Function indexOfPosLinear [src]

Consider using indexOfPos instead of this, which will automatically use a more sophisticated algorithm on larger inputs.

Prototype

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

Parameters

T: typehaystack: []const Tstart_index: usizeneedle: []const T

Example

 test indexOfPosLinear {
    try testing.expectEqual(0, indexOfPosLinear(u8, "", 0, ""));
    try testing.expectEqual(0, indexOfPosLinear(u8, "123", 0, ""));

    try testing.expectEqual(null, indexOfPosLinear(u8, "", 0, "1"));
    try testing.expectEqual(0, indexOfPosLinear(u8, "1", 0, "1"));
    try testing.expectEqual(null, indexOfPosLinear(u8, "2", 0, "1"));
    try testing.expectEqual(1, indexOfPosLinear(u8, "21", 0, "1"));
    try testing.expectEqual(null, indexOfPosLinear(u8, "222", 0, "1"));

    try testing.expectEqual(null, indexOfPosLinear(u8, "", 0, "12"));
    try testing.expectEqual(null, indexOfPosLinear(u8, "1", 0, "12"));
    try testing.expectEqual(null, indexOfPosLinear(u8, "2", 0, "12"));
    try testing.expectEqual(0, indexOfPosLinear(u8, "12", 0, "12"));
    try testing.expectEqual(null, indexOfPosLinear(u8, "21", 0, "12"));
    try testing.expectEqual(1, indexOfPosLinear(u8, "212", 0, "12"));
    try testing.expectEqual(0, indexOfPosLinear(u8, "122", 0, "12"));
    try testing.expectEqual(1, indexOfPosLinear(u8, "212112", 0, "12"));
}

Source

  pub fn indexOfPosLinear(comptime T: type, haystack: []const T, start_index: usize, needle: []const T) ?usize {
    if (needle.len > haystack.len) return null;
    var i: usize = start_index;
    const end = haystack.len - needle.len;
    while (i <= end) : (i += 1) {
        if (eql(T, haystack[i..][0..needle.len], needle)) return i;
    }
    return null;
}  