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use crate::find::find;
use std::fmt::Debug;
use std::ops::{self, RangeFrom, RangeFull, RangeTo};
use std::str::{CharIndices, Chars};
#[derive(Copy, Clone)]
pub struct Range<'a> {
pub doc: &'a str,
pub offset: usize,
pub len: usize,
}
impl<'a> Range<'a> {
pub fn empty() -> Self {
Range {
doc: "",
offset: 0,
len: 0,
}
}
pub fn new(doc: &'a str, bounds: impl RangeBounds) -> Self {
let (offset, len) = bounds.index(doc.len());
Range { doc, offset, len }
}
pub fn is_empty(&self) -> bool {
self.len == 0
}
pub fn substring(&self, bounds: impl RangeBounds) -> Self {
let (offset, len) = bounds.index(self.len);
Range {
doc: self.doc,
offset: self.offset + offset,
len,
}
}
pub fn get(&self, bounds: impl RangeBounds) -> Option<Self> {
let (offset, len) = bounds.try_index(self.len)?;
Some(Range {
doc: self.doc,
offset: self.offset + offset,
len,
})
}
pub fn split_at(&self, mid: usize) -> (Self, Self) {
(self.substring(..mid), self.substring(mid..))
}
pub fn chars(&self) -> Chars<'a> {
str(*self).chars()
}
pub fn char_indices(&self) -> CharIndices<'a> {
str(*self).char_indices()
}
pub fn bytes(&self) -> impl Iterator<Item = u8> + DoubleEndedIterator + ExactSizeIterator + 'a {
bytes(*self).iter().cloned()
}
pub fn starts_with(&self, prefix: impl AsRef<[u8]>) -> bool {
bytes(*self).starts_with(prefix.as_ref())
}
pub fn ends_with(&self, suffix: impl AsRef<[u8]>) -> bool {
bytes(*self).ends_with(suffix.as_ref())
}
pub fn find(&self, needle: impl AsRef<[u8]>) -> Option<usize> {
find(bytes(*self), needle.as_ref())
}
}
pub fn str(range: Range) -> &str {
if cfg!(debug)
&& range
.doc
.get(range.offset..range.offset + range.len)
.is_none()
{
eprintln!(
"doc={:?} offset={} len={}",
range.doc, range.offset, range.len
);
}
&range.doc[range.offset..range.offset + range.len]
}
pub fn bytes(range: Range) -> &[u8] {
&range.doc.as_bytes()[range.offset..range.offset + range.len]
}
impl AsRef<[u8]> for Range<'_> {
fn as_ref(&self) -> &[u8] {
bytes(*self)
}
}
pub trait RangeBounds: Sized + Clone + Debug {
// Returns (offset, len).
fn try_index(self, len: usize) -> Option<(usize, usize)>;
fn index(self, len: usize) -> (usize, usize) {
match self.clone().try_index(len) {
Some(range) => range,
None => panic!("index out of range, index={:?}, len={}", self, len),
}
}
}
impl RangeBounds for ops::Range<usize> {
fn try_index(self, len: usize) -> Option<(usize, usize)> {
if self.start <= self.end && self.end <= len {
Some((self.start, self.end - self.start))
} else {
None
}
}
}
impl RangeBounds for RangeFrom<usize> {
fn try_index(self, len: usize) -> Option<(usize, usize)> {
if self.start <= len {
Some((self.start, len - self.start))
} else {
None
}
}
}
impl RangeBounds for RangeTo<usize> {
fn try_index(self, len: usize) -> Option<(usize, usize)> {
if self.end <= len {
Some((0, self.end))
} else {
None
}
}
}
impl RangeBounds for RangeFull {
fn try_index(self, len: usize) -> Option<(usize, usize)> {
Some((0, len))
}
}
|
