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lua/lstrlib.c

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/*
** $Id: lstrlib.c,v 1.40 2000/02/08 16:34:31 roberto Exp roberto $
** Standard library for string operations and pattern-matching
** See Copyright Notice in lua.h
*/
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define LUA_REENTRANT
#include "lauxlib.h"
#include "lua.h"
#include "lualib.h"
static void addnchar (lua_State *L, const char *s, int n) {
char *b = luaL_openspace(L, n);
memcpy(b, s, n);
luaL_addsize(L, n);
}
static void str_len (lua_State *L) {
long l;
luaL_check_lstr(L, 1, &l);
lua_pushnumber(L, l);
}
static void closeandpush (lua_State *L) {
lua_pushlstring(L, luaL_buffer(L), luaL_getsize(L));
}
static long posrelat (long pos, long len) {
/* relative string position: negative means back from end */
return (pos>=0) ? pos : len+pos+1;
}
static void str_sub (lua_State *L) {
long l;
const char *s = luaL_check_lstr(L, 1, &l);
long start = posrelat(luaL_check_long(L, 2), l);
long end = posrelat(luaL_opt_long(L, 3, -1), l);
if (start < 1) start = 1;
if (end > l) end = l;
if (start <= end)
lua_pushlstring(L, s+start-1, end-start+1);
else lua_pushstring(L, "");
}
static void str_lower (lua_State *L) {
long l;
int i;
const char *s = luaL_check_lstr(L, 1, &l);
luaL_resetbuffer(L);
for (i=0; i<l; i++)
luaL_addchar(L, tolower((unsigned char)(s[i])));
closeandpush(L);
}
static void str_upper (lua_State *L) {
long l;
int i;
const char *s = luaL_check_lstr(L, 1, &l);
luaL_resetbuffer(L);
for (i=0; i<l; i++)
luaL_addchar(L, toupper((unsigned char)(s[i])));
closeandpush(L);
}
static void str_rep (lua_State *L) {
long l;
const char *s = luaL_check_lstr(L, 1, &l);
int n = luaL_check_int(L, 2);
luaL_resetbuffer(L);
while (n-- > 0)
addnchar(L, s, l);
closeandpush(L);
}
static void str_byte (lua_State *L) {
long l;
const char *s = luaL_check_lstr(L, 1, &l);
long pos = posrelat(luaL_opt_long(L, 2, 1), l);
luaL_arg_check(L, 0<pos && pos<=l, 2, "out of range");
lua_pushnumber(L, (unsigned char)s[pos-1]);
}
static void str_char (lua_State *L) {
int i = 0;
luaL_resetbuffer(L);
while (lua_getparam(L, ++i) != LUA_NOOBJECT) {
int c = luaL_check_int(L, i);
luaL_arg_check(L, (unsigned char)c == c, i, "invalid value");
luaL_addchar(L, (unsigned char)c);
}
closeandpush(L);
}
/*
** {======================================================
** PATTERN MATCHING
** =======================================================
*/
#ifndef MAX_CAPTURES
#define MAX_CAPTURES 32 /* arbitrary limit */
#endif
struct Capture {
const char *src_end; /* end ('\0') of source string */
int level; /* total number of captures (finished or unfinished) */
struct {
const char *init;
int len; /* -1 signals unfinished capture */
} capture[MAX_CAPTURES];
};
#define ESC '%'
#define SPECIALS "^$*+?.([%-"
static void push_captures (lua_State *L, struct Capture *cap) {
int i;
for (i=0; i<cap->level; i++) {
int l = cap->capture[i].len;
if (l == -1) lua_error(L, "unfinished capture");
lua_pushlstring(L, cap->capture[i].init, l);
}
}
static int check_capture (lua_State *L, int l, struct Capture *cap) {
l -= '1';
if (!(0 <= l && l < cap->level && cap->capture[l].len != -1))
lua_error(L, "invalid capture index");
return l;
}
static int capture_to_close (lua_State *L, struct Capture *cap) {
int level = cap->level;
for (level--; level>=0; level--)
if (cap->capture[level].len == -1) return level;
lua_error(L, "invalid pattern capture");
return 0; /* to avoid warnings */
}
const char *luaI_classend (lua_State *L, const char *p) {
switch (*p++) {
case ESC:
if (*p == '\0') lua_error(L, "malformed pattern (ends with `%')");
return p+1;
case '[':
if (*p == '^') p++;
do { /* look for a ']' */
if (*p == '\0') lua_error(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 *endclass) {
int sig = 1;
if (*(p+1) == '^') {
sig = 0;
p++; /* skip the '^' */
}
while (++p < endclass) {
if (*p == ESC) {
p++;
if (match_class(c, (unsigned char)*p))
return sig;
}
else if ((*(p+1) == '-') && (p+2 < endclass)) {
p+=2;
if ((int)(unsigned char)*(p-2) <= c && c <= (int)(unsigned char)*p)
return sig;
}
else if ((int)(unsigned char)*p == c) return sig;
}
return !sig;
}
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, (unsigned char)*(p+1));
case '[':
return matchbracketclass(c, p, ep-1);
default:
return ((unsigned char)*p == c);
}
}
static const char *match (lua_State *L, const char *s, const char *p, struct Capture *cap);
static const char *matchbalance (lua_State *L, const char *s, const char *p,
struct Capture *cap) {
if (*p == 0 || *(p+1) == 0)
lua_error(L, "unbalanced pattern");
if (*s != *p) return NULL;
else {
int b = *p;
int e = *(p+1);
int cont = 1;
while (++s < cap->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 (lua_State *L, const char *s, const char *p, const char *ep,
struct Capture *cap) {
int i = 0; /* counts maximum expand for item */
while ((s+i)<cap->src_end && luaI_singlematch((unsigned char)*(s+i), p, ep))
i++;
/* keeps trying to match mith the maximum repetitions */
while (i>=0) {
const char *res = match(L, (s+i), ep+1, cap);
if (res) return res;
i--; /* else didn't match; reduce 1 repetition to try again */
}
return NULL;
}
static const char *min_expand (lua_State *L, const char *s, const char *p, const char *ep,
struct Capture *cap) {
for (;;) {
const char *res = match(L, s, ep+1, cap);
if (res != NULL)
return res;
else if (s<cap->src_end && luaI_singlematch((unsigned char)*s, p, ep))
s++; /* try with one more repetition */
else return NULL;
}
}
static const char *start_capture (lua_State *L, const char *s, const char *p,
struct Capture *cap) {
const char *res;
int level = cap->level;
if (level >= MAX_CAPTURES) lua_error(L, "too many captures");
cap->capture[level].init = s;
cap->capture[level].len = -1;
cap->level = level+1;
if ((res=match(L, s, p+1, cap)) == NULL) /* match failed? */
cap->level--; /* undo capture */
return res;
}
static const char *end_capture (lua_State *L, const char *s, const char *p,
struct Capture *cap) {
int l = capture_to_close(L, cap);
const char *res;
cap->capture[l].len = s - cap->capture[l].init; /* close capture */
if ((res = match(L, s, p+1, cap)) == NULL) /* match failed? */
cap->capture[l].len = -1; /* undo capture */
return res;
}
static const char *match_capture (lua_State *L, const char *s, int level,
struct Capture *cap) {
int l = check_capture(L, level, cap);
int len = cap->capture[l].len;
if (cap->src_end-s >= len &&
memcmp(cap->capture[l].init, s, len) == 0)
return s+len;
else return NULL;
}
static const char *match (lua_State *L, const char *s, const char *p, struct Capture *cap) {
init: /* using goto's to optimize tail recursion */
switch (*p) {
case '(': /* start capture */
return start_capture(L, s, p, cap);
case ')': /* end capture */
return end_capture(L, s, p, cap);
case ESC: /* may be %[0-9] or %b */
if (isdigit((unsigned char)(*(p+1)))) { /* capture? */
s = match_capture(L, s, *(p+1), cap);
if (s == NULL) return NULL;
p+=2; goto init; /* else return match(L, s, p+2, cap) */
}
else if (*(p+1) == 'b') { /* balanced string? */
s = matchbalance(L, s, p+2, cap);
if (s == NULL) return NULL;
p+=4; goto init; /* else return match(L, s, p+4, cap); */
}
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 == cap->src_end) ? s : NULL; /* check end of string */
else goto dflt;
default: dflt: { /* it is a pattern item */
const char *ep = luaI_classend(L, p); /* points to what is next */
int m = s<cap->src_end && luaI_singlematch((unsigned char)*s, p, ep);
switch (*ep) {
case '?': { /* optional */
const char *res;
if (m && ((res=match(L, s+1, ep+1, cap)) != NULL))
return res;
p=ep+1; goto init; /* else return match(L, s, ep+1, cap); */
}
case '*': /* 0 or more repetitions */
return max_expand(L, s, p, ep, cap);
case '+': /* 1 or more repetitions */
return (m ? max_expand(L, s+1, p, ep, cap) : NULL);
case '-': /* 0 or more repetitions (minimum) */
return min_expand(L, s, p, ep, cap);
default:
if (!m) return NULL;
s++; p=ep; goto init; /* else return match(L, s+1, ep, cap); */
}
}
}
}
static const char *memfind (const char *s1, long l1, const char *s2, long l2) {
if (l2 == 0) return s1; /* empty strings are everywhere ;-) */
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 str_find (lua_State *L) {
long l1, l2;
const char *s = luaL_check_lstr(L, 1, &l1);
const char *p = luaL_check_lstr(L, 2, &l2);
long init = posrelat(luaL_opt_long(L, 3, 1), l1) - 1;
struct Capture cap;
luaL_arg_check(L, 0 <= init && init <= l1, 3, "out of range");
if (lua_getparam(L, 4) != LUA_NOOBJECT ||
strpbrk(p, SPECIALS) == NULL) { /* no special characters? */
const char *s2 = memfind(s+init, l1, p, l2);
if (s2) {
lua_pushnumber(L, s2-s+1);
lua_pushnumber(L, s2-s+l2);
return;
}
}
else {
int anchor = (*p == '^') ? (p++, 1) : 0;
const char *s1=s+init;
cap.src_end = s+l1;
do {
const char *res;
cap.level = 0;
if ((res=match(L, s1, p, &cap)) != NULL) {
lua_pushnumber(L, s1-s+1); /* start */
lua_pushnumber(L, res-s); /* end */
push_captures(L, &cap);
return;
}
} while (s1++<cap.src_end && !anchor);
}
lua_pushnil(L); /* not found */
}
static void add_s (lua_State *L, lua_Object newp, struct Capture *cap) {
if (lua_isstring(L, newp)) {
const char *news = lua_getstring(L, newp);
int l = lua_strlen(L, newp);
int i;
for (i=0; i<l; i++) {
if (news[i] != ESC)
luaL_addchar(L, news[i]);
else {
i++; /* skip ESC */
if (!isdigit((unsigned char)news[i]))
luaL_addchar(L, news[i]);
else {
int level = check_capture(L, news[i], cap);
addnchar(L, cap->capture[level].init, cap->capture[level].len);
}
}
}
}
else { /* is a function */
lua_Object res;
int status;
int oldbuff;
lua_beginblock(L);
push_captures(L, cap);
/* function may use buffer, so save it and create a new one */
oldbuff = luaL_newbuffer(L, 0);
status = lua_callfunction(L, newp);
/* restore old buffer */
luaL_oldbuffer(L, oldbuff);
if (status != 0) {
lua_endblock(L);
lua_error(L, NULL);
}
res = lua_getresult(L, 1);
if (lua_isstring(L, res))
addnchar(L, lua_getstring(L, res), lua_strlen(L, res));
lua_endblock(L);
}
}
static void str_gsub (lua_State *L) {
long srcl;
const char *src = luaL_check_lstr(L, 1, &srcl);
const char *p = luaL_check_string(L, 2);
lua_Object newp = lua_getparam(L, 3);
int max_s = luaL_opt_int(L, 4, srcl+1);
int anchor = (*p == '^') ? (p++, 1) : 0;
int n = 0;
struct Capture cap;
luaL_arg_check(L, lua_isstring(L, newp) || lua_isfunction(L, newp), 3,
"string or function expected");
luaL_resetbuffer(L);
cap.src_end = src+srcl;
while (n < max_s) {
const char *e;
cap.level = 0;
e = match(L, src, p, &cap);
if (e) {
n++;
add_s(L, newp, &cap);
}
if (e && e>src) /* non empty match? */
src = e; /* skip it */
else if (src < cap.src_end)
luaL_addchar(L, *src++);
else break;
if (anchor) break;
}
addnchar(L, src, cap.src_end-src);
closeandpush(L);
lua_pushnumber(L, n); /* number of substitutions */
}
/* }====================================================== */
static void luaI_addquoted (lua_State *L, int arg) {
long l;
const char *s = luaL_check_lstr(L, arg, &l);
luaL_addchar(L, '"');
while (l--) {
switch (*s) {
case '"': case '\\': case '\n':
luaL_addchar(L, '\\');
luaL_addchar(L, *s);
break;
case '\0': addnchar(L, "\\000", 4); break;
default: luaL_addchar(L, *s);
}
s++;
}
luaL_addchar(L, '"');
}
/* maximum size of each format specification (such as '%-099.99d') */
#define MAX_FORMAT 20 /* arbitrary limit */
static void str_format (lua_State *L) {
int arg = 1;
const char *strfrmt = luaL_check_string(L, arg);
luaL_resetbuffer(L);
while (*strfrmt) {
if (*strfrmt != '%')
luaL_addchar(L, *strfrmt++);
else if (*++strfrmt == '%')
luaL_addchar(L, *strfrmt++); /* %% */
else { /* format item */
struct Capture cap;
char form[MAX_FORMAT]; /* to store the format ('%...') */
char *buff; /* to store the formatted item */
const char *initf = strfrmt;
form[0] = '%';
if (isdigit((unsigned char)*initf) && *(initf+1) == '$') {
arg = *initf - '0';
initf += 2; /* skip the 'n$' */
}
arg++;
cap.src_end = strfrmt+strlen(strfrmt)+1;
cap.level = 0;
strfrmt = match(L, initf, "[-+ #0]*(%d*)%.?(%d*)", &cap);
if (cap.capture[0].len > 2 || cap.capture[1].len > 2 || /* < 100? */
strfrmt-initf > MAX_FORMAT-2)
lua_error(L, "invalid format (width or precision too long)");
strncpy(form+1, initf, strfrmt-initf+1); /* +1 to include conversion */
form[strfrmt-initf+2] = 0;
buff = luaL_openspace(L, 512); /* 512 > len(format('%99.99f', -1e308)) */
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, arg);
continue; /* skip the "addsize" at the end */
case 's': {
long l;
const char *s = luaL_check_lstr(L, arg, &l);
if (cap.capture[1].len == 0 && l >= 100) {
/* no precision and string is too long to be formatted;
keep original string */
addnchar(L, s, l);
continue; /* skip the "addsize" at the end */
}
else {
sprintf(buff, form, s);
break;
}
}
default: /* also treat cases 'pnLlh' */
lua_error(L, "invalid option in `format'");
}
luaL_addsize(L, strlen(buff));
}
}
closeandpush(L); /* push the result */
}
static const struct luaL_reg strlib[] = {
{"strlen", str_len},
{"strsub", str_sub},
{"strlower", str_lower},
{"strupper", str_upper},
{"strchar", str_char},
{"strrep", str_rep},
{"ascii", str_byte}, /* for compatibility with 3.0 and earlier */
{"strbyte", str_byte},
{"format", str_format},
{"strfind", str_find},
{"gsub", str_gsub}
};
/*
** Open string library
*/
void lua_strlibopen (lua_State *L) {
luaL_openl(L, strlib);
}
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