commit c33b97c9900c93f1c82124680808507f171cc598 · drubery.com/icfp2007

+60 -45
dna2rna/src/parser.rs
···

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       use crate::dna::Base;

     

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       use crate::dna::DnaIterator;

     

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       use crate::dna::DnaRef;

     

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       use crate::pattern::Pattern;

     

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       use crate::pattern::PatternItem;

     

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       use crate::rna::Rna;

     

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       use crate::template::Template;

     

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       use crate::template::TemplateItem;

     

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       use std::mem;

     

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       pub struct Parser<'a> {

     

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           buf: &'a DnaRef,

     

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           iter: DnaIterator<'a>,

     

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           peeked: Vec<Base>,

     

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           index: usize,

     

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       }

     

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       impl<'a> Parser<'a> {

     

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           pub fn new(buf: &'a DnaRef) -> Parser<'a> {

     

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               Parser { buf: buf, index: 0 }

     

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               Parser {

     

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                   iter: buf.iter(),

     

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                   peeked: Vec::new(),

     

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                   index: 0,

     

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               }

     

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           }

     

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           pub fn index(&self) -> usize {

     

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               self.index

     

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           }

     

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           pub fn next_is(&mut self, next: &[Base]) -> bool {

     

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               if self.index + next.len() > self.buf.len() {

     

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                   return false;

     

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           fn peek_to(&mut self, n: usize) {

     

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               while self.peeked.len() < n {

     

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                   if let Some(b) = self.iter.next() {

     

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                       self.peeked.push(b);

     

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                   } else {

     

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                       return;

     

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                   }

     

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               }

     

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           }

     

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               for i in 0..next.len() {

     

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                   if self.buf[self.index + i] != next[i] {

     

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                       return false;

     

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                   }

     

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               }

     

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           pub fn next_is(&mut self, next: &[Base]) -> bool {

     

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               self.peek_to(next.len());

     

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       	if self.peeked.len() < next.len() {

     

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       	  return false;

     

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       	}

     

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               return &self.peeked[..next.len()] == next;

     

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           }

     

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               return true;

     

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           pub fn advance(&mut self, n: usize) {

     

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               self.peek_to(n);

     

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               self.index += n;

     

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               self.peeked.drain(..n);

     

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           }

     

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           pub fn nat(&mut self) -> Option<usize> {

     
···

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               let mut bit = 1;

     

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               loop {

     

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                   if self.next_is(&[Base::P]) {

     

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                       self.index += 1;

     

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                       self.advance(1);

     

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                       return Some(ret);

     

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                   } else if self.next_is(&[Base::I]) || self.next_is(&[Base::F]) {

     

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                       self.index += 1;

     

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                       self.advance(1);

     

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                   } else if self.next_is(&[Base::C]) {

     

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                       ret += bit;

     

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                       self.index += 1;

     

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                       self.advance(1);

     

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                   } else {

     

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                       return None;

     

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                   }

     
···

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               let mut ret = Vec::new();

     

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               loop {

     

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                   if self.next_is(&[Base::C]) {

     

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                       self.index += 1;

     

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                       self.advance(1);

     

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                       ret.push(Base::I);

     

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                   } else if self.next_is(&[Base::F]) {

     

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                       self.index += 1;

     

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                       self.advance(1);

     

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                       ret.push(Base::C);

     

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                   } else if self.next_is(&[Base::P]) {

     

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                       self.index += 1;

     

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                       self.advance(1);

     

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                       ret.push(Base::F);

     

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                   } else if self.next_is(&[Base::I, Base::C]) {

     

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                       self.index += 2;

     

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                       self.advance(2);

     

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                       ret.push(Base::P);

     

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                   } else {

     

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                       return ret;

     
···

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               let mut level = 0;

     

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               loop {

     

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                   if self.next_is(&[Base::C]) {

     

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                       self.index += 1;

     

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                       self.advance(1);

     

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                       ret.push(PatternItem::Base(Base::I));

     

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                   } else if self.next_is(&[Base::F]) {

     

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                       self.index += 1;

     

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                       self.advance(1);

     

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                       ret.push(PatternItem::Base(Base::C));

     

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                   } else if self.next_is(&[Base::P]) {

     

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                       self.index += 1;

     

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                       self.advance(1);

     

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                       ret.push(PatternItem::Base(Base::F));

     

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                   } else if self.next_is(&[Base::I, Base::C]) {

     

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                       self.index += 2;

     

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                       self.advance(2);

     

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                       ret.push(PatternItem::Base(Base::P));

     

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                   } else if self.next_is(&[Base::I, Base::P]) {

     

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                       self.index += 2;

     

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                       self.advance(2);

     

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                       let n = self.nat()?;

     

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                       ret.push(PatternItem::Skip(n));

     

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                   } else if self.next_is(&[Base::I, Base::F]) {

     

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                       self.index += 3;

     

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                       self.advance(3);

     

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                       let s = self.consts();

     

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                       ret.push(PatternItem::Search(s));

     

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                   } else if self.next_is(&[Base::I, Base::I, Base::P]) {

     

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                       self.index += 3;

     

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                       self.advance(3);

     

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                       level += 1;

     

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                       ret.push(PatternItem::Open);

     

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                   } else if self.next_is(&[Base::I, Base::I, Base::C])

     

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                       || self.next_is(&[Base::I, Base::I, Base::F])

     

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                   {

     

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                       self.index += 3;

     

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                       self.advance(3);

     

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                       if level == 0 {

     

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                           return Some(ret);

     

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                       }

     

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                       level -= 1;

     

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                       ret.push(PatternItem::Close);

     

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                   } else if self.next_is(&[Base::I, Base::I, Base::I]) {

     

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                       self.index += 3;

     

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                       let mut new_rna = Vec::new();

     

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                       for i in 0..7 {

     

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                           new_rna.push(self.buf[self.index + i]);

     

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                       }

     

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                       self.advance(3);

     

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                       self.peek_to(7);

     

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                       let mut r = Vec::new();

     

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                       mem::swap(&mut r, &mut self.peeked);

     

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                       rna.push(r.try_into().unwrap());

     

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                       self.index += 7;

     

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                       rna.push(new_rna.try_into().unwrap());

     

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                   } else {

     

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                       return None;

     

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                   }

     
···

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               let mut ret = Vec::new();

     

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               loop {

     

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                   if self.next_is(&[Base::C]) {

     

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                       self.index += 1;

     

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                       self.advance(1);

     

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                       ret.push(TemplateItem::Base(Base::I));

     

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                   } else if self.next_is(&[Base::F]) {

     

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                       self.index += 1;

     

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                       self.advance(1);

     

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                       ret.push(TemplateItem::Base(Base::C));

     

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                   } else if self.next_is(&[Base::P]) {

     

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                       self.index += 1;

     

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                       self.advance(1);

     

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                       ret.push(TemplateItem::Base(Base::F));

     

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                   } else if self.next_is(&[Base::I, Base::C]) {

     

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                       self.index += 2;

     

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                       self.advance(2);

     

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                       ret.push(TemplateItem::Base(Base::P));

     

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                   } else if self.next_is(&[Base::I, Base::P]) || self.next_is(&[Base::I, Base::F]) {

     

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                       self.index += 2;

     

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                       self.advance(2);

     

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                       let l = self.nat()?;

     

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                       let n = self.nat()?;

     

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                       ret.push(TemplateItem::Ref(n, l));

     

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                   } else if self.next_is(&[Base::I, Base::I, Base::C])

     

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                       || self.next_is(&[Base::I, Base::I, Base::F])

     

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                   {

     

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                       self.index += 3;

     

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                       self.advance(3);

     

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                       return Some(ret);

     

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                   } else if self.next_is(&[Base::I, Base::I, Base::P]) {

     

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                       self.index += 3;

     

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                       self.advance(3);

     

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                       let n = self.nat()?;

     

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                       ret.push(TemplateItem::Len(n));

     

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                   } else if self.next_is(&[Base::I, Base::I, Base::I]) {

     

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                       self.index += 3;

     

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                       let mut new_rna = Vec::new();

     

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                       for i in 0..7 {

     

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                           new_rna.push(self.buf[self.index + i]);

     

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                       }

     

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                       self.advance(3);

     

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                       self.peek_to(7);

     

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                       let mut r = Vec::new();

     

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                       mem::swap(&mut r, &mut self.peeked);

     

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                       rna.push(r.try_into().unwrap());

     

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                       self.index += 7;

     

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                       rna.push(new_rna.try_into().unwrap());

     

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                   } else {

     

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                       return None;

     

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                   }