bpx 3.1.0

BPX official rust implementation
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106

// Copyright (c) 2021, BlockProject 3D
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
//     * Redistributions of source code must retain the above copyright notice,
//       this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright notice,
//       this list of conditions and the following disclaimer in the documentation
//       and/or other materials provided with the distribution.
//     * Neither the name of BlockProject 3D nor the names of its contributors
//       may be used to endorse or promote products derived from this software
//       without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

//! Utilities to manipulate the content of sections.

use std::{
    boxed::Box,
    io::{Read, Result, Seek, Write},
    vec::Vec
};

mod file;
mod memory;

const MEMORY_THRESHOLD: u32 = 100000000;

/// Opaque variant intended to manipulate section data in the form of standard IO operations.
pub trait SectionData: Read + Write + Seek
{
    /// Loads this section into memory.
    ///
    /// # Errors
    ///
    /// An [Error](crate::error::Error) is returned if the section could not be loaded.
    ///
    /// # Examples
    ///
    /// ```
    /// use bpx::encoder::Encoder;
    /// use bpx::header::SectionHeader;
    /// use bpx::Interface;
    ///
    /// let mut file = Encoder::new(Vec::<u8>::new()).unwrap();
    /// let handle = file.create_section(SectionHeader::new()).unwrap();
    /// let section = file.open_section(handle).unwrap();
    /// let data = section.load_in_memory().unwrap();
    /// assert_eq!(data.len(), 0);
    /// ```
    fn load_in_memory(&mut self) -> Result<Vec<u8>>;

    /// Returns the current size of this section.
    ///
    /// # Examples
    ///
    /// ```
    /// use bpx::encoder::Encoder;
    /// use bpx::header::SectionHeader;
    /// use bpx::Interface;
    ///
    /// let mut file = Encoder::new(Vec::<u8>::new()).unwrap();
    /// let handle = file.create_section(SectionHeader::new()).unwrap();
    /// let section = file.open_section(handle).unwrap();
    /// assert_eq!(section.size(), 0);
    /// ```
    fn size(&self) -> usize;
}

/// Creates new section data by automatically choosing the right container given a section size.
///
/// *This function is not intended for direct use.*
///
/// # Arguments
///
/// * `size`: optional size of section, if None the section will automatically reallocate to fit its content.
///
/// returns: Result<Box<dyn SectionData, Global>, Error>
///
/// # Errors
///
/// An [Error](std::io::Error) is returned in case the temporary file could not be created.
pub fn new_section_data(size: Option<u32>) -> Result<Box<dyn SectionData>>
{
    if let Some(s) = size {
        if s > MEMORY_THRESHOLD {
            return Ok(Box::new(file::FileBasedSection::new(tempfile::tempfile()?)));
        } else {
            return Ok(Box::new(memory::InMemorySection::new(vec![0; s as usize])));
        }
    }
    return Ok(Box::new(file::FileBasedSection::new(tempfile::tempfile()?)));
}