conspire/io/vtk/write/
mod.rs

1use crate::io::deflate::zlib_encode;
2use std::path::Path;
3
4const COMPRESSION_BLOCK_SIZE: usize = 32768;
5
6pub enum Compression<P>
7where
8    P: AsRef<Path>,
9{
10    On(P),
11    Off(P),
12}
13
14impl<P> AsRef<Path> for Compression<P>
15where
16    P: AsRef<Path>,
17{
18    fn as_ref(&self) -> &Path {
19        match self {
20            Compression::On(path) => path.as_ref(),
21            Compression::Off(path) => path.as_ref(),
22        }
23    }
24}
25
26pub fn data_array(data: &[u8]) -> String {
27    let mut buffer = Vec::with_capacity(8 + data.len());
28    buffer.extend_from_slice(&(data.len() as u64).to_le_bytes());
29    buffer.extend_from_slice(data);
30    base64(&buffer)
31}
32
33pub fn data_array_compressed(data: &[u8]) -> String {
34    let compressed_blocks: Vec<Vec<u8>> = data
35        .chunks(COMPRESSION_BLOCK_SIZE)
36        .map(zlib_encode)
37        .collect();
38    let num_blocks = compressed_blocks.len() as u64;
39    let last_block_size =
40        data.len() as u64 - num_blocks.saturating_sub(1) * COMPRESSION_BLOCK_SIZE as u64;
41    let mut header = Vec::with_capacity(24 + compressed_blocks.len() * 8);
42    header.extend_from_slice(&num_blocks.to_le_bytes());
43    header.extend_from_slice(&(COMPRESSION_BLOCK_SIZE as u64).to_le_bytes());
44    header.extend_from_slice(&last_block_size.to_le_bytes());
45    for block in &compressed_blocks {
46        header.extend_from_slice(&(block.len() as u64).to_le_bytes());
47    }
48    let mut payload = Vec::with_capacity(compressed_blocks.iter().map(Vec::len).sum::<usize>());
49    for block in &compressed_blocks {
50        payload.extend_from_slice(block);
51    }
52    base64(&header) + &base64(&payload)
53}
54
55pub fn base64(bytes: &[u8]) -> String {
56    const ALPHABET: &[u8; 64] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
57    let mut out = String::with_capacity(bytes.len().div_ceil(3) * 4);
58    for chunk in bytes.chunks(3) {
59        let triple = ((chunk[0] as u32) << 16)
60            | ((*chunk.get(1).unwrap_or(&0) as u32) << 8)
61            | (*chunk.get(2).unwrap_or(&0) as u32);
62        out.push(ALPHABET[(triple >> 18 & 63) as usize] as char);
63        out.push(ALPHABET[(triple >> 12 & 63) as usize] as char);
64        out.push(if chunk.len() > 1 {
65            ALPHABET[(triple >> 6 & 63) as usize] as char
66        } else {
67            '='
68        });
69        out.push(if chunk.len() > 2 {
70            ALPHABET[(triple & 63) as usize] as char
71        } else {
72            '='
73        });
74    }
75    out
76}
conspire/io/vtk/write/mod.rs

conspire/io/vtk/write/
mod.rs
