Start writing new string-slicing module.

Start: string basic alloc.

Fortune for naka's current commit: Small blessing − 小吉

include/macros.h

@@ -130,6 +130,7 @@ _mixin void _drain_val(void* x, ...) { IGNORE(x); } // This compiles to no-op on
 
 #define box(t) aligned_alloc(_Alignof(t), sizeof(t))
 #define box_value(v) ({ let _box = box(var(v)); *_box = (v); _box; })
+#define unbox_value(v) ({ let _v = (v); let _res = *_v; free(_v); _res; }
 #define stackalloc(t) __builtin_alloca_with_align(sizeof(t), _Alignof(t))
 
 // Function macros

include/str.h

@@ -21,24 +21,10 @@ enum str_ownership {
 	STR_DERRIVED_STACK,
 };
 
-//TODO: Complete rework
+typedef struct string str_t;
-typedef struct string {
+
-	usize len, cap;
+str_t* str_alloc(usize cap) _callconv(alloc);
-	struct str_meta {
+char* str_new(const char* pIN cstr) _callconv(alloc);
-		struct string* _shared derrived;
-		_Atomic usize refs;
-		void (*m_free)(void*);
-
-		enum str_ownership owned;
-	} meta;
-	union {
-		char* slice;
-		char str[];
-	};
-} *str_t;
-
-str_t* str_alloc(usize cap) _cconv(alloc);
-char* str_new(const char* pIN cstr) _cconv(alloc);
 
 void str_free(str_t* restrict str);
 

src/str.c

@@ -5,62 +5,63 @@
 
 #include <str.h>
 
-static str_t _str_alloc_new(usize reserve)
+struct string {
+	usize len, cap;
+	struct str_meta {	
+		enum str_ownership owned;
+		union _str_meta_inner {
+			// `STRF_OWNED` 
+			struct {
+				_Atomic usize refs; // Number of derrivations from this 
+				void (*m_free)(void*); // How to free (when `_MALLOC`).
+			} owned;
+			// `STRF_DERRIVED`
+			struct {
+				// String this is derrived from, can be either owned or derrived.
+				struct string* _shared parent;
+				// `str`'s offset from `parent->str`.
+				usize offset;
+			} derrived;
+		} _inner;
+	} meta;
+	// The start of this string slice. Regardless of slicing
+	char* str;
+};
+
+//TODO: We can use offsetof() to reverse the result of `str_new()` from char* (str field) to str_t*.
+
+inline static bool _str_meta_is_owned(enum str_ownership owned)
 {
-	return aligned_alloc(_Alignof(struct string), sizeof(struct string) + reserve + 1);
+	return AS(owned, u32) & AS(STRF_OWNED, u32);
 }
 
-inline static str_t _str_unbox(str_t* restrict boxed)
+inline static bool _str_is_owned(const str_t*pIN str)
 {
-	str_t unboxed = *boxed;
+	return _str_meta_is_owned(str->meta.owned);
-	free(boxed);
-	return unboxed;
 }
 
-_cconv(alloc) str_t* str_alloc(usize cap)
+static union _str_meta_inner _str_default_meta(enum str_ownership oship)
 {
-	str_t unboxed = _str_alloc_new(cap);
+	bool owned = _str_meta_is_owned(oship);
-	unboxed->cap = cap;
+	switch(oship)
-	unboxed->len = 0;
+	{
-	unboxed->meta = (struct str_meta){
+		
-		.derrived = NULL,
+	}
-		.refs = 0,
+	TODO("default str metadata");
-		.m_free = &free,
-		.owned = STR_OWNED_MALLOC,
-	};
-	memset(unboxed->str, 0, cap+1);
-
-	return box_value(unboxed);
 }
 
-void str_free(str_t* restrict str)
+static str_t _str_alloc_bare(usize cap, enum str_ownership owned)
 {
-	str_t ub = _str_unbox(str);
+	bool is_owned = _str_meta_is_owned(owned);
-
+	struct str_meta meta = {
-	void* to_free = (void*)ub;
+		.owned = owned,
-	let _cont[] = { &&_done, &&_finish_free_derrived };
+		._inner = _str_default_meta(owned),
-	usize cont = 0;
+	};
-	switch(ub->meta.owned) {
+	str_t str = {
-		case STR_DERRIVED_MALLOC:
+		.len = 0,
-			ub->meta.derrived->meta.refs -=1;
+		.cap = cap,
-			to_free = NULL;
+		.meta = meta,
-			cont = 1;
+	};
-		case STR_OWNED_MALLOC:
+	str.str = is_owned ? calloc(cap+1, 1) : NULL;
-			//TODO: How to handle this refcounting?
+	return str;
-			if(ub->meta.refs > 0) WARN("Freeing referenced string");
-			//if(ub->meta.refs == 0)
-			if(to_free)
-				(ub->meta.m_free ?: &free)(to_free);
-			/*else { 
-				ub->meta.refs -=1;
-				break;
-			}*/
-			goto _cont[cont];
-		_finish_free_derrived:
-			free(ub);
-		default:
-		_done:
-			break;
-	}
-		
 }