1 // Copyright 2013-2014 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 //! Utility mixins that apply to all Readers and Writers
13 #![allow(missing_docs)]
15 // FIXME: Not sure how this should be structured
16 // FIXME: Iteration should probably be considered separately
18 use io::{IoError, IoResult, Reader};
24 use option::Option::{Some, None};
26 use result::Result::{Ok, Err};
27 use slice::{SliceExt, AsSlice};
29 /// An iterator that reads a single byte on each iteration,
30 /// until `.read_byte()` returns `EndOfFile`.
32 /// # Notes about the Iteration Protocol
34 /// The `Bytes` may yield `None` and thus terminate
35 /// an iteration, but continue to yield elements if iteration
36 /// is attempted again.
40 /// Any error other than `EndOfFile` that is produced by the underlying Reader
41 /// is returned by the iterator and should be handled by the caller.
42 pub struct Bytes<'r, T:'r> {
46 impl<'r, R: Reader> Bytes<'r, R> {
47 /// Constructs a new byte iterator from the given Reader instance.
48 pub fn new(r: &'r mut R) -> Bytes<'r, R> {
55 impl<'r, R: Reader> Iterator<IoResult<u8>> for Bytes<'r, R> {
57 fn next(&mut self) -> Option<IoResult<u8>> {
58 match self.reader.read_byte() {
60 Err(IoError { kind: io::EndOfFile, .. }) => None,
61 Err(e) => Some(Err(e))
66 /// Converts an 8-bit to 64-bit unsigned value to a little-endian byte
67 /// representation of the given size. If the size is not big enough to
68 /// represent the value, then the high-order bytes are truncated.
72 /// * `n`: The value to convert.
73 /// * `size`: The size of the value, in bytes. This must be 8 or less, or task
74 /// panic occurs. If this is less than 8, then a value of that
75 /// many bytes is produced. For example, if `size` is 4, then a
76 /// 32-bit byte representation is produced.
77 /// * `f`: A callback that receives the value.
79 /// This function returns the value returned by the callback, for convenience.
80 pub fn u64_to_le_bytes<T, F>(n: u64, size: uint, f: F) -> T where
81 F: FnOnce(&[u8]) -> T,
85 // LLVM fails to properly optimize this when using shifts instead of the to_le* intrinsics
89 2u => f(unsafe { & transmute::<_, [u8; 2]>((n as u16).to_le()) }),
90 4u => f(unsafe { & transmute::<_, [u8; 4]>((n as u32).to_le()) }),
91 8u => f(unsafe { & transmute::<_, [u8; 8]>(n.to_le()) }),
94 let mut bytes = vec!();
98 bytes.push((n & 255_u64) as u8);
107 /// Converts an 8-bit to 64-bit unsigned value to a big-endian byte
108 /// representation of the given size. If the size is not big enough to
109 /// represent the value, then the high-order bytes are truncated.
113 /// * `n`: The value to convert.
114 /// * `size`: The size of the value, in bytes. This must be 8 or less, or task
115 /// panic occurs. If this is less than 8, then a value of that
116 /// many bytes is produced. For example, if `size` is 4, then a
117 /// 32-bit byte representation is produced.
118 /// * `f`: A callback that receives the value.
120 /// This function returns the value returned by the callback, for convenience.
121 pub fn u64_to_be_bytes<T, F>(n: u64, size: uint, f: F) -> T where
122 F: FnOnce(&[u8]) -> T,
126 // LLVM fails to properly optimize this when using shifts instead of the to_be* intrinsics
130 2u => f(unsafe { & transmute::<_, [u8; 2]>((n as u16).to_be()) }),
131 4u => f(unsafe { & transmute::<_, [u8; 4]>((n as u32).to_be()) }),
132 8u => f(unsafe { & transmute::<_, [u8; 8]>(n.to_be()) }),
134 let mut bytes = vec!();
137 let shift = (i - 1u) * 8u;
138 bytes.push((n >> shift) as u8);
146 /// Extracts an 8-bit to 64-bit unsigned big-endian value from the given byte
147 /// buffer and returns it as a 64-bit value.
151 /// * `data`: The buffer in which to extract the value.
152 /// * `start`: The offset at which to extract the value.
153 /// * `size`: The size of the value in bytes to extract. This must be 8 or
154 /// less, or task panic occurs. If this is less than 8, then only
155 /// that many bytes are parsed. For example, if `size` is 4, then a
156 /// 32-bit value is parsed.
157 pub fn u64_from_be_bytes(data: &[u8], start: uint, size: uint) -> u64 {
158 use ptr::{copy_nonoverlapping_memory};
163 if data.len() - start < size {
164 panic!("index out of bounds");
167 let mut buf = [0u8; 8];
169 let ptr = data.as_ptr().offset(start as int);
170 let out = buf.as_mut_ptr();
171 copy_nonoverlapping_memory(out.offset((8 - size) as int), ptr, size);
172 (*(out as *const u64)).to_be()
180 use io::{MemReader, BytesReader};
182 struct InitialZeroByteReader {
186 impl Reader for InitialZeroByteReader {
187 fn read(&mut self, buf: &mut [u8]) -> io::IoResult<uint> {
200 impl Reader for EofReader {
201 fn read(&mut self, _: &mut [u8]) -> io::IoResult<uint> {
202 Err(io::standard_error(io::EndOfFile))
206 struct ErroringReader;
208 impl Reader for ErroringReader {
209 fn read(&mut self, _: &mut [u8]) -> io::IoResult<uint> {
210 Err(io::standard_error(io::InvalidInput))
214 struct PartialReader {
218 impl Reader for PartialReader {
219 fn read(&mut self, buf: &mut [u8]) -> io::IoResult<uint> {
233 struct ErroringLaterReader {
237 impl Reader for ErroringLaterReader {
238 fn read(&mut self, buf: &mut [u8]) -> io::IoResult<uint> {
244 Err(io::standard_error(io::InvalidInput))
249 struct ThreeChunkReader {
253 impl Reader for ThreeChunkReader {
254 fn read(&mut self, buf: &mut [u8]) -> io::IoResult<uint> {
260 } else if self.count == 1 {
266 Err(io::standard_error(io::EndOfFile))
273 let mut reader = MemReader::new(vec!(10));
274 let byte = reader.read_byte();
275 assert!(byte == Ok(10));
279 fn read_byte_0_bytes() {
280 let mut reader = InitialZeroByteReader {
283 let byte = reader.read_byte();
284 assert!(byte == Ok(10));
289 let mut reader = EofReader;
290 let byte = reader.read_byte();
291 assert!(byte.is_err());
295 fn read_byte_error() {
296 let mut reader = ErroringReader;
297 let byte = reader.read_byte();
298 assert!(byte.is_err());
303 let mut reader = InitialZeroByteReader {
306 let byte = reader.bytes().next();
307 assert!(byte == Some(Ok(10)));
312 let mut reader = EofReader;
313 let byte = reader.bytes().next();
314 assert!(byte.is_none());
319 let mut reader = ErroringReader;
320 let mut it = reader.bytes();
321 let byte = it.next();
322 assert!(byte.unwrap().is_err());
327 let mut reader = MemReader::new(vec!(10, 11, 12, 13));
328 let bytes = reader.read_exact(4).unwrap();
329 assert!(bytes == vec!(10, 11, 12, 13));
333 fn read_bytes_partial() {
334 let mut reader = PartialReader {
337 let bytes = reader.read_exact(4).unwrap();
338 assert!(bytes == vec!(10, 11, 12, 13));
342 fn read_bytes_eof() {
343 let mut reader = MemReader::new(vec!(10, 11));
344 assert!(reader.read_exact(4).is_err());
349 let mut reader = MemReader::new(vec![10, 11, 12, 13]);
350 let mut buf = vec![8, 9];
351 assert!(reader.push_at_least(4, 4, &mut buf).is_ok());
352 assert!(buf == vec![8, 9, 10, 11, 12, 13]);
356 fn push_at_least_partial() {
357 let mut reader = PartialReader {
360 let mut buf = vec![8, 9];
361 assert!(reader.push_at_least(4, 4, &mut buf).is_ok());
362 assert!(buf == vec![8, 9, 10, 11, 12, 13]);
366 fn push_at_least_eof() {
367 let mut reader = MemReader::new(vec![10, 11]);
368 let mut buf = vec![8, 9];
369 assert!(reader.push_at_least(4, 4, &mut buf).is_err());
370 assert!(buf == vec![8, 9, 10, 11]);
374 fn push_at_least_error() {
375 let mut reader = ErroringLaterReader {
378 let mut buf = vec![8, 9];
379 assert!(reader.push_at_least(4, 4, &mut buf).is_err());
380 assert!(buf == vec![8, 9, 10]);
385 let mut reader = ThreeChunkReader {
388 let buf = reader.read_to_end().unwrap();
389 assert!(buf == vec!(10, 11, 12, 13));
394 fn read_to_end_error() {
395 let mut reader = ThreeChunkReader {
398 let buf = reader.read_to_end().unwrap();
399 assert!(buf == vec!(10, 11));
403 fn test_read_write_le_mem() {
404 let uints = [0, 1, 2, 42, 10_123, 100_123_456, ::u64::MAX];
406 let mut writer = Vec::new();
407 for i in uints.iter() {
408 writer.write_le_u64(*i).unwrap();
411 let mut reader = MemReader::new(writer);
412 for i in uints.iter() {
413 assert!(reader.read_le_u64().unwrap() == *i);
419 fn test_read_write_be() {
420 let uints = [0, 1, 2, 42, 10_123, 100_123_456, ::u64::MAX];
422 let mut writer = Vec::new();
423 for i in uints.iter() {
424 writer.write_be_u64(*i).unwrap();
427 let mut reader = MemReader::new(writer);
428 for i in uints.iter() {
429 assert!(reader.read_be_u64().unwrap() == *i);
434 fn test_read_be_int_n() {
435 let ints = [::i32::MIN, -123456, -42, -5, 0, 1, ::i32::MAX];
437 let mut writer = Vec::new();
438 for i in ints.iter() {
439 writer.write_be_i32(*i).unwrap();
442 let mut reader = MemReader::new(writer);
443 for i in ints.iter() {
444 // this tests that the sign extension is working
445 // (comparing the values as i32 would not test this)
446 assert!(reader.read_be_int_n(4).unwrap() == *i as i64);
452 //big-endian floating-point 8.1250
453 let buf = vec![0x41, 0x02, 0x00, 0x00];
455 let mut writer = Vec::new();
456 writer.write(buf.as_slice()).unwrap();
458 let mut reader = MemReader::new(writer);
459 let f = reader.read_be_f32().unwrap();
460 assert!(f == 8.1250);
464 fn test_read_write_f32() {
467 let mut writer = Vec::new();
468 writer.write_be_f32(f).unwrap();
469 writer.write_le_f32(f).unwrap();
471 let mut reader = MemReader::new(writer);
472 assert!(reader.read_be_f32().unwrap() == 8.1250);
473 assert!(reader.read_le_f32().unwrap() == 8.1250);
477 fn test_u64_from_be_bytes() {
478 use super::u64_from_be_bytes;
480 let buf = [0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09];
483 assert_eq!(u64_from_be_bytes(&buf, 0, 0), 0);
484 assert_eq!(u64_from_be_bytes(&buf, 0, 1), 0x01);
485 assert_eq!(u64_from_be_bytes(&buf, 0, 2), 0x0102);
486 assert_eq!(u64_from_be_bytes(&buf, 0, 3), 0x010203);
487 assert_eq!(u64_from_be_bytes(&buf, 0, 4), 0x01020304);
488 assert_eq!(u64_from_be_bytes(&buf, 0, 5), 0x0102030405);
489 assert_eq!(u64_from_be_bytes(&buf, 0, 6), 0x010203040506);
490 assert_eq!(u64_from_be_bytes(&buf, 0, 7), 0x01020304050607);
491 assert_eq!(u64_from_be_bytes(&buf, 0, 8), 0x0102030405060708);
494 assert_eq!(u64_from_be_bytes(&buf, 1, 0), 0);
495 assert_eq!(u64_from_be_bytes(&buf, 1, 1), 0x02);
496 assert_eq!(u64_from_be_bytes(&buf, 1, 2), 0x0203);
497 assert_eq!(u64_from_be_bytes(&buf, 1, 3), 0x020304);
498 assert_eq!(u64_from_be_bytes(&buf, 1, 4), 0x02030405);
499 assert_eq!(u64_from_be_bytes(&buf, 1, 5), 0x0203040506);
500 assert_eq!(u64_from_be_bytes(&buf, 1, 6), 0x020304050607);
501 assert_eq!(u64_from_be_bytes(&buf, 1, 7), 0x02030405060708);
502 assert_eq!(u64_from_be_bytes(&buf, 1, 8), 0x0203040506070809);
511 use self::test::Bencher;
513 // why is this a macro? wouldn't an inlined function work just as well?
514 macro_rules! u64_from_be_bytes_bench_impl {
515 ($b:expr, $size:expr, $stride:expr, $start_index:expr) =>
517 use super::u64_from_be_bytes;
519 let data = Vec::from_fn($stride*100+$start_index, |i| i as u8);
522 let mut i = $start_index;
523 while i < data.len() {
524 sum += u64_from_be_bytes(data.as_slice(), i, $size);
532 fn u64_from_be_bytes_4_aligned(b: &mut Bencher) {
533 u64_from_be_bytes_bench_impl!(b, 4, 4, 0);
537 fn u64_from_be_bytes_4_unaligned(b: &mut Bencher) {
538 u64_from_be_bytes_bench_impl!(b, 4, 4, 1);
542 fn u64_from_be_bytes_7_aligned(b: &mut Bencher) {
543 u64_from_be_bytes_bench_impl!(b, 7, 8, 0);
547 fn u64_from_be_bytes_7_unaligned(b: &mut Bencher) {
548 u64_from_be_bytes_bench_impl!(b, 7, 8, 1);
552 fn u64_from_be_bytes_8_aligned(b: &mut Bencher) {
553 u64_from_be_bytes_bench_impl!(b, 8, 8, 0);
557 fn u64_from_be_bytes_8_unaligned(b: &mut Bencher) {
558 u64_from_be_bytes_bench_impl!(b, 8, 8, 1);