Factor out 'Data' for grapheme and DisplayWidth

In the process of refactoring the whole library, so that it doesn't
expose anything called "Data" separately from user functionality.

9 files changed, 384 insertions, 169 deletions

diff --git a/.gitignore b/.gitignore
index 88df442..cd2f6ab 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,3 +11,4 @@
 
 .zig-cache/
 zig-out/
+notes.md
diff --git a/NEWS.md b/NEWS.md
new file mode 100644
index 0000000..ca8308d
--- /dev/null
+++ b/NEWS.md
@@ -0,0 +1,46 @@
+# News
+
+## zg v0.14.0 Release Notes
+
+This is the first minor point release since Sam Atman (me) took over
+maintenance of `zg` from the inimitable José Colon, aka
+@dude_the_builder.
+
+As it's a fairly complex project, I'm adding a NEWS.md so that users
+have a place to check for changes.
+
+### Data is Unmanaged
+
+This is the biggest change.  Prior to `v0.14`, all structs which need
+heap allocation no longer have a copy of their allocator.  It was felt
+that this was redundant, especially when several such structures were
+in use, and it reflects a general trend in the standard library toward
+fewer managed data structures.
+
+Getting up to speed is a matter of passing the allocator to `deinit`.
+
+This change comes courtesy of [lch361](https://lch361.net), in his
+first contribution to the repo.  Thanks Lich!
+
+### Grapheme Iterator Creation
+
+This is a modest streamlining of how a grapheme iterator is created.
+
+Before:
+
+```zig
+const gd = try grapheme.GraphemeData.init(allocator);
+defer gd.deinit();
+var iter = grapheme.Iterator.init("🤘🏻some rad string! 🤘🏿", &gd);
+```
+
+Now:
+
+```zig
+const gd = try grapheme.GraphemeData.init(allocator);
+defer gd.deinit(allocator);
+var iter = gd.iterator("🤘🏻some rad string! 🤘🏿");
+```
+
+You can still make an iterator with `grapheme.Iterator.init`, but the
+second argument has to be `&gd.gd`.
diff --git a/build.zig b/build.zig
index b555bd7..3aeccd1 100644
--- a/build.zig
+++ b/build.zig
@@ -191,33 +191,18 @@ pub fn build(b: *std.Build) void {
     });
     const code_point_tr = b.addRunArtifact(code_point_t);
 
-    // Grapheme clusters
-    const grapheme_data = b.createModule(.{
-        .root_source_file = b.path("src/GraphemeData.zig"),
-        .target = target,
-        .optimize = optimize,
-    });
-    grapheme_data.addAnonymousImport("gbp", .{ .root_source_file = gbp_gen_out });
-
-    const grapheme_data_t = b.addTest(.{
-        .name = "grapheme_data",
-        .root_module = grapheme_data,
-        .target = target,
-        .optimize = optimize,
-    });
-    const grapheme_data_tr = b.addRunArtifact(grapheme_data_t);
-
-    const grapheme = b.addModule("grapheme", .{
+    // Graphemes
+    const graphemes = b.addModule("Graphemes", .{
         .root_source_file = b.path("src/grapheme.zig"),
         .target = target,
         .optimize = optimize,
     });
-    grapheme.addImport("code_point", code_point);
-    grapheme.addImport("GraphemeData", grapheme_data);
+    graphemes.addAnonymousImport("gbp", .{ .root_source_file = gbp_gen_out });
+    graphemes.addImport("code_point", code_point);
 
     const grapheme_t = b.addTest(.{
-        .name = "grapheme",
-        .root_module = grapheme,
+        .name = "Graphemes",
+        .root_module = graphemes,
         .target = target,
         .optimize = optimize,
     });
@@ -239,31 +224,15 @@ pub fn build(b: *std.Build) void {
     const ascii_tr = b.addRunArtifact(ascii_t);
 
     // Fixed pitch font display width
-    const width_data = b.createModule(.{
-        .root_source_file = b.path("src/WidthData.zig"),
-        .target = target,
-        .optimize = optimize,
-    });
-    width_data.addAnonymousImport("dwp", .{ .root_source_file = dwp_gen_out });
-    width_data.addImport("GraphemeData", grapheme_data);
-
-    const width_data_t = b.addTest(.{
-        .name = "width_data",
-        .root_module = width_data,
-        .target = target,
-        .optimize = optimize,
-    });
-    const width_data_tr = b.addRunArtifact(width_data_t);
-
     const display_width = b.addModule("DisplayWidth", .{
         .root_source_file = b.path("src/DisplayWidth.zig"),
         .target = target,
         .optimize = optimize,
     });
+    display_width.addAnonymousImport("dwp", .{ .root_source_file = dwp_gen_out });
     display_width.addImport("ascii", ascii);
     display_width.addImport("code_point", code_point);
-    display_width.addImport("grapheme", grapheme);
-    display_width.addImport("DisplayWidthData", width_data);
+    display_width.addImport("Graphemes", graphemes);
     display_width.addOptions("options", options); // For testing
 
     const display_width_t = b.addTest(.{
@@ -361,6 +330,14 @@ pub fn build(b: *std.Build) void {
     norm_data.addImport("HangulData", hangul_data);
     norm_data.addImport("NormPropsData", normp_data);
 
+    const norm_data_t = b.addTest(.{
+        .name = "norm_data",
+        .root_module = norm_data,
+        .target = target,
+        .optimize = optimize,
+    });
+    const norm_data_tr = b.addRunArtifact(norm_data_t);
+
     const norm = b.addModule("Normalize", .{
         .root_source_file = b.path("src/Normalize.zig"),
         .target = target,
@@ -370,13 +347,13 @@ pub fn build(b: *std.Build) void {
     norm.addImport("code_point", code_point);
     norm.addImport("NormData", norm_data);
 
-    const norm_data_t = b.addTest(.{
-        .name = "norm_data",
-        .root_module = norm_data,
+    const norm_t = b.addTest(.{
+        .name = "norm",
+        .root_module = norm,
         .target = target,
         .optimize = optimize,
     });
-    const norm_data_tr = b.addRunArtifact(norm_data_t);
+    const norm_tr = b.addRunArtifact(norm_t);
 
     // General Category
     const gencat_data = b.addModule("GenCatData", .{
@@ -478,18 +455,14 @@ pub fn build(b: *std.Build) void {
         .target = target,
         .optimize = optimize,
     });
-    unicode_tests.root_module.addImport("grapheme", grapheme);
+    unicode_tests.root_module.addImport("grapheme", graphemes);
     unicode_tests.root_module.addImport("Normalize", norm);
 
     const run_unicode_tests = b.addRunArtifact(unicode_tests);
 
-    const unicode_test_step = b.step("unicode-test", "Run Unicode tests");
-    unicode_test_step.dependOn(&run_unicode_tests.step);
-
-    const test_step = b.step("test", "Run general tests");
+    const test_step = b.step("test", "Run all module tests");
+    test_step.dependOn(&run_unicode_tests.step);
     test_step.dependOn(&code_point_tr.step);
-    test_step.dependOn(&grapheme_data_tr.step);
-    test_step.dependOn(&width_data_tr.step);
     test_step.dependOn(&display_width_tr.step);
     test_step.dependOn(&grapheme_tr.step);
     test_step.dependOn(&ascii_tr.step);
@@ -499,6 +472,7 @@ pub fn build(b: *std.Build) void {
     test_step.dependOn(&hangul_data_tr.step);
     test_step.dependOn(&normp_data_tr.step);
     test_step.dependOn(&norm_data_tr.step);
+    test_step.dependOn(&norm_tr.step);
     test_step.dependOn(&gencat_data_tr.step);
     test_step.dependOn(&case_fold_tr.step);
     test_step.dependOn(&case_data_tr.step);
diff --git a/src/DisplayWidth.zig b/src/DisplayWidth.zig
index 8631bd4..11ec59e 100644
--- a/src/DisplayWidth.zig
+++ b/src/DisplayWidth.zig
@@ -2,38 +2,131 @@ const std = @import("std");
 const builtin = @import("builtin");
 const options = @import("options");
 const ArrayList = std.ArrayList;
+const compress = std.compress;
 const mem = std.mem;
 const simd = std.simd;
 const testing = std.testing;
 
 const ascii = @import("ascii");
 const CodePointIterator = @import("code_point").Iterator;
-const GraphemeIterator = @import("grapheme").Iterator;
 pub const DisplayWidthData = @import("DisplayWidthData");
 
-data: *const DisplayWidthData,
+const Graphemes = @import("Graphemes");
 
-const Self = @This();
+g_data: Graphemes,
+s1: []u16 = undefined,
+s2: []i4 = undefined,
+owns_gdata: bool,
+
+const DisplayWidth = @This();
+
+pub fn init(allocator: mem.Allocator) mem.Allocator.Error!DisplayWidth {
+    var dw: DisplayWidth = try DisplayWidth.setup(allocator);
+    errdefer {
+        allocator.free(dw.s1);
+        allocator.free(dw.s2);
+    }
+    dw.owns_gdata = true;
+    dw.g_data = try Graphemes.init(allocator);
+    errdefer dw.g_data.deinit(allocator);
+    return dw;
+}
+
+pub fn initWithGraphemeData(allocator: mem.Allocator, g_data: Graphemes) mem.Allocator.Error!DisplayWidth {
+    var dw = try DisplayWidth.setup(allocator);
+    dw.g_data = g_data;
+    dw.owns_gdata = false;
+    return dw;
+}
+
+// Sets up the DisplayWidthData, leaving the GraphemeData undefined.
+fn setup(allocator: mem.Allocator) mem.Allocator.Error!DisplayWidth {
+    const decompressor = compress.flate.inflate.decompressor;
+    const in_bytes = @embedFile("dwp");
+    var in_fbs = std.io.fixedBufferStream(in_bytes);
+    var in_decomp = decompressor(.raw, in_fbs.reader());
+    var reader = in_decomp.reader();
+
+    const endian = builtin.cpu.arch.endian();
+
+    var dw: DisplayWidth = undefined;
+
+    const stage_1_len: u16 = reader.readInt(u16, endian) catch unreachable;
+    dw.s1 = try allocator.alloc(u16, stage_1_len);
+    errdefer allocator.free(dw.s1);
+    for (0..stage_1_len) |i| dw.s1[i] = reader.readInt(u16, endian) catch unreachable;
+
+    const stage_2_len: u16 = reader.readInt(u16, endian) catch unreachable;
+    dw.s2 = try allocator.alloc(i4, stage_2_len);
+    errdefer allocator.free(dw.s2);
+    for (0..stage_2_len) |i| dw.s2[i] = @intCast(reader.readInt(i8, endian) catch unreachable);
+
+    return dw;
+}
+
+pub fn deinit(dw: *const DisplayWidth, allocator: mem.Allocator) void {
+    allocator.free(dw.s1);
+    allocator.free(dw.s2);
+    if (dw.owns_gdata) dw.g_data.deinit(allocator);
+}
+
+/// codePointWidth returns the number of cells `cp` requires when rendered
+/// in a fixed-pitch font (i.e. a terminal screen). This can range from -1 to
+/// 3, where BACKSPACE and DELETE return -1 and 3-em-dash returns 3. C0/C1
+/// control codes return 0. If `cjk` is true, ambiguous code points return 2,
+/// otherwise they return 1.
+pub fn codePointWidth(dw: DisplayWidth, cp: u21) i4 {
+    return dw.s2[dw.s1[cp >> 8] + (cp & 0xff)];
+}
+
+test "codePointWidth" {
+    const dw = try DisplayWidth.init(std.testing.allocator);
+    defer dw.deinit(std.testing.allocator);
+    try testing.expectEqual(@as(i4, 0), dw.codePointWidth(0x0000)); // null
+    try testing.expectEqual(@as(i4, -1), dw.codePointWidth(0x8)); // \b
+    try testing.expectEqual(@as(i4, -1), dw.codePointWidth(0x7f)); // DEL
+    try testing.expectEqual(@as(i4, 0), dw.codePointWidth(0x0005)); // Cf
+    try testing.expectEqual(@as(i4, 0), dw.codePointWidth(0x0007)); // \a BEL
+    try testing.expectEqual(@as(i4, 0), dw.codePointWidth(0x000A)); // \n LF
+    try testing.expectEqual(@as(i4, 0), dw.codePointWidth(0x000B)); // \v VT
+    try testing.expectEqual(@as(i4, 0), dw.codePointWidth(0x000C)); // \f FF
+    try testing.expectEqual(@as(i4, 0), dw.codePointWidth(0x000D)); // \r CR
+    try testing.expectEqual(@as(i4, 0), dw.codePointWidth(0x000E)); // SQ
+    try testing.expectEqual(@as(i4, 0), dw.codePointWidth(0x000F)); // SI
+
+    try testing.expectEqual(@as(i4, 0), dw.codePointWidth(0x070F)); // Cf
+    try testing.expectEqual(@as(i4, 1), dw.codePointWidth(0x0603)); // Cf Arabic
+
+    try testing.expectEqual(@as(i4, 1), dw.codePointWidth(0x00AD)); // soft-hyphen
+    try testing.expectEqual(@as(i4, 2), dw.codePointWidth(0x2E3A)); // two-em dash
+    try testing.expectEqual(@as(i4, 3), dw.codePointWidth(0x2E3B)); // three-em dash
+
+    try testing.expectEqual(@as(i4, 1), dw.codePointWidth(0x00BD)); // ambiguous halfwidth
+
+    try testing.expectEqual(@as(i4, 1), dw.codePointWidth('é'));
+    try testing.expectEqual(@as(i4, 2), dw.codePointWidth('😊'));
+    try testing.expectEqual(@as(i4, 2), dw.codePointWidth('统'));
+}
 
 /// strWidth returns the total display width of `str` as the number of cells
 /// required in a fixed-pitch font (i.e. a terminal screen).
-pub fn strWidth(self: Self, str: []const u8) usize {
+pub fn strWidth(dw: DisplayWidth, str: []const u8) usize {
     var total: isize = 0;
 
     // ASCII fast path
     if (ascii.isAsciiOnly(str)) {
-        for (str) |b| total += self.data.codePointWidth(b);
+        for (str) |b| total += dw.codePointWidth(b);
         return @intCast(@max(0, total));
     }
 
-    var giter = GraphemeIterator.init(str, &self.data.g_data);
+    var giter = dw.g_data.iterator(str);
 
     while (giter.next()) |gc| {
         var cp_iter = CodePointIterator{ .bytes = gc.bytes(str) };
         var gc_total: isize = 0;
 
         while (cp_iter.next()) |cp| {
-            var w = self.data.codePointWidth(cp.code);
+            var w = dw.codePointWidth(cp.code);
 
             if (w != 0) {
                 // Handle text emoji sequence.
@@ -58,41 +151,40 @@ pub fn strWidth(self: Self, str: []const u8) usize {
 }
 
 test "strWidth" {
-    const data = try DisplayWidthData.init(testing.allocator);
-    defer data.deinit(testing.allocator);
-    const self = Self{ .data = &data };
+    const dw = try DisplayWidth.init(testing.allocator);
+    defer dw.deinit(testing.allocator);
     const c0 = options.c0_width orelse 0;
 
-    try testing.expectEqual(@as(usize, 5), self.strWidth("Hello\r\n"));
-    try testing.expectEqual(@as(usize, 1), self.strWidth("\u{0065}\u{0301}"));
-    try testing.expectEqual(@as(usize, 2), self.strWidth("\u{1F476}\u{1F3FF}\u{0308}\u{200D}\u{1F476}\u{1F3FF}"));
-    try testing.expectEqual(@as(usize, 8), self.strWidth("Hello 😊"));
-    try testing.expectEqual(@as(usize, 8), self.strWidth("Héllo 😊"));
-    try testing.expectEqual(@as(usize, 8), self.strWidth("Héllo :)"));
-    try testing.expectEqual(@as(usize, 8), self.strWidth("Héllo 🇪🇸"));
-    try testing.expectEqual(@as(usize, 2), self.strWidth("\u{26A1}")); // Lone emoji
-    try testing.expectEqual(@as(usize, 1), self.strWidth("\u{26A1}\u{FE0E}")); // Text sequence
-    try testing.expectEqual(@as(usize, 2), self.strWidth("\u{26A1}\u{FE0F}")); // Presentation sequence
-    try testing.expectEqual(@as(usize, 1), self.strWidth("\u{2764}")); // Default text presentation
-    try testing.expectEqual(@as(usize, 1), self.strWidth("\u{2764}\u{FE0E}")); // Default text presentation with VS15 selector
-    try testing.expectEqual(@as(usize, 2), self.strWidth("\u{2764}\u{FE0F}")); // Default text presentation with VS16 selector
+    try testing.expectEqual(@as(usize, 5), dw.strWidth("Hello\r\n"));
+    try testing.expectEqual(@as(usize, 1), dw.strWidth("\u{0065}\u{0301}"));
+    try testing.expectEqual(@as(usize, 2), dw.strWidth("\u{1F476}\u{1F3FF}\u{0308}\u{200D}\u{1F476}\u{1F3FF}"));
+    try testing.expectEqual(@as(usize, 8), dw.strWidth("Hello 😊"));
+    try testing.expectEqual(@as(usize, 8), dw.strWidth("Héllo 😊"));
+    try testing.expectEqual(@as(usize, 8), dw.strWidth("Héllo :)"));
+    try testing.expectEqual(@as(usize, 8), dw.strWidth("Héllo 🇪🇸"));
+    try testing.expectEqual(@as(usize, 2), dw.strWidth("\u{26A1}")); // Lone emoji
+    try testing.expectEqual(@as(usize, 1), dw.strWidth("\u{26A1}\u{FE0E}")); // Text sequence
+    try testing.expectEqual(@as(usize, 2), dw.strWidth("\u{26A1}\u{FE0F}")); // Presentation sequence
+    try testing.expectEqual(@as(usize, 1), dw.strWidth("\u{2764}")); // Default text presentation
+    try testing.expectEqual(@as(usize, 1), dw.strWidth("\u{2764}\u{FE0E}")); // Default text presentation with VS15 selector
+    try testing.expectEqual(@as(usize, 2), dw.strWidth("\u{2764}\u{FE0F}")); // Default text presentation with VS16 selector
     const expect_bs: usize = if (c0 == 0) 0 else 1 + c0;
-    try testing.expectEqual(expect_bs, self.strWidth("A\x08")); // Backspace
-    try testing.expectEqual(expect_bs, self.strWidth("\x7FA")); // DEL
+    try testing.expectEqual(expect_bs, dw.strWidth("A\x08")); // Backspace
+    try testing.expectEqual(expect_bs, dw.strWidth("\x7FA")); // DEL
     const expect_long_del: usize = if (c0 == 0) 0 else 1 + (c0 * 3);
-    try testing.expectEqual(expect_long_del, self.strWidth("\x7FA\x08\x08")); // never less than 0
+    try testing.expectEqual(expect_long_del, dw.strWidth("\x7FA\x08\x08")); // never less than 0
 
     // wcwidth Python lib tests. See: https://github.com/jquast/wcwidth/blob/master/tests/test_core.py
     const empty = "";
-    try testing.expectEqual(@as(usize, 0), self.strWidth(empty));
+    try testing.expectEqual(@as(usize, 0), dw.strWidth(empty));
     const with_null = "hello\x00world";
-    try testing.expectEqual(@as(usize, 10 + c0), self.strWidth(with_null));
+    try testing.expectEqual(@as(usize, 10 + c0), dw.strWidth(with_null));
     const hello_jp = "コンニチハ, セカイ!";
-    try testing.expectEqual(@as(usize, 19), self.strWidth(hello_jp));
+    try testing.expectEqual(@as(usize, 19), dw.strWidth(hello_jp));
     const control = "\x1b[0m";
-    try testing.expectEqual(@as(usize, 3 + c0), self.strWidth(control));
+    try testing.expectEqual(@as(usize, 3 + c0), dw.strWidth(control));
     const balinese = "\u{1B13}\u{1B28}\u{1B2E}\u{1B44}";
-    try testing.expectEqual(@as(usize, 3), self.strWidth(balinese));
+    try testing.expectEqual(@as(usize, 3), dw.strWidth(balinese));
 
     // These commented out tests require a new specification for complex scripts.
     // See: https://www.unicode.org/L2/L2023/23107-terminal-suppt.pdf
@@ -106,17 +198,17 @@ test "strWidth" {
     // try testing.expectEqual(@as(usize, 3), strWidth(kannada_1));
     // The following passes but as a mere coincidence.
     const kannada_2 = "\u{0cb0}\u{0cbc}\u{0ccd}\u{0c9a}";
-    try testing.expectEqual(@as(usize, 2), self.strWidth(kannada_2));
+    try testing.expectEqual(@as(usize, 2), dw.strWidth(kannada_2));
 
     // From Rust https://github.com/jameslanska/unicode-display-width
-    try testing.expectEqual(@as(usize, 15), self.strWidth("🔥🗡🍩👩🏻‍🚀⏰💃🏼🔦👍🏻"));
-    try testing.expectEqual(@as(usize, 2), self.strWidth("🦀"));
-    try testing.expectEqual(@as(usize, 2), self.strWidth("👨‍👩‍👧‍👧"));
-    try testing.expectEqual(@as(usize, 2), self.strWidth("👩‍🔬"));
-    try testing.expectEqual(@as(usize, 9), self.strWidth("sane text"));
-    try testing.expectEqual(@as(usize, 9), self.strWidth("Ẓ̌á̲l͔̝̞̄̑͌g̖̘̘̔̔͢͞͝o̪̔T̢̙̫̈̍͞e̬͈͕͌̏͑x̺̍ṭ̓̓ͅ"));
-    try testing.expectEqual(@as(usize, 17), self.strWidth("슬라바 우크라이나"));
-    try testing.expectEqual(@as(usize, 1), self.strWidth("\u{378}"));
+    try testing.expectEqual(@as(usize, 15), dw.strWidth("🔥🗡🍩👩🏻‍🚀⏰💃🏼🔦👍🏻"));
+    try testing.expectEqual(@as(usize, 2), dw.strWidth("🦀"));
+    try testing.expectEqual(@as(usize, 2), dw.strWidth("👨‍👩‍👧‍👧"));
+    try testing.expectEqual(@as(usize, 2), dw.strWidth("👩‍🔬"));
+    try testing.expectEqual(@as(usize, 9), dw.strWidth("sane text"));
+    try testing.expectEqual(@as(usize, 9), dw.strWidth("Ẓ̌á̲l͔̝̞̄̑͌g̖̘̘̔̔͢͞͝o̪̔T̢̙̫̈̍͞e̬͈͕͌̏͑x̺̍ṭ̓̓ͅ"));
+    try testing.expectEqual(@as(usize, 17), dw.strWidth("슬라바 우크라이나"));
+    try testing.expectEqual(@as(usize, 1), dw.strWidth("\u{378}"));
 }
 
 /// centers `str` in a new string of width `total_width` (in display cells) using `pad` as padding.
@@ -124,17 +216,17 @@ test "strWidth" {
 /// receive one additional pad. This makes sure the returned string fills the requested width.
 /// Caller must free returned bytes with `allocator`.
 pub fn center(
-    self: Self,
+    dw: DisplayWidth,
     allocator: mem.Allocator,
     str: []const u8,
     total_width: usize,
     pad: []const u8,
 ) ![]u8 {
-    const str_width = self.strWidth(str);
+    const str_width = dw.strWidth(str);
     if (str_width > total_width) return error.StrTooLong;
     if (str_width == total_width) return try allocator.dupe(u8, str);
 
-    const pad_width = self.strWidth(pad);
+    const pad_width = dw.strWidth(pad);
     if (pad_width > total_width or str_width + pad_width > total_width) return error.PadTooLong;
 
     const margin_width = @divFloor((total_width - str_width), 2);
@@ -165,62 +257,61 @@ pub fn center(
 
 test "center" {
     const allocator = testing.allocator;
-    const data = try DisplayWidthData.init(allocator);
-    defer data.deinit(allocator);
-    const self = Self{ .data = &data };
+    const dw = try DisplayWidth.init(allocator);
+    defer dw.deinit(allocator);
 
     // Input and width both have odd length
-    var centered = try self.center(allocator, "abc", 9, "*");
+    var centered = try dw.center(allocator, "abc", 9, "*");
     try testing.expectEqualSlices(u8, "***abc***", centered);
 
     // Input and width both have even length
     testing.allocator.free(centered);
-    centered = try self.center(allocator, "w😊w", 10, "-");
+    centered = try dw.center(allocator, "w😊w", 10, "-");
     try testing.expectEqualSlices(u8, "---w😊w---", centered);
 
     // Input has even length, width has odd length
     testing.allocator.free(centered);
-    centered = try self.center(allocator, "1234", 9, "-");
+    centered = try dw.center(allocator, "1234", 9, "-");
     try testing.expectEqualSlices(u8, "--1234---", centered);
 
     // Input has odd length, width has even length
     testing.allocator.free(centered);
-    centered = try self.center(allocator, "123", 8, "-");
+    centered = try dw.center(allocator, "123", 8, "-");
     try testing.expectEqualSlices(u8, "--123---", centered);
 
     // Input is the same length as the width
     testing.allocator.free(centered);
-    centered = try self.center(allocator, "123", 3, "-");
+    centered = try dw.center(allocator, "123", 3, "-");
     try testing.expectEqualSlices(u8, "123", centered);
 
     // Input is empty
     testing.allocator.free(centered);
-    centered = try self.center(allocator, "", 3, "-");
+    centered = try dw.center(allocator, "", 3, "-");
     try testing.expectEqualSlices(u8, "---", centered);
 
     // Input is empty and width is zero
     testing.allocator.free(centered);
-    centered = try self.center(allocator, "", 0, "-");
+    centered = try dw.center(allocator, "", 0, "-");
     try testing.expectEqualSlices(u8, "", centered);
 
     // Input is longer than the width, which is an error
     testing.allocator.free(centered);
-    try testing.expectError(error.StrTooLong, self.center(allocator, "123", 2, "-"));
+    try testing.expectError(error.StrTooLong, dw.center(allocator, "123", 2, "-"));
 }
 
 /// padLeft returns a new string of width `total_width` (in display cells) using `pad` as padding
 /// on the left side. Caller must free returned bytes with `allocator`.
 pub fn padLeft(
-    self: Self,
+    dw: DisplayWidth,
     allocator: mem.Allocator,
     str: []const u8,
     total_width: usize,
     pad: []const u8,
 ) ![]u8 {
-    const str_width = self.strWidth(str);
+    const str_width = dw.strWidth(str);
     if (str_width > total_width) return error.StrTooLong;
 
-    const pad_width = self.strWidth(pad);
+    const pad_width = dw.strWidth(pad);
     if (pad_width > total_width or str_width + pad_width > total_width) return error.PadTooLong;
 
     const margin_width = total_width - str_width;
@@ -244,32 +335,31 @@ pub fn padLeft(
 
 test "padLeft" {
     const allocator = testing.allocator;
-    const data = try DisplayWidthData.init(allocator);
-    defer data.deinit(allocator);
-    const self = Self{ .data = &data };
+    const dw = try DisplayWidth.init(allocator);
+    defer dw.deinit(allocator);
 
-    var right_aligned = try self.padLeft(allocator, "abc", 9, "*");
+    var right_aligned = try dw.padLeft(allocator, "abc", 9, "*");
     defer testing.allocator.free(right_aligned);
     try testing.expectEqualSlices(u8, "******abc", right_aligned);
 
     testing.allocator.free(right_aligned);
-    right_aligned = try self.padLeft(allocator, "w😊w", 10, "-");
+    right_aligned = try dw.padLeft(allocator, "w😊w", 10, "-");
     try testing.expectEqualSlices(u8, "------w😊w", right_aligned);
 }
 
 /// padRight returns a new string of width `total_width` (in display cells) using `pad` as padding
 /// on the right side.  Caller must free returned bytes with `allocator`.
 pub fn padRight(
-    self: Self,
+    dw: DisplayWidth,
     allocator: mem.Allocator,
     str: []const u8,
     total_width: usize,
     pad: []const u8,
 ) ![]u8 {
-    const str_width = self.strWidth(str);
+    const str_width = dw.strWidth(str);
     if (str_width > total_width) return error.StrTooLong;
 
-    const pad_width = self.strWidth(pad);
+    const pad_width = dw.strWidth(pad);
     if (pad_width > total_width or str_width + pad_width > total_width) return error.PadTooLong;
 
     const margin_width = total_width - str_width;
@@ -294,16 +384,15 @@ pub fn padRight(
 
 test "padRight" {
     const allocator = testing.allocator;
-    const data = try DisplayWidthData.init(allocator);
-    defer data.deinit(allocator);
-    const self = Self{ .data = &data };
+    const dw = try DisplayWidth.init(allocator);
+    defer dw.deinit(allocator);
 
-    var left_aligned = try self.padRight(allocator, "abc", 9, "*");
+    var left_aligned = try dw.padRight(allocator, "abc", 9, "*");
     defer testing.allocator.free(left_aligned);
     try testing.expectEqualSlices(u8, "abc******", left_aligned);
 
     testing.allocator.free(left_aligned);
-    left_aligned = try self.padRight(allocator, "w😊w", 10, "-");
+    left_aligned = try dw.padRight(allocator, "w😊w", 10, "-");
     try testing.expectEqualSlices(u8, "w😊w------", left_aligned);
 }
 
@@ -311,7 +400,7 @@ test "padRight" {
 /// `threshold` defines how far the last column of the last word can be
 /// from the edge. Caller must free returned bytes with `allocator`.
 pub fn wrap(
-    self: Self,
+    dw: DisplayWidth,
     allocator: mem.Allocator,
     str: []const u8,
     columns: usize,
@@ -329,7 +418,7 @@ pub fn wrap(
         while (word_iter.next()) |word| {
             try result.appendSlice(word);
             try result.append(' ');
-            line_width += self.strWidth(word) + 1;
+            line_width += dw.strWidth(word) + 1;
 
             if (line_width > columns or columns - line_width <= threshold) {
                 try result.append('\n');
@@ -347,12 +436,11 @@ pub fn wrap(
 
 test "wrap" {
     const allocator = testing.allocator;
-    const data = try DisplayWidthData.init(allocator);
-    defer data.deinit(allocator);
-    const self = Self{ .data = &data };
+    const dw = try DisplayWidth.init(allocator);
+    defer dw.deinit(allocator);
 
     const input = "The quick brown fox\r\njumped over the lazy dog!";
-    const got = try self.wrap(allocator, input, 10, 3);
+    const got = try dw.wrap(allocator, input, 10, 3);
     defer testing.allocator.free(got);
     const want = "The quick \nbrown fox \njumped \nover the \nlazy dog!";
     try testing.expectEqualStrings(want, got);
diff --git a/src/GraphemeData.zig b/src/GraphemeData.zig
index 6d3174d..df025cb 100644
--- a/src/GraphemeData.zig
+++ b/src/GraphemeData.zig
@@ -36,7 +36,7 @@ s3: []u8 = undefined,
 
 const Self = @This();
 
-pub fn init(allocator: mem.Allocator) mem.Allocator.Error!Self {
+pub inline fn init(allocator: mem.Allocator) mem.Allocator.Error!Self {
     const decompressor = compress.flate.inflate.decompressor;
     const in_bytes = @embedFile("gbp");
     var in_fbs = std.io.fixedBufferStream(in_bytes);
@@ -65,23 +65,23 @@ pub fn init(allocator: mem.Allocator) mem.Allocator.Error!Self {
     return self;
 }
 
-pub fn deinit(self: *const Self, allocator: mem.Allocator) void {
+pub inline fn deinit(self: *const Self, allocator: mem.Allocator) void {
     allocator.free(self.s1);
     allocator.free(self.s2);
     allocator.free(self.s3);
 }
 
 /// Lookup the grapheme break property for a code point.
-pub fn gbp(self: Self, cp: u21) Gbp {
+pub inline fn gbp(self: Self, cp: u21) Gbp {
     return @enumFromInt(self.s3[self.s2[self.s1[cp >> 8] + (cp & 0xff)]] >> 4);
 }
 
 /// Lookup the indic syllable type for a code point.
-pub fn indic(self: Self, cp: u21) Indic {
+pub inline fn indic(self: Self, cp: u21) Indic {
     return @enumFromInt((self.s3[self.s2[self.s1[cp >> 8] + (cp & 0xff)]] >> 1) & 0x7);
 }
 
-/// Lookup the indic syllable type for a code point.
-pub fn isEmoji(self: Self, cp: u21) bool {
+/// Lookup the emoji property for a code point.
+pub inline fn isEmoji(self: Self, cp: u21) bool {
     return self.s3[self.s2[self.s1[cp >> 8] + (cp & 0xff)]] & 1 == 1;
 }
diff --git a/src/Normalize.zig b/src/Normalize.zig
index a28b708..b738b27 100644
--- a/src/Normalize.zig
+++ b/src/Normalize.zig
@@ -177,7 +177,7 @@ test "decompose" {
     const allocator = testing.allocator;
     var data: NormData = undefined;
     try NormData.init(&data, allocator);
-    defer data.deinit();
+    defer data.deinit(allocator);
     var n = Self{ .norm_data = &data };
 
     var buf: [18]u21 = undefined;
@@ -307,11 +307,11 @@ test "nfd ASCII / no-alloc" {
     const allocator = testing.allocator;
     var data: NormData = undefined;
     try NormData.init(&data, allocator);
-    defer data.deinit();
+    defer data.deinit(allocator);
     const n = Self{ .norm_data = &data };
 
     const result = try n.nfd(allocator, "Hello World!");
-    defer result.deinit();
+    defer result.deinit(allocator);
 
     try testing.expectEqualStrings("Hello World!", result.slice);
 }
@@ -320,11 +320,11 @@ test "nfd !ASCII / alloc" {
     const allocator = testing.allocator;
     var data: NormData = undefined;
     try NormData.init(&data, allocator);
-    defer data.deinit();
+    defer data.deinit(allocator);
     const n = Self{ .norm_data = &data };
 
     const result = try n.nfd(allocator, "Héllo World! \u{3d3}");
-    defer result.deinit();
+    defer result.deinit(allocator);
 
     try testing.expectEqualStrings("He\u{301}llo World! \u{3d2}\u{301}", result.slice);
 }
@@ -333,11 +333,11 @@ test "nfkd ASCII / no-alloc" {
     const allocator = testing.allocator;
     var data: NormData = undefined;
     try NormData.init(&data, allocator);
-    defer data.deinit();
+    defer data.deinit(allocator);
     const n = Self{ .norm_data = &data };
 
     const result = try n.nfkd(allocator, "Hello World!");
-    defer result.deinit();
+    defer result.deinit(allocator);
 
     try testing.expectEqualStrings("Hello World!", result.slice);
 }
@@ -346,11 +346,11 @@ test "nfkd !ASCII / alloc" {
     const allocator = testing.allocator;
     var data: NormData = undefined;
     try NormData.init(&data, allocator);
-    defer data.deinit();
+    defer data.deinit(allocator);
     const n = Self{ .norm_data = &data };
 
     const result = try n.nfkd(allocator, "Héllo World! \u{3d3}");
-    defer result.deinit();
+    defer result.deinit(allocator);
 
     try testing.expectEqualStrings("He\u{301}llo World! \u{3a5}\u{301}", result.slice);
 }
@@ -546,11 +546,11 @@ test "nfc" {
     const allocator = testing.allocator;
     var data: NormData = undefined;
     try NormData.init(&data, allocator);
-    defer data.deinit();
+    defer data.deinit(allocator);
     const n = Self{ .norm_data = &data };
 
     const result = try n.nfc(allocator, "Complex char: \u{3D2}\u{301}");
-    defer result.deinit();
+    defer result.deinit(allocator);
 
     try testing.expectEqualStrings("Complex char: \u{3D3}", result.slice);
 }
@@ -559,11 +559,11 @@ test "nfkc" {
     const allocator = testing.allocator;
     var data: NormData = undefined;
     try NormData.init(&data, allocator);
-    defer data.deinit();
+    defer data.deinit(allocator);
     const n = Self{ .norm_data = &data };
 
     const result = try n.nfkc(allocator, "Complex char: \u{03A5}\u{0301}");
-    defer result.deinit();
+    defer result.deinit(allocator);
 
     try testing.expectEqualStrings("Complex char: \u{038E}", result.slice);
 }
@@ -582,7 +582,7 @@ test "eql" {
     const allocator = testing.allocator;
     var data: NormData = undefined;
     try NormData.init(&data, allocator);
-    defer data.deinit();
+    defer data.deinit(allocator);
     const n = Self{ .norm_data = &data };
 
     try testing.expect(try n.eql(allocator, "foé", "foe\u{0301}"));
@@ -628,5 +628,4 @@ test "isLatin1Only" {
     try testing.expect(isLatin1Only(latin1_only));
     const not_latin1_only = "Héllo, World! \u{3d3}";
     try testing.expect(!isLatin1Only(not_latin1_only));
-    try testing.expect(false);
 }
diff --git a/src/WidthData.zig b/src/WidthData.zig
index b07a679..ca7eaf0 100644
--- a/src/WidthData.zig
+++ b/src/WidthData.zig
@@ -4,15 +4,36 @@ const compress = std.compress;
 const mem = std.mem;
 const testing = std.testing;
 
-const GraphemeData = @import("GraphemeData");
+const Graphemes = @import("Graphemes");
 
-g_data: GraphemeData,
+g_data: Graphemes,
 s1: []u16 = undefined,
 s2: []i4 = undefined,
+owns_gdata: bool,
 
 const Self = @This();
 
 pub fn init(allocator: mem.Allocator) mem.Allocator.Error!Self {
+    var self: Self = try Self.setup(allocator);
+    errdefer {
+        allocator.free(self.s1);
+        allocator.free(self.s2);
+    }
+    self.owns_gdata = true;
+    self.g_data = try Graphemes.init(allocator);
+    errdefer self.g_data.deinit(allocator);
+    return self;
+}
+
+pub fn initWithGraphemeData(allocator: mem.Allocator, g_data: Graphemes) mem.Allocator.Error!Self {
+    var self = try Self.setup(allocator);
+    self.g_data = g_data;
+    self.owns_gdata = false;
+    return self;
+}
+
+// Sets up the DisplayWidthData, leaving the GraphemeData undefined.
+fn setup(allocator: mem.Allocator) mem.Allocator.Error!Self {
     const decompressor = compress.flate.inflate.decompressor;
     const in_bytes = @embedFile("dwp");
     var in_fbs = std.io.fixedBufferStream(in_bytes);
@@ -21,10 +42,7 @@ pub fn init(allocator: mem.Allocator) mem.Allocator.Error!Self {
 
     const endian = builtin.cpu.arch.endian();
 
-    var self = Self{
-        .g_data = try GraphemeData.init(allocator),
-    };
-    errdefer self.g_data.deinit(allocator);
+    var self: Self = undefined;
 
     const stage_1_len: u16 = reader.readInt(u16, endian) catch unreachable;
     self.s1 = try allocator.alloc(u16, stage_1_len);
@@ -42,7 +60,7 @@ pub fn init(allocator: mem.Allocator) mem.Allocator.Error!Self {
 pub fn deinit(self: *const Self, allocator: mem.Allocator) void {
     allocator.free(self.s1);
     allocator.free(self.s2);
-    self.g_data.deinit(allocator);
+    if (self.owns_gdata) self.g_data.deinit(allocator);
 }
 
 /// codePointWidth returns the number of cells `cp` requires when rendered
diff --git a/src/grapheme.zig b/src/grapheme.zig
index 25fd71d..79cd2c6 100644
--- a/src/grapheme.zig
+++ b/src/grapheme.zig
@@ -1,10 +1,99 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const mem = std.mem;
+const Allocator = mem.Allocator;
+const compress = std.compress;
 const unicode = std.unicode;
 
 const CodePoint = @import("code_point").CodePoint;
 const CodePointIterator = @import("code_point").Iterator;
-pub const GraphemeData = @import("GraphemeData");
+
+s1: []u16 = undefined,
+s2: []u16 = undefined,
+s3: []u8 = undefined,
+
+const Graphemes = @This();
+
+pub inline fn init(allocator: mem.Allocator) mem.Allocator.Error!Graphemes {
+    const decompressor = compress.flate.inflate.decompressor;
+    const in_bytes = @embedFile("gbp");
+    var in_fbs = std.io.fixedBufferStream(in_bytes);
+    var in_decomp = decompressor(.raw, in_fbs.reader());
+    var reader = in_decomp.reader();
+
+    const endian = builtin.cpu.arch.endian();
+
+    var self = Graphemes{};
+
+    const s1_len: u16 = reader.readInt(u16, endian) catch unreachable;
+    self.s1 = try allocator.alloc(u16, s1_len);
+    errdefer allocator.free(self.s1);
+    for (0..s1_len) |i| self.s1[i] = reader.readInt(u16, endian) catch unreachable;
+
+    const s2_len: u16 = reader.readInt(u16, endian) catch unreachable;
+    self.s2 = try allocator.alloc(u16, s2_len);
+    errdefer allocator.free(self.s2);
+    for (0..s2_len) |i| self.s2[i] = reader.readInt(u16, endian) catch unreachable;
+
+    const s3_len: u16 = reader.readInt(u16, endian) catch unreachable;
+    self.s3 = try allocator.alloc(u8, s3_len);
+    errdefer allocator.free(self.s3);
+    _ = reader.readAll(self.s3) catch unreachable;
+
+    return self;
+}
+
+pub fn deinit(graphemes: *const Graphemes, allocator: mem.Allocator) void {
+    allocator.free(graphemes.s1);
+    allocator.free(graphemes.s2);
+    allocator.free(graphemes.s3);
+}
+
+/// Lookup the grapheme break property for a code point.
+pub fn gbp(graphemes: Graphemes, cp: u21) Gbp {
+    return @enumFromInt(graphemes.s3[graphemes.s2[graphemes.s1[cp >> 8] + (cp & 0xff)]] >> 4);
+}
+
+/// Lookup the indic syllable type for a code point.
+pub fn indic(graphemes: Graphemes, cp: u21) Indic {
+    return @enumFromInt((graphemes.s3[graphemes.s2[graphemes.s1[cp >> 8] + (cp & 0xff)]] >> 1) & 0x7);
+}
+
+/// Lookup the emoji property for a code point.
+pub fn isEmoji(graphemes: Graphemes, cp: u21) bool {
+    return graphemes.s3[graphemes.s2[graphemes.s1[cp >> 8] + (cp & 0xff)]] & 1 == 1;
+}
+
+pub fn iterator(graphemes: *const Graphemes, string: []const u8) Iterator {
+    return Iterator.init(string, graphemes);
+}
+
+/// Indic syllable type.
+pub const Indic = enum {
+    none,
+
+    Consonant,
+    Extend,
+    Linker,
+};
+
+/// Grapheme break property.
+pub const Gbp = enum {
+    none,
+    Control,
+    CR,
+    Extend,
+    L,
+    LF,
+    LV,
+    LVT,
+    Prepend,
+    Regional_Indicator,
+    SpacingMark,
+    T,
+    V,
+    ZWJ,
+};
 
 /// `Grapheme` represents a Unicode grapheme cluster by its length and offset in the source bytes.
 pub const Grapheme = struct {
@@ -22,12 +111,12 @@ pub const Grapheme = struct {
 pub const Iterator = struct {
     buf: [2]?CodePoint = .{ null, null },
     cp_iter: CodePointIterator,
-    data: *const GraphemeData,
+    data: *const Graphemes,
 
     const Self = @This();
 
     /// Assumes `src` is valid UTF-8.
-    pub fn init(str: []const u8, data: *const GraphemeData) Self {
+    pub fn init(str: []const u8, data: *const Graphemes) Self {
         var self = Self{ .cp_iter = .{ .bytes = str }, .data = data };
         self.advance();
         return self;
@@ -149,7 +238,7 @@ pub const Iterator = struct {
 };
 
 // Predicates
-fn isBreaker(cp: u21, data: *const GraphemeData) bool {
+fn isBreaker(cp: u21, data: *const Graphemes) bool {
     // Extract relevant properties.
     const cp_gbp_prop = data.gbp(cp);
     return cp == '\x0d' or cp == '\x0a' or cp_gbp_prop == .Control;
@@ -202,7 +291,7 @@ pub const State = struct {
 pub fn graphemeBreak(
     cp1: u21,
     cp2: u21,
-    data: *const GraphemeData,
+    data: *const Graphemes,
     state: *State,
 ) bool {
     // Extract relevant properties.
@@ -306,25 +395,25 @@ test "Segmentation ZWJ and ZWSP emoji sequences" {
     const with_zwsp = seq_1 ++ "\u{200B}" ++ seq_2;
     const no_joiner = seq_1 ++ seq_2;
 
-    const data = try GraphemeData.init(std.testing.allocator);
-    defer data.deinit(std.testing.allocator);
+    const graphemes = try Graphemes.init(std.testing.allocator);
+    defer graphemes.deinit(std.testing.allocator);
 
     {
-        var iter = Iterator.init(with_zwj, &data);
+        var iter = graphemes.iterator(with_zwj);
         var i: usize = 0;
         while (iter.next()) |_| : (i += 1) {}
         try std.testing.expectEqual(@as(usize, 1), i);
     }
 
     {
-        var iter = Iterator.init(with_zwsp, &data);
+        var iter = graphemes.iterator(with_zwsp);
         var i: usize = 0;
         while (iter.next()) |_| : (i += 1) {}
         try std.testing.expectEqual(@as(usize, 3), i);
     }
 
     {
-        var iter = Iterator.init(no_joiner, &data);
+        var iter = graphemes.iterator(no_joiner);
         var i: usize = 0;
         while (iter.next()) |_| : (i += 1) {}
         try std.testing.expectEqual(@as(usize, 2), i);
diff --git a/src/unicode_tests.zig b/src/unicode_tests.zig
index 7236ff6..de1b9ec 100644
--- a/src/unicode_tests.zig
+++ b/src/unicode_tests.zig
@@ -9,7 +9,7 @@ const unicode = std.unicode;
 
 const grapheme = @import("grapheme");
 const Grapheme = @import("grapheme").Grapheme;
-const GraphemeData = @import("grapheme").GraphemeData;
+const Graphemes = @import("grapheme");
 const GraphemeIterator = @import("grapheme").Iterator;
 const Normalize = @import("Normalize");
 
@@ -18,10 +18,10 @@ comptime {
 }
 test "Iterator.peek" {
     const peek_seq = "aΔ👨🏻‍🌾→";
-    const data = try GraphemeData.init(std.testing.allocator);
+    const data = try Graphemes.init(std.testing.allocator);
     defer data.deinit(std.testing.allocator);
 
-    var iter = grapheme.Iterator.init(peek_seq, &data);
+    var iter = data.iterator(peek_seq);
     const peek_a = iter.peek().?;
     const next_a = iter.next().?;
     try std.testing.expectEqual(peek_a, next_a);
@@ -162,7 +162,7 @@ test "Segmentation GraphemeIterator" {
     var buf_reader = std.io.bufferedReader(file.reader());
     var input_stream = buf_reader.reader();
 
-    const data = try GraphemeData.init(allocator);
+    const data = try Graphemes.init(allocator);
     defer data.deinit(allocator);
 
     var buf: [4096]u8 = undefined;
@@ -207,7 +207,7 @@ test "Segmentation GraphemeIterator" {
         }
 
         // std.debug.print("\nline {}: {s}\n", .{ line_no, all_bytes.items });
-        var iter = GraphemeIterator.init(all_bytes.items, &data);
+        var iter = data.iterator(all_bytes.items);
 
         // Chaeck.
         for (want.items) |want_gc| {