From 6bd747a57a85f4db503aa46c8dca2672456616af Mon Sep 17 00:00:00 2001
From: Avril <flanchan@cumallover.me>
Date: Thu, 15 Jul 2021 15:03:25 +0100
Subject: [PATCH] Replace `Nx()` (temp value-assigning) macros with `Nv()` to
 avoid conflict with `TRACEx()` and for more clarity.
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(merge from `strings`)

Fortune for naka's current commit: Curse − 凶
---
 include/macros.h |  32 ++++++++++++++
 src/display.c    | 112 +++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 140 insertions(+), 4 deletions(-)

diff --git a/include/macros.h b/include/macros.h
index 309c068..77a0b72 100644
--- a/include/macros.h
+++ b/include/macros.h
@@ -44,6 +44,31 @@
 #define restrict __restrict__
 #endif
 
+//  Function conventions
+
+#define _cconv__mixin _mixin
+#define _cconv__pure _pure
+#define _cconv__readonly _readonly
+#define _cconv__cold _cold
+#define _cconv__dead _dead
+#define _cconv__unused _dead
+#define _cconv__hot _hot
+#define _cconv__entry __attribute__((constructor))
+#define _cconv__exit __attribute__((destructor))
+
+// Allocates
+#define _cconv__alloc __attribute__((malloc))
+// Infallible alloc
+#define _cconv__ialloc __attribute__((malloc)) __attribute__((returns_nonnull))
+#define _cconv__nonnull __attribute__((returns_nonnull))
+
+#define _callcv(name) _cconv__ ## name
+#define _callconv(name) _callcv(name)
+
+#define _callat_entry _callcv(entry)
+#define _callat_exit  _callcv(exit)
+#define _callat(when) _callat_ ## when
+
 // Argument attribute
 
 // Used like: `int *pOUT output, const int *pIN input`
@@ -110,6 +135,8 @@ _mixin void _drain_val(void* x, ...) { IGNORE(x); } // This compiles to no-op on
 // Allocation macros
 
 #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
@@ -236,4 +263,9 @@ static_assert_eq(bswap(bswap(128lu)), 128, "bswap128 (lu) failed (3)");
 #define VERSION_REV(ver) _AS_u32(_AS_u32(ver) & 0xffu)
 _Static_assert( (VERSION_COMP(VERSION(1,2,3,4), VER_COMP_MIN) >> VER_COMP_MIN) == 2u, "invalid native version spec");
 
+// Misc.
+
+#define PTR_ASSIGN(ptr, val) ( (ptr) ? (*(ptr) = (val), (ptr)) : (ptr) )
+#define PTR_ASSIGNv(ptr, val) ({ let _ptr = (ptr); let _val = (val); PTR_ASSIGN(_ptr, _val); })
+
 #endif /* _MACROS_H */
diff --git a/src/display.c b/src/display.c
index eba9cca..5096d7a 100644
--- a/src/display.c
+++ b/src/display.c
@@ -11,8 +11,101 @@
 #define FLAGSET(f, flag) (( (f) & (flag) ) == (flag))
 #define DFLAGSET(f, flagname) FLAGSET(f, DISPF_SHOW_ ## flagname)
 
-//TODO: This probably won't work. Write wrappers for strncpy(), strncat() that return number of bytes written isntead of useless pointer that we already have.
-static usize _display_get_fmt(dispflags_t flags, bool matched, usize _len, char str[pOUT _len])
+#define CMP(x,cmp,y)  ( (x) cmp (y) ? (x) : (y) )
+#define CMPv(x,cmp,y) ({ let _x = (x); let _y = (y); CMP(_x, cmp, _y); })
+#define MIN(x, y) CMP((x), <, (y))
+#define MINv(x, y) CMPv((x), <, (y))
+#define MAX(x, y) CMP((x), >, (y))
+#define MAXv(x, y) CMPv((x), >, (y))
+
+// Returns number of bytes written to `dest`. Otherwise same as `strncpy()`.
+static usize strncpy_n(char*pOUT dest, const char* restrict src, usize n)
+{
+	usize i;
+	for(i=0;i<n;i++)
+		if(! (*dest++ = *src++)) return i;
+	dest[i] = 0;
+	return i;
+}
+
+// Will not write past `dn` bytes of `dest`, will not read past `sn` bytes of `src`. Otherwise, same as `strncpy_n()`.
+static usize s_strncpy_n(usize sn, usize dn; char dest[static pOUT dn], usize dn, const char src[static restrict sn], usize sn)
+{
+	usize i;
+	usize n = MIN(sn,dn); 
+	for(i=0;i<n;i++)
+		if(! (*dest++ = *src++)) return i;
+	if(i<dn) dest[i] = 0;
+	return i;
+}
+
+// Will not write past `dn` bytes of `dest`, will not read past `sn` bytes of `src`. Otherwise, same as `strncat_n()`.
+static inline usize s_strncat_n(usize sn, usize dn; char dest[static pOUT dn], usize dn, const char src[static restrict sn], usize sn)
+{
+	usize dl = MINv(strlen(dest), dn);
+	return s_strncpy_n(dest + dl, dn - dl, src, sn);
+}
+
+// Returns number of bytes written to (dest+strlen(dest)). Otherwise same as `strncat()`.
+static inline usize strncat_n(char*pOUT dest, const char* restrict src, usize n)
+{
+	usize dl = strlen(dest);
+	return strncpy_n(dest+dl, src, n);
+}
+
+//TODO: This isn't working at all...
+#ifdef _DEBUG_USE_UNSAFE_DISPLAY_FMT_ARGS
+_dead
+#endif
+static usize _display_get_fmt_n(dispflags_t flags, bool matched, usize _n, char str[pOUT _n])
+{
+	register usize n = _n, fw=0;
+	const char* fmts[] = { 
+				DFLAGSET(flags, FAILURES) 
+				? "failure: " 
+				: "",  
+
+				"match: ", 
+				"%lu: ", 
+				SLICE_FORMAT, 
+				" (len %lu)", 
+				(const char*)NULL,
+	};
+	usize   w = s_strncpy_n(str, n, fmts[!!matched], n); // SAFETY: Will never read past `fmts[x]` nul-terminator, so setting n as both dest and src length here is safe.
+//TODO: Fix this... It isn't working...
+#define ADDSTR(s) do { \
+		debug_assert((s)); \
+		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. */ \
+		ifU(!n) { \
+			/*XXX: Should this be `str[w-1]?` If this assert fails then yes it should. */ \
+			debug_assert(w < _n); \
+			str[w] = 0; \
+			return fw + w; \
+		} \
+		/* Increase `str` pointer by written */ \
+		str += w; \
+		/* Increase return value by written. */ \
+		fw += w; \
+	} while(0)
+
+	if(DFLAGSET(flags, NUMBER)) ADDSTR(fmts[2]);
+	if(DFLAGSET(flags, SLICE)) ADDSTR(fmts[3]);
+	if(DFLAGSET(flags, LENGTH)) ADDSTR(fmts[4]);
+	ADDSTR("\n");
+	TRACE("Output string written: %lu, (rlen %lu)", fw, n);
+#undef ADDSTR
+	return fw;
+}
+
+
+//XXX: This works, but seems inherantly unsafe. Rewrite to use the above `strn*_n()` functions for better length tracking.
+#ifndef _DEBUG_USE_UNSAFE_DISPLAY_FMT_ARGS
+_dead deprecated_message("this is unsafe, use `_display_get_fmt_n`") 
+#endif
+static usize _display_get_fmt0(dispflags_t flags, bool matched, usize _len, char str[pOUT _len])
 {
 	register usize len = _len;
 	static const char* fmts[] = { "match: ", "%lu: ", SLICE_FORMAT, " (len %lu)", "failure: ", (const char*)NULL };
@@ -30,6 +123,12 @@ static usize _display_get_fmt(dispflags_t flags, bool matched, usize _len, char
 #undef ADDSTR
 }
 
+#ifdef _DEBUG_USE_UNSAFE_DISPLAY_FMT_ARGS
+#define _display_get_fmt(...) _display_get_fmt0(__VA_ARGS__)
+#else
+#define _display_get_fmt(...) _display_get_fmt_n(__VA_ARGS__)
+#endif
+
 static void _display_normal(FILE* output, dispin_t*pIN input, dispflags_t flags)
 {
 	bool matched = input->matched;
@@ -49,9 +148,14 @@ static void _display_normal(FILE* output, dispin_t*pIN input, dispflags_t flags)
 #endif
 	INFO("Mapped region slice for %lu, pre-transform (at %p): " SLICE_FORMAT ", len: %lu", i+1, base, SLICE_FORMAT_ARGS(&cslice), cslice.len);
 
-	//Honour `flags`
+	// --- get format string from `flags` ---
 	char fmt[200]; //TODO: Find the realistic max for this.
-	fmt[_display_get_fmt(flags, matched, 100, fmt)] = 0;
+	usize fmtw = _display_get_fmt(flags, matched, sizeof(fmt)-1, fmt);
+	assert(fmtw+1 < sizeof(fmt));
+	fmt[fmtw+1] = 0;
+	// ---
+	TRACE("Format string get: `%s' (%lu)", fmt, fmtw);
+
 	fprintf(output, fmt, i+1, pos.start, pos.end, pos.end-pos.start);
 }