69 lines
2.4 KiB
Zig
69 lines
2.4 KiB
Zig
const std = @import("std");
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const unicode = std.unicode;
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const testing = std.testing;
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const ziglyph = @import("ziglyph");
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/// the method to use when calculating the width of a grapheme
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pub const Method = enum {
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unicode,
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wcwidth,
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no_zwj,
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};
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/// returns the width of the provided string, as measured by the method chosen
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pub fn gwidth(str: []const u8, method: Method) !usize {
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switch (method) {
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.unicode => {
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return try ziglyph.display_width.strWidth(str, .half);
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},
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.wcwidth => {
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var total: usize = 0;
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const utf8 = try unicode.Utf8View.init(str);
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var iter = utf8.iterator();
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while (iter.nextCodepoint()) |cp| {
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const w = ziglyph.display_width.codePointWidth(cp, .half);
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if (w < 0) continue;
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total += @intCast(w);
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}
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return total;
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},
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.no_zwj => {
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var out: [256]u8 = undefined;
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if (str.len > out.len) return error.OutOfMemory;
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const n = std.mem.replacementSize(u8, str, "\u{200D}", "");
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_ = std.mem.replace(u8, str, "\u{200D}", "", &out);
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return gwidth(out[0..n], .unicode);
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},
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}
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}
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test "gwidth: a" {
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try testing.expectEqual(1, try gwidth("a", .unicode));
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try testing.expectEqual(1, try gwidth("a", .wcwidth));
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try testing.expectEqual(1, try gwidth("a", .no_zwj));
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}
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test "gwidth: emoji with ZWJ" {
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try testing.expectEqual(2, try gwidth("👩🚀", .unicode));
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try testing.expectEqual(4, try gwidth("👩🚀", .wcwidth));
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try testing.expectEqual(4, try gwidth("👩🚀", .no_zwj));
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}
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test "gwidth: emoji with VS16 selector" {
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try testing.expectEqual(2, try gwidth("\xE2\x9D\xA4\xEF\xB8\x8F", .unicode));
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try testing.expectEqual(1, try gwidth("\xE2\x9D\xA4\xEF\xB8\x8F", .wcwidth));
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try testing.expectEqual(2, try gwidth("\xE2\x9D\xA4\xEF\xB8\x8F", .no_zwj));
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}
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test "gwidth: emoji with skin tone selector" {
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try testing.expectEqual(2, try gwidth("👋🏿", .unicode));
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try testing.expectEqual(4, try gwidth("👋🏿", .wcwidth));
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try testing.expectEqual(2, try gwidth("👋🏿", .no_zwj));
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}
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test "gwidth: invalid string" {
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try testing.expectError(error.InvalidUtf8, gwidth("\xc3\x28", .unicode));
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try testing.expectError(error.InvalidUtf8, gwidth("\xc3\x28", .wcwidth));
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try testing.expectError(error.InvalidUtf8, gwidth("\xc3\x28", .no_zwj));
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}
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