refactor: de-duplicate utf8_write_transform & utf8_partial_write_transform

build.zig.zon

@@ -30,8 +30,8 @@
             .hash = "fuzzig-0.1.1-Ji0xivxIAQBD0g8O_NV_0foqoPf3elsg9Sc3pNfdVH4D",
         },
         .vaxis = .{
-            .url = "git+https://github.com/neurocyte/libvaxis?ref=main#95034c7114601178467b42e69588cdd4c1d39eb1",
-            .hash = "vaxis-0.5.1-BWNV_PJJCQArtOy_n76jGWoqoBpnM5FKElA_i1IaYYcF",
+            .url = "git+https://github.com/neurocyte/libvaxis?ref=main#4fc5a651a85574c3dfdddebc1d9038fd6bb4e067",
+            .hash = "vaxis-0.5.1-BWNV_EBKCQDqoQZvUE22SBMKYTlZtIIEdLx2X8CfRDHf",
         },
         .zeit = .{
             .url = "git+https://github.com/rockorager/zeit?ref=zig-0.15#ed2ca60db118414bda2b12df2039e33bad3b0b88",

src/buffer/unicode.zig

@@ -112,8 +112,8 @@ pub const TransformError = error{
     WriteFailed,
 };
 
-fn utf8_write_transform(comptime field: uucode.FieldEnum, writer: *std.Io.Writer, text: []const u8) TransformError!void {
-    const view: Utf8View = .initUnchecked(text);
+fn utf8_write_transform_T(comptime View: anytype, comptime field: uucode.FieldEnum, writer: *std.Io.Writer, text: []const u8) TransformError!@typeInfo(@TypeOf(View.iterator)).@"fn".return_type.? {
+    const view: View = .initUnchecked(text);
     var it = view.iterator();
     while (it.nextCodepoint()) |cp| {
         const cp_ = switch (field) {
@@ -125,21 +125,15 @@ fn utf8_write_transform(comptime field: uucode.FieldEnum, writer: *std.Io.Writer
         const size = try utf8Encode(cp_, &utf8_buf);
         try writer.writeAll(utf8_buf[0..size]);
     }
+    return it;
+}
+
+fn utf8_write_transform(comptime field: uucode.FieldEnum, writer: *std.Io.Writer, text: []const u8) TransformError!void {
+    _ = try utf8_write_transform_T(Utf8View, field, writer, text);
 }
 
 fn utf8_partial_write_transform(comptime field: uucode.FieldEnum, writer: *std.Io.Writer, text: []const u8) TransformError![]const u8 {
-    const view: Utf8PartialView = .initUnchecked(text);
-    var it = view.iterator();
-    while (it.nextCodepoint()) |cp| {
-        const cp_ = switch (field) {
-            .simple_uppercase_mapping, .simple_lowercase_mapping => uucode.get(field, cp) orelse cp,
-            .case_folding_simple => uucode.get(field, cp),
-            else => @compileError(@tagName(field) ++ " is not a unicode transformation"),
-        };
-        var utf8_buf: [6]u8 = undefined;
-        const size = try utf8Encode(cp_, &utf8_buf);
-        try writer.writeAll(utf8_buf[0..size]);
-    }
+    const it = try utf8_write_transform_T(Utf8PartialView, field, writer, text);
     return text[0..it.end];
 }
 
@@ -150,12 +144,14 @@ fn utf8_transform(comptime field: uucode.FieldEnum, allocator: std.mem.Allocator
     return result.toOwnedSlice();
 }
 
-fn utf8_predicate(comptime field: uucode.FieldEnum, text: []const u8) bool {
+fn utf8_predicate_all(comptime field: uucode.FieldEnum, text: []const u8) bool {
     const view: Utf8View = .initUnchecked(text);
     var it = view.iterator();
     while (it.nextCodepoint()) |cp| {
         const result = switch (field) {
             .is_lowercase => uucode.get(field, cp),
+            .changes_when_casefolded => uucode.get(field, cp),
+            .changes_when_lowercased => uucode.get(field, cp),
             else => @compileError(@tagName(field) ++ " is not a unicode predicate"),
         };
         if (!result) return false;
@@ -163,6 +159,21 @@ fn utf8_predicate(comptime field: uucode.FieldEnum, text: []const u8) bool {
     return true;
 }
 
+fn utf8_predicate_any(comptime field: uucode.FieldEnum, text: []const u8) bool {
+    const view: Utf8View = .initUnchecked(text);
+    var it = view.iterator();
+    while (it.nextCodepoint()) |cp| {
+        const result = switch (field) {
+            .is_lowercase => uucode.get(field, cp),
+            .changes_when_casefolded => uucode.get(field, cp),
+            .changes_when_lowercased => uucode.get(field, cp),
+            else => @compileError(@tagName(field) ++ " is not a unicode predicate"),
+        };
+        if (result) return true;
+    }
+    return false;
+}
+
 pub fn to_upper(allocator: std.mem.Allocator, text: []const u8) TransformError![]u8 {
     return utf8_transform(.simple_uppercase_mapping, allocator, text);
 }
@@ -184,14 +195,14 @@ pub fn case_folded_write_partial(writer: *std.Io.Writer, text: []const u8) Trans
 }
 
 pub fn switch_case(allocator: std.mem.Allocator, text: []const u8) TransformError![]u8 {
-    return if (utf8_predicate(.is_lowercase, text))
-        to_upper(allocator, text)
+    return if (utf8_predicate_any(.changes_when_lowercased, text))
+        to_lower(allocator, text)
     else
-        to_lower(allocator, text);
+        to_upper(allocator, text);
 }
 
 pub fn is_lowercase(text: []const u8) bool {
-    return utf8_predicate(.is_lowercase, text);
+    return utf8_predicate_all(.is_lowercase, text);
 }
 
 const std = @import("std");