lua/lstrlib.c
1998-01-27 17:11:36 -02:00

510 lines
12 KiB
C

/*
** $Id: lstrlib.c,v 1.7 1998/01/09 14:57:43 roberto Exp roberto $
** Standard library for strings and pattern-matching
** See Copyright Notice in lua.h
*/
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "lauxlib.h"
#include "lua.h"
#include "lualib.h"
static void addnchar (char *s, int n)
{
char *b = luaL_openspace(n);
strncpy(b, s, n);
luaL_addsize(n);
}
static void addstr (char *s)
{
addnchar(s, strlen(s));
}
static void str_len (void)
{
lua_pushnumber(strlen(luaL_check_string(1)));
}
static void closeandpush (void)
{
luaL_addchar(0);
lua_pushstring(luaL_buffer());
}
static void str_sub (void)
{
char *s = luaL_check_string(1);
long l = strlen(s);
long start = (long)luaL_check_number(2);
long end = (long)luaL_opt_number(3, -1);
if (start < 0) start = l+start+1;
if (end < 0) end = l+end+1;
if (1 <= start && start <= end && end <= l) {
luaL_resetbuffer();
addnchar(s+start-1, end-start+1);
closeandpush();
}
else lua_pushstring("");
}
static void str_lower (void)
{
char *s;
luaL_resetbuffer();
for (s = luaL_check_string(1); *s; s++)
luaL_addchar(tolower((unsigned char)*s));
closeandpush();
}
static void str_upper (void)
{
char *s;
luaL_resetbuffer();
for (s = luaL_check_string(1); *s; s++)
luaL_addchar(toupper((unsigned char)*s));
closeandpush();
}
static void str_rep (void)
{
char *s = luaL_check_string(1);
int n = (int)luaL_check_number(2);
luaL_resetbuffer();
while (n-- > 0)
addstr(s);
closeandpush();
}
static void str_ascii (void)
{
char *s = luaL_check_string(1);
long pos = (long)luaL_opt_number(2, 1) - 1;
luaL_arg_check(0<=pos && pos<strlen(s), 2, "out of range");
lua_pushnumber((unsigned char)s[pos]);
}
/*
** =======================================================
** PATTERN MATCHING
** =======================================================
*/
#define MAX_CAPT 9
struct Capture {
int level; /* total number of captures (finished or unfinished) */
struct {
char *init;
int len; /* -1 signals unfinished capture */
} capture[MAX_CAPT];
};
#define ESC '%'
#define SPECIALS "^$*?.([%-"
static void push_captures (struct Capture *cap)
{
int i;
for (i=0; i<cap->level; i++) {
int l = cap->capture[i].len;
char *buff = luaL_openspace(l+1);
if (l == -1) lua_error("unfinished capture");
strncpy(buff, cap->capture[i].init, l);
buff[l] = 0;
lua_pushstring(buff);
}
}
static int check_cap (int l, struct Capture *cap)
{
l -= '1';
if (!(0 <= l && l < cap->level && cap->capture[l].len != -1))
lua_error("invalid capture index");
return l;
}
static int capture_to_close (struct Capture *cap)
{
int level = cap->level;
for (level--; level>=0; level--)
if (cap->capture[level].len == -1) return level;
lua_error("invalid pattern capture");
return 0; /* to avoid warnings */
}
static char *bracket_end (char *p)
{
return (*p == 0) ? NULL : strchr((*p=='^') ? p+2 : p+1, ']');
}
static int matchclass (int c, int cl)
{
int res;
if (c == 0) return 0;
switch (tolower((unsigned char)cl)) {
case 'w' : res = isalnum((unsigned char)c); break;
case 'd' : res = isdigit((unsigned char)c); break;
case 's' : res = isspace((unsigned char)c); break;
case 'a' : res = isalpha((unsigned char)c); break;
case 'p' : res = ispunct((unsigned char)c); break;
case 'l' : res = islower((unsigned char)c); break;
case 'u' : res = isupper((unsigned char)c); break;
case 'c' : res = iscntrl((unsigned char)c); break;
default: return (cl == c);
}
return (islower((unsigned char)cl) ? res : !res);
}
int luaI_singlematch (int c, char *p, char **ep)
{
switch (*p) {
case '.':
*ep = p+1;
return (c != 0);
case '\0':
*ep = p;
return 0;
case ESC:
if (*(++p) == '\0')
luaL_verror("incorrect pattern (ends with `%c')", ESC);
*ep = p+1;
return matchclass(c, *p);
case '[': {
char *end = bracket_end(p+1);
int sig = *(p+1) == '^' ? (p++, 0) : 1;
if (end == NULL) lua_error("incorrect pattern (missing `]')");
*ep = end+1;
if (c == 0) return 0;
while (++p < end) {
if (*p == ESC) {
if (((p+1) < end) && matchclass(c, *++p)) return sig;
}
else if ((*(p+1) == '-') && (p+2 < end)) {
p+=2;
if (*(p-2) <= c && c <= *p) return sig;
}
else if (*p == c) return sig;
}
return !sig;
}
default:
*ep = p+1;
return (*p == c);
}
}
static char *matchbalance (char *s, int b, int e)
{
if (*s != b) return NULL;
else {
int cont = 1;
while (*(++s)) {
if (*s == e) {
if (--cont == 0) return s+1;
}
else if (*s == b) cont++;
}
}
return NULL; /* string ends out of balance */
}
static char *matchitem (char *s, char *p, struct Capture *cap, char **ep)
{
if (*p == ESC) {
p++;
if (isdigit((unsigned char)*p)) { /* capture */
int l = check_cap(*p, cap);
*ep = p+1;
if (strncmp(cap->capture[l].init, s, cap->capture[l].len) == 0)
return s+cap->capture[l].len;
else return NULL;
}
else if (*p == 'b') { /* balanced string */
p++;
if (*p == 0 || *(p+1) == 0)
lua_error("unbalanced pattern");
*ep = p+2;
return matchbalance(s, *p, *(p+1));
}
else p--; /* and go through */
}
return (luaI_singlematch(*s, p, ep) ? s+1 : NULL);
}
static char *match (char *s, char *p, struct Capture *cap)
{
init: /* using goto's to optimize tail recursion */
switch (*p) {
case '(': { /* start capture */
char *res;
if (cap->level >= MAX_CAPT) lua_error("too many captures");
cap->capture[cap->level].init = s;
cap->capture[cap->level].len = -1;
cap->level++;
if ((res=match(s, p+1, cap)) == NULL) /* match failed? */
cap->level--; /* undo capture */
return res;
}
case ')': { /* end capture */
int l = capture_to_close(cap);
char *res;
cap->capture[l].len = s - cap->capture[l].init; /* close capture */
if ((res = match(s, p+1, cap)) == NULL) /* match failed? */
cap->capture[l].len = -1; /* undo capture */
return res;
}
case '\0': case '$': /* (possibly) end of pattern */
if (*p == 0 || (*(p+1) == 0 && *s == 0))
return s;
/* else go through */
default: { /* it is a pattern item */
char *ep; /* get what is next */
char *s1 = matchitem(s, p, cap, &ep);
switch (*ep) {
case '*': { /* repetition */
char *res;
if (s1 && (res = match(s1, p, cap)))
return res;
p=ep+1; goto init; /* else return match(s, ep+1, cap); */
}
case '?': { /* optional */
char *res;
if (s1 && (res = match(s1, ep+1, cap)))
return res;
p=ep+1; goto init; /* else return match(s, ep+1, cap); */
}
case '-': { /* repetition */
char *res;
if ((res = match(s, ep+1, cap)) != 0)
return res;
else if (s1) {
s = s1;
goto init; /* return match(s1, p, cap); */
}
else
return NULL;
}
default:
if (s1) { s=s1; p=ep; goto init; } /* return match(s1, ep, cap); */
else return NULL;
}
}
}
}
static void str_find (void)
{
char *s = luaL_check_string(1);
char *p = luaL_check_string(2);
long init = (long)luaL_opt_number(3, 1) - 1;
luaL_arg_check(0 <= init && init <= strlen(s), 3, "out of range");
if (lua_getparam(4) != LUA_NOOBJECT ||
strpbrk(p, SPECIALS) == NULL) { /* no special caracters? */
char *s2 = strstr(s+init, p);
if (s2) {
lua_pushnumber(s2-s+1);
lua_pushnumber(s2-s+strlen(p));
}
}
else {
int anchor = (*p == '^') ? (p++, 1) : 0;
char *s1=s+init;
do {
struct Capture cap;
char *res;
cap.level = 0;
if ((res=match(s1, p, &cap)) != NULL) {
lua_pushnumber(s1-s+1); /* start */
lua_pushnumber(res-s); /* end */
push_captures(&cap);
return;
}
} while (*s1++ && !anchor);
}
}
static void add_s (lua_Object newp, struct Capture *cap)
{
if (lua_isstring(newp)) {
char *news = lua_getstring(newp);
while (*news) {
if (*news != ESC || !isdigit((unsigned char)*++news))
luaL_addchar(*news++);
else {
int l = check_cap(*news++, cap);
addnchar(cap->capture[l].init, cap->capture[l].len);
}
}
}
else if (lua_isfunction(newp)) {
lua_Object res;
int status;
int oldbuff;
lua_beginblock();
push_captures(cap);
/* function may use buffer, so save it and create a new one */
oldbuff = luaL_newbuffer(0);
status = lua_callfunction(newp);
/* restore old buffer */
luaL_oldbuffer(oldbuff);
if (status != 0) {
lua_endblock();
lua_error(NULL);
}
res = lua_getresult(1);
addstr(lua_isstring(res) ? lua_getstring(res) : "");
lua_endblock();
}
else luaL_arg_check(0, 3, "string or function expected");
}
static void str_gsub (void)
{
char *src = luaL_check_string(1);
char *p = luaL_check_string(2);
lua_Object newp = lua_getparam(3);
int max_s = (int)luaL_opt_number(4, strlen(src)+1);
int anchor = (*p == '^') ? (p++, 1) : 0;
int n = 0;
luaL_resetbuffer();
while (n < max_s) {
struct Capture cap;
char *e;
cap.level = 0;
e = match(src, p, &cap);
if (e) {
n++;
add_s(newp, &cap);
}
if (e && e>src) /* non empty match? */
src = e; /* skip it */
else if (*src)
luaL_addchar(*src++);
else break;
if (anchor) break;
}
addstr(src);
closeandpush();
lua_pushnumber(n); /* number of substitutions */
}
static void luaI_addquoted (char *s)
{
luaL_addchar('"');
for (; *s; s++) {
if (strchr("\"\\\n", *s))
luaL_addchar('\\');
luaL_addchar(*s);
}
luaL_addchar('"');
}
#define MAX_FORMAT 200
static void str_format (void)
{
int arg = 1;
char *strfrmt = luaL_check_string(arg);
luaL_resetbuffer();
while (*strfrmt) {
if (*strfrmt != '%')
luaL_addchar(*strfrmt++);
else if (*++strfrmt == '%')
luaL_addchar(*strfrmt++); /* %% */
else { /* format item */
char form[MAX_FORMAT]; /* store the format ('%...') */
struct Capture cap;
char *buff;
char *initf = strfrmt;
form[0] = '%';
cap.level = 0;
if (isdigit((unsigned char)initf[0]) && initf[1] == '$') {
arg = initf[0] - '0';
initf += 2; /* skip the 'n$' */
}
arg++;
strfrmt = match(initf, "[-+ #0]*(%d*)%.?(%d*)", &cap);
if (cap.capture[0].len > 2 || cap.capture[1].len > 2) /* < 100? */
lua_error("invalid format (width or precision too long)");
strncpy(form+1, initf, strfrmt-initf+1); /* +1 to include convertion */
form[strfrmt-initf+2] = 0;
buff = luaL_openspace(1000); /* to store the formatted value */
switch (*strfrmt++) {
case 'q':
luaI_addquoted(luaL_check_string(arg));
continue;
case 's': {
char *s = luaL_check_string(arg);
buff = luaL_openspace(strlen(s));
sprintf(buff, form, s);
break;
}
case 'c': case 'd': case 'i': case 'o':
case 'u': case 'x': case 'X':
sprintf(buff, form, (int)luaL_check_number(arg));
break;
case 'e': case 'E': case 'f': case 'g': case 'G':
sprintf(buff, form, luaL_check_number(arg));
break;
default: /* also treat cases 'pnLlh' */
lua_error("invalid option in `format'");
}
luaL_addsize(strlen(buff));
}
}
closeandpush(); /* push the result */
}
static struct luaL_reg strlib[] = {
{"strlen", str_len},
{"strsub", str_sub},
{"strlower", str_lower},
{"strupper", str_upper},
{"strrep", str_rep},
{"ascii", str_ascii},
{"format", str_format},
{"strfind", str_find},
{"gsub", str_gsub}
};
/*
** Open string library
*/
void strlib_open (void)
{
luaL_openlib(strlib, (sizeof(strlib)/sizeof(strlib[0])));
}