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 lua_WChar *match (MatchState *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 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 (iswdigit(*(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 lua_WChar *ep = luaI_classend(ms, p); /* points to what is next */
int m = s<ms->src_end && luaI_singlematch(*s, p, ep);
switch (*ep) {
case '?': { /* optional */
const lua_WChar *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 int read_pattern (lua_State *L, FILE *f, const char *p) {
int inskip = 0; /* {skip} level */
int c = NEED_OTHER;
luaL_Buffer b;
luaL_buffinit(L, &b);
while (*p != '\0') {
switch (*p) {
case '{':
inskip++;
p++;
continue;
case '}':
if (!inskip) lua_error(L, "unbalanced braces in read pattern");
inskip--;
p++;
continue;
default: {
const char *ep = luaI_classend(L, p); /* get what is next */
int m; /* match result */
if (c == NEED_OTHER) c = getc(f);
m = (c==EOF) ? 0 : luaI_singlematch(c, p, ep);
if (m) {
if (!inskip) luaL_putchar(&b, c);
c = NEED_OTHER;
}
switch (*ep) {
case '+': /* repetition (1 or more) */
if (!m) goto break_while; /* pattern fails? */
/* else go through */
case '*': /* repetition (0 or more) */
while (m) { /* reads the same item until it fails */
c = getc(f);
m = (c==EOF) ? 0 : luaI_singlematch(c, p, ep);
if (m && !inskip) luaL_putchar(&b, c);
}
/* go through to continue reading the pattern */
case '?': /* optional */
p = ep+1; /* continues reading the pattern */
continue;
default:
if (!m) goto break_while; /* pattern fails? */
p = ep; /* else continues reading the pattern */
}
}
}
} break_while:
if (c != NEED_OTHER) ungetc(c, f);
luaL_pushresult(&b); /* close buffer */
return (*p == '\0');
}
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: {
switch (*(p+1)) {
case '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); */
}
case 'f': { /* frontier? */
const char *ep; char previous;
p += 2;
if (*p != '[')
luaL_error(ms->L, "missing `[' after `%%f' in pattern");
ep = luaI_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)) return NULL;
p=ep; goto init; /* else return match(ms, s, ep); */
}
default: {
if (isdigit(uchar(*(p+1)))) { /* capture results (%0-%9)? */
s = match_capture(ms, s, *(p+1));
if (s == NULL) return NULL;
p+=2; goto init; /* else return match(ms, s, p+2) */
}
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); */
}
}
}
}
}
