53 lines
2.0 KiB
Rust
53 lines
2.0 KiB
Rust
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use syntax::ast;
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use super::err::*;
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/// Depending on the target only one variant is ever used in a compilation.
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/// Anything else is an error. This invariant is checked at several locations
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#[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, Hash, Eq, PartialEq)]
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pub enum ConstUsize {
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Us16(u16),
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Us32(u32),
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Us64(u64),
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}
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pub use self::ConstUsize::*;
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impl ConstUsize {
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pub fn as_u64(self, target_uint_ty: ast::UintTy) -> u64 {
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match (self, target_uint_ty) {
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(Us16(i), ast::UintTy::U16) => i as u64,
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(Us32(i), ast::UintTy::U32) => i as u64,
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(Us64(i), ast::UintTy::U64) => i,
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_ => panic!("unable to convert self ({:?}) to target usize ({:?})",
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self, target_uint_ty),
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}
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}
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pub fn new(i: u64, target_uint_ty: ast::UintTy) -> Result<Self, ConstMathErr> {
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match target_uint_ty {
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ast::UintTy::U16 if i as u16 as u64 == i => Ok(Us16(i as u16)),
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ast::UintTy::U16 => Err(ULitOutOfRange(ast::UintTy::Us)),
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ast::UintTy::U32 if i as u32 as u64 == i => Ok(Us32(i as u32)),
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ast::UintTy::U32 => Err(ULitOutOfRange(ast::UintTy::Us)),
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ast::UintTy::U64 => Ok(Us64(i)),
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_ => unreachable!(),
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}
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}
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pub fn new_truncating(i: u64, target_uint_ty: ast::UintTy) -> Self {
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match target_uint_ty {
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ast::UintTy::U16 => Us16(i as u16),
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ast::UintTy::U32 => Us32(i as u32),
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ast::UintTy::U64 => Us64(i),
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_ => unreachable!(),
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}
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}
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}
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