diff options
Diffstat (limited to 'src/libsyntax')
| -rw-r--r-- | src/libsyntax/print/pp.rs | 71 |
1 files changed, 19 insertions, 52 deletions
diff --git a/src/libsyntax/print/pp.rs b/src/libsyntax/print/pp.rs index a1fa126818f..4a92ad8ddb2 100644 --- a/src/libsyntax/print/pp.rs +++ b/src/libsyntax/print/pp.rs @@ -61,6 +61,7 @@ //! line (which it can't) and so naturally place the content on its own line to //! avoid combining it with other lines and making matters even worse. +use std::collections::VecDeque; use std::fmt; use std::io; @@ -164,7 +165,7 @@ pub fn mk_printer<'a>(out: Box<io::Write+'a>, linewidth: usize) -> Printer<'a> { debug!("mk_printer {}", linewidth); let token = vec![Token::Eof; n]; let size = vec![0; n]; - let scan_stack = vec![0; n]; + let scan_stack = VecDeque::with_capacity(n); Printer { out: out, buf_len: n, @@ -177,9 +178,6 @@ pub fn mk_printer<'a>(out: Box<io::Write+'a>, linewidth: usize) -> Printer<'a> { left_total: 0, right_total: 0, scan_stack: scan_stack, - scan_stack_empty: true, - top: 0, - bottom: 0, print_stack: Vec::new(), pending_indentation: 0 } @@ -241,9 +239,8 @@ pub fn mk_printer<'a>(out: Box<io::Write+'a>, linewidth: usize) -> Printer<'a> { /// approximation for purposes of line breaking). /// /// The "input side" of the printer is managed as an abstract process called -/// SCAN, which uses 'scan_stack', 'scan_stack_empty', 'top' and 'bottom', to -/// manage calculating 'size'. SCAN is, in other words, the process of -/// calculating 'size' entries. +/// SCAN, which uses 'scan_stack', to manage calculating 'size'. SCAN is, in +/// other words, the process of calculating 'size' entries. /// /// The "output side" of the printer is managed by an abstract process called /// PRINT, which uses 'print_stack', 'margin' and 'space' to figure out what to @@ -286,13 +283,7 @@ pub struct Printer<'a> { /// Begin (if there is any) on top of it. Stuff is flushed off the /// bottom as it becomes irrelevant due to the primary ring-buffer /// advancing. - scan_stack: Vec<usize> , - /// Top==bottom disambiguator - scan_stack_empty: bool, - /// Index of top of scan_stack - top: usize, - /// Index of bottom of scan_stack - bottom: usize, + scan_stack: VecDeque<usize> , /// Stack of blocks-in-progress being flushed by print print_stack: Vec<PrintStackElem> , /// Buffered indentation to avoid writing trailing whitespace @@ -311,7 +302,7 @@ impl<'a> Printer<'a> { debug!("pp Vec<{},{}>", self.left, self.right); match token { Token::Eof => { - if !self.scan_stack_empty { + if !self.scan_stack.is_empty() { self.check_stack(0); self.advance_left()?; } @@ -319,7 +310,7 @@ impl<'a> Printer<'a> { Ok(()) } Token::Begin(b) => { - if self.scan_stack_empty { + if self.scan_stack.is_empty() { self.left_total = 1; self.right_total = 1; self.left = 0; @@ -334,7 +325,7 @@ impl<'a> Printer<'a> { Ok(()) } Token::End => { - if self.scan_stack_empty { + if self.scan_stack.is_empty() { debug!("pp End/print Vec<{},{}>", self.left, self.right); self.print(token, 0) } else { @@ -348,7 +339,7 @@ impl<'a> Printer<'a> { } } Token::Break(b) => { - if self.scan_stack_empty { + if self.scan_stack.is_empty() { self.left_total = 1; self.right_total = 1; self.left = 0; @@ -365,7 +356,7 @@ impl<'a> Printer<'a> { Ok(()) } Token::String(s, len) => { - if self.scan_stack_empty { + if self.scan_stack.is_empty() { debug!("pp String('{}')/print Vec<{},{}>", s, self.left, self.right); self.print(Token::String(s, len), len) @@ -387,12 +378,10 @@ impl<'a> Printer<'a> { if self.right_total - self.left_total > self.space { debug!("scan window is {}, longer than space on line ({})", self.right_total - self.left_total, self.space); - if !self.scan_stack_empty { - if self.left == self.scan_stack[self.bottom] { - debug!("setting {} to infinity and popping", self.left); - let scanned = self.scan_pop_bottom(); - self.size[scanned] = SIZE_INFINITY; - } + if Some(&self.left) == self.scan_stack.back() { + debug!("setting {} to infinity and popping", self.left); + let scanned = self.scan_pop_bottom(); + self.size[scanned] = SIZE_INFINITY; } self.advance_left()?; if self.left != self.right { @@ -403,38 +392,16 @@ impl<'a> Printer<'a> { } pub fn scan_push(&mut self, x: usize) { debug!("scan_push {}", x); - if self.scan_stack_empty { - self.scan_stack_empty = false; - } else { - self.top += 1; - self.top %= self.buf_len; - assert!(self.top != self.bottom); - } - self.scan_stack[self.top] = x; + self.scan_stack.push_front(x); } pub fn scan_pop(&mut self) -> usize { - assert!(!self.scan_stack_empty); - let x = self.scan_stack[self.top]; - if self.top == self.bottom { - self.scan_stack_empty = true; - } else { - self.top += self.buf_len - 1; self.top %= self.buf_len; - } - x + self.scan_stack.pop_front().unwrap() } pub fn scan_top(&mut self) -> usize { - assert!(!self.scan_stack_empty); - self.scan_stack[self.top] + *self.scan_stack.front().unwrap() } pub fn scan_pop_bottom(&mut self) -> usize { - assert!(!self.scan_stack_empty); - let x = self.scan_stack[self.bottom]; - if self.top == self.bottom { - self.scan_stack_empty = true; - } else { - self.bottom += 1; self.bottom %= self.buf_len; - } - x + self.scan_stack.pop_back().unwrap() } pub fn advance_right(&mut self) { self.right += 1; @@ -476,7 +443,7 @@ impl<'a> Printer<'a> { Ok(()) } pub fn check_stack(&mut self, k: isize) { - if !self.scan_stack_empty { + if !self.scan_stack.is_empty() { let x = self.scan_top(); match self.token[x] { Token::Begin(_) => { |