Sindbad~EG File Manager
use core::{arch::x86_64::*, cmp, mem::size_of};
const VECTOR_SIZE: usize = size_of::<__m128i>();
const VECTOR_ALIGN: usize = VECTOR_SIZE - 1;
// The number of bytes to loop at in one iteration of memchr/memrchr.
const LOOP_SIZE: usize = 4 * VECTOR_SIZE;
// The number of bytes to loop at in one iteration of memchr2/memrchr2 and
// memchr3/memrchr3. There was no observable difference between 64 and 32 bytes
// in benchmarks. memchr3 in particular only gets a very slight speed up from
// the loop unrolling.
const LOOP_SIZE2: usize = 2 * VECTOR_SIZE;
#[target_feature(enable = "sse2")]
pub unsafe fn memchr(n1: u8, haystack: &[u8]) -> Option<usize> {
// What follows is a fast SSE2-only algorithm to detect the position of
// `n1` in `haystack` if it exists. From what I know, this is the "classic"
// algorithm. I believe it can be found in places like glibc and Go's
// standard library. It appears to be well known and is elaborated on in
// more detail here: https://gms.tf/stdfind-and-memchr-optimizations.html
//
// While this routine is very long, the basic idea is actually very simple
// and can be expressed straight-forwardly in pseudo code:
//
// needle = (n1 << 15) | (n1 << 14) | ... | (n1 << 1) | n1
// // Note: shift amount in bytes
//
// while i <= haystack.len() - 16:
// // A 16 byte vector. Each byte in chunk corresponds to a byte in
// // the haystack.
// chunk = haystack[i:i+16]
// // Compare bytes in needle with bytes in chunk. The result is a 16
// // byte chunk where each byte is 0xFF if the corresponding bytes
// // in needle and chunk were equal, or 0x00 otherwise.
// eqs = cmpeq(needle, chunk)
// // Return a 32 bit integer where the most significant 16 bits
// // are always 0 and the lower 16 bits correspond to whether the
// // most significant bit in the correspond byte in `eqs` is set.
// // In other words, `mask as u16` has bit i set if and only if
// // needle[i] == chunk[i].
// mask = movemask(eqs)
//
// // Mask is 0 if there is no match, and non-zero otherwise.
// if mask != 0:
// // trailing_zeros tells us the position of the least significant
// // bit that is set.
// return i + trailing_zeros(mask)
//
// // haystack length may not be a multiple of 16, so search the rest.
// while i < haystack.len():
// if haystack[i] == n1:
// return i
//
// // No match found.
// return NULL
//
// In fact, we could loosely translate the above code to Rust line-for-line
// and it would be a pretty fast algorithm. But, we pull out all the stops
// to go as fast as possible:
//
// 1. We use aligned loads. That is, we do some finagling to make sure our
// primary loop not only proceeds in increments of 16 bytes, but that
// the address of haystack's pointer that we dereference is aligned to
// 16 bytes. 16 is a magic number here because it is the size of SSE2
// 128-bit vector. (For the AVX2 algorithm, 32 is the magic number.)
// Therefore, to get aligned loads, our pointer's address must be evenly
// divisible by 16.
// 2. Our primary loop proceeds 64 bytes at a time instead of 16. It's
// kind of like loop unrolling, but we combine the equality comparisons
// using a vector OR such that we only need to extract a single mask to
// determine whether a match exists or not. If so, then we do some
// book-keeping to determine the precise location but otherwise mush on.
// 3. We use our "chunk" comparison routine in as many places as possible,
// even if it means using unaligned loads. In particular, if haystack
// starts with an unaligned address, then we do an unaligned load to
// search the first 16 bytes. We then start our primary loop at the
// smallest subsequent aligned address, which will actually overlap with
// previously searched bytes. But we're OK with that. We do a similar
// dance at the end of our primary loop. Finally, to avoid a
// byte-at-a-time loop at the end, we do a final 16 byte unaligned load
// that may overlap with a previous load. This is OK because it converts
// a loop into a small number of very fast vector instructions.
//
// The primary downside of this algorithm is that it's effectively
// completely unsafe. Therefore, we have to be super careful to avoid
// undefined behavior:
//
// 1. We use raw pointers everywhere. Not only does dereferencing a pointer
// require the pointer to be valid, but we actually can't even store the
// address of an invalid pointer (unless it's 1 past the end of
// haystack) without sacrificing performance.
// 2. _mm_loadu_si128 is used when you don't care about alignment, and
// _mm_load_si128 is used when you do care. You cannot use the latter
// on unaligned pointers.
// 3. We make liberal use of debug_assert! to check assumptions.
// 4. We make a concerted effort to stick with pointers instead of indices.
// Indices are nicer because there's less to worry about with them (see
// above about pointer offsets), but I could not get the compiler to
// produce as good of code as what the below produces. In any case,
// pointers are what we really care about here, and alignment is
// expressed a bit more naturally with them.
//
// In general, most of the algorithms in this crate have a similar
// structure to what you see below, so this comment applies fairly well to
// all of them.
let vn1 = _mm_set1_epi8(n1 as i8);
let len = haystack.len();
let loop_size = cmp::min(LOOP_SIZE, len);
let start_ptr = haystack.as_ptr();
let end_ptr = start_ptr.add(haystack.len());
let mut ptr = start_ptr;
if haystack.len() < VECTOR_SIZE {
while ptr < end_ptr {
if *ptr == n1 {
return Some(sub(ptr, start_ptr));
}
ptr = ptr.offset(1);
}
return None;
}
if let Some(i) = forward_search1(start_ptr, end_ptr, ptr, vn1) {
return Some(i);
}
ptr = ptr.add(VECTOR_SIZE - (start_ptr as usize & VECTOR_ALIGN));
debug_assert!(ptr > start_ptr && end_ptr.sub(VECTOR_SIZE) >= start_ptr);
while loop_size == LOOP_SIZE && ptr <= end_ptr.sub(loop_size) {
debug_assert_eq!(0, (ptr as usize) % VECTOR_SIZE);
let a = _mm_load_si128(ptr as *const __m128i);
let b = _mm_load_si128(ptr.add(VECTOR_SIZE) as *const __m128i);
let c = _mm_load_si128(ptr.add(2 * VECTOR_SIZE) as *const __m128i);
let d = _mm_load_si128(ptr.add(3 * VECTOR_SIZE) as *const __m128i);
let eqa = _mm_cmpeq_epi8(vn1, a);
let eqb = _mm_cmpeq_epi8(vn1, b);
let eqc = _mm_cmpeq_epi8(vn1, c);
let eqd = _mm_cmpeq_epi8(vn1, d);
let or1 = _mm_or_si128(eqa, eqb);
let or2 = _mm_or_si128(eqc, eqd);
let or3 = _mm_or_si128(or1, or2);
if _mm_movemask_epi8(or3) != 0 {
let mut at = sub(ptr, start_ptr);
let mask = _mm_movemask_epi8(eqa);
if mask != 0 {
return Some(at + forward_pos(mask));
}
at += VECTOR_SIZE;
let mask = _mm_movemask_epi8(eqb);
if mask != 0 {
return Some(at + forward_pos(mask));
}
at += VECTOR_SIZE;
let mask = _mm_movemask_epi8(eqc);
if mask != 0 {
return Some(at + forward_pos(mask));
}
at += VECTOR_SIZE;
let mask = _mm_movemask_epi8(eqd);
debug_assert!(mask != 0);
return Some(at + forward_pos(mask));
}
ptr = ptr.add(loop_size);
}
while ptr <= end_ptr.sub(VECTOR_SIZE) {
debug_assert!(sub(end_ptr, ptr) >= VECTOR_SIZE);
if let Some(i) = forward_search1(start_ptr, end_ptr, ptr, vn1) {
return Some(i);
}
ptr = ptr.add(VECTOR_SIZE);
}
if ptr < end_ptr {
debug_assert!(sub(end_ptr, ptr) < VECTOR_SIZE);
ptr = ptr.sub(VECTOR_SIZE - sub(end_ptr, ptr));
debug_assert_eq!(sub(end_ptr, ptr), VECTOR_SIZE);
return forward_search1(start_ptr, end_ptr, ptr, vn1);
}
None
}
#[target_feature(enable = "sse2")]
pub unsafe fn memchr2(n1: u8, n2: u8, haystack: &[u8]) -> Option<usize> {
let vn1 = _mm_set1_epi8(n1 as i8);
let vn2 = _mm_set1_epi8(n2 as i8);
let len = haystack.len();
let loop_size = cmp::min(LOOP_SIZE2, len);
let start_ptr = haystack.as_ptr();
let end_ptr = start_ptr.add(haystack.len());
let mut ptr = start_ptr;
if haystack.len() < VECTOR_SIZE {
while ptr < end_ptr {
if *ptr == n1 || *ptr == n2 {
return Some(sub(ptr, start_ptr));
}
ptr = ptr.offset(1);
}
return None;
}
if let Some(i) = forward_search2(start_ptr, end_ptr, ptr, vn1, vn2) {
return Some(i);
}
ptr = ptr.add(VECTOR_SIZE - (start_ptr as usize & VECTOR_ALIGN));
debug_assert!(ptr > start_ptr && end_ptr.sub(VECTOR_SIZE) >= start_ptr);
while loop_size == LOOP_SIZE2 && ptr <= end_ptr.sub(loop_size) {
debug_assert_eq!(0, (ptr as usize) % VECTOR_SIZE);
let a = _mm_load_si128(ptr as *const __m128i);
let b = _mm_load_si128(ptr.add(VECTOR_SIZE) as *const __m128i);
let eqa1 = _mm_cmpeq_epi8(vn1, a);
let eqb1 = _mm_cmpeq_epi8(vn1, b);
let eqa2 = _mm_cmpeq_epi8(vn2, a);
let eqb2 = _mm_cmpeq_epi8(vn2, b);
let or1 = _mm_or_si128(eqa1, eqb1);
let or2 = _mm_or_si128(eqa2, eqb2);
let or3 = _mm_or_si128(or1, or2);
if _mm_movemask_epi8(or3) != 0 {
let mut at = sub(ptr, start_ptr);
let mask1 = _mm_movemask_epi8(eqa1);
let mask2 = _mm_movemask_epi8(eqa2);
if mask1 != 0 || mask2 != 0 {
return Some(at + forward_pos2(mask1, mask2));
}
at += VECTOR_SIZE;
let mask1 = _mm_movemask_epi8(eqb1);
let mask2 = _mm_movemask_epi8(eqb2);
return Some(at + forward_pos2(mask1, mask2));
}
ptr = ptr.add(loop_size);
}
while ptr <= end_ptr.sub(VECTOR_SIZE) {
if let Some(i) = forward_search2(start_ptr, end_ptr, ptr, vn1, vn2) {
return Some(i);
}
ptr = ptr.add(VECTOR_SIZE);
}
if ptr < end_ptr {
debug_assert!(sub(end_ptr, ptr) < VECTOR_SIZE);
ptr = ptr.sub(VECTOR_SIZE - sub(end_ptr, ptr));
debug_assert_eq!(sub(end_ptr, ptr), VECTOR_SIZE);
return forward_search2(start_ptr, end_ptr, ptr, vn1, vn2);
}
None
}
#[target_feature(enable = "sse2")]
pub unsafe fn memchr3(
n1: u8,
n2: u8,
n3: u8,
haystack: &[u8],
) -> Option<usize> {
let vn1 = _mm_set1_epi8(n1 as i8);
let vn2 = _mm_set1_epi8(n2 as i8);
let vn3 = _mm_set1_epi8(n3 as i8);
let len = haystack.len();
let loop_size = cmp::min(LOOP_SIZE2, len);
let start_ptr = haystack.as_ptr();
let end_ptr = start_ptr.add(haystack.len());
let mut ptr = start_ptr;
if haystack.len() < VECTOR_SIZE {
while ptr < end_ptr {
if *ptr == n1 || *ptr == n2 || *ptr == n3 {
return Some(sub(ptr, start_ptr));
}
ptr = ptr.offset(1);
}
return None;
}
if let Some(i) = forward_search3(start_ptr, end_ptr, ptr, vn1, vn2, vn3) {
return Some(i);
}
ptr = ptr.add(VECTOR_SIZE - (start_ptr as usize & VECTOR_ALIGN));
debug_assert!(ptr > start_ptr && end_ptr.sub(VECTOR_SIZE) >= start_ptr);
while loop_size == LOOP_SIZE2 && ptr <= end_ptr.sub(loop_size) {
debug_assert_eq!(0, (ptr as usize) % VECTOR_SIZE);
let a = _mm_load_si128(ptr as *const __m128i);
let b = _mm_load_si128(ptr.add(VECTOR_SIZE) as *const __m128i);
let eqa1 = _mm_cmpeq_epi8(vn1, a);
let eqb1 = _mm_cmpeq_epi8(vn1, b);
let eqa2 = _mm_cmpeq_epi8(vn2, a);
let eqb2 = _mm_cmpeq_epi8(vn2, b);
let eqa3 = _mm_cmpeq_epi8(vn3, a);
let eqb3 = _mm_cmpeq_epi8(vn3, b);
let or1 = _mm_or_si128(eqa1, eqb1);
let or2 = _mm_or_si128(eqa2, eqb2);
let or3 = _mm_or_si128(eqa3, eqb3);
let or4 = _mm_or_si128(or1, or2);
let or5 = _mm_or_si128(or3, or4);
if _mm_movemask_epi8(or5) != 0 {
let mut at = sub(ptr, start_ptr);
let mask1 = _mm_movemask_epi8(eqa1);
let mask2 = _mm_movemask_epi8(eqa2);
let mask3 = _mm_movemask_epi8(eqa3);
if mask1 != 0 || mask2 != 0 || mask3 != 0 {
return Some(at + forward_pos3(mask1, mask2, mask3));
}
at += VECTOR_SIZE;
let mask1 = _mm_movemask_epi8(eqb1);
let mask2 = _mm_movemask_epi8(eqb2);
let mask3 = _mm_movemask_epi8(eqb3);
return Some(at + forward_pos3(mask1, mask2, mask3));
}
ptr = ptr.add(loop_size);
}
while ptr <= end_ptr.sub(VECTOR_SIZE) {
if let Some(i) =
forward_search3(start_ptr, end_ptr, ptr, vn1, vn2, vn3)
{
return Some(i);
}
ptr = ptr.add(VECTOR_SIZE);
}
if ptr < end_ptr {
debug_assert!(sub(end_ptr, ptr) < VECTOR_SIZE);
ptr = ptr.sub(VECTOR_SIZE - sub(end_ptr, ptr));
debug_assert_eq!(sub(end_ptr, ptr), VECTOR_SIZE);
return forward_search3(start_ptr, end_ptr, ptr, vn1, vn2, vn3);
}
None
}
#[target_feature(enable = "sse2")]
pub unsafe fn memrchr(n1: u8, haystack: &[u8]) -> Option<usize> {
let vn1 = _mm_set1_epi8(n1 as i8);
let len = haystack.len();
let loop_size = cmp::min(LOOP_SIZE, len);
let start_ptr = haystack.as_ptr();
let end_ptr = start_ptr.add(haystack.len());
let mut ptr = end_ptr;
if haystack.len() < VECTOR_SIZE {
while ptr > start_ptr {
ptr = ptr.offset(-1);
if *ptr == n1 {
return Some(sub(ptr, start_ptr));
}
}
return None;
}
ptr = ptr.sub(VECTOR_SIZE);
if let Some(i) = reverse_search1(start_ptr, end_ptr, ptr, vn1) {
return Some(i);
}
ptr = (end_ptr as usize & !VECTOR_ALIGN) as *const u8;
debug_assert!(start_ptr <= ptr && ptr <= end_ptr);
while loop_size == LOOP_SIZE && ptr >= start_ptr.add(loop_size) {
debug_assert_eq!(0, (ptr as usize) % VECTOR_SIZE);
ptr = ptr.sub(loop_size);
let a = _mm_load_si128(ptr as *const __m128i);
let b = _mm_load_si128(ptr.add(VECTOR_SIZE) as *const __m128i);
let c = _mm_load_si128(ptr.add(2 * VECTOR_SIZE) as *const __m128i);
let d = _mm_load_si128(ptr.add(3 * VECTOR_SIZE) as *const __m128i);
let eqa = _mm_cmpeq_epi8(vn1, a);
let eqb = _mm_cmpeq_epi8(vn1, b);
let eqc = _mm_cmpeq_epi8(vn1, c);
let eqd = _mm_cmpeq_epi8(vn1, d);
let or1 = _mm_or_si128(eqa, eqb);
let or2 = _mm_or_si128(eqc, eqd);
let or3 = _mm_or_si128(or1, or2);
if _mm_movemask_epi8(or3) != 0 {
let mut at = sub(ptr.add(3 * VECTOR_SIZE), start_ptr);
let mask = _mm_movemask_epi8(eqd);
if mask != 0 {
return Some(at + reverse_pos(mask));
}
at -= VECTOR_SIZE;
let mask = _mm_movemask_epi8(eqc);
if mask != 0 {
return Some(at + reverse_pos(mask));
}
at -= VECTOR_SIZE;
let mask = _mm_movemask_epi8(eqb);
if mask != 0 {
return Some(at + reverse_pos(mask));
}
at -= VECTOR_SIZE;
let mask = _mm_movemask_epi8(eqa);
debug_assert!(mask != 0);
return Some(at + reverse_pos(mask));
}
}
while ptr >= start_ptr.add(VECTOR_SIZE) {
ptr = ptr.sub(VECTOR_SIZE);
if let Some(i) = reverse_search1(start_ptr, end_ptr, ptr, vn1) {
return Some(i);
}
}
if ptr > start_ptr {
debug_assert!(sub(ptr, start_ptr) < VECTOR_SIZE);
return reverse_search1(start_ptr, end_ptr, start_ptr, vn1);
}
None
}
#[target_feature(enable = "sse2")]
pub unsafe fn memrchr2(n1: u8, n2: u8, haystack: &[u8]) -> Option<usize> {
let vn1 = _mm_set1_epi8(n1 as i8);
let vn2 = _mm_set1_epi8(n2 as i8);
let len = haystack.len();
let loop_size = cmp::min(LOOP_SIZE2, len);
let start_ptr = haystack.as_ptr();
let end_ptr = start_ptr.add(haystack.len());
let mut ptr = end_ptr;
if haystack.len() < VECTOR_SIZE {
while ptr > start_ptr {
ptr = ptr.offset(-1);
if *ptr == n1 || *ptr == n2 {
return Some(sub(ptr, start_ptr));
}
}
return None;
}
ptr = ptr.sub(VECTOR_SIZE);
if let Some(i) = reverse_search2(start_ptr, end_ptr, ptr, vn1, vn2) {
return Some(i);
}
ptr = (end_ptr as usize & !VECTOR_ALIGN) as *const u8;
debug_assert!(start_ptr <= ptr && ptr <= end_ptr);
while loop_size == LOOP_SIZE2 && ptr >= start_ptr.add(loop_size) {
debug_assert_eq!(0, (ptr as usize) % VECTOR_SIZE);
ptr = ptr.sub(loop_size);
let a = _mm_load_si128(ptr as *const __m128i);
let b = _mm_load_si128(ptr.add(VECTOR_SIZE) as *const __m128i);
let eqa1 = _mm_cmpeq_epi8(vn1, a);
let eqb1 = _mm_cmpeq_epi8(vn1, b);
let eqa2 = _mm_cmpeq_epi8(vn2, a);
let eqb2 = _mm_cmpeq_epi8(vn2, b);
let or1 = _mm_or_si128(eqa1, eqb1);
let or2 = _mm_or_si128(eqa2, eqb2);
let or3 = _mm_or_si128(or1, or2);
if _mm_movemask_epi8(or3) != 0 {
let mut at = sub(ptr.add(VECTOR_SIZE), start_ptr);
let mask1 = _mm_movemask_epi8(eqb1);
let mask2 = _mm_movemask_epi8(eqb2);
if mask1 != 0 || mask2 != 0 {
return Some(at + reverse_pos2(mask1, mask2));
}
at -= VECTOR_SIZE;
let mask1 = _mm_movemask_epi8(eqa1);
let mask2 = _mm_movemask_epi8(eqa2);
return Some(at + reverse_pos2(mask1, mask2));
}
}
while ptr >= start_ptr.add(VECTOR_SIZE) {
ptr = ptr.sub(VECTOR_SIZE);
if let Some(i) = reverse_search2(start_ptr, end_ptr, ptr, vn1, vn2) {
return Some(i);
}
}
if ptr > start_ptr {
debug_assert!(sub(ptr, start_ptr) < VECTOR_SIZE);
return reverse_search2(start_ptr, end_ptr, start_ptr, vn1, vn2);
}
None
}
#[target_feature(enable = "sse2")]
pub unsafe fn memrchr3(
n1: u8,
n2: u8,
n3: u8,
haystack: &[u8],
) -> Option<usize> {
let vn1 = _mm_set1_epi8(n1 as i8);
let vn2 = _mm_set1_epi8(n2 as i8);
let vn3 = _mm_set1_epi8(n3 as i8);
let len = haystack.len();
let loop_size = cmp::min(LOOP_SIZE2, len);
let start_ptr = haystack.as_ptr();
let end_ptr = start_ptr.add(haystack.len());
let mut ptr = end_ptr;
if haystack.len() < VECTOR_SIZE {
while ptr > start_ptr {
ptr = ptr.offset(-1);
if *ptr == n1 || *ptr == n2 || *ptr == n3 {
return Some(sub(ptr, start_ptr));
}
}
return None;
}
ptr = ptr.sub(VECTOR_SIZE);
if let Some(i) = reverse_search3(start_ptr, end_ptr, ptr, vn1, vn2, vn3) {
return Some(i);
}
ptr = (end_ptr as usize & !VECTOR_ALIGN) as *const u8;
debug_assert!(start_ptr <= ptr && ptr <= end_ptr);
while loop_size == LOOP_SIZE2 && ptr >= start_ptr.add(loop_size) {
debug_assert_eq!(0, (ptr as usize) % VECTOR_SIZE);
ptr = ptr.sub(loop_size);
let a = _mm_load_si128(ptr as *const __m128i);
let b = _mm_load_si128(ptr.add(VECTOR_SIZE) as *const __m128i);
let eqa1 = _mm_cmpeq_epi8(vn1, a);
let eqb1 = _mm_cmpeq_epi8(vn1, b);
let eqa2 = _mm_cmpeq_epi8(vn2, a);
let eqb2 = _mm_cmpeq_epi8(vn2, b);
let eqa3 = _mm_cmpeq_epi8(vn3, a);
let eqb3 = _mm_cmpeq_epi8(vn3, b);
let or1 = _mm_or_si128(eqa1, eqb1);
let or2 = _mm_or_si128(eqa2, eqb2);
let or3 = _mm_or_si128(eqa3, eqb3);
let or4 = _mm_or_si128(or1, or2);
let or5 = _mm_or_si128(or3, or4);
if _mm_movemask_epi8(or5) != 0 {
let mut at = sub(ptr.add(VECTOR_SIZE), start_ptr);
let mask1 = _mm_movemask_epi8(eqb1);
let mask2 = _mm_movemask_epi8(eqb2);
let mask3 = _mm_movemask_epi8(eqb3);
if mask1 != 0 || mask2 != 0 || mask3 != 0 {
return Some(at + reverse_pos3(mask1, mask2, mask3));
}
at -= VECTOR_SIZE;
let mask1 = _mm_movemask_epi8(eqa1);
let mask2 = _mm_movemask_epi8(eqa2);
let mask3 = _mm_movemask_epi8(eqa3);
return Some(at + reverse_pos3(mask1, mask2, mask3));
}
}
while ptr >= start_ptr.add(VECTOR_SIZE) {
ptr = ptr.sub(VECTOR_SIZE);
if let Some(i) =
reverse_search3(start_ptr, end_ptr, ptr, vn1, vn2, vn3)
{
return Some(i);
}
}
if ptr > start_ptr {
debug_assert!(sub(ptr, start_ptr) < VECTOR_SIZE);
return reverse_search3(start_ptr, end_ptr, start_ptr, vn1, vn2, vn3);
}
None
}
#[target_feature(enable = "sse2")]
pub unsafe fn forward_search1(
start_ptr: *const u8,
end_ptr: *const u8,
ptr: *const u8,
vn1: __m128i,
) -> Option<usize> {
debug_assert!(sub(end_ptr, start_ptr) >= VECTOR_SIZE);
debug_assert!(start_ptr <= ptr);
debug_assert!(ptr <= end_ptr.sub(VECTOR_SIZE));
let chunk = _mm_loadu_si128(ptr as *const __m128i);
let mask = _mm_movemask_epi8(_mm_cmpeq_epi8(chunk, vn1));
if mask != 0 {
Some(sub(ptr, start_ptr) + forward_pos(mask))
} else {
None
}
}
#[target_feature(enable = "sse2")]
unsafe fn forward_search2(
start_ptr: *const u8,
end_ptr: *const u8,
ptr: *const u8,
vn1: __m128i,
vn2: __m128i,
) -> Option<usize> {
debug_assert!(sub(end_ptr, start_ptr) >= VECTOR_SIZE);
debug_assert!(start_ptr <= ptr);
debug_assert!(ptr <= end_ptr.sub(VECTOR_SIZE));
let chunk = _mm_loadu_si128(ptr as *const __m128i);
let eq1 = _mm_cmpeq_epi8(chunk, vn1);
let eq2 = _mm_cmpeq_epi8(chunk, vn2);
if _mm_movemask_epi8(_mm_or_si128(eq1, eq2)) != 0 {
let mask1 = _mm_movemask_epi8(eq1);
let mask2 = _mm_movemask_epi8(eq2);
Some(sub(ptr, start_ptr) + forward_pos2(mask1, mask2))
} else {
None
}
}
#[target_feature(enable = "sse2")]
pub unsafe fn forward_search3(
start_ptr: *const u8,
end_ptr: *const u8,
ptr: *const u8,
vn1: __m128i,
vn2: __m128i,
vn3: __m128i,
) -> Option<usize> {
debug_assert!(sub(end_ptr, start_ptr) >= VECTOR_SIZE);
debug_assert!(start_ptr <= ptr);
debug_assert!(ptr <= end_ptr.sub(VECTOR_SIZE));
let chunk = _mm_loadu_si128(ptr as *const __m128i);
let eq1 = _mm_cmpeq_epi8(chunk, vn1);
let eq2 = _mm_cmpeq_epi8(chunk, vn2);
let eq3 = _mm_cmpeq_epi8(chunk, vn3);
let or = _mm_or_si128(eq1, eq2);
if _mm_movemask_epi8(_mm_or_si128(or, eq3)) != 0 {
let mask1 = _mm_movemask_epi8(eq1);
let mask2 = _mm_movemask_epi8(eq2);
let mask3 = _mm_movemask_epi8(eq3);
Some(sub(ptr, start_ptr) + forward_pos3(mask1, mask2, mask3))
} else {
None
}
}
#[target_feature(enable = "sse2")]
unsafe fn reverse_search1(
start_ptr: *const u8,
end_ptr: *const u8,
ptr: *const u8,
vn1: __m128i,
) -> Option<usize> {
debug_assert!(sub(end_ptr, start_ptr) >= VECTOR_SIZE);
debug_assert!(start_ptr <= ptr);
debug_assert!(ptr <= end_ptr.sub(VECTOR_SIZE));
let chunk = _mm_loadu_si128(ptr as *const __m128i);
let mask = _mm_movemask_epi8(_mm_cmpeq_epi8(vn1, chunk));
if mask != 0 {
Some(sub(ptr, start_ptr) + reverse_pos(mask))
} else {
None
}
}
#[target_feature(enable = "sse2")]
unsafe fn reverse_search2(
start_ptr: *const u8,
end_ptr: *const u8,
ptr: *const u8,
vn1: __m128i,
vn2: __m128i,
) -> Option<usize> {
debug_assert!(sub(end_ptr, start_ptr) >= VECTOR_SIZE);
debug_assert!(start_ptr <= ptr);
debug_assert!(ptr <= end_ptr.sub(VECTOR_SIZE));
let chunk = _mm_loadu_si128(ptr as *const __m128i);
let eq1 = _mm_cmpeq_epi8(chunk, vn1);
let eq2 = _mm_cmpeq_epi8(chunk, vn2);
if _mm_movemask_epi8(_mm_or_si128(eq1, eq2)) != 0 {
let mask1 = _mm_movemask_epi8(eq1);
let mask2 = _mm_movemask_epi8(eq2);
Some(sub(ptr, start_ptr) + reverse_pos2(mask1, mask2))
} else {
None
}
}
#[target_feature(enable = "sse2")]
unsafe fn reverse_search3(
start_ptr: *const u8,
end_ptr: *const u8,
ptr: *const u8,
vn1: __m128i,
vn2: __m128i,
vn3: __m128i,
) -> Option<usize> {
debug_assert!(sub(end_ptr, start_ptr) >= VECTOR_SIZE);
debug_assert!(start_ptr <= ptr);
debug_assert!(ptr <= end_ptr.sub(VECTOR_SIZE));
let chunk = _mm_loadu_si128(ptr as *const __m128i);
let eq1 = _mm_cmpeq_epi8(chunk, vn1);
let eq2 = _mm_cmpeq_epi8(chunk, vn2);
let eq3 = _mm_cmpeq_epi8(chunk, vn3);
let or = _mm_or_si128(eq1, eq2);
if _mm_movemask_epi8(_mm_or_si128(or, eq3)) != 0 {
let mask1 = _mm_movemask_epi8(eq1);
let mask2 = _mm_movemask_epi8(eq2);
let mask3 = _mm_movemask_epi8(eq3);
Some(sub(ptr, start_ptr) + reverse_pos3(mask1, mask2, mask3))
} else {
None
}
}
/// Compute the position of the first matching byte from the given mask. The
/// position returned is always in the range [0, 15].
///
/// The mask given is expected to be the result of _mm_movemask_epi8.
fn forward_pos(mask: i32) -> usize {
// We are dealing with little endian here, where the most significant byte
// is at a higher address. That means the least significant bit that is set
// corresponds to the position of our first matching byte. That position
// corresponds to the number of zeros after the least significant bit.
mask.trailing_zeros() as usize
}
/// Compute the position of the first matching byte from the given masks. The
/// position returned is always in the range [0, 15]. Each mask corresponds to
/// the equality comparison of a single byte.
///
/// The masks given are expected to be the result of _mm_movemask_epi8, where
/// at least one of the masks is non-zero (i.e., indicates a match).
fn forward_pos2(mask1: i32, mask2: i32) -> usize {
debug_assert!(mask1 != 0 || mask2 != 0);
forward_pos(mask1 | mask2)
}
/// Compute the position of the first matching byte from the given masks. The
/// position returned is always in the range [0, 15]. Each mask corresponds to
/// the equality comparison of a single byte.
///
/// The masks given are expected to be the result of _mm_movemask_epi8, where
/// at least one of the masks is non-zero (i.e., indicates a match).
fn forward_pos3(mask1: i32, mask2: i32, mask3: i32) -> usize {
debug_assert!(mask1 != 0 || mask2 != 0 || mask3 != 0);
forward_pos(mask1 | mask2 | mask3)
}
/// Compute the position of the last matching byte from the given mask. The
/// position returned is always in the range [0, 15].
///
/// The mask given is expected to be the result of _mm_movemask_epi8.
fn reverse_pos(mask: i32) -> usize {
// We are dealing with little endian here, where the most significant byte
// is at a higher address. That means the most significant bit that is set
// corresponds to the position of our last matching byte. The position from
// the end of the mask is therefore the number of leading zeros in a 16
// bit integer, and the position from the start of the mask is therefore
// 16 - (leading zeros) - 1.
VECTOR_SIZE - (mask as u16).leading_zeros() as usize - 1
}
/// Compute the position of the last matching byte from the given masks. The
/// position returned is always in the range [0, 15]. Each mask corresponds to
/// the equality comparison of a single byte.
///
/// The masks given are expected to be the result of _mm_movemask_epi8, where
/// at least one of the masks is non-zero (i.e., indicates a match).
fn reverse_pos2(mask1: i32, mask2: i32) -> usize {
debug_assert!(mask1 != 0 || mask2 != 0);
reverse_pos(mask1 | mask2)
}
/// Compute the position of the last matching byte from the given masks. The
/// position returned is always in the range [0, 15]. Each mask corresponds to
/// the equality comparison of a single byte.
///
/// The masks given are expected to be the result of _mm_movemask_epi8, where
/// at least one of the masks is non-zero (i.e., indicates a match).
fn reverse_pos3(mask1: i32, mask2: i32, mask3: i32) -> usize {
debug_assert!(mask1 != 0 || mask2 != 0 || mask3 != 0);
reverse_pos(mask1 | mask2 | mask3)
}
/// Subtract `b` from `a` and return the difference. `a` should be greater than
/// or equal to `b`.
fn sub(a: *const u8, b: *const u8) -> usize {
debug_assert!(a >= b);
(a as usize) - (b as usize)
}
Sindbad File Manager Version 1.0, Coded By Sindbad EG ~ The Terrorists