1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 use std::cmp::Ordering;
13 use syntax::ast::{self, Visibility, Attribute, MetaItem, MetaItem_};
14 use syntax::codemap::{CodeMap, Span, BytePos};
18 use comment::FindUncommented;
19 use rewrite::{Rewrite, RewriteContext};
23 // Computes the length of a string's last line, minus offset.
25 pub fn extra_offset(text: &str, offset: Indent) -> usize {
26 match text.rfind('\n') {
27 // 1 for newline character
28 Some(idx) => text.len() - idx - 1 - offset.width(),
34 pub fn span_after(original: Span, needle: &str, codemap: &CodeMap) -> BytePos {
35 let snippet = codemap.span_to_snippet(original).unwrap();
36 let offset = snippet.find_uncommented(needle).unwrap() + needle.len();
38 original.lo + BytePos(offset as u32)
42 pub fn format_visibility(vis: Visibility) -> &'static str {
44 Visibility::Public => "pub ",
45 Visibility::Inherited => "",
50 pub fn format_unsafety(unsafety: ast::Unsafety) -> &'static str {
52 ast::Unsafety::Unsafe => "unsafe ",
53 ast::Unsafety::Normal => "",
58 pub fn format_mutability(mutability: ast::Mutability) -> &'static str {
60 ast::Mutability::MutMutable => "mut ",
61 ast::Mutability::MutImmutable => "",
66 // FIXME(#451): include "C"?
67 pub fn format_abi(abi: abi::Abi) -> String {
68 format!("extern {} ", abi)
71 // The width of the first line in s.
73 pub fn first_line_width(s: &str) -> usize {
80 // The width of the last line in s.
82 pub fn last_line_width(s: &str) -> usize {
84 Some(n) => s.len() - n - 1,
90 fn is_skip(meta_item: &MetaItem) -> bool {
91 match meta_item.node {
92 MetaItem_::MetaWord(ref s) => *s == SKIP_ANNOTATION,
93 MetaItem_::MetaList(ref s, ref l) => *s == "cfg_attr" && l.len() == 2 && is_skip(&l[1]),
99 pub fn contains_skip(attrs: &[Attribute]) -> bool {
100 attrs.iter().any(|a| is_skip(&a.node.value))
103 // Find the end of a TyParam
105 pub fn end_typaram(typaram: &ast::TyParam) -> BytePos {
110 ast::RegionTyParamBound(ref lt) => lt.span,
111 ast::TraitTyParamBound(ref prt, _) => prt.span,
114 .unwrap_or(typaram.span)
119 pub fn semicolon_for_expr(expr: &ast::Expr) -> bool {
121 ast::Expr_::ExprRet(..) |
122 ast::Expr_::ExprAgain(..) |
123 ast::Expr_::ExprBreak(..) => true,
129 pub fn semicolon_for_stmt(stmt: &ast::Stmt) -> bool {
131 ast::Stmt_::StmtSemi(ref expr, _) => {
133 ast::Expr_::ExprWhile(..) |
134 ast::Expr_::ExprWhileLet(..) |
135 ast::Expr_::ExprLoop(..) |
136 ast::Expr_::ExprForLoop(..) => false,
140 ast::Stmt_::StmtExpr(..) => false,
146 pub fn trim_newlines(input: &str) -> &str {
147 match input.find(|c| c != '\n' && c != '\r') {
149 let end = input.rfind(|c| c != '\n' && c != '\r').unwrap_or(0) + 1;
157 #[cfg(target_pointer_width="64")]
158 // Based on the trick layed out at
159 // http://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2
160 pub fn round_up_to_power_of_two(mut x: usize) -> usize {
161 x = x.wrapping_sub(1);
172 #[cfg(target_pointer_width="32")]
173 pub fn round_up_to_power_of_two(mut x: usize) -> usize {
174 x = x.wrapping_sub(1);
183 // Macro for deriving implementations of Decodable for enums
185 macro_rules! impl_enum_decodable {
186 ( $e:ident, $( $x:ident ),* ) => {
187 impl ::rustc_serialize::Decodable for $e {
188 fn decode<D: ::rustc_serialize::Decoder>(d: &mut D) -> Result<Self, D::Error> {
189 let s = try!(d.read_str());
192 stringify!($x) => Ok($e::$x),
194 _ => Err(d.error("Bad variant")),
199 impl ::std::str::FromStr for $e {
200 type Err = &'static str;
202 fn from_str(s: &str) -> Result<Self, Self::Err> {
205 stringify!($x) => Ok($e::$x),
207 _ => Err("Bad variant"),
212 impl ::config::ConfigType for $e {
213 fn get_variant_names() -> String {
214 let mut variants = Vec::new();
216 variants.push(stringify!($x));
218 format!("[{}]", variants.join("|"))
224 // Same as try!, but for Option
226 macro_rules! try_opt {
227 ($expr:expr) => (match $expr {
229 None => { return None; }
233 // Wraps string-like values in an Option. Returns Some when the string adheres
234 // to the Rewrite constraints defined for the Rewrite trait and else otherwise.
235 pub fn wrap_str<S: AsRef<str>>(s: S, max_width: usize, width: usize, offset: Indent) -> Option<S> {
237 let snippet = s.as_ref();
239 if !snippet.contains('\n') && snippet.len() > width {
242 let mut lines = snippet.lines();
244 // The caller of this function has already placed `offset`
245 // characters on the first line.
246 let first_line_max_len = try_opt!(max_width.checked_sub(offset.width()));
247 if lines.next().unwrap().len() > first_line_max_len {
251 // The other lines must fit within the maximum width.
252 if lines.find(|line| line.len() > max_width).is_some() {
256 // `width` is the maximum length of the last line, excluding
258 // A special check for the last line, since the caller may
259 // place trailing characters on this line.
260 if snippet.lines().rev().next().unwrap().len() > offset.width() + width {
269 impl Rewrite for String {
270 fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
271 wrap_str(self, context.config.max_width, width, offset).map(ToOwned::to_owned)
275 // Binary search in integer range. Returns the first Ok value returned by the
277 // The callback takes an integer and returns either an Ok, or an Err indicating
278 // whether the `guess' was too high (Ordering::Less), or too low.
279 // This function is guaranteed to try to the hi value first.
280 pub fn binary_search<C, T>(mut lo: usize, mut hi: usize, callback: C) -> Option<T>
281 where C: Fn(usize) -> Result<T, Ordering>
286 match callback(middle) {
287 Ok(val) => return Some(val),
288 Err(Ordering::Less) => {
295 middle = (hi + lo) / 2;
302 fn bin_search_test() {
306 j if j > 4 => Err(Ordering::Less),
307 j if j < 4 => Err(Ordering::Greater),
312 assert_eq!(Some(()), binary_search(1, 10, &closure));
313 assert_eq!(None, binary_search(1, 3, &closure));
314 assert_eq!(Some(()), binary_search(0, 44, &closure));
315 assert_eq!(Some(()), binary_search(4, 125, &closure));
316 assert_eq!(None, binary_search(6, 100, &closure));
320 fn power_rounding() {
321 assert_eq!(0, round_up_to_power_of_two(0));
322 assert_eq!(1, round_up_to_power_of_two(1));
323 assert_eq!(64, round_up_to_power_of_two(33));
324 assert_eq!(256, round_up_to_power_of_two(256));