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lua/lstrlib.c

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/*
** $Id: lstrlib.c,v 1.186 2014/02/25 14:30:21 roberto Exp roberto $
** Standard library for string operations and pattern-matching
** See Copyright Notice in lua.h
*/
#include <ctype.h>
#include <limits.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define lstrlib_c
#define LUA_LIB
#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"
/*
** maximum number of captures that a pattern can do during
** pattern-matching. This limit is arbitrary.
*/
#if !defined(LUA_MAXCAPTURES)
#define LUA_MAXCAPTURES 32
#endif
/* macro to `unsign' a character */
#define uchar(c) ((unsigned char)(c))
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, 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;
}
/* reasonable limit to avoid arithmetic overflow and strings too big */
#if INT_MAX / 2 <= 0x10000000
#define MAXSIZE ((size_t)(INT_MAX / 2))
#else
#define MAXSIZE ((size_t)0x10000000)
#endif
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 = n * l + (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 */
n = (int)(pose - posi + 1);
if (posi + n <= pose) /* arithmetic overflow? */
return luaL_error(L, "string slice too long");
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_toboolean(L, 2);
luaL_checktype(L, 1, LUA_TFUNCTION);
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 {
int matchdepth; /* control for recursive depth (to avoid C stack overflow) */
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 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 " LUA_QL("%%") ")");
return p+1;
}
case '[': {
if (*p == '^') p++;
do { /* look for a `]' */
if (p == ms->p_end)
luaL_error(ms->L, "malformed pattern (missing " LUA_QL("]") ")");
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 " LUA_QL("%%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 " LUA_QL("[") " after "
LUA_QL("%%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 */
/* go through */
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");
}
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 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 - 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 */
}
ms.L = L;
ms.matchdepth = MAXCCALLS;
ms.src_init = s;
ms.src_end = s + ls;
ms.p_end = p + lp;
do {
const char *res;
ms.level = 0;
lua_assert(ms.matchdepth == MAXCCALLS);
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);
}
static int gmatch_aux (lua_State *L) {
MatchState ms;
size_t ls, lp;
const char *s = lua_tolstring(L, lua_upvalueindex(1), &ls);
const char *p = lua_tolstring(L, lua_upvalueindex(2), &lp);
const char *src;
ms.L = L;
ms.matchdepth = MAXCCALLS;
ms.src_init = s;
ms.src_end = s+ls;
ms.p_end = p + lp;
for (src = s + (size_t)lua_tointeger(L, lua_upvalueindex(3));
src <= ms.src_end;
src++) {
const char *e;
ms.level = 0;
lua_assert(ms.matchdepth == MAXCCALLS);
if ((e = match(&ms, src, p)) != NULL) {
lua_Integer newstart = e-s;
if (e == src) newstart++; /* empty match? go at least one position */
lua_pushinteger(L, newstart);
lua_replace(L, lua_upvalueindex(3));
return push_captures(&ms, src, e);
}
}
return 0; /* not found */
}
static int gmatch (lua_State *L) {
luaL_checkstring(L, 1);
luaL_checkstring(L, 2);
lua_settop(L, 2);
lua_pushinteger(L, 0);
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;
const char *news = lua_tolstring(ms->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(ms->L, "invalid use of " LUA_QL("%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_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);
const char *p = luaL_checklstring(L, 2, &lp);
int tr = lua_type(L, 3);
size_t max_s = luaL_optinteger(L, 4, srcl+1);
int anchor = (*p == '^');
size_t n = 0;
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 */
}
ms.L = L;
ms.matchdepth = MAXCCALLS;
ms.src_init = src;
ms.src_end = src+srcl;
ms.p_end = p + lp;
while (n < max_s) {
const char *e;
ms.level = 0;
lua_assert(ms.matchdepth == MAXCCALLS);
e = match(&ms, src, p);
if (e) {
n++;
add_value(&ms, &b, src, e, tr);
}
if (e && e>src) /* non empty match? */
src = e; /* skip it */
else if (src < ms.src_end)
luaL_addchar(&b, *src++);
else break;
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
** =======================================================
*/
/* 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")
** (+2 for length modifiers; +10 accounts for %99.99x plus margin of error)
*/
#define MAX_FORMAT (sizeof(FLAGS) + 2 + 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--) {
if (*s == '"' || *s == '\\' || *s == '\n') {
luaL_addchar(b, '\\');
luaL_addchar(b, *s);
}
else if (*s == '\0' || iscntrl(uchar(*s))) {
char buff[10];
if (!isdigit(uchar(*(s+1))))
sprintf(buff, "\\%d", (int)uchar(*s));
else
sprintf(buff, "\\%03d", (int)uchar(*s));
luaL_addstring(b, buff);
}
else
luaL_addchar(b, *s);
s++;
}
luaL_addchar(b, '"');
}
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 = sprintf(buff, form, luaL_checkint(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 = sprintf(buff, form, n);
break;
}
case 'e': case 'E': case 'f':
#if defined(LUA_USE_AFORMAT)
case 'a': case 'A':
#endif
case 'g': case 'G': {
addlenmod(form, LUA_NUMBER_FRMLEN);
nb = sprintf(buff, form, luaL_checknumber(L, arg));
break;
}
case 'q': {
addquoted(L, &b, arg);
break;
}
case 's': {
size_t l;
const char *s = luaL_tolstring(L, arg, &l);
if (!strchr(form, '.') && l >= 100) {
/* no precision and string is too long to be formatted;
keep original string */
luaL_addvalue(&b);
break;
}
else {
nb = sprintf(buff, form, s);
lua_pop(L, 1); /* remove result from 'luaL_tolstring' */
break;
}
}
default: { /* also treat cases `pnLlh' */
return luaL_error(L, "invalid option " LUA_QL("%%%c") " to "
LUA_QL("format"), *(strfrmt - 1));
}
}
luaL_addsize(&b, nb);
}
}
luaL_pushresult(&b);
return 1;
}
/* }====================================================== */
/*
** {======================================================
** PACK/UNPACK
** =======================================================
*/
/* maximum size for the binary representation of an integer */
#define MAXINTSIZE 8
/* number of bits in a character */
#define NB CHAR_BIT
/* mask for one character (NB ones) */
#define MC (((lua_Integer)1 << NB) - 1)
/* mask for one character without sign ((NB - 1) ones) */
#define SM (((lua_Integer)1 << (NB - 1)) - 1)
#define SZINT ((int)sizeof(lua_Integer))
static union {
int dummy;
char little; /* true iff machine is little endian */
} const nativeendian = {1};
static int getendian (lua_State *L, int arg) {
const char *endian = luaL_optstring(L, arg,
(nativeendian.little ? "l" : "b"));
if (*endian == 'n') /* native? */
return nativeendian.little;
luaL_argcheck(L, *endian == 'l' || *endian == 'b', arg,
"endianess must be 'l'/'b'/'n'");
return (*endian == 'l');
}
static int getintsize (lua_State *L, int arg) {
int size = luaL_optint(L, arg, 0);
if (size == 0) size = SZINT;
luaL_argcheck(L, 1 <= size && size <= MAXINTSIZE, arg,
"integer size out of valid range");
return size;
}
static int packint (char *buff, lua_Integer n, int littleendian, int size) {
int i;
if (littleendian) {
for (i = 0; i < size - 1; i++) {
buff[i] = (n & MC);
n >>= NB;
}
}
else {
for (i = size - 1; i > 0; i--) {
buff[i] = (n & MC);
n >>= NB;
}
}
buff[i] = (n & MC); /* last byte */
/* test for overflow: OK if there are only zeros left in higher bytes,
or if there are only oneś left and packed number is negative (signal
bit, the higher bit in last byte, is one) */
return ((n & ~MC) == 0 || (n | SM) == ~(lua_Integer)0);
}
static int packint_l (lua_State *L) {
char buff[MAXINTSIZE];
lua_Integer n = luaL_checkinteger(L, 1);
int size = getintsize(L, 2);
int endian = getendian(L, 3);
if (packint(buff, n, endian, size))
lua_pushlstring(L, buff, size);
else
luaL_error(L, "integer does not fit into given size (%d)", size);
return 1;
}
/* mask to check higher-order byte in a Lua integer */
#define HIGHERBYTE (MC << (NB * (SZINT - 1)))
/* mask to check higher-order byte + signal bit of next byte */
#define HIGHERBYTE1 (HIGHERBYTE | (HIGHERBYTE >> 1))
static int unpackint (const char *buff, lua_Integer *res,
int littleendian, int size) {
lua_Integer n = 0;
int i;
for (i = 0; i < size; i++) {
if (i >= SZINT) { /* will throw away a byte? */
/* check for overflow: it is OK to throw away leading zeros for a
positive number; leading ones for a negative number; and one
last leading zero to allow unsigned integers with a 1 in
its "signal bit" */
if (!((n & HIGHERBYTE1) == 0 || /* zeros for pos. number */
(n & HIGHERBYTE1) == HIGHERBYTE1 || /* ones for neg. number */
((n & HIGHERBYTE) == 0 && i == size - 1))) /* last zero */
return 0; /* overflow */
}
n <<= NB;
n |= (lua_Integer)(unsigned char)buff[littleendian ? size - 1 - i : i];
}
if (size < SZINT) { /* need sign extension? */
lua_Integer mask = (~(lua_Integer)0) << (size*NB - 1);
if (n & mask) /* negative value? */
n |= mask; /* signal extension */
}
*res = n;
return 1;
}
static int unpackint_l (lua_State *L) {
lua_Integer res;
size_t len;
const char *s = luaL_checklstring(L, 1, &len);
lua_Integer pos = posrelat(luaL_optinteger(L, 2, 1), len);
int size = getintsize(L, 3);
int endian = getendian(L, 4);
luaL_argcheck(L, 1 <= pos && (size_t)pos + size - 1 <= len, 1,
"string too short");
if(unpackint(s + pos - 1, &res, endian, size))
lua_pushinteger(L, res);
else
luaL_error(L, "result does not fit into a Lua integer");
return 1;
}
static void correctendianess (lua_State *L, char *b, int size, int endianarg) {
int endian = getendian(L, endianarg);
if (endian != nativeendian.little) { /* not native endianess? */
int i = 0;
while (i < --size) {
char temp = b[i];
b[i++] = b[size];
b[size] = temp;
}
}
}
#define DEFAULTFLOATSIZE \
(sizeof(lua_Number) == sizeof(float) ? "f" : "d")
static int getfloatsize (lua_State *L, int arg) {
const char *size = luaL_optstring(L, arg, "n");
if (*size == 'n') size = DEFAULTFLOATSIZE;
luaL_argcheck(L, *size == 'd' || *size == 'f', arg,
"size must be 'f'/'d'/'n'");
return (*size == 'd' ? sizeof(double) : sizeof(float));
}
static int packfloat_l (lua_State *L) {
float f; double d;
char *pn; /* pointer to number */
lua_Number n = luaL_checknumber(L, 1);
int size = getfloatsize(L, 2);
if (size == sizeof(double)) {
d = (double)n;
pn = (char*)&d;
}
else {
f = (float)n;
pn = (char*)&f;
}
correctendianess(L, pn, size, 3);
lua_pushlstring(L, pn, size);
return 1;
}
static int unpackfloat_l (lua_State *L) {
lua_Number res;
size_t len;
const char *s = luaL_checklstring(L, 1, &len);
lua_Integer pos = posrelat(luaL_optinteger(L, 2, 1), len);
int size = getfloatsize(L, 3);
luaL_argcheck(L, 1 <= pos && (size_t)pos + size - 1 <= len, 1,
"string too short");
if (size == sizeof(double)) {
double d;
memcpy(&d, s + pos - 1, size);
correctendianess(L, (char*)&d, size, 4);
res = (lua_Number)d;
}
else {
float f;
memcpy(&f, s + pos - 1, size);
correctendianess(L, (char*)&f, size, 4);
res = (lua_Number)f;
}
lua_pushnumber(L, res);
return 1;
}
/* }====================================================== */
static const luaL_Reg strlib[] = {
{"byte", str_byte},
{"char", str_char},
{"dump", str_dump},
{"find", str_find},
{"format", str_format},
{"gmatch", gmatch},
{"gsub", str_gsub},
{"len", str_len},
{"lower", str_lower},
{"match", str_match},
{"rep", str_rep},
{"reverse", str_reverse},
{"sub", str_sub},
{"upper", str_upper},
{"packfloat", packfloat_l},
{"packint", packint_l},
{"unpackfloat", unpackfloat_l},
{"unpackint", unpackint_l},
{NULL, NULL}
};
static void createmetatable (lua_State *L) {
lua_createtable(L, 0, 1); /* table to be metatable for strings */
lua_pushliteral(L, ""); /* dummy string */
lua_pushvalue(L, -2); /* copy table */
lua_setmetatable(L, -2); /* set table as metatable for strings */
lua_pop(L, 1); /* pop dummy string */
lua_pushvalue(L, -2); /* get string library */
lua_setfield(L, -2, "__index"); /* metatable.__index = string */
lua_pop(L, 1); /* pop metatable */
}
/*
** Open string library
*/
LUAMOD_API int luaopen_string (lua_State *L) {
luaL_newlib(L, strlib);
createmetatable(L);
return 1;
}
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