Cell *program(Node **a, int n) /* execute an awk program */
{ /* a[0] = BEGIN, a[1] = body, a[2] = END */
Cell *x;
if (setjmp(env) != 0)
goto ex;
if (a[0]) { /* BEGIN */
x = execute(a[0]);
if (isexit(x))
return(true);
if (isjump(x))
ERROR "illegal break, continue, next or nextfile from BEGIN" FATAL;
tempfree(x);
}
if (a[1] || a[2])
while (getrec(record) > 0) {
x = execute(a[1]);
if (isexit(x))
break;
tempfree(x);
}
ex:
if (setjmp(env) != 0) /* handles exit within END */
goto ex1;
if (a[2]) { /* END */
x = execute(a[2]);
if (isbreak(x) || isnext(x) || iscont(x))
ERROR "illegal break, continue, next or nextfile from END" FATAL;
tempfree(x);
}
ex1:
return(true);
}
static int iter_aux (lua_State *L) {
size_t len;
const char *s = luaL_checklstring(L, 1, &len);
lua_Integer n = lua_tointeger(L, 2) - 1;
if (n < 0) /* first iteration? */
n = 0; /* start from here */
else if (n < (lua_Integer)len) {
n++; /* skip current byte */
while (iscont(s + n)) n++; /* and its continuations */
}
if (n >= (lua_Integer)len)
return 0; /* no more codepoints */
else {
int code;
const char *next = utf8_decode(s + n, &code);
if (next == NULL || iscont(next))
return luaL_error(L, "invalid UTF-8 code");
lua_pushinteger(L, n + 1);
lua_pushinteger(L, code);
return 2;
}
}
/*
** offset(s, n, [i]) -> index where n-th character counting from
** position 'i' starts; 0 means character at 'i'.
*/
static int byteoffset (lua_State *L) {
size_t len;
const char *s = luaL_checklstring(L, 1, &len);
lua_Integer n = luaL_checkinteger(L, 2);
lua_Integer posi = (n >= 0) ? 1 : len + 1;
posi = u_posrelat(luaL_optinteger(L, 3, posi), len);
luaL_argcheck(L, 1 <= posi && --posi <= (lua_Integer)len, 3,
"position out of range");
if (n == 0) {
/* find beginning of current byte sequence */
while (posi > 0 && iscont(s + posi)) posi--;
}
else {
if (iscont(s + posi))
luaL_error(L, "initial position is a continuation byte");
if (n < 0) {
while (n < 0 && posi > 0) { /* move back */
do { /* find beginning of previous character */
posi--;
} while (posi > 0 && iscont(s + posi));
n++;
}
}
else {
n--; /* do not move for 1st character */
while (n > 0 && posi < (lua_Integer)len) {
do { /* find beginning of next character */
posi++;
} while (iscont(s + posi)); /* (cannot pass final '\0') */
n--;
}
}
}
if (n == 0) /* did it find given character? */
lua_pushinteger(L, posi + 1);
else /* no such character */
lua_pushnil(L);
return 1;
}