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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

lastIndexOf

Doc Source

Public Function

std.mem.lastIndexOf

pub fn findLast(comptime T: type, haystack: []const T, needle: []const T) ?usize

Find the index in a slice of a sub-slice, searching from the end backwards. To start looking at a different index, slice the haystack first. Uses the Reverse Boyer-Moore-Horspool algorithm on large inputs; lastIndexOfLinear on small inputs.

Params

T: type
haystack: []const T
needle: []const T

File

mem.zig:1528

pub fn findLast(comptime T: type, haystack: []const T, needle: []const T) ?usize {
    if (needle.len > haystack.len) return null;
    if (needle.len == 0) return haystack.len;

    if (!std.meta.hasUniqueRepresentation(T) or haystack.len < 52 or needle.len <= 4)
        return findLastLinear(T, haystack, needle);

    const haystack_bytes = sliceAsBytes(haystack);
    const needle_bytes = sliceAsBytes(needle);

    var skip_table: [256]usize = undefined;
    boyerMooreHorspoolPreprocessReverse(needle_bytes, skip_table[0..]);

    var i: usize = haystack_bytes.len - needle_bytes.len;
    while (true) {
        if (i % @sizeOf(T) == 0 and mem.eql(u8, haystack_bytes[i .. i + needle_bytes.len], needle_bytes)) {
            return @divExact(i, @sizeOf(T));
        }
        const skip = skip_table[haystack_bytes[i]];
        if (skip > i) break;
        i -= skip;
    }

    return null;
}