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This is an example of documentation generated by ZigDoc, an alternative to Zig's built-in Auto Doc feature. See also examples in other modes/formats. The project being documented here (as the example) is the Zig standard library. Public Function

binarySearch

Public Function
std.sort.binarySearch
pub fn binarySearch(
    comptime T: type,
    items: []const T,
    context: anytype,
    comptime compareFn: fn (@TypeOf(context), T) std.math.Order,
) ?usize

Returns the index of an element in items returning .eq when given to compareFn.

  • If there are multiple such elements, returns the index of any one of them.
  • If there are no such elements, returns null.

items must be sorted in ascending order with respect to compareFn:

[0]                                                   [len]
┌───┬───┬─/ /─┬───┬───┬───┬─/ /─┬───┬───┬───┬─/ /─┬───┐
│.lt│.lt│ \ \ │.lt│.eq│.eq│ \ \ │.eq│.gt│.gt│ \ \ │.gt│
└───┴───┴─/ /─┴───┴───┴───┴─/ /─┴───┴───┴───┴─/ /─┴───┘
├─────────────────┼─────────────────┼─────────────────┤
 ↳ zero or more    ↳ zero or more    ↳ zero or more
                  ├─────────────────┤
                   ↳ if not null, returned
                     index is in this range

O(log n) time complexity.

See also: lowerBound,upperBound,partitionPoint,equalRange.

Params

  • T: type
  • items: []const T
  • context
  • compareFn: fn (@TypeOf(context), T) std.math.Order

File

sort.zig:450
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pub fn binarySearch(
    comptime T: type,
    items: []const T,
    context: anytype,
    comptime compareFn: fn (@TypeOf(context), T) std.math.Order,
) ?usize {
    var low: usize = 0;
    var high: usize = items.len;

    while (low < high) {
        // Avoid overflowing in the midpoint calculation
        const mid = low + (high - low) / 2;
        switch (compareFn(context, items[mid])) {
            .eq => return mid,
            .gt => low = mid + 1,
            .lt => high = mid,
        }
    }
    return null;
}