435 lines
15 KiB
Rust
435 lines
15 KiB
Rust
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// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use unicode_width::UnicodeWidthChar;
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use super::*;
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/// Find all newlines, multi-byte characters, and non-narrow characters in a
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/// FileMap.
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///
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/// This function will use an SSE2 enhanced implementation if hardware support
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/// is detected at runtime.
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pub fn analyze_filemap(
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src: &str,
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filemap_start_pos: BytePos)
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-> (Vec<BytePos>, Vec<MultiByteChar>, Vec<NonNarrowChar>)
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{
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let mut lines = vec![filemap_start_pos];
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let mut multi_byte_chars = vec![];
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let mut non_narrow_chars = vec![];
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// Calls the right implementation, depending on hardware support available.
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analyze_filemap_dispatch(src,
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filemap_start_pos,
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&mut lines,
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&mut multi_byte_chars,
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&mut non_narrow_chars);
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// The code above optimistically registers a new line *after* each \n
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// it encounters. If that point is already outside the filemap, remove
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// it again.
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if let Some(&last_line_start) = lines.last() {
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let file_map_end = filemap_start_pos + BytePos::from_usize(src.len());
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assert!(file_map_end >= last_line_start);
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if last_line_start == file_map_end {
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lines.pop();
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}
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}
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(lines, multi_byte_chars, non_narrow_chars)
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}
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cfg_if! {
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if #[cfg(all(any(target_arch = "x86", target_arch = "x86_64"),
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not(stage0)))] {
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fn analyze_filemap_dispatch(src: &str,
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filemap_start_pos: BytePos,
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lines: &mut Vec<BytePos>,
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multi_byte_chars: &mut Vec<MultiByteChar>,
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non_narrow_chars: &mut Vec<NonNarrowChar>) {
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if is_x86_feature_detected!("sse2") {
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unsafe {
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analyze_filemap_sse2(src,
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filemap_start_pos,
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lines,
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multi_byte_chars,
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non_narrow_chars);
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}
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} else {
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analyze_filemap_generic(src,
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src.len(),
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filemap_start_pos,
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lines,
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multi_byte_chars,
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non_narrow_chars);
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}
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}
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/// Check 16 byte chunks of text at a time. If the chunk contains
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/// something other than printable ASCII characters and newlines, the
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/// function falls back to the generic implementation. Otherwise it uses
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/// SSE2 intrinsics to quickly find all newlines.
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#[target_feature(enable = "sse2")]
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unsafe fn analyze_filemap_sse2(src: &str,
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output_offset: BytePos,
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lines: &mut Vec<BytePos>,
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multi_byte_chars: &mut Vec<MultiByteChar>,
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non_narrow_chars: &mut Vec<NonNarrowChar>) {
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#[cfg(target_arch = "x86")]
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use std::arch::x86::*;
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#[cfg(target_arch = "x86_64")]
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use std::arch::x86_64::*;
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const CHUNK_SIZE: usize = 16;
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let src_bytes = src.as_bytes();
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let chunk_count = src.len() / CHUNK_SIZE;
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// This variable keeps track of where we should start decoding a
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// chunk. If a multi-byte character spans across chunk boundaries,
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// we need to skip that part in the next chunk because we already
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// handled it.
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let mut intra_chunk_offset = 0;
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for chunk_index in 0 .. chunk_count {
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let ptr = src_bytes.as_ptr() as *const __m128i;
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let chunk = _mm_loadu_si128(ptr.offset(chunk_index as isize));
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// For character in the chunk, see if its byte value is < 0, which
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// indicates that it's part of a UTF-8 char.
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let multibyte_test = _mm_cmplt_epi8(chunk, _mm_set1_epi8(0));
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// Create a bit mask from the comparison results.
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let multibyte_mask = _mm_movemask_epi8(multibyte_test);
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// If the bit mask is all zero, we only have ASCII chars here:
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if multibyte_mask == 0 {
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assert!(intra_chunk_offset == 0);
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// Check if there are any control characters in the chunk. All
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// control characters that we can encounter at this point have a
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// byte value less than 32 or ...
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let control_char_test0 = _mm_cmplt_epi8(chunk, _mm_set1_epi8(32));
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let control_char_mask0 = _mm_movemask_epi8(control_char_test0);
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// ... it's the ASCII 'DEL' character with a value of 127.
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let control_char_test1 = _mm_cmpeq_epi8(chunk, _mm_set1_epi8(127));
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let control_char_mask1 = _mm_movemask_epi8(control_char_test1);
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let control_char_mask = control_char_mask0 | control_char_mask1;
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if control_char_mask != 0 {
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// Check for newlines in the chunk
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let newlines_test = _mm_cmpeq_epi8(chunk, _mm_set1_epi8(b'\n' as i8));
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let newlines_mask = _mm_movemask_epi8(newlines_test);
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if control_char_mask == newlines_mask {
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// All control characters are newlines, record them
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let mut newlines_mask = 0xFFFF0000 | newlines_mask as u32;
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let output_offset = output_offset +
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BytePos::from_usize(chunk_index * CHUNK_SIZE + 1);
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loop {
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let index = newlines_mask.trailing_zeros();
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if index >= CHUNK_SIZE as u32 {
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// We have arrived at the end of the chunk.
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break
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}
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lines.push(BytePos(index) + output_offset);
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// Clear the bit, so we can find the next one.
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newlines_mask &= (!1) << index;
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}
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// We are done for this chunk. All control characters were
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// newlines and we took care of those.
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continue
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} else {
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// Some of the control characters are not newlines,
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// fall through to the slow path below.
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}
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} else {
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// No control characters, nothing to record for this chunk
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continue
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}
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}
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// The slow path.
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// There are control chars in here, fallback to generic decoding.
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let scan_start = chunk_index * CHUNK_SIZE + intra_chunk_offset;
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intra_chunk_offset = analyze_filemap_generic(
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&src[scan_start .. ],
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CHUNK_SIZE - intra_chunk_offset,
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BytePos::from_usize(scan_start) + output_offset,
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lines,
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multi_byte_chars,
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non_narrow_chars
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);
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}
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// There might still be a tail left to analyze
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let tail_start = chunk_count * CHUNK_SIZE + intra_chunk_offset;
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if tail_start < src.len() {
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analyze_filemap_generic(&src[tail_start as usize ..],
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src.len() - tail_start,
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output_offset + BytePos::from_usize(tail_start),
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lines,
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multi_byte_chars,
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non_narrow_chars);
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}
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}
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} else {
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// The target (or compiler version) does not support SSE2 ...
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fn analyze_filemap_dispatch(src: &str,
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filemap_start_pos: BytePos,
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lines: &mut Vec<BytePos>,
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multi_byte_chars: &mut Vec<MultiByteChar>,
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non_narrow_chars: &mut Vec<NonNarrowChar>) {
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analyze_filemap_generic(src,
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src.len(),
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filemap_start_pos,
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lines,
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multi_byte_chars,
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non_narrow_chars);
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}
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}
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}
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// `scan_len` determines the number of bytes in `src` to scan. Note that the
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// function can read past `scan_len` if a multi-byte character start within the
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// range but extends past it. The overflow is returned by the function.
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fn analyze_filemap_generic(src: &str,
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scan_len: usize,
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output_offset: BytePos,
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lines: &mut Vec<BytePos>,
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multi_byte_chars: &mut Vec<MultiByteChar>,
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non_narrow_chars: &mut Vec<NonNarrowChar>)
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-> usize
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{
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assert!(src.len() >= scan_len);
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let mut i = 0;
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let src_bytes = src.as_bytes();
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while i < scan_len {
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let byte = unsafe {
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// We verified that i < scan_len <= src.len()
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*src_bytes.get_unchecked(i as usize)
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};
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// How much to advance in order to get to the next UTF-8 char in the
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// string.
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let mut char_len = 1;
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if byte < 32 {
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// This is an ASCII control character, it could be one of the cases
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// that are interesting to us.
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let pos = BytePos::from_usize(i) + output_offset;
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match byte {
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b'\n' => {
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lines.push(pos + BytePos(1));
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}
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b'\t' => {
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non_narrow_chars.push(NonNarrowChar::Tab(pos));
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}
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_ => {
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non_narrow_chars.push(NonNarrowChar::ZeroWidth(pos));
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}
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}
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} else if byte >= 127 {
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// The slow path:
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// This is either ASCII control character "DEL" or the beginning of
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// a multibyte char. Just decode to `char`.
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let c = (&src[i..]).chars().next().unwrap();
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char_len = c.len_utf8();
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let pos = BytePos::from_usize(i) + output_offset;
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if char_len > 1 {
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assert!(char_len >=2 && char_len <= 4);
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let mbc = MultiByteChar {
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pos,
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bytes: char_len as u32,
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};
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multi_byte_chars.push(mbc);
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}
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// Assume control characters are zero width.
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// FIXME: How can we decide between `width` and `width_cjk`?
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let char_width = UnicodeWidthChar::width(c).unwrap_or(0);
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if char_width != 1 {
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non_narrow_chars.push(NonNarrowChar::new(pos, char_width));
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}
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}
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i += char_len;
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}
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i - scan_len
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}
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macro_rules! test {
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(case: $test_name:ident,
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text: $text:expr,
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filemap_start_pos: $filemap_start_pos:expr,
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lines: $lines:expr,
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multi_byte_chars: $multi_byte_chars:expr,
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non_narrow_chars: $non_narrow_chars:expr,) => (
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#[test]
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fn $test_name() {
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let (lines, multi_byte_chars, non_narrow_chars) =
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analyze_filemap($text, BytePos($filemap_start_pos));
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let expected_lines: Vec<BytePos> = $lines
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.into_iter()
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.map(|pos| BytePos(pos))
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.collect();
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assert_eq!(lines, expected_lines);
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let expected_mbcs: Vec<MultiByteChar> = $multi_byte_chars
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.into_iter()
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.map(|(pos, bytes)| MultiByteChar {
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pos: BytePos(pos),
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bytes,
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})
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.collect();
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assert_eq!(multi_byte_chars, expected_mbcs);
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let expected_nncs: Vec<NonNarrowChar> = $non_narrow_chars
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.into_iter()
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.map(|(pos, width)| {
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NonNarrowChar::new(BytePos(pos), width)
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})
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.collect();
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assert_eq!(non_narrow_chars, expected_nncs);
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})
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}
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test!(
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case: empty_text,
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text: "",
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filemap_start_pos: 0,
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lines: vec![],
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multi_byte_chars: vec![],
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non_narrow_chars: vec![],
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);
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test!(
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case: newlines_short,
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text: "a\nc",
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filemap_start_pos: 0,
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lines: vec![0, 2],
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multi_byte_chars: vec![],
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non_narrow_chars: vec![],
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);
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test!(
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case: newlines_long,
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text: "012345678\nabcdef012345678\na",
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filemap_start_pos: 0,
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lines: vec![0, 10, 26],
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multi_byte_chars: vec![],
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non_narrow_chars: vec![],
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);
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test!(
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case: newline_and_multi_byte_char_in_same_chunk,
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text: "01234β789\nbcdef0123456789abcdef",
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filemap_start_pos: 0,
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lines: vec![0, 11],
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multi_byte_chars: vec![(5, 2)],
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non_narrow_chars: vec![],
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);
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test!(
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case: newline_and_control_char_in_same_chunk,
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text: "01234\u{07}6789\nbcdef0123456789abcdef",
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filemap_start_pos: 0,
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lines: vec![0, 11],
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multi_byte_chars: vec![],
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non_narrow_chars: vec![(5, 0)],
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);
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||
|
|
test!(
|
||
|
|
case: multi_byte_char_short,
|
||
|
|
text: "aβc",
|
||
|
|
filemap_start_pos: 0,
|
||
|
|
lines: vec![0],
|
||
|
|
multi_byte_chars: vec![(1, 2)],
|
||
|
|
non_narrow_chars: vec![],
|
||
|
|
);
|
||
|
|
|
||
|
|
test!(
|
||
|
|
case: multi_byte_char_long,
|
||
|
|
text: "0123456789abcΔf012345β",
|
||
|
|
filemap_start_pos: 0,
|
||
|
|
lines: vec![0],
|
||
|
|
multi_byte_chars: vec![(13, 2), (22, 2)],
|
||
|
|
non_narrow_chars: vec![],
|
||
|
|
);
|
||
|
|
|
||
|
|
test!(
|
||
|
|
case: multi_byte_char_across_chunk_boundary,
|
||
|
|
text: "0123456789abcdeΔ123456789abcdef01234",
|
||
|
|
filemap_start_pos: 0,
|
||
|
|
lines: vec![0],
|
||
|
|
multi_byte_chars: vec![(15, 2)],
|
||
|
|
non_narrow_chars: vec![],
|
||
|
|
);
|
||
|
|
|
||
|
|
test!(
|
||
|
|
case: multi_byte_char_across_chunk_boundary_tail,
|
||
|
|
text: "0123456789abcdeΔ....",
|
||
|
|
filemap_start_pos: 0,
|
||
|
|
lines: vec![0],
|
||
|
|
multi_byte_chars: vec![(15, 2)],
|
||
|
|
non_narrow_chars: vec![],
|
||
|
|
);
|
||
|
|
|
||
|
|
test!(
|
||
|
|
case: non_narrow_short,
|
||
|
|
text: "0\t2",
|
||
|
|
filemap_start_pos: 0,
|
||
|
|
lines: vec![0],
|
||
|
|
multi_byte_chars: vec![],
|
||
|
|
non_narrow_chars: vec![(1, 4)],
|
||
|
|
);
|
||
|
|
|
||
|
|
test!(
|
||
|
|
case: non_narrow_long,
|
||
|
|
text: "01\t3456789abcdef01234567\u{07}9",
|
||
|
|
filemap_start_pos: 0,
|
||
|
|
lines: vec![0],
|
||
|
|
multi_byte_chars: vec![],
|
||
|
|
non_narrow_chars: vec![(2, 4), (24, 0)],
|
||
|
|
);
|
||
|
|
|
||
|
|
test!(
|
||
|
|
case: output_offset_all,
|
||
|
|
text: "01\t345\n789abcΔf01234567\u{07}9\nbcΔf",
|
||
|
|
filemap_start_pos: 1000,
|
||
|
|
lines: vec![0 + 1000, 7 + 1000, 27 + 1000],
|
||
|
|
multi_byte_chars: vec![(13 + 1000, 2), (29 + 1000, 2)],
|
||
|
|
non_narrow_chars: vec![(2 + 1000, 4), (24 + 1000, 0)],
|
||
|
|
);
|