compiler/rustc_serialize/src/opaque.rs

   1 use crate::leb128::{self, read_signed_leb128, write_signed_leb128};
   2 use crate::serialize;
   3 use std::borrow::Cow;
   4
   5 // -----------------------------------------------------------------------------
   6 // Encoder
   7 // -----------------------------------------------------------------------------
   8
   9 pub type EncodeResult = Result<(), !>;
  10
  11 pub struct Encoder {
  12     pub data: Vec<u8>,
  13 }
  14
  15 impl Encoder {
  16     pub fn new(data: Vec<u8>) -> Encoder {
  17         Encoder { data }
  18     }
  19
  20     pub fn into_inner(self) -> Vec<u8> {
  21         self.data
  22     }
  23
  24     #[inline]
  25     pub fn emit_raw_bytes(&mut self, s: &[u8]) {
  26         self.data.extend_from_slice(s);
  27     }
  28 }
  29
  30 macro_rules! write_uleb128 {
  31     ($enc:expr, $value:expr, $fun:ident) => {{
  32         leb128::$fun(&mut $enc.data, $value);
  33         Ok(())
  34     }};
  35 }
  36
  37 macro_rules! write_sleb128 {
  38     ($enc:expr, $value:expr) => {{
  39         write_signed_leb128(&mut $enc.data, $value as i128);
  40         Ok(())
  41     }};
  42 }
  43
  44 impl serialize::Encoder for Encoder {
  45     type Error = !;
  46
  47     #[inline]
  48     fn emit_unit(&mut self) -> EncodeResult {
  49         Ok(())
  50     }
  51
  52     #[inline]
  53     fn emit_usize(&mut self, v: usize) -> EncodeResult {
  54         write_uleb128!(self, v, write_usize_leb128)
  55     }
  56
  57     #[inline]
  58     fn emit_u128(&mut self, v: u128) -> EncodeResult {
  59         write_uleb128!(self, v, write_u128_leb128)
  60     }
  61
  62     #[inline]
  63     fn emit_u64(&mut self, v: u64) -> EncodeResult {
  64         write_uleb128!(self, v, write_u64_leb128)
  65     }
  66
  67     #[inline]
  68     fn emit_u32(&mut self, v: u32) -> EncodeResult {
  69         write_uleb128!(self, v, write_u32_leb128)
  70     }
  71
  72     #[inline]
  73     fn emit_u16(&mut self, v: u16) -> EncodeResult {
  74         write_uleb128!(self, v, write_u16_leb128)
  75     }
  76
  77     #[inline]
  78     fn emit_u8(&mut self, v: u8) -> EncodeResult {
  79         self.data.push(v);
  80         Ok(())
  81     }
  82
  83     #[inline]
  84     fn emit_isize(&mut self, v: isize) -> EncodeResult {
  85         write_sleb128!(self, v)
  86     }
  87
  88     #[inline]
  89     fn emit_i128(&mut self, v: i128) -> EncodeResult {
  90         write_sleb128!(self, v)
  91     }
  92
  93     #[inline]
  94     fn emit_i64(&mut self, v: i64) -> EncodeResult {
  95         write_sleb128!(self, v)
  96     }
  97
  98     #[inline]
  99     fn emit_i32(&mut self, v: i32) -> EncodeResult {
 100         write_sleb128!(self, v)
 101     }
 102
 103     #[inline]
 104     fn emit_i16(&mut self, v: i16) -> EncodeResult {
 105         write_sleb128!(self, v)
 106     }
 107
 108     #[inline]
 109     fn emit_i8(&mut self, v: i8) -> EncodeResult {
 110         let as_u8: u8 = unsafe { ::std::mem::transmute(v) };
 111         self.emit_u8(as_u8)
 112     }
 113
 114     #[inline]
 115     fn emit_bool(&mut self, v: bool) -> EncodeResult {
 116         self.emit_u8(if v { 1 } else { 0 })
 117     }
 118
 119     #[inline]
 120     fn emit_f64(&mut self, v: f64) -> EncodeResult {
 121         let as_u64: u64 = v.to_bits();
 122         self.emit_u64(as_u64)
 123     }
 124
 125     #[inline]
 126     fn emit_f32(&mut self, v: f32) -> EncodeResult {
 127         let as_u32: u32 = v.to_bits();
 128         self.emit_u32(as_u32)
 129     }
 130
 131     #[inline]
 132     fn emit_char(&mut self, v: char) -> EncodeResult {
 133         self.emit_u32(v as u32)
 134     }
 135
 136     #[inline]
 137     fn emit_str(&mut self, v: &str) -> EncodeResult {
 138         self.emit_usize(v.len())?;
 139         self.emit_raw_bytes(v.as_bytes());
 140         Ok(())
 141     }
 142 }
 143
 144 impl Encoder {
 145     #[inline]
 146     pub fn position(&self) -> usize {
 147         self.data.len()
 148     }
 149 }
 150
 151 // -----------------------------------------------------------------------------
 152 // Decoder
 153 // -----------------------------------------------------------------------------
 154
 155 pub struct Decoder<'a> {
 156     pub data: &'a [u8],
 157     position: usize,
 158 }
 159
 160 impl<'a> Decoder<'a> {
 161     #[inline]
 162     pub fn new(data: &'a [u8], position: usize) -> Decoder<'a> {
 163         Decoder { data, position }
 164     }
 165
 166     #[inline]
 167     pub fn position(&self) -> usize {
 168         self.position
 169     }
 170
 171     #[inline]
 172     pub fn set_position(&mut self, pos: usize) {
 173         self.position = pos
 174     }
 175
 176     #[inline]
 177     pub fn advance(&mut self, bytes: usize) {
 178         self.position += bytes;
 179     }
 180
 181     #[inline]
 182     pub fn read_raw_bytes(&mut self, s: &mut [u8]) -> Result<(), String> {
 183         let start = self.position;
 184         let end = start + s.len();
 185
 186         s.copy_from_slice(&self.data[start..end]);
 187
 188         self.position = end;
 189
 190         Ok(())
 191     }
 192 }
 193
 194 macro_rules! read_uleb128 {
 195     ($dec:expr, $fun:ident) => {{
 196         let (value, bytes_read) = leb128::$fun(&$dec.data[$dec.position..]);
 197         $dec.position += bytes_read;
 198         Ok(value)
 199     }};
 200 }
 201
 202 macro_rules! read_sleb128 {
 203     ($dec:expr, $t:ty) => {{
 204         let (value, bytes_read) = read_signed_leb128($dec.data, $dec.position);
 205         $dec.position += bytes_read;
 206         Ok(value as $t)
 207     }};
 208 }
 209
 210 impl<'a> serialize::Decoder for Decoder<'a> {
 211     type Error = String;
 212
 213     #[inline]
 214     fn read_nil(&mut self) -> Result<(), Self::Error> {
 215         Ok(())
 216     }
 217
 218     #[inline]
 219     fn read_u128(&mut self) -> Result<u128, Self::Error> {
 220         read_uleb128!(self, read_u128_leb128)
 221     }
 222
 223     #[inline]
 224     fn read_u64(&mut self) -> Result<u64, Self::Error> {
 225         read_uleb128!(self, read_u64_leb128)
 226     }
 227
 228     #[inline]
 229     fn read_u32(&mut self) -> Result<u32, Self::Error> {
 230         read_uleb128!(self, read_u32_leb128)
 231     }
 232
 233     #[inline]
 234     fn read_u16(&mut self) -> Result<u16, Self::Error> {
 235         read_uleb128!(self, read_u16_leb128)
 236     }
 237
 238     #[inline]
 239     fn read_u8(&mut self) -> Result<u8, Self::Error> {
 240         let value = self.data[self.position];
 241         self.position += 1;
 242         Ok(value)
 243     }
 244
 245     #[inline]
 246     fn read_usize(&mut self) -> Result<usize, Self::Error> {
 247         read_uleb128!(self, read_usize_leb128)
 248     }
 249
 250     #[inline]
 251     fn read_i128(&mut self) -> Result<i128, Self::Error> {
 252         read_sleb128!(self, i128)
 253     }
 254
 255     #[inline]
 256     fn read_i64(&mut self) -> Result<i64, Self::Error> {
 257         read_sleb128!(self, i64)
 258     }
 259
 260     #[inline]
 261     fn read_i32(&mut self) -> Result<i32, Self::Error> {
 262         read_sleb128!(self, i32)
 263     }
 264
 265     #[inline]
 266     fn read_i16(&mut self) -> Result<i16, Self::Error> {
 267         read_sleb128!(self, i16)
 268     }
 269
 270     #[inline]
 271     fn read_i8(&mut self) -> Result<i8, Self::Error> {
 272         let as_u8 = self.data[self.position];
 273         self.position += 1;
 274         unsafe { Ok(::std::mem::transmute(as_u8)) }
 275     }
 276
 277     #[inline]
 278     fn read_isize(&mut self) -> Result<isize, Self::Error> {
 279         read_sleb128!(self, isize)
 280     }
 281
 282     #[inline]
 283     fn read_bool(&mut self) -> Result<bool, Self::Error> {
 284         let value = self.read_u8()?;
 285         Ok(value != 0)
 286     }
 287
 288     #[inline]
 289     fn read_f64(&mut self) -> Result<f64, Self::Error> {
 290         let bits = self.read_u64()?;
 291         Ok(f64::from_bits(bits))
 292     }
 293
 294     #[inline]
 295     fn read_f32(&mut self) -> Result<f32, Self::Error> {
 296         let bits = self.read_u32()?;
 297         Ok(f32::from_bits(bits))
 298     }
 299
 300     #[inline]
 301     fn read_char(&mut self) -> Result<char, Self::Error> {
 302         let bits = self.read_u32()?;
 303         Ok(::std::char::from_u32(bits).unwrap())
 304     }
 305
 306     #[inline]
 307     fn read_str(&mut self) -> Result<Cow<'_, str>, Self::Error> {
 308         let len = self.read_usize()?;
 309         let s = ::std::str::from_utf8(&self.data[self.position..self.position + len]).unwrap();
 310         self.position += len;
 311         Ok(Cow::Borrowed(s))
 312     }
 313
 314     #[inline]
 315     fn error(&mut self, err: &str) -> Self::Error {
 316         err.to_string()
 317     }
 318 }