std.mem: expose the simpler linear functions
The new defaults that came in with
644400054c
are nice, however, it is still
possible that someone knows their inputs are always small and wants to
use the simpler implementations. We keep the default to make the choice
at runtime, but expose the linear functions in the public interface of
std.mem.
Also improved the doc comments.
master
parent
644400054c
commit
b0684bf084
|
@ -853,7 +853,9 @@ pub fn indexOf(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.
|
||||
fn lastIndexOfLinear(comptime T: type, haystack: []const T, needle: []const T) ?usize {
|
||||
/// Consider using `lastIndexOf` instead of this, which will automatically use a
|
||||
/// more sophisticated algorithm on larger inputs.
|
||||
pub fn lastIndexOfLinear(comptime T: type, haystack: []const T, needle: []const T) ?usize {
|
||||
var i: usize = haystack.len - needle.len;
|
||||
while (true) : (i -= 1) {
|
||||
if (mem.eql(T, haystack[i .. i + needle.len], needle)) return i;
|
||||
|
@ -861,7 +863,9 @@ fn lastIndexOfLinear(comptime T: type, haystack: []const T, needle: []const T) ?
|
|||
}
|
||||
}
|
||||
|
||||
fn indexOfPosLinear(comptime T: type, haystack: []const T, start_index: usize, needle: []const T) ?usize {
|
||||
/// Consider using `indexOfPos` instead of this, which will automatically use a
|
||||
/// more sophisticated algorithm on larger inputs.
|
||||
pub fn indexOfPosLinear(comptime T: type, haystack: []const T, start_index: usize, needle: []const T) ?usize {
|
||||
var i: usize = start_index;
|
||||
const end = haystack.len - needle.len;
|
||||
while (i <= end) : (i += 1) {
|
||||
|
@ -897,7 +901,8 @@ fn boyerMooreHorspoolPreprocess(pattern: []const u8, table: *[256]usize) void {
|
|||
}
|
||||
/// 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.
|
||||
// Reverse boyer-moore-horspool algorithm
|
||||
/// Uses the Reverse boyer-moore-horspool algorithm on large inputs;
|
||||
/// `lastIndexOfLinear` on small inputs.
|
||||
pub fn lastIndexOf(comptime T: type, haystack: []const T, needle: []const T) ?usize {
|
||||
if (needle.len > haystack.len) return null;
|
||||
if (needle.len == 0) return haystack.len;
|
||||
|
@ -922,7 +927,7 @@ pub fn lastIndexOf(comptime T: type, haystack: []const T, needle: []const T) ?us
|
|||
return null;
|
||||
}
|
||||
|
||||
// Boyer-moore-horspool algorithm
|
||||
/// Uses Boyer-moore-horspool algorithm on large inputs; `indexOfPosLinear` on small inputs.
|
||||
pub fn indexOfPos(comptime T: type, haystack: []const T, start_index: usize, needle: []const T) ?usize {
|
||||
if (needle.len > haystack.len) return null;
|
||||
if (needle.len == 0) return 0;
|
||||
|
|
Loading…
Reference in New Issue