`TRANSMUTE()`: Fix input type size not being properly checked.

Fortune for naka's current commit: Future curse − 末凶

include/str.h

@@ -0,0 +1,31 @@
+//! Better string handling
+#ifndef _STR_H
+#define _STR_H
+
+#include <macros.h>
+#include <ints.h>
+
+#define STRF_OWNED	AS(1ul << 5, int)
+#define STRF_DERIVED 	AS(1ul << 6, int)
+enum str_ownership {
+	STR_NULL = 0,
+
+	STR_OWNED = STRF_OWNED,
+	STR_OWNED_STATIC,
+	STR_OWNED_MALLOC,
+	STR_OWNED_STACK,
+
+	STR_DERIVED = STRF_DERIVED,
+	STR_DERIVED_STATIC,
+	STR_DERIVED_MALLOC,
+	STR_DERIVED_STACK,
+};
+
+typedef struct string str_t;
+
+str_t* str_alloc(usize cap) _callconv(alloc);
+char* str_new(const char* pIN cstr) _callconv(alloc);
+
+void str_free(str_t* restrict str);
+
+#endif /* _STR_H */

src/display.c

@@ -78,7 +78,7 @@ static usize _display_get_fmt_n(dispflags_t flags, bool matched, usize _n, char
 		w = MINv(s_strncat_n(str, n, (s), n), n); \
 		/* Remove written from `n` */ \
 		n -= w; \
-		/* Check if we have written into the limit (if so, w will be equal to n above, since w is high-bounded to n by `MINv()` above. So if n is 0, we have hit the limit. */ \
+		/* Check if we have written into the limit (if so, w will be equal to n above, since w is high-bounded to n by `MINx()` above. So if n is 0, we have hit the limit. */ \
 		ifU(!n) { \
 			/*XXX: Should this be `str[w-1]?` If this assert fails then yes it should. */ \
 			debug_assert(w < _n); \

src/str.c

@@ -0,0 +1,197 @@
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include <str.h>
+
+struct string {
+	usize len, cap;
+	struct str_meta {	
+		enum str_ownership owned;
+		union _str_meta_inner {
+			// `STRF_OWNED` 
+			struct str_meta_owned {
+				_Atomic usize refs; // Number of derrivations from this 
+				void (*m_free)(void*); // How to free (when `_MALLOC`).
+				_Atomic bool orphan; // If a `derive` references this parent somehow, but this string has been `str_free()`d. Tell the derived string that sets the `refs` to 0 to free it.
+			} owned;
+			// `STRF_DERIVED`
+			struct str_meta_derived {
+				// String this is derived from, can be either owned or derived.
+				struct string* _shared parent;
+				// `str`'s offset from `parent->str`.
+				usize offset;
+			} derived;
+		} _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 isize _str_wrap_index(usize _max, isize wr)
+{
+	isize max = (isize)_max;
+	ifU(max<0) FATAL("max too large, must be <= isize::max (%lu)", SIZE_MAX>>1);
+	else if(!max) return 0;
+
+	while(wr<0) wr = max + wr;
+	wr = wr >=max ? wr % max : wr;
+	debug_assert(wr>0);
+	return wr;
+}
+
+// Create a cstring (nul-terminated) from `from`. This string is statically allocated and should not be modified.
+// `sl` - Max size of `from` buffer. If 0, then just free the allocated buffer and return empty string;
+// `from` - Non-nul-terminated string buffer to copy from. 
+// `len` - A pointer to a wrappable index for `from`. If `len` is negative, then offset from `sl`, if it's positive, offset from 0; if it's NULL, use `sl` itself. It is wrapped around `sl` in the case that the computed offset is >= sl.
+//
+// # Notes
+// Don't `free()` this returned pointer, this function handles that on call and on program exit.
+static const char* _str_raw_to_cstrsa(usize sl, const char from[restrict sl], isize*pINOUT len)
+{
+	static _Thread_local char* _ma_buf = NULL;
+
+	if(!sl) {
+		free(_ma_buf); //free(NULL) is allowed.
+		_ma_buf=NULL;
+		return "";
+	}
+
+	_callcv(exit) void _cleanup() { free(_ma_buf); _ma_buf = NULL; }
+
+	isize fp = (isize) (sl & (SIZE_MAX >> 1));
+	if(!len) len = &fp;
+	TRACE("copying wrapped %ld bytes from buffer %p[%lu]", *len, from, sl);
+	
+	
+	usize rl = (usize) (*len = _str_wrap_index(sl, *len));
+	
+	if(_ma_buf)	_ma_buf = realloc(_ma_buf, rl+1);
+	else		_ma_buf = malloc(rl+1);
+	memmove(_ma_buf, from, rl);
+	_ma_buf[rl] = 0;
+	return (const char*)_ma_buf;
+}
+
+inline static bool _str_meta_is_owned(enum str_ownership owned)
+{
+	return AS(owned, u32) & AS(STRF_OWNED, u32);
+}
+
+// Returns true for owned, false for derived
+inline static  bool _str_meta_parts_from(enum str_ownership o, union _str_meta_inner *pIN inner, struct str_meta_owned* *pOUT own, struct str_meta_derived* *pOUT derive)
+{
+	if(_str_meta_is_owned(o))
+		return (PTR_ASSIGN(own, &inner->owned), true);
+	else	return (PTR_ASSIGN(derive, &inner->derived), false);
+}
+
+inline static bool _str_is_owned(const str_t*pIN str)
+{
+	return _str_meta_is_owned(str->meta.owned);
+}
+
+inline static bool _str_is_owned_parts(str_t*pIN str, struct str_meta_owned* *pOUT own, struct str_meta_derived* *pOUT derive)
+{
+	return _str_meta_parts_from(str->meta.owned, &str->meta._inner, own, derive);
+}
+
+static union _str_meta_inner _str_default_meta(enum str_ownership oship, bool *pOUT owned)
+{
+	union _str_meta_inner output;
+	
+	struct str_meta_owned* o_own = NULL;
+	struct str_meta_derived* o_der = NULL;
+
+	// PTR_ASSIGNv always evaluates both args, so this is fine
+	PTR_ASSIGNv(owned,
+			_str_meta_parts_from(oship, &output, 
+				&o_own,
+				&o_der)
+	);
+	switch(oship)
+	{
+		case STR_OWNED_STACK:
+		case STR_OWNED_STATIC:
+			debug_assert(o_own);
+			*o_own = (struct str_meta_owned){ 
+				.refs = 0,
+				.m_free = NULL,	
+				.orphan = false,
+			};
+			break;
+		case STR_OWNED_MALLOC:
+			debug_assert(o_own);
+			*o_own = (struct str_meta_owned){
+				.refs = 0,
+				.m_free = &free,
+				.orphan = false,
+			};
+			break;
+
+		case STR_DERIVED_STATIC:
+		case STR_DERIVED_STACK:
+		case STR_DERIVED_MALLOC:
+			debug_assert(o_der);
+			*o_der = (struct str_meta_derived){
+				.parent = NULL,
+				.offset = 0,
+			};
+			break;
+		default:
+			ERROR("Cannot assign metadata from ownership type 0x%x, returning 0'd metadata", AS(oship, u32));	
+			memset(&output, 0, sizeof(output));
+	}
+	return output;
+}
+
+/// Allocates a bare new str_t. The metadata will be incomplete for `derived` string slices, and `str` will be `NULL`. For `owned` strings, `str` will be `calloc()`ed to `cap+1`.
+static str_t _str_alloc_bare(usize cap, enum str_ownership owned)
+{
+	bool is_owned;
+	let meta_inner = _str_default_meta(owned, &is_owned);
+	struct str_meta meta = {
+		.owned = owned,
+		._inner = meta_inner,
+	};
+	str_t str = {
+		.len = 0,
+		.cap = cap,
+		.meta = meta,
+	};
+	str.str = is_owned ? calloc(cap+1, 1) : NULL;
+	return str;
+}
+
+static void _str_force_free(struct str_meta_owned*pIN o_own, void* ptr)
+{
+	(o_own->m_free ?: &free)(ptr);
+}
+
+void str_free(str_t* restrict strp)
+{
+	str_t str = unbox_value(strp);
+	
+	struct str_meta_owned* o_own = NULL;
+	struct str_meta_derived* o_der = NULL;
+
+	if(_str_is_owned_parts(&str, &o_own, &o_der))
+	{
+		debug_assert(o_own);
+		if(o_own->refs > 0) o_own->orphan = true;
+		else if(str.meta.owned == STR_OWNED_MALLOC && str.str)
+			_str_force_free(o_own, str.str);
+	}
+	else {
+		debug_assert(o_der);
+		TODO(" \
+		//TODO: Find top-level parent (traverse list of potentially derived `o_der->parent`s. \
+		//TODO: While doing so, compute the full offset that this slice has from the top owned parent. \
+		//TODO: Then, decrement its `refs` \
+		//TODO: Then, if it is marked as `orphan`, and we have decremented its `refs` to 0, free its `ptr`. \
+		");
+	}
+}