static int wsinglematch (lua_WChar c, const lua_WChar *p, const lua_WChar *ep) {
switch (*p) {
case '.': return 1; /* matches any char */
case WL_ESC: return wmatch_class(c, *(p+1));
case '[': return wmatchbracketclass(c, p, ep-1);
default: return (*p == c);
}
}
static const lua_WChar *wmatch (WMatchState *ms, const lua_WChar *s, const lua_WChar *p) {
init: /* using goto's to optimize tail recursion */
switch (*p) {
case '(': { /* start capture */
if (*(p+1) == ')') /* position capture? */
return wstart_capture(ms, s, p+2, CAP_POSITION);
else
return wstart_capture(ms, s, p+1, CAP_UNFINISHED);
}
case ')': { /* end capture */
return wend_capture(ms, s, p+1);
}
case WL_ESC: {
switch (*(p+1)) {
case 'b': { /* balanced string? */
s = wmatchbalance(ms, s, p+2);
if (s == NULL) return NULL;
p+=4;
goto init; /* else return wmatch(ms, s, p+4); */
}
case 'f': { /* frontier? */
const lua_WChar *ep;
lua_WChar previous;
p += 2;
if (*p != '[')
luaL_error(ms->L, "missing " LUA_QL("[") " after "
LUA_QL("%%f") " in pattern");
ep = wclassend(ms, p); /* points to what is next */
previous = (s == ms->src_init) ? '\0' : *(s-1);
if (wmatchbracketclass(previous, p, ep-1) ||
!wmatchbracketclass(*s, p, ep-1)) return NULL;
p=ep;
goto init; /* else return wmatch(ms, s, ep); */
}
default: {
if (iswdigit(*(p+1))) { /* capture results (%0-%9)? */
s = wmatch_capture(ms, s, *(p+1));
if (s == NULL) return NULL;
p+=2;
goto init; /* else return wmatch(ms, s, p+2) */
}
goto dflt; /* case default */
}
}
}
case '\0': { /* end of pattern */
return s; /* wmatch 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 lua_WChar *ep = wclassend(ms, p); /* points to what is next */
int m = s<ms->src_end && wsinglematch(*s, p, ep);
switch (*ep) {
case '?': { /* optional */
const lua_WChar *res;
if (m && ((res=wmatch(ms, s+1, ep+1)) != NULL))
return res;
p=ep+1;
goto init; /* else return wmatch(ms, s, ep+1); */
}
case '*': { /* 0 or more repetitions */
return wmax_expand(ms, s, p, ep);
}
case '+': { /* 1 or more repetitions */
return (m ? wmax_expand(ms, s+1, p, ep) : NULL);
}
case '-': { /* 0 or more repetitions (minimum) */
return wmin_expand(ms, s, p, ep);
}
default: {
if (!m) return NULL;
s++;
p=ep;
goto init; /* else return wmatch(ms, s+1, ep); */
}
}
}
}
}
