qubit_io/std_io/impls/
input.rs

1// =============================================================================
2//    Copyright (c) 2026 Haixing Hu.
3//
4//    SPDX-License-Identifier: Apache-2.0
5//
6//    Licensed under the Apache License, Version 2.0.
7// =============================================================================
8
9//! Standard [`Read`](std::io::Read) implementations of item input traits.
10
11use std::io::{
12    Read,
13    Result,
14};
15
16use crate::{
17    Input,
18    UncheckedSlice,
19    traits::validate_read_count,
20};
21
22/// Bridges byte-oriented standard readers to item-oriented input.
23impl<R> Input for R
24where
25    R: Read + ?Sized,
26{
27    /// Bytes read by the standard Read implementation.
28    type Item = u8;
29
30    /// Reads bytes into a caller-validated indexed output range.
31    ///
32    /// # Parameters
33    ///
34    /// - `output`: Destination byte slice.
35    /// - `index`: Start offset inside `output`.
36    /// - `count`: Maximum number of bytes to read.
37    ///
38    /// # Returns
39    ///
40    /// The number of bytes reported by the standard reader.
41    ///
42    /// # Errors
43    ///
44    /// Returns the error reported by the standard reader.
45    ///
46    /// # Panics
47    ///
48    /// Panics in debug builds if the requested destination range does not fit.
49    ///
50    /// # Safety
51    ///
52    /// The caller must ensure that index through index plus count is a valid
53    /// range inside output without overflowing.
54    #[inline(always)]
55    unsafe fn read_unchecked(
56        &mut self,
57        output: &mut [u8],
58        index: usize,
59        count: usize,
60    ) -> Result<usize> {
61        // SAFETY: The caller guarantees that the range is valid inside output.
62        let target =
63            unsafe { UncheckedSlice::subslice_mut(output, index, count) };
64        Read::read(self, target)
65    }
66
67    /// Reads bytes into the complete output slice.
68    ///
69    /// # Parameters
70    ///
71    /// - `output`: Destination byte slice.
72    ///
73    /// # Returns
74    ///
75    /// The number of bytes read into `output`.
76    ///
77    /// # Errors
78    ///
79    /// Returns [`std::io::ErrorKind::InvalidData`] if the reader reports more
80    /// bytes than `output` holds, or the error reported by the standard reader.
81    #[inline(always)]
82    fn read(&mut self, output: &mut [Self::Item]) -> Result<usize> {
83        let read = Read::read(self, output)?;
84        validate_read_count(read, output.len())?;
85        Ok(read)
86    }
87}
qubit_io/std_io/impls/input.rs

qubit_io/std_io/impls/
input.rs
