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Move static code outside of unciode.py.
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| @@ -0,0 +1,76 @@ | ||
| // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT | ||
| // file at the top-level directory of this distribution and at | ||
| // http://rust-lang.org/COPYRIGHT. | ||
| // | ||
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | ||
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | ||
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | ||
| // option. This file may not be copied, modified, or distributed | ||
| // except according to those terms. | ||
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| /// BoolTrie is a trie for representing a set of Unicode codepoints. It is | ||
| /// implemented with postfix compression (sharing of identical child nodes), | ||
| /// which gives both compact size and fast lookup. | ||
| /// | ||
| /// The space of Unicode codepoints is divided into 3 subareas, each | ||
| /// represented by a trie with different depth. In the first (0..0x800), there | ||
| /// is no trie structure at all; each u64 entry corresponds to a bitvector | ||
| /// effectively holding 64 bool values. | ||
| /// | ||
| /// In the second (0x800..0x10000), each child of the root node represents a | ||
| /// 64-wide subrange, but instead of storing the full 64-bit value of the leaf, | ||
| /// the trie stores an 8-bit index into a shared table of leaf values. This | ||
| /// exploits the fact that in reasonable sets, many such leaves can be shared. | ||
| /// | ||
| /// In the third (0x10000..0x110000), each child of the root node represents a | ||
| /// 4096-wide subrange, and the trie stores an 8-bit index into a 64-byte slice | ||
| /// of a child tree. Each of these 64 bytes represents an index into the table | ||
| /// of shared 64-bit leaf values. This exploits the sparse structure in the | ||
| /// non-BMP range of most Unicode sets. | ||
| pub struct BoolTrie { | ||
| // 0..0x800 (corresponding to 1 and 2 byte utf-8 sequences) | ||
| pub r1: [u64; 32], // leaves | ||
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| // 0x800..0x10000 (corresponding to 3 byte utf-8 sequences) | ||
| pub r2: [u8; 992], // first level | ||
| pub r3: &'static [u64], // leaves | ||
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| // 0x10000..0x110000 (corresponding to 4 byte utf-8 sequences) | ||
| pub r4: [u8; 256], // first level | ||
| pub r5: &'static [u8], // second level | ||
| pub r6: &'static [u64], // leaves | ||
| } | ||
| impl BoolTrie { | ||
| pub fn lookup(&self, c: char) -> bool { | ||
| let c = c as usize; | ||
| if c < 0x800 { | ||
| trie_range_leaf(c, self.r1[c >> 6]) | ||
| } else if c < 0x10000 { | ||
| let child = self.r2[(c >> 6) - 0x20]; | ||
| trie_range_leaf(c, self.r3[child as usize]) | ||
| } else { | ||
| let child = self.r4[(c >> 12) - 0x10]; | ||
| let leaf = self.r5[((child as usize) << 6) + ((c >> 6) & 0x3f)]; | ||
| trie_range_leaf(c, self.r6[leaf as usize]) | ||
| } | ||
| } | ||
| } | ||
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| pub struct SmallBoolTrie { | ||
| pub(crate) r1: &'static [u8], // first level | ||
| pub(crate) r2: &'static [u64], // leaves | ||
| } | ||
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| impl SmallBoolTrie { | ||
| pub fn lookup(&self, c: char) -> bool { | ||
| let c = c as usize; | ||
| match self.r1.get(c >> 6) { | ||
| Some(&child) => trie_range_leaf(c, self.r2[child as usize]), | ||
| None => false, | ||
| } | ||
| } | ||
| } | ||
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| fn trie_range_leaf(c: usize, bitmap_chunk: u64) -> bool { | ||
| ((bitmap_chunk >> (c & 63)) & 1) != 0 | ||
| } |
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