use crate::mem as basic;
use crate::utils::B1Sgl;
use crate::utils::_ascii_stochas;
#[cfg(any(target_arch = "x86_64", target_arch = "x86"))]
use super::cpuid;
use core::sync::atomic::AtomicPtr;
use core::sync::atomic::Ordering;
type FuncType = fn(&[u8], &[u8]) -> Option<usize>;
const FUNC: FuncType = fnptr_setup_func;
static FUNC_PTR_ATOM: AtomicPtr<FuncType> = AtomicPtr::new(FUNC as *mut FuncType);
#[inline(never)]
fn fnptr_setup_func(haystack: &[u8], needle: &[u8]) -> Option<usize> {
#[cfg(target_arch = "x86_64")]
let func = if cpuid::has_avx2() {
_memrmem_avx2
} else {
_memrmem_sse2
};
#[cfg(target_arch = "x86")]
let func = if cpuid::has_avx2() {
_memrmem_avx2
} else if cpuid::has_sse2() {
_memrmem_sse2
} else {
_memrmem_basic
};
FUNC_PTR_ATOM.store(func as *mut FuncType, Ordering::Relaxed);
unsafe { func(haystack, needle) }
}
#[inline(always)]
pub(crate) fn _memrmem_impl(haystack: &[u8], needle: &[u8]) -> Option<usize> {
let func_u = FUNC_PTR_ATOM.load(Ordering::Relaxed);
#[allow(clippy::crosspointer_transmute)]
let func: FuncType = unsafe { core::mem::transmute(func_u) };
func(haystack, needle)
}
unsafe fn _memrmem_basic(haystack: &[u8], needle: &[u8]) -> Option<usize> {
basic::_memrmem_impl(haystack, needle)
}
#[cfg(any(target_arch = "x86_64", target_arch = "x86"))]
#[target_feature(enable = "sse2")]
#[allow(clippy::missing_safety_doc)]
pub unsafe fn _memrmem_sse2(haystack: &[u8], needle: &[u8]) -> Option<usize> {
_memrmem_sse2_impl(haystack, needle)
}
#[cfg(any(target_arch = "x86_64", target_arch = "x86"))]
#[target_feature(enable = "avx2")]
#[allow(clippy::missing_safety_doc)]
pub unsafe fn _memrmem_avx2(haystack: &[u8], needle: &[u8]) -> Option<usize> {
_memrmem_avx2_impl(haystack, needle)
}
#[inline(always)]
fn _memrmem_sse2_impl(haystack: &[u8], needle: &[u8]) -> Option<usize> {
let hay_len = haystack.len();
let nee_len = needle.len();
if hay_len < nee_len {
return None;
}
if nee_len == 0 {
return Some(hay_len);
}
let byte_1st = needle[0];
let byte_last = needle[nee_len - 1];
if byte_1st.is_ascii() && byte_last.is_ascii() {
let weight_1st = _ascii_stochas(byte_1st);
let weight_last = _ascii_stochas(byte_last);
if weight_1st <= weight_last {
_memrmem_sse2_impl_1st(haystack, needle)
} else {
_memrmem_sse2_impl_last(haystack, needle)
}
} else if byte_last.is_ascii() {
_memrmem_sse2_impl_1st(haystack, needle)
} else {
_memrmem_sse2_impl_last(haystack, needle)
}
}
#[inline(always)]
fn _memrmem_sse2_impl_1st(haystack: &[u8], needle: &[u8]) -> Option<usize> {
let hay_len = haystack.len();
let nee_len = needle.len();
let nee_1st_byte = needle[0];
let mut curr_idx = hay_len - nee_len;
while curr_idx > 0 {
let r =
unsafe { super::_memrchr_sgl_sse2(&haystack[..curr_idx], B1Sgl::new(nee_1st_byte)) };
if let Some(pos) = r {
let r_idx = pos;
if unsafe { super::_memeq_sse2(&haystack[r_idx..(r_idx + nee_len)], needle) } {
return Some(r_idx);
}
curr_idx = pos;
} else {
return None;
}
}
None
}
#[inline(always)]
fn _memrmem_sse2_impl_last(haystack: &[u8], needle: &[u8]) -> Option<usize> {
let hay_len = haystack.len();
let nee_len = needle.len();
let nee_last_idx = nee_len - 1;
let nee_last_byte = needle[nee_last_idx];
let mut curr_idx = hay_len;
while curr_idx > 0 {
let r =
unsafe { super::_memrchr_sgl_sse2(&haystack[..curr_idx], B1Sgl::new(nee_last_byte)) };
if let Some(pos) = r {
if pos >= nee_last_idx {
let r_idx = pos - nee_last_idx;
if unsafe { super::_memeq_sse2(&haystack[r_idx..(r_idx + nee_len)], needle) } {
return Some(r_idx);
}
curr_idx = pos;
} else {
return None;
}
} else {
return None;
}
}
None
}
#[inline(always)]
fn _memrmem_avx2_impl(haystack: &[u8], needle: &[u8]) -> Option<usize> {
let hay_len = haystack.len();
let nee_len = needle.len();
if hay_len < nee_len {
return None;
}
if nee_len == 0 {
return Some(hay_len);
}
let byte_1st = needle[0];
let byte_last = needle[nee_len - 1];
if byte_1st.is_ascii() && byte_last.is_ascii() {
let weight_1st = _ascii_stochas(byte_1st);
let weight_last = _ascii_stochas(byte_last);
if weight_1st <= weight_last {
_memrmem_avx2_impl_1st(haystack, needle)
} else {
_memrmem_avx2_impl_last(haystack, needle)
}
} else if byte_last.is_ascii() {
_memrmem_avx2_impl_1st(haystack, needle)
} else {
_memrmem_avx2_impl_last(haystack, needle)
}
}
#[inline(always)]
fn _memrmem_avx2_impl_1st(haystack: &[u8], needle: &[u8]) -> Option<usize> {
let hay_len = haystack.len();
let nee_len = needle.len();
let nee_1st_byte = needle[0];
let mut curr_idx = hay_len - nee_len;
while curr_idx > 0 {
let r =
unsafe { super::_memrchr_sgl_avx2(&haystack[..curr_idx], B1Sgl::new(nee_1st_byte)) };
if let Some(pos) = r {
let r_idx = pos;
if unsafe { super::_memeq_avx2(&haystack[r_idx..(r_idx + nee_len)], needle) } {
return Some(r_idx);
}
curr_idx = pos;
} else {
return None;
}
}
None
}
#[inline(always)]
fn _memrmem_avx2_impl_last(haystack: &[u8], needle: &[u8]) -> Option<usize> {
let hay_len = haystack.len();
let nee_len = needle.len();
let nee_last_idx = nee_len - 1;
let nee_last_byte = needle[nee_last_idx];
let mut curr_idx = hay_len;
while curr_idx > 0 {
let r =
unsafe { super::_memrchr_sgl_avx2(&haystack[..curr_idx], B1Sgl::new(nee_last_byte)) };
if let Some(pos) = r {
if pos >= nee_last_idx {
let r_idx = pos - nee_last_idx;
if unsafe { super::_memeq_avx2(&haystack[r_idx..(r_idx + nee_len)], needle) } {
return Some(r_idx);
}
curr_idx = pos;
} else {
return None;
}
} else {
return None;
}
}
None
}