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/*
** $Id: lstrlib.c $
** 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 <math.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#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, 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 initial string position
** (negative means back from end): clip result to [1, inf).
** The length of any string in Lua must fit in a lua_Integer,
** so there are no overflows in the casts.
** The inverted comparison avoids a possible overflow
** computing '-pos'.
*/
static size_t posrelatI (lua_Integer pos, size_t len) {
if (pos > 0)
return (size_t)pos;
else if (pos == 0)
return 1;
else if (pos < -(lua_Integer)len) /* inverted comparison */
return 1; /* clip to 1 */
else return len + (size_t)pos + 1;
}
/*
** Gets an optional ending string position from argument 'arg',
** with default value 'def'.
** Negative means back from end: clip result to [0, len]
*/
static size_t getendpos (lua_State *L, int arg, lua_Integer def,
size_t len) {
lua_Integer pos = luaL_optinteger(L, arg, def);
if (pos > (lua_Integer)len)
return len;
else if (pos >= 0)
return (size_t)pos;
else if (pos < -(lua_Integer)len)
return 0;
else return len + (size_t)pos + 1;
}
static int str_sub (lua_State *L) {
size_t l;
const char *s = luaL_checklstring(L, 1, &l);
size_t start = posrelatI(luaL_checkinteger(L, 2), l);
size_t end = getendpos(L, 3, -1, 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;
}
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_unlikely(l + lsep < l || l + lsep > MAXSIZE / n))
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 pi = luaL_optinteger(L, 2, 1);
size_t posi = posrelatI(pi, l);
size_t pose = getendpos(L, 3, pi, l);
int n, i;
if (posi > pose) return 0; /* empty interval; return no values */
if (l_unlikely(pose - posi >= (size_t)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_Unsigned c = (lua_Unsigned)luaL_checkinteger(L, i);
luaL_argcheck(L, c <= (lua_Unsigned)UCHAR_MAX, i, "value out of range");
p[i - 1] = uchar(c);
}
luaL_pushresultsize(&b, n);
return 1;
}
/*
** Buffer to store the result of 'string.dump'. It must be initialized
** after the call to 'lua_dump', to ensure that the function is on the
** top of the stack when 'lua_dump' is called. ('luaL_buffinit' might
** push stuff.)
*/
struct str_Writer {
int init; /* true iff buffer has been initialized */
luaL_Buffer B;
};
static int writer (lua_State *L, const void *b, size_t size, void *ud) {
struct str_Writer *state = (struct str_Writer *)ud;
if (!state->init) {
state->init = 1;
luaL_buffinit(L, &state->B);
}
luaL_addlstring(&state->B, (const char *)b, size);
return 0;
}
static int str_dump (lua_State *L) {
struct str_Writer state;
int strip = lua_toboolean(L, 2);
luaL_checktype(L, 1, LUA_TFUNCTION);
lua_settop(L, 1); /* ensure function is on the top of the stack */
state.init = 0;
if (l_unlikely(lua_dump(L, writer, &state, strip) != 0))
return luaL_error(L, "unable to dump given function");
luaL_pushresult(&state.B);
return 1;
}
/*
** {======================================================
** METAMETHODS
** =======================================================
*/
#if defined(LUA_NOCVTS2N) /* { */
/* no coercion from strings to numbers */
static const luaL_Reg stringmetamethods[] = {
{"__index", NULL}, /* placeholder */
{NULL, NULL}
};
#else /* }{ */
static int tonum (lua_State *L, int arg) {
if (lua_type(L, arg) == LUA_TNUMBER) { /* already a number? */
lua_pushvalue(L, arg);
return 1;
}
else { /* check whether it is a numerical string */
size_t len;
const char *s = lua_tolstring(L, arg, &len);
return (s != NULL && lua_stringtonumber(L, s) == len + 1);
}
}
static void trymt (lua_State *L, const char *mtname) {
lua_settop(L, 2); /* back to the original arguments */
if (l_unlikely(lua_type(L, 2) == LUA_TSTRING ||
!luaL_getmetafield(L, 2, mtname)))
luaL_error(L, "attempt to %s a '%s' with a '%s'", mtname + 2,
luaL_typename(L, -2), luaL_typename(L, -1));
lua_insert(L, -3); /* put metamethod before arguments */
lua_call(L, 2, 1); /* call metamethod */
}
static int arith (lua_State *L, int op, const char *mtname) {
if (tonum(L, 1) && tonum(L, 2))
lua_arith(L, op); /* result will be on the top */
else
trymt(L, mtname);
return 1;
}
static int arith_add (lua_State *L) {
return arith(L, LUA_OPADD, "__add");
}
static int arith_sub (lua_State *L) {
return arith(L, LUA_OPSUB, "__sub");
}
static int arith_mul (lua_State *L) {
return arith(L, LUA_OPMUL, "__mul");
}
static int arith_mod (lua_State *L) {
return arith(L, LUA_OPMOD, "__mod");
}
static int arith_pow (lua_State *L) {
return arith(L, LUA_OPPOW, "__pow");
}
static int arith_div (lua_State *L) {
return arith(L, LUA_OPDIV, "__div");
}
static int arith_idiv (lua_State *L) {
return arith(L, LUA_OPIDIV, "__idiv");
}
static int arith_unm (lua_State *L) {
return arith(L, LUA_OPUNM, "__unm");
}
static const luaL_Reg stringmetamethods[] = {
{"__add", arith_add},
{"__sub", arith_sub},
{"__mul", arith_mul},
{"__mod", arith_mod},
{"__pow", arith_pow},
{"__div", arith_div},
{"__idiv", arith_idiv},
{"__unm", arith_unm},
{"__index", NULL}, /* placeholder */
{NULL, NULL}
};
#endif /* } */
/* }====================================================== */
/*
** {======================================================
** 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_unlikely(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 (l_unlikely(p == ms->p_end))
luaL_error(ms->L, "malformed pattern (ends with '%%')");
return p+1;
}
case '[': {
if (*p == '^') p++;
do { /* look for a ']' */
if (l_unlikely(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 (l_unlikely(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 (l_unlikely(ms->matchdepth-- == 0))
luaL_error(ms->L, "pattern too complex");
init: /* using goto 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 (l_unlikely(*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 */
}
}
/*
** get information about the i-th capture. If there are no captures
** and 'i==0', return information about the whole match, which
** is the range 's'..'e'. If the capture is a string, return
** its length and put its address in '*cap'. If it is an integer
** (a position), push it on the stack and return CAP_POSITION.
*/
static size_t get_onecapture (MatchState *ms, int i, const char *s,
const char *e, const char **cap) {
if (i >= ms->level) {
if (l_unlikely(i != 0))
luaL_error(ms->L, "invalid capture index %%%d", i + 1);
*cap = s;
return e - s;
}
else {
ptrdiff_t capl = ms->capture[i].len;
*cap = ms->capture[i].init;
if (l_unlikely(capl == CAP_UNFINISHED))
luaL_error(ms->L, "unfinished capture");
else if (capl == CAP_POSITION)
lua_pushinteger(ms->L, (ms->capture[i].init - ms->src_init) + 1);
return capl;
}
}
/*
** Push the i-th capture on the stack.
*/
static void push_onecapture (MatchState *ms, int i, const char *s,
const char *e) {
const char *cap;
ptrdiff_t l = get_onecapture(ms, i, s, e, &cap);
if (l != CAP_POSITION)
lua_pushlstring(ms->L, cap, l);
/* else position was already pushed */
}
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);
size_t init = posrelatI(luaL_optinteger(L, 3, 1), ls) - 1;
if (init > ls) { /* start after string's end? */
luaL_pushfail(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, ls - init, 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;
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);
}
luaL_pushfail(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);
size_t init = posrelatI(luaL_optinteger(L, 3, 1), ls) - 1;
GMatchState *gm;
lua_settop(L, 2); /* keep strings on closure to avoid being collected */
gm = (GMatchState *)lua_newuserdatauv(L, sizeof(GMatchState), 0);
if (init > ls) /* start after string's end? */
init = ls + 1; /* avoid overflows in 's + init' */
prepstate(&gm->ms, L, s, ls, p, lp);
gm->src = s + init; 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;
lua_State *L = ms->L;
const char *news = lua_tolstring(L, 3, &l);
const char *p;
while ((p = (char *)memchr(news, L_ESC, l)) != NULL) {
luaL_addlstring(b, news, p - news);
p++; /* skip ESC */
if (*p == L_ESC) /* '%%' */
luaL_addchar(b, *p);
else if (*p == '0') /* '%0' */
luaL_addlstring(b, s, e - s);
else if (isdigit(uchar(*p))) { /* '%n' */
const char *cap;
ptrdiff_t resl = get_onecapture(ms, *p - '1', s, e, &cap);
if (resl == CAP_POSITION)
luaL_addvalue(b); /* add position to accumulated result */
else
luaL_addlstring(b, cap, resl);
}
else
luaL_error(L, "invalid use of '%c' in replacement string", L_ESC);
l -= p + 1 - news;
news = p + 1;
}
luaL_addlstring(b, news, l);
}
/*
** Add the replacement value to the string buffer 'b'.
** Return true if the original string was changed. (Function calls and
** table indexing resulting in nil or false do not change the subject.)
*/
static int 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: { /* call the function */
int n;
lua_pushvalue(L, 3); /* push the function */
n = push_captures(ms, s, e); /* all captures as arguments */
lua_call(L, n, 1); /* call it */
break;
}
case LUA_TTABLE: { /* index the table */
push_onecapture(ms, 0, s, e); /* first capture is the index */
lua_gettable(L, 3);
break;
}
default: { /* LUA_TNUMBER or LUA_TSTRING */
add_s(ms, b, s, e); /* add value to the buffer */
return 1; /* something changed */
}
}
if (!lua_toboolean(L, -1)) { /* nil or false? */
lua_pop(L, 1); /* remove value */
luaL_addlstring(b, s, e - s); /* keep original text */
return 0; /* no changes */
}
else if (l_unlikely(!lua_isstring(L, -1)))
return luaL_error(L, "invalid replacement value (a %s)",
luaL_typename(L, -1));
else {
luaL_addvalue(b); /* add result to accumulator */
return 1; /* something changed */
}
}
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 */
int changed = 0; /* change flag */
MatchState ms;
luaL_Buffer b;
luaL_argexpected(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||
tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,
"string/function/table");
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++;
changed = add_value(&ms, &b, src, e, tr) | changed;
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;
}
if (!changed) /* no changes? */
lua_pushvalue(L, 1); /* return original string */
else { /* something changed */
luaL_addlstring(&b, src, ms.src_end-src);
luaL_pushresult(&b); /* create and return new string */
}
lua_pushinteger(L, n); /* number of substitutions */
return 2;
}
/* }====================================================== */
/*
** {======================================================
** STRING FORMAT
** =======================================================
*/
#if !defined(lua_number2strx) /* { */
/*
** Hexadecimal floating-point formatter
*/
#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_floatatt(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 sign */
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 (l_unlikely(fmt[SIZELENMOD] != 'a'))
return luaL_error(L, "modifiers for format '%%a'/'%%A' not implemented");
return n;
}
#endif /* } */
/*
** Maximum size for items formatted with '%f'. This size is produced
** by format('%.99f', -maxfloat), and is equal to 99 + 3 ('-', '.',
** and '\0') + number of decimal digits to represent maxfloat (which
** is maximum exponent + 1). (99+3+1, adding some extra, 110)
*/
#define MAX_ITEMF (110 + l_floatatt(MAX_10_EXP))
/*
** All formats except '%f' do not need that large limit. The other
** float formats use exponents, so that they fit in the 99 limit for
** significant digits; 's' for large strings and 'q' add items directly
** to the buffer; all integer formats also fit in the 99 limit. The
** worst case are floats: they may need 99 significant digits, plus
** '0x', '-', '.', 'e+XXXX', and '\0'. Adding some extra, 120.
*/
#define MAX_ITEM 120
/* valid flags in a format specification */
#if !defined(L_FMTFLAGSF)
/* valid flags for a, A, e, E, f, F, g, and G conversions */
#define L_FMTFLAGSF "-+#0 "
/* valid flags for o, x, and X conversions */
#define L_FMTFLAGSX "-#0"
/* valid flags for d and i conversions */
#define L_FMTFLAGSI "-+0 "
/* valid flags for u conversions */
#define L_FMTFLAGSU "-0"
/* valid flags for c, p, and s conversions */
#define L_FMTFLAGSC "-"
#endif
发表于 2023-11-7 10:52:46
