replace ArrayLists with bounded storage

1 files changed, 9 insertions, 7 deletions

diff --git a/src/gui/fonts.zig b/src/gui/fonts.zig
index e21f4674..1ad7dd84 100644
--- a/src/gui/fonts.zig
+++ b/src/gui/fonts.zig
@@ -65,7 +65,8 @@ pub var want: ?[]const u8 = null;
 /// four in vendor/stb/font.c plus a UTF-16BE decode, and this file is where it
 /// would land.
 pub fn list(arena: std.mem.Allocator, want_name: ?[]const u8) []const Font {
-    var out: std.ArrayList(Font) = .empty;
+    var found: [max_fonts]Font = undefined;
+    var found_len: usize = 0;
     // Zig 0.16 moved the filesystem behind std.Io; the blocking
     // single-threaded implementation is the synchronous walk a sans-IO core
     // wants, the same one look.find uses.
@@ -87,7 +88,7 @@ pub fn list(arena: std.mem.Allocator, want_name: ?[]const u8) []const Font {
         var w = dir.walkSelectively(arena) catch continue;
         defer w.deinit();
         var steps: usize = 0;
-        while (steps < max_steps and out.items.len < max_fonts) {
+        while (steps < max_steps and found_len < found.len) {
             steps += 1; // an unreadable dir burns a step too, so it cannot spin
             const e = (w.next(io) catch continue) orelse break;
             if (e.kind == .directory) {
@@ -103,21 +104,22 @@ pub fn list(arena: std.mem.Allocator, want_name: ?[]const u8) []const Font {
             if (want_name) |wn| {
                 if (!std.mem.eql(u8, wn, name)) continue;
             } else if (!monospaced(path)) continue;
-            out.append(arena, .{
+            found[found_len] = .{
                 .name = arena.dupe(u8, name) catch break,
                 .path = arena.dupe(u8, path) catch break,
-            }) catch break;
-            if (want_name != null) return out.items; // asked for one, found it
+            };
+            found_len += 1;
+            if (want_name != null) return arena.dupe(Font, found[0..found_len]) catch &.{}; // asked for one, found it
         }
     }
     // readdir order is undefined; sort so the picker is the same list twice
     // running and n/N walks a font's own variants in a row
-    std.mem.sort(Font, out.items, {}, struct {
+    std.mem.sort(Font, found[0..found_len], {}, struct {
         fn lt(_: void, a: Font, b: Font) bool {
             return std.mem.lessThan(u8, a.name, b.name);
         }
     }.lt);
-    return out.items;
+    return arena.dupe(Font, found[0..found_len]) catch &.{};
 }
 
 /// Is every glyph in this font the same width? The terminal grid IS a