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const std = @import("std");
const simd = std.simd;
const testing = std.testing;
const CodePointIterator = @import("code_point").Iterator;
const GraphemeIterator = @import("grapheme").Iterator;
const dwp = @import("dwp");
/// 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(cp: u21) i3 {
return dwp.stage_2[dwp.stage_1[cp >> 8] + (cp & 0xff)];
}
// Returns true if `str` only contains ASCII bytes. Uses SIMD if possible.
fn isAsciiOnly(str: []const u8) bool {
const vec_len = simd.suggestVectorLength(u8) orelse return for (str) |b| {
if (b > 127) break false;
} else true;
const Vec = @Vector(vec_len, u8);
var remaining = str;
while (true) {
if (remaining.len < vec_len) return for (remaining) |b| {
if (b > 127) break false;
} else true;
const v1 = remaining[0..vec_len].*;
const v2: Vec = @splat(127);
if (@reduce(.Or, v1 > v2)) return false;
remaining = remaining[vec_len..];
}
return true;
}
/// 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(str: []const u8) usize {
var total: isize = 0;
// ASCII fast path
if (isAsciiOnly(str)) {
for (str) |b| total += codePointWidth(b);
return @intCast(@max(0, total));
}
var giter = GraphemeIterator.init(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 = codePointWidth(cp.code);
if (w != 0) {
// Handle text emoji sequence.
if (cp_iter.next()) |ncp| {
// emoji text sequence.
if (ncp.code == 0xFE0E) w = 1;
}
// Only adding width of first non-zero-width code point.
if (gc_total == 0) {
gc_total = w;
break;
}
}
}
total += gc_total;
}
return @intCast(@max(0, total));
}
test "display_width Width" {
try testing.expectEqual(@as(i3, 0), codePointWidth(0x0000)); // null
try testing.expectEqual(@as(i3, -1), codePointWidth(0x8)); // \b
try testing.expectEqual(@as(i3, -1), codePointWidth(0x7f)); // DEL
try testing.expectEqual(@as(i3, 0), codePointWidth(0x0005)); // Cf
try testing.expectEqual(@as(i3, 0), codePointWidth(0x0007)); // \a BEL
try testing.expectEqual(@as(i3, 0), codePointWidth(0x000A)); // \n LF
try testing.expectEqual(@as(i3, 0), codePointWidth(0x000B)); // \v VT
try testing.expectEqual(@as(i3, 0), codePointWidth(0x000C)); // \f FF
try testing.expectEqual(@as(i3, 0), codePointWidth(0x000D)); // \r CR
try testing.expectEqual(@as(i3, 0), codePointWidth(0x000E)); // SQ
try testing.expectEqual(@as(i3, 0), codePointWidth(0x000F)); // SI
try testing.expectEqual(@as(i3, 0), codePointWidth(0x070F)); // Cf
try testing.expectEqual(@as(i3, 1), codePointWidth(0x0603)); // Cf Arabic
try testing.expectEqual(@as(i3, 1), codePointWidth(0x00AD)); // soft-hyphen
try testing.expectEqual(@as(i3, 2), codePointWidth(0x2E3A)); // two-em dash
try testing.expectEqual(@as(i3, 3), codePointWidth(0x2E3B)); // three-em dash
try testing.expectEqual(@as(i3, 1), codePointWidth(0x00BD)); // ambiguous halfwidth
try testing.expectEqual(@as(i3, 1), codePointWidth('é'));
try testing.expectEqual(@as(i3, 2), codePointWidth('😊'));
try testing.expectEqual(@as(i3, 2), codePointWidth('统'));
try testing.expectEqual(@as(usize, 5), strWidth("Hello\r\n"));
try testing.expectEqual(@as(usize, 1), strWidth("\u{0065}\u{0301}"));
try testing.expectEqual(@as(usize, 2), strWidth("\u{1F476}\u{1F3FF}\u{0308}\u{200D}\u{1F476}\u{1F3FF}"));
try testing.expectEqual(@as(usize, 8), strWidth("Hello 😊"));
try testing.expectEqual(@as(usize, 8), strWidth("Héllo 😊"));
try testing.expectEqual(@as(usize, 8), strWidth("Héllo :)"));
try testing.expectEqual(@as(usize, 8), strWidth("Héllo 🇪🇸"));
try testing.expectEqual(@as(usize, 2), strWidth("\u{26A1}")); // Lone emoji
try testing.expectEqual(@as(usize, 1), strWidth("\u{26A1}\u{FE0E}")); // Text sequence
try testing.expectEqual(@as(usize, 2), strWidth("\u{26A1}\u{FE0F}")); // Presentation sequence
try testing.expectEqual(@as(usize, 0), strWidth("A\x08")); // Backspace
try testing.expectEqual(@as(usize, 0), strWidth("\x7FA")); // DEL
try testing.expectEqual(@as(usize, 0), strWidth("\x7FA\x08\x08")); // never less than o
// wcwidth Python lib tests. See: https://github.com/jquast/wcwidth/blob/master/tests/test_core.py
const empty = "";
try testing.expectEqual(@as(usize, 0), strWidth(empty));
const with_null = "hello\x00world";
try testing.expectEqual(@as(usize, 10), strWidth(with_null));
const hello_jp = "コンニチハ, セカイ!";
try testing.expectEqual(@as(usize, 19), strWidth(hello_jp));
const control = "\x1b[0m";
try testing.expectEqual(@as(usize, 3), strWidth(control));
const balinese = "\u{1B13}\u{1B28}\u{1B2E}\u{1B44}";
try testing.expectEqual(@as(usize, 3), strWidth(balinese));
// These commented out tests require a new specification for complex scripts.
// See: https://www.unicode.org/L2/L2023/23107-terminal-suppt.pdf
// const jamo = "\u{1100}\u{1160}";
// try testing.expectEqual(@as(usize, 3), strWidth(jamo));
// const devengari = "\u{0915}\u{094D}\u{0937}\u{093F}";
// try testing.expectEqual(@as(usize, 3), strWidth(devengari));
// const tamal = "\u{0b95}\u{0bcd}\u{0bb7}\u{0bcc}";
// try testing.expectEqual(@as(usize, 5), strWidth(tamal));
// const kannada_1 = "\u{0cb0}\u{0ccd}\u{0c9d}\u{0cc8}";
// 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), strWidth(kannada_2));
// From Rust https://github.com/jameslanska/unicode-display-width
try testing.expectEqual(@as(usize, 15), strWidth("🔥🗡🍩👩🏻🚀⏰💃🏼🔦👍🏻"));
try testing.expectEqual(@as(usize, 2), strWidth("🦀"));
try testing.expectEqual(@as(usize, 2), strWidth("👨👩👧👧"));
try testing.expectEqual(@as(usize, 2), strWidth("👩🔬"));
try testing.expectEqual(@as(usize, 9), strWidth("sane text"));
try testing.expectEqual(@as(usize, 9), strWidth("Ẓ̌á̲l͔̝̞̄̑͌g̖̘̘̔̔͢͞͝o̪̔T̢̙̫̈̍͞e̬͈͕͌̏͑x̺̍ṭ̓̓ͅ"));
try testing.expectEqual(@as(usize, 17), strWidth("슬라바 우크라이나"));
try testing.expectEqual(@as(usize, 1), strWidth("\u{378}"));
}
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