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 span_after_last(original: Span, needle: &str, codemap: &CodeMap) -> BytePos {
43 let snippet = codemap.span_to_snippet(original).unwrap();
46 while let Some(additional_offset) = snippet[offset..].find_uncommented(needle) {
47 offset += additional_offset + needle.len();
50 original.lo + BytePos(offset as u32)
54 pub fn format_visibility(vis: Visibility) -> &'static str {
56 Visibility::Public => "pub ",
57 Visibility::Inherited => "",
62 pub fn format_unsafety(unsafety: ast::Unsafety) -> &'static str {
64 ast::Unsafety::Unsafe => "unsafe ",
65 ast::Unsafety::Normal => "",
70 pub fn format_mutability(mutability: ast::Mutability) -> &'static str {
72 ast::Mutability::MutMutable => "mut ",
73 ast::Mutability::MutImmutable => "",
78 // FIXME(#451): include "C"?
79 pub fn format_abi(abi: abi::Abi) -> String {
80 format!("extern {} ", abi)
83 // The width of the first line in s.
85 pub fn first_line_width(s: &str) -> usize {
92 // The width of the last line in s.
94 pub fn last_line_width(s: &str) -> usize {
96 Some(n) => s.len() - n - 1,
102 fn is_skip(meta_item: &MetaItem) -> bool {
103 match meta_item.node {
104 MetaItem_::MetaWord(ref s) => *s == SKIP_ANNOTATION,
105 MetaItem_::MetaList(ref s, ref l) => *s == "cfg_attr" && l.len() == 2 && is_skip(&l[1]),
111 pub fn contains_skip(attrs: &[Attribute]) -> bool {
112 attrs.iter().any(|a| is_skip(&a.node.value))
115 // Find the end of a TyParam
117 pub fn end_typaram(typaram: &ast::TyParam) -> BytePos {
120 .map_or(typaram.span, |bound| {
122 ast::RegionTyParamBound(ref lt) => lt.span,
123 ast::TraitTyParamBound(ref prt, _) => prt.span,
130 pub fn semicolon_for_expr(expr: &ast::Expr) -> bool {
132 ast::Expr_::ExprRet(..) |
133 ast::Expr_::ExprAgain(..) |
134 ast::Expr_::ExprBreak(..) => true,
140 pub fn semicolon_for_stmt(stmt: &ast::Stmt) -> bool {
142 ast::Stmt_::StmtSemi(ref expr, _) => {
144 ast::Expr_::ExprWhile(..) |
145 ast::Expr_::ExprWhileLet(..) |
146 ast::Expr_::ExprLoop(..) |
147 ast::Expr_::ExprForLoop(..) => false,
151 ast::Stmt_::StmtExpr(..) => false,
157 pub fn trim_newlines(input: &str) -> &str {
158 match input.find(|c| c != '\n' && c != '\r') {
160 let end = input.rfind(|c| c != '\n' && c != '\r').unwrap_or(0) + 1;
168 #[cfg(target_pointer_width="64")]
169 // Based on the trick layed out at
170 // http://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2
171 pub fn round_up_to_power_of_two(mut x: usize) -> usize {
172 x = x.wrapping_sub(1);
183 #[cfg(target_pointer_width="32")]
184 pub fn round_up_to_power_of_two(mut x: usize) -> usize {
185 x = x.wrapping_sub(1);
194 // Macro for deriving implementations of Decodable for enums
196 macro_rules! impl_enum_decodable {
197 ( $e:ident, $( $x:ident ),* ) => {
198 impl ::rustc_serialize::Decodable for $e {
199 fn decode<D: ::rustc_serialize::Decoder>(d: &mut D) -> Result<Self, D::Error> {
200 use std::ascii::AsciiExt;
201 let s = try!(d.read_str());
203 if stringify!($x).eq_ignore_ascii_case(&s) {
207 Err(d.error("Bad variant"))
211 impl ::std::str::FromStr for $e {
212 type Err = &'static str;
214 fn from_str(s: &str) -> Result<Self, Self::Err> {
215 use std::ascii::AsciiExt;
217 if stringify!($x).eq_ignore_ascii_case(s) {
225 impl ::config::ConfigType for $e {
226 fn get_variant_names() -> String {
227 let mut variants = Vec::new();
229 variants.push(stringify!($x));
231 format!("[{}]", variants.join("|"))
237 // Same as try!, but for Option
239 macro_rules! try_opt {
240 ($expr:expr) => (match $expr {
242 None => { return None; }
246 // Wraps string-like values in an Option. Returns Some when the string adheres
247 // to the Rewrite constraints defined for the Rewrite trait and else otherwise.
248 pub fn wrap_str<S: AsRef<str>>(s: S, max_width: usize, width: usize, offset: Indent) -> Option<S> {
250 let snippet = s.as_ref();
252 if !snippet.contains('\n') && snippet.len() > width {
255 let mut lines = snippet.lines();
257 // The caller of this function has already placed `offset`
258 // characters on the first line.
259 let first_line_max_len = try_opt!(max_width.checked_sub(offset.width()));
260 if lines.next().unwrap().len() > first_line_max_len {
264 // The other lines must fit within the maximum width.
265 if lines.find(|line| line.len() > max_width).is_some() {
269 // `width` is the maximum length of the last line, excluding
271 // A special check for the last line, since the caller may
272 // place trailing characters on this line.
273 if snippet.lines().rev().next().unwrap().len() > offset.width() + width {
282 impl Rewrite for String {
283 fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
284 wrap_str(self, context.config.max_width, width, offset).map(ToOwned::to_owned)
288 // Binary search in integer range. Returns the first Ok value returned by the
290 // The callback takes an integer and returns either an Ok, or an Err indicating
291 // whether the `guess' was too high (Ordering::Less), or too low.
292 // This function is guaranteed to try to the hi value first.
293 pub fn binary_search<C, T>(mut lo: usize, mut hi: usize, callback: C) -> Option<T>
294 where C: Fn(usize) -> Result<T, Ordering>
299 match callback(middle) {
300 Ok(val) => return Some(val),
301 Err(Ordering::Less) => {
308 middle = (hi + lo) / 2;
315 fn bin_search_test() {
319 j if j > 4 => Err(Ordering::Less),
320 j if j < 4 => Err(Ordering::Greater),
325 assert_eq!(Some(()), binary_search(1, 10, &closure));
326 assert_eq!(None, binary_search(1, 3, &closure));
327 assert_eq!(Some(()), binary_search(0, 44, &closure));
328 assert_eq!(Some(()), binary_search(4, 125, &closure));
329 assert_eq!(None, binary_search(6, 100, &closure));
333 fn power_rounding() {
334 assert_eq!(0, round_up_to_power_of_two(0));
335 assert_eq!(1, round_up_to_power_of_two(1));
336 assert_eq!(64, round_up_to_power_of_two(33));
337 assert_eq!(256, round_up_to_power_of_two(256));