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/// php-src: ext/standard/strnatcmp.c `strnatcmp_ex` (PHP 8.5.2)
///
/// Operating on byte slices, an out-of-range index reads as 0, reproducing the NUL terminator
/// that the C implementation relies on.
pub fn strnatcmp_ex(a: &[u8], b: &[u8], fold_case: bool) -> i64 {
let a_len = a.len();
let b_len = b.len();
if a_len == 0 || b_len == 0 {
return match a_len.cmp(&b_len) {
std::cmp::Ordering::Less => -1,
std::cmp::Ordering::Greater => 1,
std::cmp::Ordering::Equal => 0,
};
}
let mut ap = 0usize;
let mut bp = 0usize;
let mut leading = true;
loop {
let mut ca = natcmp_at(a, ap);
let mut cb = natcmp_at(b, bp);
// Skip over leading zeros.
while leading && ca == b'0' && natcmp_at(a, ap + 1).is_ascii_digit() {
ap += 1;
ca = natcmp_at(a, ap);
}
while leading && cb == b'0' && natcmp_at(b, bp + 1).is_ascii_digit() {
bp += 1;
cb = natcmp_at(b, bp);
}
leading = false;
// Skip consecutive whitespace.
while natcmp_is_space(ca) {
ap += 1;
ca = natcmp_at(a, ap);
}
while natcmp_is_space(cb) {
bp += 1;
cb = natcmp_at(b, bp);
}
// Process a run of digits.
if ca.is_ascii_digit() && cb.is_ascii_digit() {
let fractional = ca == b'0' || cb == b'0';
let result = if fractional {
natcmp_compare_left(a, &mut ap, b, &mut bp)
} else {
natcmp_compare_right(a, &mut ap, b, &mut bp)
};
if result != 0 {
return result;
}
}
if ap == a_len && bp == b_len {
return 0;
} else if ap == a_len {
return -1;
} else if bp == b_len {
return 1;
}
if fold_case {
ca = natcmp_at(a, ap).to_ascii_uppercase();
cb = natcmp_at(b, bp).to_ascii_uppercase();
} else {
ca = natcmp_at(a, ap);
cb = natcmp_at(b, bp);
}
if ca < cb {
return -1;
} else if ca > cb {
return 1;
}
ap += 1;
bp += 1;
}
}
/// php-src: ext/standard/strnatcmp.c (no direct counterpart) (PHP 8.5.2)
fn natcmp_at(s: &[u8], i: usize) -> u8 {
if i < s.len() { s[i] } else { 0 }
}
/// php-src: ext/standard/strnatcmp.c `isspace(3)` usage (PHP 8.5.2)
fn natcmp_is_space(c: u8) -> bool {
matches!(c, b' ' | b'\t' | b'\n' | 0x0b | 0x0c | b'\r')
}
/// php-src: ext/standard/strnatcmp.c `compare_right` (PHP 8.5.2)
///
/// Compare two right-aligned numbers: the longest run of digits wins; failing that, the first
/// differing digit decides, but only once magnitudes are known equal (tracked in `bias`).
fn natcmp_compare_right(a: &[u8], ap: &mut usize, b: &[u8], bp: &mut usize) -> i64 {
let mut bias = 0i64;
loop {
let ca = natcmp_at(a, *ap);
let cb = natcmp_at(b, *bp);
let a_digit = ca.is_ascii_digit();
let b_digit = cb.is_ascii_digit();
if !a_digit && !b_digit {
return bias;
} else if !a_digit {
return -1;
} else if !b_digit {
return 1;
} else if ca < cb {
if bias == 0 {
bias = -1;
}
} else if ca > cb && bias == 0 {
bias = 1;
}
*ap += 1;
*bp += 1;
}
}
/// php-src: ext/standard/strnatcmp.c `compare_left` (PHP 8.5.2)
///
/// Compare two left-aligned numbers: the first differing digit decides.
fn natcmp_compare_left(a: &[u8], ap: &mut usize, b: &[u8], bp: &mut usize) -> i64 {
loop {
let ca = natcmp_at(a, *ap);
let cb = natcmp_at(b, *bp);
let a_digit = ca.is_ascii_digit();
let b_digit = cb.is_ascii_digit();
if !a_digit && !b_digit {
return 0;
} else if !a_digit {
return -1;
} else if !b_digit {
return 1;
} else if ca < cb {
return -1;
} else if ca > cb {
return 1;
}
*ap += 1;
*bp += 1;
}
}
|
