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lua/lstrlib.c

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/*
** $Id: lstrlib.c,v 1.86 2002/06/25 19:16:44 roberto Exp roberto $
** Standard library for string operations and pattern-matching
** See Copyright Notice in lua.h
*/
#include <ctype.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"
/* macro to `unsign' a character */
#ifndef uchar
#define uchar(c) ((unsigned char)(c))
#endif
typedef long sint32; /* a signed version for size_t */
static int str_len (lua_State *L) {
size_t l;
luaL_check_lstr(L, 1, &l);
lua_pushnumber(L, l);
return 1;
}
static sint32 posrelat (sint32 pos, size_t len) {
/* relative string position: negative means back from end */
return (pos>=0) ? pos : (sint32)len+pos+1;
}
static int str_sub (lua_State *L) {
size_t l;
const char *s = luaL_check_lstr(L, 1, &l);
sint32 start = posrelat(luaL_check_long(L, 2), l);
sint32 end = posrelat(luaL_opt_long(L, 3, -1), l);
if (start < 1) start = 1;
if (end > (sint32)l) end = l;
if (start <= end)
lua_pushlstring(L, s+start-1, end-start+1);
else lua_pushliteral(L, "");
return 1;
}
static int str_lower (lua_State *L) {
size_t l;
size_t i;
luaL_Buffer b;
const char *s = luaL_check_lstr(L, 1, &l);
luaL_buffinit(L, &b);
for (i=0; i<l; i++)
luaL_putchar(&b, tolower(uchar(s[i])));
luaL_pushresult(&b);
return 1;
}
static int str_upper (lua_State *L) {
size_t l;
size_t i;
luaL_Buffer b;
const char *s = luaL_check_lstr(L, 1, &l);
luaL_buffinit(L, &b);
for (i=0; i<l; i++)
luaL_putchar(&b, toupper(uchar(s[i])));
luaL_pushresult(&b);
return 1;
}
static int str_rep (lua_State *L) {
size_t l;
luaL_Buffer b;
const char *s = luaL_check_lstr(L, 1, &l);
int n = luaL_check_int(L, 2);
luaL_buffinit(L, &b);
while (n-- > 0)
luaL_addlstring(&b, s, l);
luaL_pushresult(&b);
return 1;
}
static int str_byte (lua_State *L) {
size_t l;
const char *s = luaL_check_lstr(L, 1, &l);
sint32 pos = posrelat(luaL_opt_long(L, 2, 1), l);
luaL_arg_check(L, 0 < pos && (size_t)(pos) <= l, 2, "out of range");
lua_pushnumber(L, uchar(s[pos-1]));
return 1;
}
static int str_char (lua_State *L) {
int n = lua_gettop(L); /* number of arguments */
int i;
luaL_Buffer b;
luaL_buffinit(L, &b);
for (i=1; i<=n; i++) {
int c = luaL_check_int(L, i);
luaL_arg_check(L, uchar(c) == c, i, "invalid value");
luaL_putchar(&b, uchar(c));
}
luaL_pushresult(&b);
return 1;
}
/*
** {======================================================
** PATTERN MATCHING
** =======================================================
*/
#ifndef MAX_CAPTURES
#define MAX_CAPTURES 32 /* arbitrary limit */
#endif
#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 */
lua_State *L;
int level; /* total number of captures (finished or unfinished) */
struct {
const char *init;
sint32 len;
} capture[MAX_CAPTURES];
} MatchState;
#define 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");
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 *luaI_classend (MatchState *ms, const char *p) {
switch (*p++) {
case ESC:
if (*p == '\0')
luaL_error(ms->L, "malformed pattern (ends with `%')");
return p+1;
case '[':
if (*p == '^') p++;
do { /* look for a `]' */
if (*p == '\0')
luaL_error(ms->L, "malformed pattern (missing `]')");
if (*(p++) == ESC && *p != '\0')
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 '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;
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 == ESC) {
p++;
if (match_class(c, *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 luaI_singlematch (int c, const char *p, const char *ep) {
switch (*p) {
case '.': /* matches any char */
return 1;
case ESC:
return match_class(c, *(p+1));
case '[':
return matchbracketclass(c, p, ep-1);
default:
return (uchar(*p) == c);
}
}
static const char *match (MatchState *ms, const char *s, const char *p);
static const char *matchbalance (MatchState *ms, const char *s,
const char *p) {
if (*p == 0 || *(p+1) == 0)
luaL_error(ms->L, "unbalanced pattern");
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) {
sint32 i = 0; /* counts maximum expand for item */
while ((s+i)<ms->src_end && luaI_singlematch(uchar(*(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 (s<ms->src_end && luaI_singlematch(uchar(*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 >= MAX_CAPTURES) 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) {
init: /* using goto's to optimize tail recursion */
switch (*p) {
case '(': /* start capture */
if (*(p+1) == ')') /* position capture? */
return start_capture(ms, s, p+2, CAP_POSITION);
else
return start_capture(ms, s, p+1, CAP_UNFINISHED);
case ')': /* end capture */
return end_capture(ms, s, p+1);
case ESC: /* may be %[0-9] or %b */
if (isdigit(uchar(*(p+1)))) { /* capture? */
s = match_capture(ms, s, *(p+1));
if (s == NULL) return NULL;
p+=2; goto init; /* else return match(ms, s, p+2) */
}
else if (*(p+1) == 'b') { /* balanced string? */
s = matchbalance(ms, s, p+2);
if (s == NULL) return NULL;
p+=4; goto init; /* else return match(ms, s, p+4); */
}
else goto dflt; /* case default */
case '\0': /* end of pattern */
return s; /* match succeeded */
case '$':
if (*(p+1) == '\0') /* is the `$' the last char in pattern? */
return (s == ms->src_end) ? s : NULL; /* check end of string */
else goto dflt;
default: dflt: { /* it is a pattern item */
const char *ep = luaI_classend(ms, p); /* points to what is next */
int m = s<ms->src_end && luaI_singlematch(uchar(*s), p, ep);
switch (*ep) {
case '?': { /* optional */
const char *res;
if (m && ((res=match(ms, s+1, ep+1)) != NULL))
return res;
p=ep+1; goto init; /* else return match(ms, s, ep+1); */
}
case '*': /* 0 or more repetitions */
return max_expand(ms, s, p, ep);
case '+': /* 1 or more repetitions */
return (m ? max_expand(ms, s+1, p, ep) : NULL);
case '-': /* 0 or more repetitions (minimum) */
return min_expand(ms, s, p, ep);
default:
if (!m) return NULL;
s++; p=ep; goto init; /* else return match(ms, s+1, ep); */
}
}
}
}
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) {
int l = ms->capture[i].len;
if (l == CAP_UNFINISHED) luaL_error(ms->L, "unfinished capture");
if (l == CAP_POSITION)
lua_pushnumber(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;
luaL_check_stack(ms->L, ms->level, "too many captures");
if (ms->level == 0 && s) { /* no explicit captures? */
lua_pushlstring(ms->L, s, e-s); /* return whole match */
return 1;
}
else { /* return all captures */
for (i=0; i<ms->level; i++)
push_onecapture(ms, i);
return ms->level; /* number of strings pushed */
}
}
static int str_find (lua_State *L) {
size_t l1, l2;
const char *s = luaL_check_lstr(L, 1, &l1);
const char *p = luaL_check_lstr(L, 2, &l2);
sint32 init = posrelat(luaL_opt_long(L, 3, 1), l1) - 1;
luaL_arg_check(L, 0 <= init && (size_t)(init) <= l1, 3, "out of range");
if (lua_toboolean(L, 4) || /* explicit request? */
strpbrk(p, SPECIALS) == NULL) { /* or no special characters? */
/* do a plain search */
const char *s2 = lmemfind(s+init, l1-init, p, l2);
if (s2) {
lua_pushnumber(L, s2-s+1);
lua_pushnumber(L, s2-s+l2);
return 2;
}
}
else {
MatchState ms;
int anchor = (*p == '^') ? (p++, 1) : 0;
const char *s1=s+init;
ms.L = L;
ms.src_init = s;
ms.src_end = s+l1;
do {
const char *res;
ms.level = 0;
if ((res=match(&ms, s1, p)) != NULL) {
lua_pushnumber(L, s1-s+1); /* start */
lua_pushnumber(L, res-s); /* end */
return push_captures(&ms, NULL, 0) + 2;
}
} while (s1++<ms.src_end && !anchor);
}
lua_pushnil(L); /* not found */
return 1;
}
static int gfind_aux (lua_State *L) {
MatchState ms;
const char *s = lua_tostring(L, lua_upvalueindex(1));
size_t ls = lua_strlen(L, lua_upvalueindex(1));
const char *p = lua_tostring(L, lua_upvalueindex(2));
const char *src;
ms.L = L;
ms.src_init = s;
ms.src_end = s+ls;
for (src = s + (size_t)lua_tonumber(L, lua_upvalueindex(3));
src <= ms.src_end;
src++) {
const char *e;
ms.level = 0;
if ((e = match(&ms, src, p)) != NULL) {
int newstart = e-s;
if (e == src) newstart++; /* empty match? go at least one position */
lua_pushnumber(L, newstart);
lua_replace(L, lua_upvalueindex(3));
return push_captures(&ms, src, e);
}
}
return 0; /* not found */
}
static int gfind (lua_State *L) {
luaL_check_string(L, 1);
luaL_check_string(L, 2);
lua_settop(L, 2);
lua_pushnumber(L, 0);
lua_pushcclosure(L, gfind_aux, 3);
return 1;
}
static void add_s (MatchState *ms, luaL_Buffer *b,
const char *s, const char *e) {
lua_State *L = ms->L;
if (lua_isstring(L, 3)) {
const char *news = lua_tostring(L, 3);
size_t l = lua_strlen(L, 3);
size_t i;
for (i=0; i<l; i++) {
if (news[i] != ESC)
luaL_putchar(b, news[i]);
else {
i++; /* skip ESC */
if (!isdigit(uchar(news[i])))
luaL_putchar(b, news[i]);
else {
int level = check_capture(ms, news[i]);
push_onecapture(ms, level);
luaL_addvalue(b); /* add capture to accumulated result */
}
}
}
}
else { /* is a function */
int n;
lua_pushvalue(L, 3);
n = push_captures(ms, s, e);
lua_call(L, n, 1);
if (lua_isstring(L, -1))
luaL_addvalue(b); /* add return to accumulated result */
else
lua_pop(L, 1); /* function result is not a string: pop it */
}
}
static int str_gsub (lua_State *L) {
size_t srcl;
const char *src = luaL_check_lstr(L, 1, &srcl);
const char *p = luaL_check_string(L, 2);
int max_s = luaL_opt_int(L, 4, srcl+1);
int anchor = (*p == '^') ? (p++, 1) : 0;
int n = 0;
MatchState ms;
luaL_Buffer b;
luaL_arg_check(L,
lua_gettop(L) >= 3 && (lua_isstring(L, 3) || lua_isfunction(L, 3)),
3, "string or function expected");
luaL_buffinit(L, &b);
ms.L = L;
ms.src_init = src;
ms.src_end = src+srcl;
while (n < max_s) {
const char *e;
ms.level = 0;
e = match(&ms, src, p);
if (e) {
n++;
add_s(&ms, &b, src, e);
}
if (e && e>src) /* non empty match? */
src = e; /* skip it */
else if (src < ms.src_end)
luaL_putchar(&b, *src++);
else break;
if (anchor) break;
}
luaL_addlstring(&b, src, ms.src_end-src);
luaL_pushresult(&b);
lua_pushnumber(L, n); /* number of substitutions */
return 2;
}
/* }====================================================== */
/* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */
#define MAX_ITEM 512
/* maximum size of each format specification (such as '%-099.99d') */
#define MAX_FORMAT 20
static void luaI_addquoted (lua_State *L, luaL_Buffer *b, int arg) {
size_t l;
const char *s = luaL_check_lstr(L, arg, &l);
luaL_putchar(b, '"');
while (l--) {
switch (*s) {
case '"': case '\\': case '\n':
luaL_putchar(b, '\\');
luaL_putchar(b, *s);
break;
case '\0': luaL_addlstring(b, "\\000", 4); break;
default: luaL_putchar(b, *s);
}
s++;
}
luaL_putchar(b, '"');
}
static const char *scanformat (lua_State *L, const char *strfrmt,
char *form, int *hasprecision) {
const char *p = strfrmt;
while (strchr("-+ #0", *p)) p++; /* skip flags */
if (isdigit(uchar(*p))) p++; /* skip width */
if (isdigit(uchar(*p))) p++; /* (2 digits at most) */
if (*p == '.') {
p++;
*hasprecision = 1;
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)");
if (p-strfrmt+2 > MAX_FORMAT) /* +2 to include `%' and the specifier */
luaL_error(L, "invalid format (too long)");
form[0] = '%';
strncpy(form+1, strfrmt, p-strfrmt+1);
form[p-strfrmt+2] = 0;
return p;
}
static int str_format (lua_State *L) {
int arg = 1;
size_t sfl;
const char *strfrmt = luaL_check_lstr(L, arg, &sfl);
const char *strfrmt_end = strfrmt+sfl;
luaL_Buffer b;
luaL_buffinit(L, &b);
while (strfrmt < strfrmt_end) {
if (*strfrmt != '%')
luaL_putchar(&b, *strfrmt++);
else if (*++strfrmt == '%')
luaL_putchar(&b, *strfrmt++); /* %% */
else { /* format item */
char form[MAX_FORMAT]; /* to store the format (`%...') */
char buff[MAX_ITEM]; /* to store the formatted item */
int hasprecision = 0;
if (isdigit(uchar(*strfrmt)) && *(strfrmt+1) == '$')
return luaL_error(L, "obsolete `format' option (d$)");
arg++;
strfrmt = scanformat(L, strfrmt, form, &hasprecision);
switch (*strfrmt++) {
case 'c': case 'd': case 'i':
sprintf(buff, form, luaL_check_int(L, arg));
break;
case 'o': case 'u': case 'x': case 'X':
sprintf(buff, form, (unsigned int)(luaL_check_number(L, arg)));
break;
case 'e': case 'E': case 'f':
case 'g': case 'G':
sprintf(buff, form, luaL_check_number(L, arg));
break;
case 'q':
luaI_addquoted(L, &b, arg);
continue; /* skip the `addsize' at the end */
case 's': {
size_t l;
const char *s = luaL_check_lstr(L, arg, &l);
if (!hasprecision && l >= 100) {
/* no precision and string is too long to be formatted;
keep original string */
lua_pushvalue(L, arg);
luaL_addvalue(&b);
continue; /* skip the `addsize' at the end */
}
else {
sprintf(buff, form, s);
break;
}
}
default: /* also treat cases `pnLlh' */
return luaL_error(L, "invalid option in `format'");
}
luaL_addlstring(&b, buff, strlen(buff));
}
}
luaL_pushresult(&b);
return 1;
}
static const luaL_reg strlib[] = {
{"len", str_len},
{"sub", str_sub},
{"lower", str_lower},
{"upper", str_upper},
{"char", str_char},
{"rep", str_rep},
{"byte", str_byte},
{"format", str_format},
{"find", str_find},
{"gfind", gfind},
{"gsub", str_gsub},
{NULL, NULL}
};
/*
** Open string library
*/
LUALIB_API int lua_strlibopen (lua_State *L) {
luaL_opennamedlib(L, LUA_STRLIBNAME, strlib, 0);
return 0;
}
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