/*
** Join the ktables from p1 and p2 the ktable for the new pattern at the
** top of the stack, reusing them when possible.
*/
static void joinktables (lua_State *L, int p1, TTree *t2, int p2) {
int n1, n2;
lua_getfenv(L, p1); /* get ktables */
lua_getfenv(L, p2);
n1 = ktablelen(L, -2);
n2 = ktablelen(L, -1);
if (n1 == 0 && n2 == 0) /* are both tables empty? */
lua_pop(L, 2); /* nothing to be done; pop tables */
else if (n2 == 0 || lua_equal(L, -2, -1)) { /* 2nd table empty or equal? */
lua_pop(L, 1); /* pop 2nd table */
lua_setfenv(L, -2); /* set 1st ktable into new pattern */
}
else if (n1 == 0) { /* first table is empty? */
lua_setfenv(L, -3); /* set 2nd table into new pattern */
lua_pop(L, 1); /* pop 1st table */
}
else {
lua_createtable(L, n1 + n2, 0); /* create ktable for new pattern */
/* stack: new p; ktable p1; ktable p2; new ktable */
concattable(L, -3, -1); /* from p1 into new ktable */
concattable(L, -2, -1); /* from p2 into new ktable */
lua_setfenv(L, -4); /* new ktable becomes 'p' environment */
lua_pop(L, 2); /* pop other ktables */
correctkeys(t2, n1); /* correction for indices from p2 */
}
}
/*
** Concatentate the contents of table 'idx1' into table 'idx2'.
** (Assume that both indices are negative.)
** Return the original length of table 'idx2'
*/
static int concattable (lua_State *L, int idx1, int idx2) {
int i;
int n1 = ktablelen(L, idx1);
int n2 = ktablelen(L, idx2);
if (n1 == 0) return 0; /* nothing to correct */
for (i = 1; i <= n1; i++) {
lua_rawgeti(L, idx1, i);
lua_rawseti(L, idx2 - 1, n2 + i); /* correct 'idx2' */
}
return n2;
}
/*
** Concatentate the contents of table 'idx1' into table 'idx2'.
** (Assume that both indices are negative.)
** Return the original length of table 'idx2' (or 0, if no
** element was added, as there is no need to correct any index).
*/
static int concattable (lua_State *L, int idx1, int idx2) {
int i;
int n1 = ktablelen(L, idx1);
int n2 = ktablelen(L, idx2);
if (n1 + n2 > USHRT_MAX)
luaL_error(L, "too many Lua values in pattern");
if (n1 == 0) return 0; /* nothing to correct */
for (i = 1; i <= n1; i++) {
lua_rawgeti(L, idx1, i);
lua_rawseti(L, idx2 - 1, n2 + i); /* correct 'idx2' */
}
return n2;
}
