Bruce/lua-immutable
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Fixed some edge case stuff with varargs, and added incremental GC.

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This commit is contained in:
Bruce Hill 2018-02-12 17:16:06 -08:00
parent 2630b3ad1d
commit bd5ed55ebd
1 changed files with 21 additions and 10 deletions
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31
limmutable.c
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@ -38,16 +38,21 @@ static int SHARED_CLASS_METATABLE;
static int Lcreate_instance(lua_State *L)
{
size_t n_args = lua_gettop(L)-1;
// arg 1: class table, ...
lua_getfield(L, 1, "__fields");
size_t n = lua_objlen(L, -1);
if (n_args > n) {
luaL_error(L, "Too many args: expected %d, but got %d", n, n_args);
}
lua_pop(L, 1);
// Compute the hash:
lua_Integer hash = (lua_Integer)lua_topointer(L, 1); // Hash depends on the metatable used in creation
for (lua_Integer i=1; i <=(lua_Integer)n; i++) {
lua_Integer item_hash;
switch (lua_type(L, 1+i)) {
int type = n > n_args ? LUA_TNIL : lua_type(L, 1+i);
switch (type) {
case LUA_TNIL: case LUA_TNONE:
// Arbitrarily chosen value
item_hash = 0x97167da9;
@ -55,8 +60,8 @@ static int Lcreate_instance(lua_State *L)
case LUA_TNUMBER:
{
// Cast float bits to integer
lua_Number n = lua_tonumber(L, 1+i);
item_hash = *((lua_Integer*)&n);
lua_Number num = lua_tonumber(L, 1+i);
item_hash = *((lua_Integer*)&num);
break;
}
case LUA_TBOOLEAN:
@ -98,7 +103,7 @@ static int Lcreate_instance(lua_State *L)
// Stack: [buckets, nil]
lua_pop(L, 1);
// Stack: [buckets]
lua_createtable(L, 1, 0);
lua_createtable(L, 0, 1);
// Stack: [buckets, bucket]
lua_pushlightuserdata(L, (void*)&SHARED_BUCKET_METATABLE);
lua_gettable(L, LUA_REGISTRYINDEX);
@ -116,7 +121,7 @@ static int Lcreate_instance(lua_State *L)
while (lua_next(L, -2) != 0) { // for hash_collider_inst, hash_collider in pairs(bucket) do
// Stack: [buckets, bucket, hash_collider_inst, hash_collider]
int bucket_item_matches = 1;
// Perform a full equality check
// Shallow equality check:
lua_pushnil(L);
while (lua_next(L, -2) != 0) { // for i, collider_value in pairs(hash_collider) do
// Stack: [buckets, bucket, hash_collider_inst, hash_collider, i, value]
@ -135,7 +140,7 @@ static int Lcreate_instance(lua_State *L)
if (bucket_item_matches) {
// Stack: [buckets, bucket, hash_collider_inst, hash_collider]
lua_pop(L, 1);
// Found matching singleton
// Found matching pre-existing instance
return 1;
}
}
@ -154,14 +159,21 @@ static int Lcreate_instance(lua_State *L)
// Stack [buckets, bucket, inst_userdata, inst_userdata]
lua_createtable(L, n, 0); // Create the table to store the instance's data
// Stack [buckets, bucket, inst_userdata, inst_userdata, inst_table]
for (lua_Integer i=1; i <=(lua_Integer)n; i++) {
lua_Integer i;
for (i=1; i <= (lua_Integer)n_args; i++) {
lua_pushvalue(L, i+1);
// Stack [buckets, bucket, inst_userdata, inst_userdata, inst_table, arg #1+i]
lua_rawseti(L, -2, i);
}
for (; i <= (lua_Integer)n; i++) {
lua_pushnil(L);
// Stack [buckets, bucket, inst_userdata, inst_userdata, inst_table, nil]
lua_rawseti(L, -2, i);
}
// Stack [buckets, bucket, inst_userdata, inst_userdata, inst_table]
lua_settable(L, -4); // buckets[inst_userdata] = inst_table
// Stack [buckets, bucket, inst_userdata]
lua_gc(L, LUA_GCSTEP, 1);
return 1;
}
@ -499,8 +511,7 @@ static const luaL_Reg Rinstance_metamethods[] =
static int Lmake_class(lua_State *L)
{
// immutable([fields], [methods/metamethods])
lua_newtable(L);
lua_createtable(L, 0, 16); // Rough guess, 16 fields from Rinstance_metamethods + __fields, etc.
// Stack: [CLS]
// Populate CLS.__len, CLS.__index, CLS.__pairs, etc.
luaL_register(L,NULL,Rinstance_metamethods);
@ -525,7 +536,7 @@ static int Lmake_class(lua_State *L)
}
// Stack: [CLS]
lua_newtable(L);
lua_createtable(L, 0, 32); // Rough guess: at least 32 instances concurrently
// Stack: [CLS, CLS.buckets]
lua_setfield(L, -2, "__instances");