mirror of
https://gitee.com/openharmony/third_party_rust_nom
synced 2024-11-27 01:30:32 +00:00
322 lines
7.5 KiB
Rust
322 lines
7.5 KiB
Rust
/*
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#[macro_use]
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extern crate nom;
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extern crate bytes;
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use nom::{Compare,CompareResult,InputLength,InputIter,Slice,HexDisplay};
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use std::str;
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use std::str::FromStr;
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use bytes::{Buf,MutBuf};
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use bytes::buf::{BlockBuf,BlockBufCursor};
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use std::ops::{Range,RangeTo,RangeFrom,RangeFull};
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use std::iter::{Enumerate,Iterator};
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use std::fmt;
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use std::cmp::{min,PartialEq};
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#[derive(Clone,Copy)]
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#[repr(C)]
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pub struct BlockSlice<'a> {
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buf: &'a BlockBuf,
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start: usize,
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end: usize,
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}
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impl<'a> BlockSlice<'a> {
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fn cursor(&self) -> WrapCursor<'a> {
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let mut cur = self.buf.buf();
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cur.advance(self.start);
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WrapCursor {
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cursor: cur,
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length: self.end - self.start,
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}
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}
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}
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impl<'a> fmt::Debug for BlockSlice<'a> {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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write!(f, "BlockSlice {{ start: {}, end: {}, data:\n{}\n}}", self.start, self.end, self.buf.bytes().unwrap_or(&b""[..]).to_hex(16))
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}
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}
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impl<'a> PartialEq for BlockSlice<'a> {
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fn eq(&self, other: &BlockSlice<'a>) -> bool {
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let bufs = (self.buf as *const BlockBuf) == (other.buf as *const BlockBuf);
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self.start == other.start && self.end == other.end && bufs
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}
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}
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impl<'a> Slice<Range<usize>> for BlockSlice<'a> {
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fn slice(&self, range:Range<usize>) -> Self {
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BlockSlice {
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buf: self.buf,
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start: self.start + range.start,
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//FIXME: check for valid end here
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end: self.start + range.end,
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}
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}
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}
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impl<'a> Slice<RangeTo<usize>> for BlockSlice<'a> {
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fn slice(&self, range:RangeTo<usize>) -> Self {
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self.slice(0..range.end)
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}
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}
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impl<'a> Slice<RangeFrom<usize>> for BlockSlice<'a> {
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fn slice(&self, range:RangeFrom<usize>) -> Self {
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self.slice(range.start..self.end - self.start)
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}
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}
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impl<'a> Slice<RangeFull> for BlockSlice<'a> {
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fn slice(&self, _:RangeFull) -> Self {
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BlockSlice {
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buf: self.buf,
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start: self.start,
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end: self.end,
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}
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}
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}
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impl<'a> InputIter for BlockSlice<'a> {
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type Item = u8;
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type RawItem = u8;
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type Iter = Enumerate<WrapCursor<'a>>;
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type IterElem = WrapCursor<'a>;
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fn iter_indices(&self) -> Self::Iter {
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self.cursor().enumerate()
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}
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fn iter_elements(&self) -> Self::IterElem {
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self.cursor()
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}
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fn position<P>(&self, predicate: P) -> Option<usize> where P: Fn(Self::RawItem) -> bool {
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self.cursor().position(|b| predicate(b))
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}
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fn slice_index(&self, count:usize) -> Option<usize> {
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if self.end - self.start >= count {
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Some(count)
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} else {
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None
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}
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}
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}
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impl<'a> InputLength for BlockSlice<'a> {
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fn input_len(&self) -> usize {
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self.end - self.start
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}
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}
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impl<'a,'b> Compare<&'b[u8]> for BlockSlice<'a> {
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fn compare(&self, t: &'b[u8]) -> CompareResult {
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let len = self.end - self.start;
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let blen = t.len();
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let m = if len < blen { len } else { blen };
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let reduced = self.slice(..m);
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let b = &t[..m];
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for (a,b) in reduced.cursor().zip(b.iter()) {
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if a != *b {
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return CompareResult::Error;
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}
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}
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if m < blen {
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CompareResult::Incomplete
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} else {
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CompareResult::Ok
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}
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}
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#[inline(always)]
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fn compare_no_case(&self, t: &'b[u8]) -> CompareResult {
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let len = self.end - self.start;
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let blen = t.len();
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let m = if len < blen { len } else { blen };
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let reduced = self.slice(..m);
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let other = &t[..m];
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if !reduced.cursor().zip(other).all(|(a, b)| {
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match (a,*b) {
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(0...64, 0...64) | (91...96, 91...96) | (123...255, 123...255) => a == *b,
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(65...90, 65...90) | (97...122, 97...122) | (65...90, 97...122 ) |(97...122, 65...90) => {
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a & 0b01000000 == *b & 0b01000000
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}
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_ => false
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}
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}) {
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CompareResult::Error
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} else if m < blen {
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CompareResult::Incomplete
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} else {
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CompareResult::Ok
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}
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}
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}
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impl<'a,'b> Compare<&'b str> for BlockSlice<'a> {
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fn compare(&self, t: &'b str) -> CompareResult {
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self.compare(str::as_bytes(t))
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}
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fn compare_no_case(&self, t: &'b str) -> CompareResult {
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self.compare_no_case(str::as_bytes(t))
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}
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}
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//Wrapper to implement Iterator on BlockBufCursor
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pub struct WrapCursor<'a> {
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pub cursor: BlockBufCursor<'a>,
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pub length: usize,
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}
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impl<'a> Iterator for WrapCursor<'a> {
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type Item = u8;
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fn next(&mut self) -> Option<u8> {
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//println!("NEXT: length={}, remaining={}", self.length, self.cursor.remaining());
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if min(self.length, self.cursor.remaining()) > 0 {
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self.length -=1;
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Some(self.cursor.read_u8())
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} else {
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None
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}
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}
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}
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//Reimplement eat_separator instead of fixing iterators
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#[macro_export]
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macro_rules! block_eat_separator (
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($i:expr, $arr:expr) => (
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{
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use nom::{InputLength,InputIter,Slice};
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if ($i).input_len() == 0 {
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Ok(($i, ($i).slice(0..0)))
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} else {
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match ($i).iter_indices().position(|(_, item)| {
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for (_,c) in ($arr).iter_indices() {
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if *c == item { return false; }
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}
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true
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}) {
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Some(index) => {
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Ok((($i).slice(index..), ($i).slice(..index)))
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},
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None => {
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Ok((($i).slice(($i).input_len()..), $i))
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}
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}
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}
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}
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)
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);
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#[macro_export]
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macro_rules! block_named (
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($name:ident, $submac:ident!( $($args:tt)* )) => (
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fn $name<'a>( i: BlockSlice<'a> ) -> nom::IResult<BlockSlice<'a>, BlockSlice<'a>, u32> {
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$submac!(i, $($args)*)
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}
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);
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($name:ident<$o:ty>, $submac:ident!( $($args:tt)* )) => (
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fn $name<'a>( i: BlockSlice<'a> ) -> nom::IResult<BlockSlice<'a>, $o, u32> {
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$submac!(i, $($args)*)
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}
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);
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);
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block_named!(sp, block_eat_separator!(&b" \t\r\n"[..]));
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macro_rules! block_ws (
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($i:expr, $($args:tt)*) => (
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{
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sep!($i, sp, $($args)*)
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}
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)
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);
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block_named!(digit, is_a!("0123456789"));
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block_named!(parens<i64>, block_ws!(delimited!( tag!("("), expr, tag!(")") )) );
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block_named!(factor<i64>, alt!(
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map_res!(
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block_ws!(digit),
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to_i64
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)
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| parens
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)
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);
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block_named!(term <i64>, do_parse!(
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init: factor >>
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res: fold_many0!(
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pair!(alt!(tag!("*") | tag!("/")), factor),
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init,
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|acc, (op, val): (BlockSlice, i64)| {
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if (op.cursor().next().unwrap() as char) == '*' { acc * val } else { acc / val }
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}
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) >>
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(res)
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)
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);
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block_named!(expr <i64>, do_parse!(
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init: term >>
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res: fold_many0!(
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pair!(alt!(tag!("+") | tag!("-")), term),
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init,
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|acc, (op, val): (BlockSlice, i64)| {
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if (op.cursor().next().unwrap() as char) == '+' { acc + val } else { acc - val }
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}
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) >>
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(res)
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)
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);
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fn blockbuf_from(input: &[u8]) -> BlockBuf {
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let mut b = BlockBuf::new(2, 100);
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b.copy_from(input);
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b
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}
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fn sl<'a>(input: &'a BlockBuf) -> BlockSlice<'a> {
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BlockSlice {
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buf: input,
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start: 0,
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end: input.len(),
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}
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}
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fn to_i64<'a>(input: BlockSlice<'a>) -> Result<i64, ()> {
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let v: Vec<u8> = input.cursor().collect();
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match str::from_utf8(&v) {
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Err(_) => Err(()),
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Ok(s) => match FromStr::from_str(s) {
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Err(_) => Err(()),
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Ok(i) => Ok(i)
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}
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}
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}
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#[test]
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fn factor_test() {
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let a = blockbuf_from(&b"3"[..]);
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println!("calculated: {:?}", factor(sl(&a)));
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}
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#[test]
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fn parens_test() {
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let input1 = blockbuf_from(&b" 2* ( 3 + 4 ) "[..]);
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println!("calculated 1: {:?}", expr(sl(&input1)));
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let input2 = blockbuf_from(&b" 2*2 / ( 5 - 1) + 3"[..]);
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println!("calculated 2: {:?}", expr(sl(&input2)));
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}
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*/
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