Zig 0.17.0-dev (Split by item)

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joinMaybeZ

mem.joinMaybeZ

fn joinMaybeZ(allocator: Allocator, separator: []const u8, slices: []const []const u8, zero: bool) Allocator.Error![]u8

File

lib/std/mem.zig:3498

Code

fn joinMaybeZ(allocator: Allocator, separator: []const u8, slices: []const []const u8, zero: bool) Allocator.Error![]u8 {
    if (slices.len == 0) return if (zero) try allocator.dupe(u8, &[1]u8{0}) else &[0]u8{};

    const total_len = blk: {
        var sum: usize = separator.len * (slices.len - 1);
        for (slices) |slice| sum += slice.len;
        if (zero) sum += 1;
        break :blk sum;
    };

    const buf = try allocator.alloc(u8, total_len);
    errdefer allocator.free(buf);

    @memcpy(buf[0..slices[0].len], slices[0]);
    var buf_index: usize = slices[0].len;
    for (slices[1..]) |slice| {
        @memcpy(buf[buf_index .. buf_index + separator.len], separator);
        buf_index += separator.len;
        @memcpy(buf[buf_index .. buf_index + slice.len], slice);
        buf_index += slice.len;
    }

    if (zero) buf[buf.len - 1] = 0;

    // No need for shrink since buf is exactly the correct size.
    return buf;
}