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| 1 | +// Copyright 2012 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. |
| 4 | +// |
| 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. |
| 10 | + |
| 11 | +// This test deserializes an enum in-place by transmuting to a union that |
| 12 | +// should have the same layout, and manipulating the tag and payloads |
| 13 | +// independently. This verifies that `repr(some_int)` has a stable representation, |
| 14 | +// and that we don't miscompile these kinds of manipulations. |
| 15 | + |
| 16 | +use std::time::Duration; |
| 17 | +use std::mem; |
| 18 | + |
| 19 | +#[repr(C, u8)] |
| 20 | +#[derive(Copy, Clone, Eq, PartialEq, Debug)] |
| 21 | +enum MyEnum { |
| 22 | + A(u32), // Single primitive value |
| 23 | + B { x: u8, y: i16 }, // Composite, and the offset of `y` depends on tag being internal |
| 24 | + C, // Empty |
| 25 | + D(Option<u32>), // Contains an enum |
| 26 | + E(Duration), // Contains a struct |
| 27 | +} |
| 28 | + |
| 29 | +#[repr(C)] |
| 30 | +struct MyEnumRepr { |
| 31 | + tag: MyEnumTag, |
| 32 | + payload: MyEnumPayload, |
| 33 | +} |
| 34 | + |
| 35 | +#[repr(C)] |
| 36 | +#[allow(non_snake_case)] |
| 37 | +union MyEnumPayload { |
| 38 | + A: MyEnumVariantA, |
| 39 | + B: MyEnumVariantB, |
| 40 | + D: MyEnumVariantD, |
| 41 | + E: MyEnumVariantE, |
| 42 | +} |
| 43 | + |
| 44 | +#[repr(u8)] #[derive(Copy, Clone)] enum MyEnumTag { A, B, C, D, E } |
| 45 | +#[repr(C)] #[derive(Copy, Clone)] struct MyEnumVariantA(u32); |
| 46 | +#[repr(C)] #[derive(Copy, Clone)] struct MyEnumVariantB {x: u8, y: i16 } |
| 47 | +#[repr(C)] #[derive(Copy, Clone)] struct MyEnumVariantD(Option<u32>); |
| 48 | +#[repr(C)] #[derive(Copy, Clone)] struct MyEnumVariantE(Duration); |
| 49 | + |
| 50 | +fn main() { |
| 51 | + let result: Vec<Result<MyEnum, ()>> = vec![ |
| 52 | + Ok(MyEnum::A(17)), |
| 53 | + Ok(MyEnum::B { x: 206, y: 1145 }), |
| 54 | + Ok(MyEnum::C), |
| 55 | + Err(()), |
| 56 | + Ok(MyEnum::D(Some(407))), |
| 57 | + Ok(MyEnum::D(None)), |
| 58 | + Ok(MyEnum::E(Duration::from_secs(100))), |
| 59 | + Err(()), |
| 60 | + ]; |
| 61 | + |
| 62 | + // Binary serialized version of the above (little-endian) |
| 63 | + let input: Vec<u8> = vec![ |
| 64 | + 0, 17, 0, 0, 0, |
| 65 | + 1, 206, 121, 4, |
| 66 | + 2, |
| 67 | + 8, /* invalid tag value */ |
| 68 | + 3, 0, 151, 1, 0, 0, |
| 69 | + 3, 1, |
| 70 | + 4, 100, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 71 | + 0, /* incomplete value */ |
| 72 | + ]; |
| 73 | + |
| 74 | + let mut output = vec![]; |
| 75 | + let mut buf = &input[..]; |
| 76 | + |
| 77 | + unsafe { |
| 78 | + // This should be safe, because we don't match on it unless it's fully formed, |
| 79 | + // and it doesn't have a destructor. |
| 80 | + let mut dest: MyEnum = mem::uninitialized(); |
| 81 | + while buf.len() > 0 { |
| 82 | + match parse_my_enum(&mut dest, &mut buf) { |
| 83 | + Ok(()) => output.push(Ok(dest)), |
| 84 | + Err(()) => output.push(Err(())), |
| 85 | + } |
| 86 | + } |
| 87 | + } |
| 88 | + |
| 89 | + assert_eq!(output, result); |
| 90 | +} |
| 91 | + |
| 92 | +fn parse_my_enum<'a>(dest: &'a mut MyEnum, buf: &mut &[u8]) -> Result<(), ()> { |
| 93 | + unsafe { |
| 94 | + // Should be correct to do this transmute. |
| 95 | + let dest: &'a mut MyEnumRepr = mem::transmute(dest); |
| 96 | + let tag = read_u8(buf)?; |
| 97 | + |
| 98 | + dest.tag = match tag { |
| 99 | + 0 => MyEnumTag::A, |
| 100 | + 1 => MyEnumTag::B, |
| 101 | + 2 => MyEnumTag::C, |
| 102 | + 3 => MyEnumTag::D, |
| 103 | + 4 => MyEnumTag::E, |
| 104 | + _ => return Err(()), |
| 105 | + }; |
| 106 | + |
| 107 | + match dest.tag { |
| 108 | + MyEnumTag::A => { |
| 109 | + dest.payload.A.0 = read_u32_le(buf)?; |
| 110 | + } |
| 111 | + MyEnumTag::B => { |
| 112 | + dest.payload.B.x = read_u8(buf)?; |
| 113 | + dest.payload.B.y = read_u16_le(buf)? as i16; |
| 114 | + } |
| 115 | + MyEnumTag::C => { |
| 116 | + /* do nothing */ |
| 117 | + } |
| 118 | + MyEnumTag::D => { |
| 119 | + let is_some = read_u8(buf)? == 0; |
| 120 | + if is_some { |
| 121 | + dest.payload.D.0 = Some(read_u32_le(buf)?); |
| 122 | + } else { |
| 123 | + dest.payload.D.0 = None; |
| 124 | + } |
| 125 | + } |
| 126 | + MyEnumTag::E => { |
| 127 | + let secs = read_u64_le(buf)?; |
| 128 | + let nanos = read_u32_le(buf)?; |
| 129 | + dest.payload.E.0 = Duration::new(secs, nanos); |
| 130 | + } |
| 131 | + } |
| 132 | + Ok(()) |
| 133 | + } |
| 134 | +} |
| 135 | + |
| 136 | + |
| 137 | + |
| 138 | +// reader helpers |
| 139 | + |
| 140 | +fn read_u64_le(buf: &mut &[u8]) -> Result<u64, ()> { |
| 141 | + if buf.len() < 8 { return Err(()) } |
| 142 | + let val = (buf[0] as u64) << 0 |
| 143 | + | (buf[1] as u64) << 8 |
| 144 | + | (buf[2] as u64) << 16 |
| 145 | + | (buf[3] as u64) << 24 |
| 146 | + | (buf[4] as u64) << 32 |
| 147 | + | (buf[5] as u64) << 40 |
| 148 | + | (buf[6] as u64) << 48 |
| 149 | + | (buf[7] as u64) << 56; |
| 150 | + *buf = &buf[8..]; |
| 151 | + Ok(val) |
| 152 | +} |
| 153 | + |
| 154 | +fn read_u32_le(buf: &mut &[u8]) -> Result<u32, ()> { |
| 155 | + if buf.len() < 4 { return Err(()) } |
| 156 | + let val = (buf[0] as u32) << 0 |
| 157 | + | (buf[1] as u32) << 8 |
| 158 | + | (buf[2] as u32) << 16 |
| 159 | + | (buf[3] as u32) << 24; |
| 160 | + *buf = &buf[4..]; |
| 161 | + Ok(val) |
| 162 | +} |
| 163 | + |
| 164 | +fn read_u16_le(buf: &mut &[u8]) -> Result<u16, ()> { |
| 165 | + if buf.len() < 2 { return Err(()) } |
| 166 | + let val = (buf[0] as u16) << 0 |
| 167 | + | (buf[1] as u16) << 8; |
| 168 | + *buf = &buf[2..]; |
| 169 | + Ok(val) |
| 170 | +} |
| 171 | + |
| 172 | +fn read_u8(buf: &mut &[u8]) -> Result<u8, ()> { |
| 173 | + if buf.len() < 1 { return Err(()) } |
| 174 | + let val = buf[0]; |
| 175 | + *buf = &buf[1..]; |
| 176 | + Ok(val) |
| 177 | +} |
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