Moved case fold stuff to src/Caser.zig

1 files changed, 109 insertions, 0 deletions

diff --git a/src/Caser.zig b/src/Caser.zig
new file mode 100644
index 0000000..d02370a
--- /dev/null
+++ b/src/Caser.zig
@@ -0,0 +1,109 @@
+const std = @import("std");
+const mem = std.mem;
+const testing = std.testing;
+
+const ascii = @import("ascii");
+pub const FoldData = @import("FoldData");
+const Normalizer = @import("Normalizer");
+
+fold_data: *const FoldData,
+
+const Self = @This();
+
+fn caseFold(
+    self: Self,
+    allocator: mem.Allocator,
+    cps: []const u21,
+) ![]const u21 {
+    var cfcps = std.ArrayList(u21).init(allocator);
+    defer cfcps.deinit();
+
+    for (cps) |cp| {
+        const cf = self.fold_data.caseFold(cp);
+
+        if (cf.len == 0) {
+            try cfcps.append(cp);
+        } else {
+            try cfcps.appendSlice(cf);
+        }
+    }
+
+    return try cfcps.toOwnedSlice();
+}
+
+fn changesWhenCaseFolded(self: Self, cps: []const u21) bool {
+    return for (cps) |cp| {
+        if (self.fold_data.changesWhenCaseFolded(cp)) break true;
+    } else false;
+}
+
+pub fn compatCaselessMatch(
+    self: Self,
+    allocator: mem.Allocator,
+    normalizer: *const Normalizer,
+    a: []const u8,
+    b: []const u8,
+) !bool {
+    if (ascii.isAsciiOnly(a) and ascii.isAsciiOnly(b)) return std.ascii.eqlIgnoreCase(a, b);
+
+    // Process a
+    const nfd_a = try normalizer.nfxdCodePoints(allocator, a, .nfd);
+    defer allocator.free(nfd_a);
+
+    var need_frr_cf_nfd_a = false;
+    var cf_nfd_a: []const u21 = nfd_a;
+    if (self.changesWhenCaseFolded(nfd_a)) {
+        cf_nfd_a = try self.caseFold(allocator, nfd_a);
+        need_frr_cf_nfd_a = true;
+    }
+    defer if (need_frr_cf_nfd_a) allocator.free(cf_nfd_a);
+
+    const nfkd_cf_nfd_a = try normalizer.nfkdCodePoints(allocator, cf_nfd_a);
+    defer allocator.free(nfkd_cf_nfd_a);
+    const cf_nfkd_cf_nfd_a = try self.caseFold(allocator, nfkd_cf_nfd_a);
+    defer allocator.free(cf_nfkd_cf_nfd_a);
+    const nfkd_cf_nfkd_cf_nfd_a = try normalizer.nfkdCodePoints(allocator, cf_nfkd_cf_nfd_a);
+    defer allocator.free(nfkd_cf_nfkd_cf_nfd_a);
+
+    // Process b
+    const nfd_b = try normalizer.nfxdCodePoints(allocator, b, .nfd);
+    defer allocator.free(nfd_b);
+
+    var need_frr_cf_nfd_b = false;
+    var cf_nfd_b: []const u21 = nfd_b;
+    if (self.changesWhenCaseFolded(nfd_b)) {
+        cf_nfd_b = try self.caseFold(allocator, nfd_b);
+        need_frr_cf_nfd_b = true;
+    }
+    defer if (need_frr_cf_nfd_b) allocator.free(cf_nfd_b);
+
+    const nfkd_cf_nfd_b = try normalizer.nfkdCodePoints(allocator, cf_nfd_b);
+    defer allocator.free(nfkd_cf_nfd_b);
+    const cf_nfkd_cf_nfd_b = try self.caseFold(allocator, nfkd_cf_nfd_b);
+    defer allocator.free(cf_nfkd_cf_nfd_b);
+    const nfkd_cf_nfkd_cf_nfd_b = try normalizer.nfkdCodePoints(allocator, cf_nfkd_cf_nfd_b);
+    defer allocator.free(nfkd_cf_nfkd_cf_nfd_b);
+
+    return mem.eql(u21, nfkd_cf_nfkd_cf_nfd_a, nfkd_cf_nfkd_cf_nfd_b);
+}
+
+test "compatCaselessMatch" {
+    const allocator = testing.allocator;
+
+    var norm_data = try Normalizer.NormData.init(allocator);
+    defer norm_data.deinit();
+    const n = Normalizer{ .norm_data = &norm_data };
+
+    var fold_data = try FoldData.init(allocator);
+    defer fold_data.deinit();
+    const caser = Self{ .fold_data = &fold_data };
+
+    try testing.expect(try caser.compatCaselessMatch(allocator, &n, "ascii only!", "ASCII Only!"));
+
+    const a = "Héllo World! \u{3d3}";
+    const b = "He\u{301}llo World! \u{3a5}\u{301}";
+    try testing.expect(try caser.compatCaselessMatch(allocator, &n, a, b));
+
+    const c = "He\u{301}llo World! \u{3d2}\u{301}";
+    try testing.expect(try caser.compatCaselessMatch(allocator, &n, a, c));
+}