replace ncurses_refs.c workaround with pure Zig workaround

Signed-off-by: Eric Joldasov <bratishkaerik@getgoogleoff.me>

Makefile

@@ -80,7 +80,7 @@ static-%.tar.gz:
 	@# Alternative approach, bypassing zig-build
 	cd static-$* && ${ZIG} build-exe -target $*\
 		-Iinst/include -Iinst/include/ncursesw -lc inst/lib/libncursesw.a\
-		--cache-dir zig-cache -static -fstrip -O ReleaseFast ../src/main.zig ../src/ncurses_refs.c
+		--cache-dir zig-cache -static -fstrip -O ReleaseFast ../src/main.zig
 	cd static-$* && mv main ncdu && tar -czf ../static-$*.tar.gz ncdu
 	rm -rf static-$*
 

build.zig

@@ -51,5 +51,4 @@ pub fn build(b: *std.Build) void {
 pub fn linkNcurses(compile_step: *std.Build.CompileStep) void {
     compile_step.linkSystemLibrary("ncursesw");
     compile_step.linkLibC();
-    compile_step.addCSourceFile(.{ .file = .{ .path = "src/ncurses_refs.c" }, .flags = &.{} });
 }

src/ncurses_refs.c

@@ -1,27 +0,0 @@
-/* SPDX-FileCopyrightText: 2021-2023 Yoran Heling <projects@yorhel.nl>
- * SPDX-License-Identifier: MIT
- */
-
-#include <curses.h>
-
-/* Zig @cImport() has problems with the ACS_* macros. Two, in fact:
- *
- * 1. Naively using the ACS_* macros results in:
- *
- *      error: cannot store runtime value in compile time variable
- *      return acs_map[NCURSES_CAST(u8, c)];
- *                    ^
- *    That error doesn't make much sense to me, but it might be
- *    related to https://github.com/ziglang/zig/issues/5344?
- *
- * 2. The 'acs_map' extern variable isn't being linked correctly?
- *    Haven't investigated this one deeply enough yet, but attempting
- *    to dereference acs_map from within Zig leads to a segfault;
- *    its pointer value doesn't make any sense.
- */
-chtype ncdu_acs_ulcorner() { return ACS_ULCORNER; }
-chtype ncdu_acs_llcorner() { return ACS_LLCORNER; }
-chtype ncdu_acs_urcorner() { return ACS_URCORNER; }
-chtype ncdu_acs_lrcorner() { return ACS_LRCORNER; }
-chtype ncdu_acs_hline()    { return ACS_VLINE   ; }
-chtype ncdu_acs_vline()    { return ACS_HLINE   ; }

src/ui.zig

@@ -192,14 +192,6 @@ test "shorten" {
     try t("ą́ą́ą́ą́ą́ą́", 5, "ą́...̨́ą́"); // Combining marks, similarly bad.
 }
 
-// ncurses_refs.c
-extern fn ncdu_acs_ulcorner() c.chtype;
-extern fn ncdu_acs_llcorner() c.chtype;
-extern fn ncdu_acs_urcorner() c.chtype;
-extern fn ncdu_acs_lrcorner() c.chtype;
-extern fn ncdu_acs_hline()    c.chtype;
-extern fn ncdu_acs_vline()    c.chtype;
-
 const StyleAttr = struct { fg: i16, bg: i16, attr: u32 };
 const StyleDef = struct {
     name: []const u8,
@@ -535,20 +527,21 @@ pub const Box = struct {
         style(.default);
         if (width < 6 or height < 3) return s;
 
-        const ulcorner = ncdu_acs_ulcorner();
+        const acs_map = @extern(*[128]c.chtype, .{ .name = "acs_map" });
-        const llcorner = ncdu_acs_llcorner();
+        const ulcorner = acs_map['l'];
-        const urcorner = ncdu_acs_urcorner();
+        const llcorner = acs_map['m'];
-        const lrcorner = ncdu_acs_lrcorner();
+        const urcorner = acs_map['k'];
-        const acs_hline = ncdu_acs_hline();
+        const lrcorner = acs_map['j'];
-        const acs_vline = ncdu_acs_vline();
+        const acs_hline = acs_map['q'];
+        const acs_vline = acs_map['x'];
 
         var i: u32 = 0;
         while (i < height) : (i += 1) {
             s.move(i, 0);
-            addch(if (i == 0) ulcorner else if (i == height-1) llcorner else acs_hline);
+            addch(if (i == 0) ulcorner else if (i == height-1) llcorner else acs_vline);
-            hline(if (i == 0 or i == height-1) acs_vline else ' ', width-2);
+            hline(if (i == 0 or i == height-1) acs_hline else ' ', width-2);
             s.move(i, width-1);
-            addch(if (i == 0) urcorner else if (i == height-1) lrcorner else acs_hline);
+            addch(if (i == 0) urcorner else if (i == height-1) lrcorner else acs_vline);
         }
 
         s.move(0, 3);