jbe@0: #include <lua.h>
jbe@0: #include <lauxlib.h>
jbe@0: #include "seqlualib.h"
jbe@0: 
jbe@30: #define SEQLUA_ITERTYPE_IPAIRS 1
jbe@30: #define SEQLUA_ITERTYPE_CALL   2
jbe@30: #define SEQLUA_ITERTYPE_INDEX  3
jbe@30: #define SEQLUA_ITERTYPE_RAW    4
jbe@0: 
jbe@0: void seqlua_iterinit(lua_State *L, seqlua_Iterator *iter, int idx) {
jbe@30:   if (luaL_getmetafield(L, idx, "__ipairs")) {
jbe@30:     lua_pushvalue(L, idx);
jbe@30:     lua_call(L, 1, 3);
jbe@30:     iter->itertype = SEQLUA_ITERTYPE_IPAIRS;
jbe@30:   } else {
jbe@30:     if (lua_type(L, idx) == LUA_TFUNCTION) {
jbe@30:       iter->itertype = SEQLUA_ITERTYPE_CALL;
jbe@30:     } else if (
jbe@30:       luaL_getmetafield(L, idx, "__index") ||
jbe@30:       luaL_getmetafield(L, idx, "__len")
jbe@30:     ) {
jbe@30:       lua_pop(L, 1);
jbe@31:       iter->len = luaL_len(L, idx);
jbe@30:       iter->itertype = SEQLUA_ITERTYPE_INDEX;
jbe@30:     } else {
jbe@30:       luaL_checktype(L, idx, LUA_TTABLE);
jbe@30:       iter->itertype = SEQLUA_ITERTYPE_RAW;
jbe@30:     }
jbe@30:     // always occupy 3 stack indicies
jbe@30:     lua_pushnil(L);
jbe@30:     lua_pushnil(L);
jbe@30:     lua_pushnil(L);
jbe@30:     iter->idx = idx;
jbe@30:   }
jbe@0:   iter->L = L;
jbe@0:   iter->i = 0;
jbe@0: }
jbe@0: 
jbe@0: int seqlua_iternext(seqlua_Iterator *iter) {
jbe@0:   lua_State *L = iter->L;
jbe@0:   lua_Integer i = ++iter->i;
jbe@0:   switch (iter->itertype) {
jbe@30:   case SEQLUA_ITERTYPE_IPAIRS:
jbe@30:     lua_pushvalue(L, -3);
jbe@30:     lua_pushvalue(L, -3);
jbe@30:     lua_pushvalue(L, -3);
jbe@30:     lua_call(L, 2, 2);
jbe@30:     if (lua_isnil(L, -2)) {
jbe@30:       lua_pop(L, 5);
jbe@30:       return 0;
jbe@30:     }
jbe@30:     lua_remove(L, -3);
jbe@30:     return 1;
jbe@30:   case SEQLUA_ITERTYPE_CALL:
jbe@8:     lua_pushvalue(L, iter->idx);
jbe@0:     lua_call(L, 0, 1);
jbe@0:     break;
jbe@30:   case SEQLUA_ITERTYPE_INDEX:
jbe@30:     if (i > iter->len) {
jbe@30:       lua_pop(L, 3);
jbe@30:       return 0;
jbe@30:     }
jbe@0:     lua_pushinteger(L, i);
jbe@8:     lua_gettable(L, iter->idx);
jbe@30:     return 1;
jbe@0:   case SEQLUA_ITERTYPE_RAW:
jbe@8:     lua_rawgeti(L, iter->idx, i);
jbe@8:     break;
jbe@0:   }
jbe@0:   if (lua_isnil(L, -1)) {
jbe@30:     lua_pop(L, 4);
jbe@0:     return 0;
jbe@0:   }
jbe@0:   return 1;
jbe@0: }
jbe@0: