feat: Add an interval utility for range operations

src/bun.zig

@@ -3798,6 +3798,8 @@ pub fn getUseSystemCA(globalObject: *jsc.JSGlobalObject, callFrame: *jsc.CallFra
     return jsc.JSValue.jsBoolean(Arguments.Bun__Node__UseSystemCA);
 }
 
+pub const math = @import("./math.zig");
+
 const CopyFile = @import("./copy_file.zig");
 const builtin = @import("builtin");
 const std = @import("std");

src/math.zig

@@ -0,0 +1 @@
+pub const interval = @import("./math/interval.zig");

src/math/interval.zig

@@ -0,0 +1,196 @@
+//! Mathematical intervals and operations on them.
+
+/// Represents a mathematical interval with a start and an end of type `T`. The interval may be
+/// `open (x, y)`, `closed [x, y]`, `left-closed [x, y)` or `right-closed (x, y]`.
+fn Interval(
+    comptime T: type,
+    comptime closed_trait: enum { open, closed, left_closed, right_closed },
+) type {
+    switch (@typeInfo(T)) {
+        .int, .float, .comptime_int, .comptime_float => {},
+        else => {
+            @compileError("Interval type T must be an integer or floating-point type.");
+        },
+    }
+
+    return struct {
+        const Self = @This();
+        pub const closedness = closed_trait;
+
+        /// Check if the left side of the interval is closed.
+        pub const left_closed = switch (closedness) {
+            .open => false,
+            .closed => true,
+            .left_closed => true,
+            .right_closed => false,
+        };
+
+        /// Check if the right side of the interval is closed.
+        pub const right_closed = switch (closedness) {
+            .open => false,
+            .closed => true,
+            .left_closed => false,
+            .right_closed => true,
+        };
+
+        start: T,
+        end: T,
+
+        /// Errors thrown in .init
+        pub const InitError = error{InvalidInterval};
+
+        /// Initializes a new interval with the given start and end values.
+        ///
+        /// Note that this function may return either Self or !Self, depending on whether it is
+        /// used in a comptime or non-comptime context. In a comptime context (ie. both arguments
+        /// are comptime), it will return Self and emit a compile error if the interval is invalid.
+        /// In a non-comptime context, it will return !Self and return an error if the interval is
+        /// invalid.
+        pub fn init(start: anytype, end: anytype) Self.comptimeInitType(start, end) {
+            if (start > end) {
+                if (comptime Self.isInitComptime(start, end)) {
+                    @compileError(std.fmt.comptimePrint(
+                        "Invalid interval with start ({}) greater than end ({})",
+                        .{ start, end },
+                    ));
+                } else {
+                    return error.InvalidInterval;
+                }
+            }
+
+            return .{
+                .start = start,
+                .end = end,
+            };
+        }
+
+        /// Check if two intervals are equal.
+        pub fn eql(self: *const Self, other: anytype) bool {
+            return self.start == other.start and self.end == other.end and
+                closedness == other.closedness;
+        }
+
+        /// Test whether the given value is contained within the interval.
+        pub fn contains(self: *const Self, value: T) bool {
+            switch (closedness) {
+                .open => return (value > self.start) and (value < self.end),
+                .closed => return (value >= self.start) and (value <= self.end),
+                .left_closed => return (value >= self.start) and (value < self.end),
+                .right_closed => return (value > self.start) and (value <= self.end),
+            }
+        }
+
+        /// An interval is empty if it could not mathematically contain any values.
+        pub fn isEmpty(self: *const Self) bool {
+            return self.start == self.end and closedness != .closed;
+        }
+
+        /// Test whether this interval intersects with another interval.
+        pub fn intersects(self: *const Self, other: anytype) bool {
+            if (self.isEmpty() or other.isEmpty()) {
+                return false;
+            }
+
+            if (self.end < other.start or self.start > other.end) {
+                return false;
+            }
+
+            if (self.end == other.start) {
+                return self.right_closed and other.left_closed;
+            }
+
+            if (self.start == other.end) {
+                return self.left_closed and other.right_closed;
+            }
+
+            return true;
+        }
+
+        /// Clamp a value to be within the interval.
+        pub fn clamp(self: *const Self, value: T) T {
+            if (closedness != .closed) {
+                // The reason we do this is to avoid ambiguity. Should open intervals clamp to the
+                // very edge or to the epsilon? Hard to answer, so we just disallow it for now.
+                @compileError("Clamping values within an interval is only supported for closed " ++
+                    "intervals.");
+            }
+
+            if (value < self.start) {
+                return self.start;
+            }
+
+            if (value > self.end) {
+                return self.end;
+            }
+
+            return value;
+        }
+
+        /// Format the interval using the given format string and options.
+        ///
+        /// The format specifier is given to the start and end values in that order.
+        pub fn format(
+            self: *const Self,
+            comptime fmt: []const u8,
+            options: std.fmt.FormatOptions,
+            writer: anytype,
+        ) !void {
+            _ = options;
+
+            const lp, const rp = switch (closedness) {
+                .open => .{ "(", ")" },
+                .closed => .{ "[", "]" },
+                .left_closed => .{ "[", ")" },
+                .right_closed => .{ "(", "]" },
+            };
+
+            const f = std.fmt.comptimePrint("{s}{{{s}}},{{{s}}}{s}", .{ lp, fmt, fmt, rp });
+
+            try writer.print(f, .{ self.start, self.end });
+        }
+
+        fn isInitComptime(start: anytype, end: anytype) bool {
+            const start_is_comptime = switch (@typeInfo(@TypeOf(start))) {
+                .comptime_int, .comptime_float => true,
+                else => false,
+            };
+            const end_is_comptime = switch (@typeInfo(@TypeOf(end))) {
+                .comptime_int, .comptime_float => true,
+                else => false,
+            };
+
+            return start_is_comptime and end_is_comptime;
+        }
+
+        fn comptimeInitType(start: anytype, end: anytype) type {
+            return if (Self.isInitComptime(start, end)) Self else InitError!Self;
+        }
+    };
+}
+
+/// Closed interval [a, b]
+pub fn Closed(comptime T: type) type {
+    return Interval(T, .closed);
+}
+
+/// Open interval (a, b)
+pub fn Open(comptime T: type) type {
+    return Interval(T, .open);
+}
+
+/// Left-closed interval [a, b)
+pub fn LeftClosed(comptime T: type) type {
+    return Interval(T, .left_closed);
+}
+
+/// Right-closed interval (a, b]
+pub fn RightClosed(comptime T: type) type {
+    return Interval(T, .right_closed);
+}
+
+/// Create an interval which spans the possible range of values for the given type `T`.
+pub fn Int(comptime T: type) Closed(T) {
+    return Closed(T).init(@as(T, std.math.minInt(T)), @as(T, std.math.maxInt(T)));
+}
+
+const std = @import("std");

src/string/immutable/visible.zig

@@ -1,47 +1,31 @@
 pub fn isZeroWidthCodepointType(comptime T: type, cp: T) bool {
-    if (cp <= 0x1f) {
-        return true;
-    }
-
-    if (cp >= 0x7f and cp <= 0x9f) {
-        // C1 control characters
-        return true;
-    }
+    const c1_control_chars = bun.math.interval.Closed(T).init(0x7f, 0x9f);
+    const combining_diacritical_marks = bun.math.interval.Closed(T).init(0x300, 0x36f);
+    const modifying_invisible_chars = bun.math.interval.Closed(T).init(0x200b, 0x200f);
+    const combining_diacritical_marks_for_symbols = bun.math.interval.Closed(T).init(0x20d0, 0x20ff);
+    const variation_selectors_1 = bun.math.interval.Closed(T).init(0xfe00, 0xfe0f);
+    const combining_half_marks = bun.math.interval.Closed(T).init(0xfe20, 0xfe2f);
+    const variation_selectors_2 = bun.math.interval.Closed(T).init(0xe0100, 0xe01ef);
 
     if (comptime @sizeOf(T) == 1) {
         return false;
     }
 
-    if (cp >= 0x300 and cp <= 0x36f) {
-        // Combining Diacritical Marks
-        return true;
-    }
-
-    if (cp >= 0x200b and cp <= 0x200f) {
-        // Modifying Invisible Characters
-        return true;
-    }
-
-    if (cp >= 0x20d0 and cp <= 0x20ff)
-        // Combining Diacritical Marks for Symbols
-        return true;
-
-    if (cp >= 0xfe00 and cp <= 0xfe0f)
-        // Variation Selectors
-        return true;
-    if (cp >= 0xfe20 and cp <= 0xfe2f)
-        // Combining Half Marks
-        return true;
-
     if (cp == 0xfeff)
         // Zero Width No-Break Space (BOM, ZWNBSP)
         return true;
 
-    if (cp >= 0xe0100 and cp <= 0xe01ef)
-        // Variation Selectors
+    if (cp <= 0x1f) {
         return true;
+    }
 
-    return false;
+    return c1_control_chars.contains(cp) or
+        combining_diacritical_marks.contains(cp) or
+        modifying_invisible_chars.contains(cp) or
+        combining_diacritical_marks_for_symbols.contains(cp) or
+        variation_selectors_1.contains(cp) or
+        combining_half_marks.contains(cp) or
+        variation_selectors_2.contains(cp);
 }
 
 /// Official unicode reference: https://www.unicode.org/Public/UCD/latest/ucd/EastAsianWidth.txt