int
lua_amf_decode(lua_State *L)
{
int ver;
int top;
size_t pos;
size_t buf_size;
const char *buf;
amf_cursor *cur;
ver = luaL_checkint(L, 1);
check_amf_ver(ver, 1);
buf = luaL_checklstring(L, 2, &buf_size);
pos = luaL_optint(L, 3, 0);
luaL_argcheck(L, pos >= 0, 3,
"input offset may not be negative");
buf_size = min(luaL_optint(L, 4, buf_size), (int)buf_size);
luaL_argcheck(L, buf_size >= pos, 4, "input buf overflow");
top = lua_gettop(L);
cur = amf_cursor_new(buf, buf_size);
if (ver == AMF_VER0) {
lua_newtable(L);
amf0_decode(L, cur, top+1);
} else {
lua_newtable(L);
lua_newtable(L);
lua_newtable(L);
amf3_decode(L, cur, top + 1, top + 2, top + 3);
}
if (cur->err) {
lua_pushnil(L);
lua_pushstring(L, cur->err_msg);
} else {
//obj is at top of the stack
lua_pushnil(L);
}
lua_pushinteger(L, buf_size - cur->left);
amf_cursor_free(cur);
return 3;
}
void
amf0_decode(lua_State *L, amf_cursor *c, int ridx)
{
amf_cursor_need(c, 1);
switch (c->p[0]) {
case AMF0_BOOLEAN:
amf_cursor_need(c, 2);
lua_pushboolean(L, c->p[1] == 0x01 ? 1 : 0);
amf_cursor_consume(c, 2);
break;
case AMF0_NULL:
case AMF0_UNDEFINED:
lua_pushnil(L);
amf_cursor_consume(c, 1);
break;
case AMF0_NUMBER:
amf_cursor_need(c, 9);
assert(sizeof(double) == 8);
double d;
memcpy(&d, c->p + 1, 8);
reverse_if_little_endian(&d, 8);
lua_pushnumber(L, d);
amf_cursor_consume(c, 9);
break;
case AMF0_STRING:
amf_cursor_consume(c, 1);
amf0_decode_string(L, c, 16);
break;
case AMF0_L_STRING:
amf_cursor_consume(c, 1);
amf0_decode_string(L, c, 32);
break;
case AMF0_OBJECT:
amf_cursor_consume(c, 1);
amf0_decode_to_lua_table(L, c, ridx);
break;
case AMF0_ECMA_ARRAY:
/* the property count, basicly 0 */
amf_cursor_skip(c, 5);
amf0_decode_to_lua_table(L, c, ridx);
break;
case AMF0_STRICT_ARRAY:
amf_cursor_need(c, 5);
uint32_t count = c->p[1] << 24
| c->p[2] << 16
| c->p[3] << 8
| c->p[4];
amf_cursor_consume(c, 5);
assert(count <= INT_MAX);
if (count > INT_MAX) {
c->err = AMF_CUR_ERR_BADFMT;
c->err_msg = "strict array elements count overflow";
return;
}
lua_createtable(L, (int)count, 0);
amf0_decode_remember_ref(L, -1, ridx);
for (int i = 1; i <= (int)count; i++) {
amf0_decode(L, c, ridx);
amf_cursor_checkerr(c);
lua_rawseti(L, -2, i);
}
break;
case AMF0_TYPED_OBJECT:
amf_cursor_consume(c, 1);
amf0_decode_string(L, c, 16);
amf0_decode_to_lua_table(L, c, ridx);
/* push alias name */
lua_pushstring(L, "__amf_alias__");
lua_pushvalue(L, -3);
lua_rawset(L, -3);
/* remove alias from stack */
lua_remove(L, -2);
break;
case AMF0_REFERENCE:
amf_cursor_need(c, 3);
uint16_t ref = c->p[1] << 8 | c->p[2];
amf_cursor_consume(c, 3);
lua_rawgeti(L, ridx, ref + 1);
if (lua_isnil(L, -1)) {
c->err = AMF_CUR_ERR_BADFMT;
c->err_msg = "reference not found";
return;
}
break;
case AMF0_AVMPLUS: {
lua_newtable(L);
lua_newtable(L);
int sidx = lua_gettop(L);
amf3_decode(L, c, sidx, ridx, sidx - 1);
break;
}
default:
c->err = AMF_CUR_ERR_BADFMT;
}
}