_Integer posrelat (lua_Integer pos, size_t len) {
if (pos >= 0) return pos;
else if (0u - (size_t)pos > len) return 0;
else return (lua_Integer)len + pos + 1;
}
static int str_sub (lua_State *L) {
size_t l;
const char *s = luaL_checklstring(L, 1, &l);
lua_Integer start = posrelat(luaL_checkinteger(L, 2), l);
lua_Integer end = posrelat(luaL_optinteger(L, 3, -1), l);
if (start < 1) start = 1;
if (end > (lua_Integer)l) end = l;
if (start <= end)
lua_pushlstring(L, s + start - 1, (size_t)(end - start) + 1);
else lua_pushliteral(L, "");
return 1;
}
static int str_reverse (lua_State *L) {
size_t l, i;
luaL_Buffer b;
const char *s = luaL_checklstring(L, 1, &l);
char *p = luaL_buffinitsize(L, &b, l);
for (i = 0; i < l; i++)
p[i] = s[l - i - 1];
luaL_pushresultsize(&b, l);
return 1;
}
static int str_lower (lua_State *L) {
size_t l;
size_t i;
luaL_Buffer b;
const char *s = luaL_checklstring(L, 1, &l);
char *p = luaL_buffinitsize(L, &b, l);
for (i=0; i<l; i++)
p[i] = tolower(uchar(s[i]));
luaL_pushresultsize(&b, l);
return 1;
}
static int str_upper (lua_State *L) {
size_t l;
size_t i;
luaL_Buffer b;
const char *s = luaL_checklstring(L, 1, &l);
char *p = luaL_buffinitsize(L, &b, l);
for (i=0; i<l; i++)
p[i] = toupper(uchar(s[i]));
luaL_pushresultsize(&b, l);
return 1;
}
static int str_rep (lua_State *L) {
size_t l, lsep;
const char *s = luaL_checklstring(L, 1, &l);
lua_Integer n = luaL_checkinteger(L, 2);
const char *sep = luaL_optlstring(L, 3, "", &lsep);
if (n <= 0) lua_pushliteral(L, "");
else if (l + lsep < l || l + lsep > MAXSIZE / n) /* may overflow? */
return luaL_error(L, "resulting string too large");
else {
size_t totallen = (size_t)n * l + (size_t)(n - 1) * lsep;
luaL_Buffer b;
char *p = luaL_buffinitsize(L, &b, totallen);
while (n-- > 1) { /* first n-1 copies (followed by separator) */
memcpy(p, s, l * sizeof(char)); p += l;
if (lsep > 0) { /* empty 'memcpy' is not that cheap */
memcpy(p, sep, lsep * sizeof(char));
p += lsep;
}
}
memcpy(p, s, l * sizeof(char)); /* last copy (not followed by separator) */
luaL_pushresultsize(&b, totallen);
}
return 1;
}
static int str_byte (lua_State *L) {
size_t l;
const char *s = luaL_checklstring(L, 1, &l);
lua_Integer posi = posrelat(luaL_optinteger(L, 2, 1), l);
lua_Integer pose = posrelat(luaL_optinteger(L, 3, posi), l);
int n, i;
if (posi < 1) posi = 1;
if (pose > (lua_Integer)l) pose = l;
if (posi > pose) return 0; /* empty interval; return no values */
if (pose - posi >= INT_MAX) /* arithmetic overflow? */
return luaL_error(L, "string slice too long");
n = (int)(pose - posi) + 1;
luaL_checkstack(L, n, "string slice too long");
for (i=0; i<n; i++)
lua_pushinteger(L, uchar(s[posi+i-1]));
return n;
}
static int str_char (lua_State *L) {
int n = lua_gettop(L); /* number of arguments */
int i;
luaL_Buffer b;
char *p = luaL_buffinitsize(L, &b, n);
for (i=1; i<=n; i++) {
lua_Integer c = luaL_checkinteger(L, i);
luaL_argcheck(L, uchar(c) == c, i, "value out of range");
p[i - 1] = uchar(c);
}
luaL_pushresultsize(&b, n);
return 1;
}
static int writer (lua_State *L, const void *b, size_t size, void *B) {
(void)L;
luaL_addlstring((luaL_Buffer *) B, (const char *)b, size);
return 0;
}
static int str_dump (lua_State *L) {
luaL_Buffer b;
int strip = lua_tointeger(L, 2);
if (lua_isboolean(L, 2) && lua_toboolean(L, 2))
strip = 2;
luaL_checktype(L, 1, LUA_TFUNCTION);
luaL_argcheck(L, 3 > (unsigned)(strip), 1, "strip out of range");
lua_settop(L, 1);
luaL_buffinit(L,&b);
if (lua_dump(L, writer, &b, strip) != 0)
return luaL_error(L, "unable to dump given function");
luaL_pushresult(&b);
return 1;
}
/*
** {======================================================
** PATTERN MATCHING
** =======================================================
*/
#define CAP_UNFINISHED (-1)
#define CAP_POSITION (-2)
typedef struct MatchState {
const char *src_init; /* init of source string */
const char *src_end; /* end ('\0') of source string */
const char *p_end; /* end ('\0') of pattern */
lua_State *L;
int matchdepth; /* control for recursive depth (to avoid C stack overflow) */
unsigned char level; /* total number of captures (finished or unfinished) */
struct {
const char *init;
ptrdiff_t len;
} capture[LUA_MAXCAPTURES];
} MatchState;
/* recursive function */
static const char *match (MatchState *ms, const char *s, const char *p);
/* maximum recursion depth for 'match' */
#if !defined(MAXCCALLS)
#define MAXCCALLS 200
#endif
#define L_ESC '%'
#define SPECIALS "^$*+?.([%-"
static int check_capture (MatchState *ms, int l) {
l -= '1';
if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED)
return luaL_error(ms->L, "invalid capture index %%%d", l + 1);
return l;
}
static int capture_to_close (MatchState *ms) {
int level = ms->level;
for (level--; level>=0; level--)
if (ms->capture[level].len == CAP_UNFINISHED) return level;
return luaL_error(ms->L, "invalid pattern capture");
}
static const char *classend (MatchState *ms, const char *p) {
switch (*p++) {
case L_ESC: {
if (p == ms->p_end)
luaL_error(ms->L, "malformed pattern (ends with '%%')");
return p+1;
}
case '[': {
if (*p == '^') p++;
do { /* look for a ']' */
if (p == ms->p_end)
luaL_error(ms->L, "malformed pattern (missing ']')");
if (*(p++) == L_ESC && p < ms->p_end)
p++; /* skip escapes (e.g. '%]') */
} while (*p != ']');
return p+1;
}
default: {
return p;
}
}
}
static int match_class (int c, int cl) {
int res;
switch (tolower(cl)) {
case 'a' : res = isalpha(c); break;
case 'c' : res = iscntrl(c); break;
case 'd' : res = isdigit(c); break;
case 'g' : res = isgraph(c); break;
case 'l' : res = islower(c); break;
case 'p' : res = ispunct(c); break;
case 's' : res = isspace(c); break;
case 'u' : res = isupper(c); break;
case 'w' : res = isalnum(c); break;
case 'x' : res = isxdigit(c); break;
case 'z' : res = (c == 0); break; /* deprecated option */
default: return (cl == c);
}
return (islower(cl) ? res : !res);
}
static int matchbracketclass (int c, const char *p, const char *ec) {
int sig = 1;
if (*(p+1) == '^') {
sig = 0;
p++; /* skip the '^' */
}
while (++p < ec) {
if (*p == L_ESC) {
p++;
if (match_class(c, uchar(*p)))
return sig;
}
else if ((*(p+1) == '-') && (p+2 < ec)) {
p+=2;
if (uchar(*(p-2)) <= c && c <= uchar(*p))
return sig;
}
else if (uchar(*p) == c) return sig;
}
return !sig;
}
static int singlematch (MatchState *ms, const char *s, const char *p,
const char *ep) {
if (s >= ms->src_end)
return 0;
else {
int c = uchar(*s);
switch (*p) {
case '.': return 1; /* matches any char */
case L_ESC: return match_class(c, uchar(*(p+1)));
case '[': return matchbracketclass(c, p, ep-1);
default: return (uchar(*p) == c);
}
}
}
static const char *matchbalance (MatchState *ms, const char *s,
const char *p) {
if (p >= ms->p_end - 1)
luaL_error(ms->L, "malformed pattern (missing arguments to '%%b')");
if (*s != *p) return NULL;
else {
int b = *p;
int e = *(p+1);
int cont = 1;
while (++s < ms->src_end) {
if (*s == e) {
if (--cont == 0) return s+1;
}
else if (*s == b) cont++;
}
}
return NULL; /* string ends out of balance */
}
static const char *max_expand (MatchState *ms, const char *s,
const char *p, const char *ep) {
ptrdiff_t i = 0; /* counts maximum expand for item */
while (singlematch(ms, s + i, p, ep))
i++;
/* keeps trying to match with the maximum repetitions */
while (i>=0) {
const char *res = match(ms, (s+i), ep+1);
if (res) return res;
i--; /* else didn't match; reduce 1 repetition to try again */
}
return NULL;
}
static const char *min_expand (MatchState *ms, const char *s,
const char *p, const char *ep) {
for (;;) {
const char *res = match(ms, s, ep+1);
if (res != NULL)
return res;
else if (singlematch(ms, s, p, ep))
s++; /* try with one more repetition */
else return NULL;
}
}
static const char *start_capture (MatchState *ms, const char *s,
const char *p, int what) {
const char *res;
int level = ms->level;
if (level >= LUA_MAXCAPTURES) luaL_error(ms->L, "too many captures");
ms->capture[level].init = s;
ms->capture[level].len = what;
ms->level = level+1;
if ((res=match(ms, s, p)) == NULL) /* match failed? */
ms->level--; /* undo capture */
return res;
}
static const char *end_capture (MatchState *ms, const char *s,
const char *p) {
int l = capture_to_close(ms);
const char *res;
ms->capture[l].len = s - ms->capture[l].init; /* close capture */
if ((res = match(ms, s, p)) == NULL) /* match failed? */
ms->capture[l].len = CAP_UNFINISHED; /* undo capture */
return res;
}
static const char *match_capture (MatchState *ms, const char *s, int l) {
size_t len;
l = check_capture(ms, l);
len = ms->capture[l].len;
if ((size_t)(ms->src_end-s) >= len &&
memcmp(ms->capture[l].init, s, len) == 0)
return s+len;
else return NULL;
}
static const char *match (MatchState *ms, const char *s, const char *p) {
if (ms->matchdepth-- == 0)
luaL_error(ms->L, "pattern too complex");
init: /* using goto's to optimize tail recursion */
if (p != ms->p_end) { /* end of pattern? */
switch (*p) {
case '(': { /* start capture */
if (*(p + 1) == ')') /* position capture? */
s = start_capture(ms, s, p + 2, CAP_POSITION);
else
s = start_capture(ms, s, p + 1, CAP_UNFINISHED);
break;
}
case ')': { /* end capture */
s = end_capture(ms, s, p + 1);
break;
}
case '$': {
if ((p + 1) != ms->p_end) /* is the '$' the last char in pattern? */
goto dflt; /* no; go to default */
s = (s == ms->src_end) ? s : NULL; /* check end of string */
break;
}
case L_ESC: { /* escaped sequences not in the format class[*+?-]? */
switch (*(p + 1)) {
case 'b': { /* balanced string? */
s = matchbalance(ms, s, p + 2);
if (s != NULL) {
p += 4; goto init; /* return match(ms, s, p + 4); */
} /* else fail (s == NULL) */
break;
}
case 'f': { /* frontier? */
const char *ep; char previous;
p += 2;
if (*p != '[')
luaL_error(ms->L, "missing '[' after '%%f' in pattern");
ep = classend(ms, p); /* points to what is next */
previous = (s == ms->src_init) ? '\0' : *(s - 1);
if (!matchbracketclass(uchar(previous), p, ep - 1) &&
matchbracketclass(uchar(*s), p, ep - 1)) {
p = ep; goto init; /* return match(ms, s, ep); */
}
s = NULL; /* match failed */
break;
}
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
case '8': case '9': { /* capture results (%0-%9)? */
s = match_capture(ms, s, uchar(*(p + 1)));
if (s != NULL) {
p += 2; goto init; /* return match(ms, s, p + 2) */
}
break;
}
default: goto dflt;
}
break;
}
default: dflt: { /* pattern class plus optional suffix */
const char *ep = classend(ms, p); /* points to optional suffix */
/* does not match at least once? */
if (!singlematch(ms, s, p, ep)) {
if (*ep == '*' || *ep == '?' || *ep == '-') { /* accept empty? */
p = ep + 1; goto init; /* return match(ms, s, ep + 1); */
}
else /* '+' or no suffix */
s = NULL; /* fail */
}
else { /* matched once */
switch (*ep) { /* handle optional suffix */
case '?': { /* optional */
const char *res;
if ((res = match(ms, s + 1, ep + 1)) != NULL)
s = res;
else {
p = ep + 1; goto init; /* else return match(ms, s, ep + 1); */
}
break;
}
case '+': /* 1 or more repetitions */
s++; /* 1 match already done */
/* FALLTHROUGH */
case '*': /* 0 or more repetitions */
s = max_expand(ms, s, p, ep);
break;
case '-': /* 0 or more repetitions (minimum) */
s = min_expand(ms, s, p, ep);
break;
default: /* no suffix */
s++; p = ep; goto init; /* return match(ms, s + 1, ep); */
}
}
break;
}
}
}
ms->matchdepth++;
return s;
}
static const char *lmemfind (const char *s1, size_t l1,
const char *s2, size_t l2) {
if (l2 == 0) return s1; /* empty strings are everywhere */
else if (l2 > l1) return NULL; /* avoids a negative 'l1' */
else {
const char *init; /* to search for a '*s2' inside 's1' */
l2--; /* 1st char will be checked by 'memchr' */
l1 = l1-l2; /* 's2' cannot be found after that */
while (l1 > 0 && (init = (const char *)memchr(s1, *s2, l1)) != NULL) {
init++; /* 1st char is already checked */
if (memcmp(init, s2+1, l2) == 0)
return init-1;
else { /* correct 'l1' and 's1' to try again */
l1 -= init-s1;
s1 = init;
}
}
return NULL; /* not found */
}
}
static void push_onecapture (MatchState *ms, int i, const char *s,
const char *e) {
if (i >= ms->level) {
if (i == 0) /* ms->level == 0, too */
lua_pushlstring(ms->L, s, e - s); /* add whole match */
else
luaL_error(ms->L, "invalid capture index %%%d", i + 1);
}
else {
ptrdiff_t l = ms->capture[i].len;
if (l == CAP_UNFINISHED) luaL_error(ms->L, "unfinished capture");
if (l == CAP_POSITION)
lua_pushinteger(ms->L, (ms->capture[i].init - ms->src_init) + 1);
else
lua_pushlstring(ms->L, ms->capture[i].init, l);
}
}
static int push_captures (MatchState *ms, const char *s, const char *e) {
int i;
int nlevels = (ms->level == 0 && s) ? 1 : ms->level;
luaL_checkstack(ms->L, nlevels, "too many captures");
for (i = 0; i < nlevels; i++)
push_onecapture(ms, i, s, e);
return nlevels; /* number of strings pushed */
}
/* check whether pattern has no special characters */
static int nospecials (const char *p, size_t l) {
size_t upto = 0;
do {
if (strpbrk(p + upto, SPECIALS))
return 0; /* pattern has a special character */
upto += strlen(p + upto) + 1; /* may have more after \0 */
} while (upto <= l);
return 1; /* no special chars found */
}
static void prepstate (MatchState *ms, lua_State *L,
const char *s, size_t ls, const char *p, size_t lp) {
ms->L = L;
ms->matchdepth = MAXCCALLS;
ms->src_init = s;
ms->src_end = s + ls;
ms->p_end = p + lp;
}
static void reprepstate (MatchState *ms) {
ms->level = 0;
lua_assert(ms->matchdepth == MAXCCALLS);
}
static int str_find_aux (lua_State *L, int find) {
size_t ls, lp;
const char *s = luaL_checklstring(L, 1, &ls);
const char *p = luaL_checklstring(L, 2, &lp);
lua_Integer init = posrelat(luaL_optinteger(L, 3, 1), ls);
if (init < 1) init = 1;
else if (init > (lua_Integer)ls + 1) { /* start after string's end? */
lua_pushnil(L); /* cannot find anything */
return 1;
}
/* explicit request or no special characters? */
if (find && (lua_toboolean(L, 4) || nospecials(p, lp))) {
/* do a plain search */
const char *s2 = lmemfind(s + init - 1, ls - (size_t)init + 1, p, lp);
if (s2) {
lua_pushinteger(L, (s2 - s) + 1);
lua_pushinteger(L, (s2 - s) + lp);
return 2;
}
}
else {
MatchState ms;
const char *s1 = s + init - 1;
int anchor = (*p == '^');
if (anchor) {
p++; lp--; /* skip anchor character */
}
prepstate(&ms, L, s, ls, p, lp);
do {
const char *res;
reprepstate(&ms);
if ((res=match(&ms, s1, p)) != NULL) {
if (find) {
lua_pushinteger(L, (s1 - s) + 1); /* start */
lua_pushinteger(L, res - s); /* end */
return push_captures(&ms, NULL, 0) + 2;
}
else
return push_captures(&ms, s1, res);
}
} while (s1++ < ms.src_end && !anchor);
}
lua_pushnil(L); /* not found */
return 1;
}
static int str_find (lua_State *L) {
return str_find_aux(L, 1);
}
static int str_match (lua_State *L) {
return str_find_aux(L, 0);
}
/* state for 'gmatch' */
typedef struct GMatchState {
const char *src; /* current position */
const char *p; /* pattern */
const char *lastmatch; /* end of last match */
MatchState ms; /* match state */
} GMatchState;
static int gmatch_aux (lua_State *L) {
GMatchState *gm = (GMatchState *)lua_touserdata(L, lua_upvalueindex(3));
const char *src;
gm->ms.L = L;
for (src = gm->src; src <= gm->ms.src_end; src++) {
const char *e;
reprepstate(&gm->ms);
if ((e = match(&gm->ms, src, gm->p)) != NULL && e != gm->lastmatch) {
gm->src = gm->lastmatch = e;
return push_captures(&gm->ms, src, e);
}
}
return 0; /* not found */
}
static int gmatch (lua_State *L) {
size_t ls, lp;
const char *s = luaL_checklstring(L, 1, &ls);
const char *p = luaL_checklstring(L, 2, &lp);
GMatchState *gm;
lua_settop(L, 2); /* keep them on closure to avoid being collected */
gm = (GMatchState *)lua_newuserdata(L, sizeof(GMatchState));
prepstate(&gm->ms, L, s, ls, p, lp);
gm->src = s; gm->p = p; gm->lastmatch = NULL;
lua_pushcclosure(L, gmatch_aux, 3);
return 1;
}
static void add_s (MatchState *ms, luaL_Buffer *b, const char *s,
const char *e) {
size_t l, i;
lua_State *L = ms->L;
const char *news = lua_tolstring(L, 3, &l);
for (i = 0; i < l; i++) {
if (news[i] != L_ESC)
luaL_addchar(b, news[i]);
else {
i++; /* skip ESC */
if (!isdigit(uchar(news[i]))) {
if (news[i] != L_ESC)
luaL_error(L, "invalid use of '%c' in replacement string", L_ESC);
luaL_addchar(b, news[i]);
}
else if (news[i] == '0')
luaL_addlstring(b, s, e - s);
else {
push_onecapture(ms, news[i] - '1', s, e);
luaL_tolstring(L, -1, NULL); /* if number, convert it to string */
lua_remove(L, -2); /* remove original value */
luaL_addvalue(b); /* add capture to accumulated result */
}
}
}
}
static void add_value (MatchState *ms, luaL_Buffer *b, const char *s,
const char *e, int tr) {
lua_State *L = ms->L;
switch (tr) {
case LUA_TFUNCTION: {
int n;
lua_pushvalue(L, 3);
n = push_captures(ms, s, e);
lua_call(L, n, 1);
break;
}
case LUA_TTABLE: {
push_onecapture(ms, 0, s, e);
lua_gettable(L, 3);
break;
}
default: { /* LUA_TNUMBER or LUA_TSTRING */
add_s(ms, b, s, e);
return;
}
}
if (!lua_toboolean(L, -1)) { /* nil or false? */
lua_pop(L, 1);
lua_pushlstring(L, s, e - s); /* keep original text */
}
else if (!lua_isstring(L, -1))
luaL_error(L, "invalid replacement value (a %s)", luaL_typename(L, -1));
luaL_addvalue(b); /* add result to accumulator */
}
static int str_gsub (lua_State *L) {
size_t srcl, lp;
const char *src = luaL_checklstring(L, 1, &srcl); /* subject */
const char *p = luaL_checklstring(L, 2, &lp); /* pattern */
const char *lastmatch = NULL; /* end of last match */
int tr = lua_type(L, 3); /* replacement type */
lua_Integer max_s = luaL_optinteger(L, 4, srcl + 1); /* max replacements */
int anchor = (*p == '^');
lua_Integer n = 0; /* replacement count */
MatchState ms;
luaL_Buffer b;
luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||
tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,
"string/function/table expected");
luaL_buffinit(L, &b);
if (anchor) {
p++; lp--; /* skip anchor character */
}
prepstate(&ms, L, src, srcl, p, lp);
while (n < max_s) {
const char *e;
reprepstate(&ms); /* (re)prepare state for new match */
if ((e = match(&ms, src, p)) != NULL && e != lastmatch) { /* match? */
n++;
add_value(&ms, &b, src, e, tr); /* add replacement to buffer */
src = lastmatch = e;
}
else if (src < ms.src_end) /* otherwise, skip one character */
luaL_addchar(&b, *src++);
else break; /* end of subject */
if (anchor) break;
}
luaL_addlstring(&b, src, ms.src_end-src);
luaL_pushresult(&b);
lua_pushinteger(L, n); /* number of substitutions */
return 2;
}
/* }====================================================== */
/*
** {======================================================
** STRING FORMAT
** =======================================================
*/
#if !defined(lua_number2strx) /* { */
/*
** Hexadecimal floating-point formatter
*/
#include <math.h>
#define SIZELENMOD (sizeof(LUA_NUMBER_FRMLEN)/sizeof(char))
/*
** Number of bits that goes into the first digit. It can be any value
** between 1 and 4; the following definition tries to align the number
** to nibble boundaries by making what is left after that first digit a
** multiple of 4.
*/
#define L_NBFD ((l_mathlim(MANT_DIG) - 1) % 4 + 1)
/*
** Add integer part of 'x' to buffer and return new 'x'
*/
static lua_Number adddigit (char *buff, int n, lua_Number x) {
lua_Number dd = l_mathop(floor)(x); /* get integer part from 'x' */
int d = (int)dd;
buff[n] = (d < 10 ? d + '0' : d - 10 + 'a'); /* add to buffer */
return x - dd; /* return what is left */
}
static int num2straux (char *buff, int sz, lua_Number x) {
/* if 'inf' or 'NaN', format it like '%g' */
if (x != x || x == (lua_Number)HUGE_VAL || x == -(lua_Number)HUGE_VAL)
return l_sprintf(buff, sz, LUA_NUMBER_FMT, (LUAI_UACNUMBER)x);
else if (x == 0) { /* can be -0... */
/* create "0" or "-0" followed by exponent */
return l_sprintf(buff, sz, LUA_NUMBER_FMT "x0p+0", (LUAI_UACNUMBER)x);
}
else {
int e;
lua_Number m = l_mathop(frexp)(x, &e); /* 'x' fraction and exponent */
int n = 0; /* character count */
if (m < 0) { /* is number negative? */
buff[n++] = '-'; /* add signal */
m = -m; /* make it positive */
}
buff[n++] = '0'; buff[n++] = 'x'; /* add "0x" */
m = adddigit(buff, n++, m * (1 << L_NBFD)); /* add first digit */
e -= L_NBFD; /* this digit goes before the radix point */
if (m > 0) { /* more digits? */
buff[n++] = lua_getlocaledecpoint(); /* add radix point */
do { /* add as many digits as needed */
m = adddigit(buff, n++, m * 16);
} while (m > 0);
}
n += l_sprintf(buff + n, sz - n, "p%+d", e); /* add exponent */
lua_assert(n < sz);
return n;
}
}
static int lua_number2strx (lua_State *L, char *buff, int sz,
const char *fmt, lua_Number x) {
int n = num2straux(buff, sz, x);
if (fmt[SIZELENMOD] == 'A') {
int i;
for (i = 0; i < n; i++)
buff[i] = toupper(uchar(buff[i]));
}
else if (fmt[SIZELENMOD] != 'a')
return luaL_error(L, "modifiers for format '%%a'/'%%A' not implemented");
return n;
}
#endif /* } */
/*
** Maximum size of each formatted item. Unlike standard Lua which is
** based on the maximum size is produceD by format('%.99f', -maxfloat),
** NodeMCU just limits this to 128.
*/
#define MAX_ITEM 128
/* valid flags in a format specification */
#define FLAGS "-+ #0"
/*
** maximum size of each format specification (such as "%-099.99d")
*/
#define MAX_FORMAT 32
static void addquoted (luaL_Buffer *b, const char *s, size_t len) {
luaL_addchar(b, '"');
while (len--) {
if (*s == '"' || *s == '\\' || *s == '\n') {
luaL_addchar(b, '\\');
luaL_addchar(b, *s);
}
else if (iscntrl(uchar(*s))) {
char buff[10];
if (!isdigit(uchar(*(s+1))))
l_sprintf(buff, sizeof(buff), "\\%d", (int)uchar(*s));
else
l_sprintf(buff, sizeof(buff), "\\%03d", (int)uchar(*s));
luaL_addstring(b, buff);
}
else
luaL_addchar(b, *s);
s++;
}
luaL_addchar(b, '"');
}
/*
** Ensures the 'buff' string uses a dot as the radix character.
*/
static void checkdp (char *buff, int nb) {
if (memchr(buff, '.', nb) == NULL) { /* no dot? */
char point = lua_getlocaledecpoint(); /* try locale point */
char *ppoint = (char *)memchr(buff, point, nb);
if (ppoint) *ppoint = '.'; /* change it to a dot */
}
}
static void addliteral (lua_State *L, luaL_Buffer *b, int arg) {
switch (lua_type(L, arg)) {
case LUA_TSTRING: {
size_t len;
const char *s = lua_tolstring(L, arg, &len);
addquoted(b, s, len);
break;
}
case LUA_TNUMBER: {
char *buff = luaL_prepbuffsize(b, MAX_ITEM);
int nb;
if (!lua_isinteger(L, arg)) { /* float? */
lua_Number n = lua_tonumber(L, arg); /* write as hexa ('%a') */
nb = lua_number2strx(L, buff, MAX_ITEM, "%" LUA_NUMBER_FRMLEN "a", n);
checkdp(buff, nb); /* ensure it uses a dot */
}
else { /* integers */
lua_Integer n = lua_tointeger(L, arg);
const char *format = (n == LUA_MININTEGER) /* corner case? */
? "0x%" LUA_INTEGER_FRMLEN "x" /* use hexa */
: LUA_INTEGER_FMT; /* else use default format */
nb = l_sprintf(buff, MAX_ITEM, format, (LUAI_UACINT)n);
}
luaL_addsize(b, nb);
break;
}
case LUA_TNIL: case LUA_TBOOLEAN: {
luaL_tolstring(L, arg, NULL);
luaL_addvalue(b);
break;
}
default: {
luaL_argerror(L, arg, "value has no literal form");
}
}
}
static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {
const char *p = strfrmt;
while (*p != '\0' && strchr(FLAGS, *p) != NULL) p++; /* skip flags */
if ((size_t)(p - strfrmt) >= sizeof(FLAGS)/sizeof(char))
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++) = '%';
memcpy(form, strfrmt, ((p - strfrmt) + 1) * sizeof(char));
form += (p - strfrmt) + 1;
*form = '\0';
return p;
}
/*
** add length modifier into formats
*/
static void addlenmod (char *form, const char *lenmod) {
size_t l = strlen(form);
size_t lm = strlen(lenmod);
char spec = form[l - 1];
strcpy(form + l - 1, lenmod);
form[l + lm - 1] = spec;
form[l + lm] = '\0';
}
static int str_format (lua_State *L) {
int top = lua_gettop(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 = luaL_prepbuffsize(&b, MAX_ITEM); /* to put formatted item */
int nb = 0; /* number of bytes in added item */
if (++arg > top)
luaL_argerror(L, arg, "no value");
strfrmt = scanformat(L, strfrmt, form);
switch (*strfrmt++) {
case 'c': {
nb = l_sprintf(buff, MAX_ITEM, form, (int)luaL_checkinteger(L, arg));
break;
}
case 'd': case 'i':
case 'o': case 'u': case 'x': case 'X': {
lua_Integer n = luaL_checkinteger(L, arg);
addlenmod(form, LUA_INTEGER_FRMLEN);
nb = l_sprintf(buff, MAX_ITEM, form, (LUAI_UACINT)n);
break;
}
case 'a': case 'A':
addlenmod(form, LUA_NUMBER_FRMLEN);
nb = lua_number2strx(L, buff, MAX_ITEM, form,
luaL_checknumber(L, arg));
break;
case 'e': case 'E': case 'f':
case 'g': case 'G': {
lua_Number n = luaL_checknumber(L, arg);
addlenmod(form, LUA_NUMBER_FRMLEN);
nb = l_sprintf(buff, MAX_ITEM, form, (LUAI_UACNUMBER)n);
break;
}
case 'q': {
addliteral(L, &b, arg);
break;
}
case 's': {
size_t l;
const char *s = luaL_tolstring(L, arg, &l);
if (form[2] == '\0') /* no modifiers? */
luaL_addvalue(&b); /* keep entire string */
else {
luaL_argcheck(L, l == strlen(s), arg, "string contains zeros");
if (!strchr(form, '.') && l >= 100) {
/* no precision and string is too long to be formatted */
luaL_addvalue(&b); /* keep entire string */
}
else { /* format the string into 'buff' */
nb = l_sprintf(buff, MAX_ITEM, form, s);
lua_pop(L, 1); /* remove result from 'luaL_tolstring' */
}
}
break;
}
default: { /* also treat cases 'pnLlh' */
return luaL_error(L, "invalid option '%%%c' to 'format'",
*(strfrmt - 1));
}
}
lua_assert(nb < MAX_ITEM);
luaL_addsize(&b, nb);
}
}
luaL_pushresult(&b);
return 1;
}
static int str_format2 (lua_State *L) {
if (lua_type(L, 2) == LUA_TTABLE) {
int i,n=lua_rawlen(L,2);
lua_settop(L,2);
for (i = 1; i <= n; i++)
lua_rawgeti(L, 2, i);
lua_remove(L, 2);
}
return str_format(L);
}
/* }====================================================== */
/*
** {======================================================
** PACK/UNPACK
** =======================================================
*/
/* value used for padding */
#if !defined(LUAL_PACKPADBYTE)
#define LUAL_PACKPADBYTE 0x00
#endif
/* maximum size for the binary representation of an integer */
#define MAXINTSIZE 16
/* number of bits in a character */
#define NB CHAR_BIT
/* mask for one character (NB 1's) */
#define MC ((1 << NB) - 1)
/* size of a lua_Integer */
#define SZINT ((int)sizeof(lua_Integer))
/* dummy union to get native endianness */
static const union {
int dummy;
char little; /* true iff machine is little endian */
} nativeendian = {1};
/* dummy structure to get native alignment requirements */
struct cD {
char c;
union { double d; void *p; lua_Integer i; lua_Number n; } u;
};
#define MAXALIGN (offsetof(struct cD, u))
/*
** Union for serializing floats
*/
typedef union Ftypes {
float f;
double d;
lua_Number n;
char buff[5 * sizeof(lua_Number)]; /* enough for any float type */
} Ftypes;
/*
** information to pack/unpack stuff
*/
typedef struct Header {
lua_State *L;
int islittle;
int maxalign;
} Header;
/*
** options for pack/unpack
*/
typedef enum KOption {
Kint, /* signed integers */
Kuint, /* unsigned integers */
Kfloat, /* floating-point numbers */
Kchar, /* fixed-length strings */
Kstring, /* strings with prefixed length */
Kzstr, /* zero-terminated strings */
Kpadding, /* padding */
Kpaddalign, /* padding for alignment */
Knop /* no-op (configuration or spaces) */
} KOption;
/*
** Read an integer numeral from string 'fmt' or return 'df' if
** there is no numeral
*/
static int digit (int c) { return '0' <= c && c <= '9'; }
static int getnum (const char **fmt, int df) {
if (!digit(**fmt)) /* no number? */
return df; /* return default value */
else {
int a = 0;
do {
a = a*10 + (*((*fmt)++) - '0');
} while (digit(**fmt) && a <= ((int)MAXSIZE - 9)/10);
return a;
}
}
/*
** Read an integer numeral and raises an error if it is larger
** than the maximum size for integers.
*/
static int getnumlimit (Header *h, const char **fmt, int df) {
int sz = getnum(fmt, df);
if (sz > MAXINTSIZE || sz <= 0)
return luaL_error(h->L, "integral size (%d) out of limits [1,%d]",
sz, MAXINTSIZE);
return sz;
}
/*
** Initialize Header
*/
static void initheader (lua_State *L, Header *h) {
h->L = L;
h->islittle = nativeendian.little;
h->maxalign = 1;
}
/*
** Read and classify next option. 'size' is filled with option's size.
*/
static KOption getoption (Header *h, const char **fmt, int *size) {
int opt = *((*fmt)++);
*size = 0; /* default */
switch (opt) {
case 'b': *size = sizeof(char); return Kint;
case 'B': *size = sizeof(char); return Kuint;
case 'h': *size = sizeof(short); return Kint;
case 'H': *size = sizeof(short); return Kuint;
case 'l': *size = sizeof(long); return Kint;
case 'L': *size = sizeof(long); return Kuint;
case 'j': *size = sizeof(lua_Integer); return Kint;
case 'J': *size = sizeof(lua_Integer); return Kuint;
case 'T': *size = sizeof(size_t); return Kuint;
case 'f': *size = sizeof(float); return Kfloat;
case 'd': *size = sizeof(double); return Kfloat;
case 'n': *size = sizeof(lua_Number); return Kfloat;
case 'i': *size = getnumlimit(h, fmt, sizeof(int)); return Kint;
case 'I': *size = getnumlimit(h, fmt, sizeof(int)); return Kuint;
case 's': *size = getnumlimit(h, fmt, sizeof(size_t)); return Kstring;
case 'c':
*size = getnum(fmt, -1);
if (*size == -1)
luaL_error(h->L, "missing size for format option 'c'");
return Kchar;
case 'z': return Kzstr;
case 'x': *size = 1; return Kpadding;
case 'X': return Kpaddalign;
case ' ': break;
case '<': h->islittle = 1; break;
case '>': h->islittle = 0; break;
case '=': h->islittle = nativeendian.little; break;
case '!': h->maxalign = getnumlimit(h, fmt, MAXALIGN); break;
default: luaL_error(h->L, "invalid format option '%c'", opt);
}
return Knop;
}
/*
** Read, classify, and fill other details about the next option.
** 'psize' is filled with option's size, 'notoalign' with its
** alignment requirements.
** Local variable 'size' gets the size to be aligned. (Kpadal option
** always gets its full alignment, other options are limited by
** the maximum alignment ('maxalign'). Kchar option needs no alignment
** despite its size.
*/
static KOption getdetails (Header *h, size_t totalsize,
const char **fmt, int *psize, int *ntoalign) {
KOption opt = getoption(h, fmt, psize);
int align = *psize; /* usually, alignment follows size */
if (opt == Kpaddalign) { /* 'X' gets alignment from following option */
if (**fmt == '\0' || getoption(h, fmt, &align) == Kchar || align == 0)
luaL_argerror(h->L, 1, "invalid next option for option 'X'");
}
if (align <= 1 || opt == Kchar) /* need no alignment? */
*ntoalign = 0;
else {
if (align > h->maxalign) /* enforce maximum alignment */
align = h->maxalign;
if ((align & (align - 1)) != 0) /* is 'align' not a power of 2? */
luaL_argerror(h->L, 1, "format asks for alignment not power of 2");
*ntoalign = (align - (int)(totalsize & (align - 1))) & (align - 1);
}
return opt;
}
/*
** Pack integer 'n' with 'size' bytes and 'islittle' endianness.
** The final 'if' handles the case when 'size' is larger than
** the size of a Lua integer, correcting the extra sign-extension
** bytes if necessary (by default they would be zeros).
*/
static void packint (luaL_Buffer *b, lua_Unsigned n,
int islittle, int size, int neg) {
char *buff = luaL_prepbuffsize(b, size);
int i;
buff[islittle ? 0 : size - 1] = (char)(n & MC); /* first byte */
for (i = 1; i < size; i++) {
n >>= NB;
buff[islittle ? i : size - 1 - i] = (char)(n & MC);
}
if (neg && size > SZINT) { /* negative number need sign extension? */
for (i = SZINT; i < size; i++) /* correct extra bytes */
buff[islittle ? i : size - 1 - i] = (char)MC;
}
luaL_addsize(b, size); /* add result to buffer */
}
/*
** Copy 'size' bytes from 'src' to 'dest', correcting endianness if
** given 'islittle' is different from native endianness.
*/
static void copywithendian (volatile char *dest, volatile const char *src,
int size, int islittle) {
if (islittle == nativeendian.little) {
while (size-- != 0)
*(dest++) = *(src++);
}
else {
dest += size - 1;
while (size-- != 0)
*(dest--) = *(src++);
}
}
static int str_pack (lua_State *L) {
luaL_Buffer b;
Header h;
const char *fmt = luaL_checkstring(L, 1); /* format string */
int arg = 1; /* current argument to pack */
size_t totalsize = 0; /* accumulate total size of result */
initheader(L, &h);
lua_pushnil(L); /* mark to separate arguments from string buffer */
luaL_buffinit(L, &b);
while (*fmt != '\0') {
int size, ntoalign;
KOption opt = getdetails(&h, totalsize, &fmt, &size, &ntoalign);
totalsize += ntoalign + size;
while (ntoalign-- > 0)
luaL_addchar(&b, LUAL_PACKPADBYTE); /* fill alignment */
arg++;
switch (opt) {
case Kint: { /* signed integers */
lua_Integer n = luaL_checkinteger(L, arg);
if (size < SZINT) { /* need overflow check? */
lua_Integer lim = (lua_Integer)1 << ((size * NB) - 1);
luaL_argcheck(L, -lim <= n && n < lim, arg, "integer overflow");
}
packint(&b, (lua_Unsigned)n, h.islittle, size, (n < 0));
break;
}
case Kuint: { /* unsigned integers */
lua_Integer n = luaL_checkinteger(L, arg);
if (size < SZINT) /* need overflow check? */
luaL_argcheck(L, (lua_Unsigned)n < ((lua_Unsigned)1 << (size * NB)),
arg, "unsigned overflow");
packint(&b, (lua_Unsigned)n, h.islittle, size, 0);
break;
}
case Kfloat: { /* floating-point options */
volatile Ftypes u;
char *buff = luaL_prepbuffsize(&b, size);
lua_Number n = luaL_checknumber(L, arg); /* get argument */
if (size == sizeof(u.f)) u.f = (float)n; /* copy it into 'u' */
else if (size == sizeof(u.d)) u.d = (double)n;
else u.n = n;
/* move 'u' to final result, correcting endianness if needed */
copywithendian(buff, u.buff, size, h.islittle);
luaL_addsize(&b, size);
break;
}
case Kchar: { /* fixed-size string */
size_t len;
const char *s = luaL_checklstring(L, arg, &len);
luaL_argcheck(L, len <= (size_t)size, arg,
"string longer than given size");
luaL_addlstring(&b, s, len); /* add string */
while (len++ < (size_t)size) /* pad extra space */
luaL_addchar(&b, LUAL_PACKPADBYTE);
break;
}
case Kstring: { /* strings with length count */
size_t len;
const char *s = luaL_checklstring(L, arg, &len);
luaL_argcheck(L, size >= (int)sizeof(size_t) ||
len < ((size_t)1 << (size * NB)),
arg, "string length does not fit in given size");
packint(&b, (lua_Unsigned)len, h.islittle, size, 0); /* pack length */
luaL_addlstring(&b, s, len);
totalsize += len;
break;
}
case Kzstr: { /* zero-terminated string */
size_t len;
const char *s = luaL_checklstring(L, arg, &len);
luaL_argcheck(L, strlen(s) == len, arg, "string contains zeros");
luaL_addlstring(&b, s, len);
luaL_addchar(&b, '\0'); /* add zero at the end */
totalsize += len + 1;
break;
}
case Kpadding: luaL_addchar(&b, LUAL_PACKPADBYTE); /* FALLTHROUGH */
case Kpaddalign: case Knop:
arg--; /* undo increment */
break;
}
}
luaL_pushresult(&b);
return 1;
}
static int str_packsize (lua_State *L) {
Header h;
const char *fmt = luaL_checkstring(L, 1); /* format string */
size_t totalsize = 0; /* accumulate total size of result */
initheader(L, &h);
while (*fmt != '\0') {
int size, ntoalign;
KOption opt = getdetails(&h, totalsize, &fmt, &size, &ntoalign);
size += ntoalign; /* total space used by option */
luaL_argcheck(L, totalsize <= MAXSIZE - size, 1,
"format result too large");
totalsize += size;
switch (opt) {
case Kstring: /* strings with length count */
case Kzstr: /* zero-terminated string */
luaL_argerror(L, 1, "variable-length format");
/* call never return, but to avoid warnings: *//* FALLTHROUGH */
default: break;
}
}
lua_pushinteger(L, (lua_Integer)totalsize);
return 1;
}
/*
** Unpack an integer with 'size' bytes and 'islittle' endianness.
** If size is smaller than the size of a Lua integer and integer
** is signed, must do sign extension (propagating the sign to the
** higher bits); if size is larger than the size of a Lua integer,
** it must check the unread bytes to see whether they do not cause an
** overflow.
*/
static lua_Integer unpackint (lua_State *L, const char *str,
int islittle, int size, int issigned) {
lua_Unsigned res = 0;
int i;
int limit = (size <= SZINT) ? size : SZINT;
for (i = limit - 1; i >= 0; i--) {
res <<= NB;
res |= (lua_Unsigned)(unsigned char)str[islittle ? i : size - 1 - i];
}
if (size < SZINT) { /* real size smaller than lua_Integer? */
if (issigned) { /* needs sign extension? */
lua_Unsigned mask = (lua_Unsigned)1 << (size*NB - 1);
res = ((res ^ mask) - mask); /* do sign extension */
}
}
else if (size > SZINT) { /* must check unread bytes */
int mask = (!issigned || (lua_Integer)res >= 0) ? 0 : MC;
for (i = limit; i < size; i++) {
if ((unsigned char)str[islittle ? i : size - 1 - i] != mask)
luaL_error(L, "%d-byte integer does not fit into Lua Integer", size);
}
}
return (lua_Integer)res;
}
static int str_unpack (lua_State *L) {
Header h;
const char *fmt = luaL_checkstring(L, 1);
size_t ld;
const char *data = luaL_checklstring(L, 2, &ld);
size_t pos = (size_t)posrelat(luaL_optinteger(L, 3, 1), ld) - 1;
int n = 0; /* number of results */
luaL_argcheck(L, pos <= ld, 3, "initial position out of string");
initheader(L, &h);
while (*fmt != '\0') {
int size, ntoalign;
KOption opt = getdetails(&h, pos, &fmt, &size, &ntoalign);
if ((size_t)ntoalign + size > ~pos || pos + ntoalign + size > ld)
luaL_argerror(L, 2, "data string too short");
pos += ntoalign; /* skip alignment */
/* stack space for item + next position */
luaL_checkstack(L, 2, "too many results");
n++;
switch (opt) {
case Kint:
case Kuint: {
lua_Integer res = unpackint(L, data + pos, h.islittle, size,
(opt == Kint));
lua_pushinteger(L, res);
break;
}
case Kfloat: {
volatile Ftypes u;
lua_Number num;
copywithendian(u.buff, data + pos, size, h.islittle);
if (size == sizeof(u.f)) num = (lua_Number)u.f;
else if (size == sizeof(u.d)) num = (lua_Number)u.d;
else num = u.n;
lua_pushnumber(L, num);
break;
}
case Kchar: {
lua_pushlstring(L, data + pos, size);
break;
}
case Kstring: {
size_t len = (size_t)unpackint(L, data + pos, h.islittle, size, 0);
luaL_argcheck(L, pos + len + size <= ld, 2, "data string too short");
lua_pushlstring(L, data + pos + size, len);
pos += len; /* skip string */
break;
}
case Kzstr: {
size_t len = (int)strlen(data + pos);
lua_pushlstring(L, data + pos, len);
pos += len + 1; /* skip string plus final '\0' */
break;
}
case Kpaddalign: case Kpadding: case Knop:
n--; /* undo increment */
break;
}
pos += size;
}
lua_pushinteger(L, pos + 1); /* next position */
return n + 1;
}
/* }====================================================== */
LROT_BEGIN(strlib, NULL, LROT_MASK_INDEX)
LROT_TABENTRY( __index, strlib )
LROT_FUNCENTRY( __mod, str_format2 )
LROT_FUNCENTRY( byte, str_byte )
LROT_FUNCENTRY( char, str_char )
LROT_FUNCENTRY( dump, str_dump )
LROT_FUNCENTRY( find, str_find )
LROT_FUNCENTRY( format, str_format )
LROT_FUNCENTRY( gmatch, gmatch )
LROT_FUNCENTRY( gsub, str_gsub )
LROT_FUNCENTRY( len, str_len )
LROT_FUNCENTRY( lower, str_lower )
LROT_FUNCENTRY( match, str_match )
LROT_FUNCENTRY( rep, str_rep )
LROT_FUNCENTRY( reverse, str_reverse )
LROT_FUNCENTRY( sub, str_sub )
LROT_FUNCENTRY( upper, str_upper )
LROT_FUNCENTRY( pack, str_pack )
LROT_FUNCENTRY( packsize, str_packsize )
LROT_FUNCENTRY( unpack, str_unpack )
LROT_END(strlib, NULL, LROT_MASK_INDEX)
/*
** Open string library
*/
LUAMOD_API int luaopen_string (lua_State *L) {
lua_pushliteral(L, ""); /* dummy string */
lua_pushrotable(L, LROT_TABLEREF(strlib));
lua_setmetatable(L, -2); /* set table as metatable for strings */
lua_pop(L, 1); /* pop dummy string */
return 0;
}