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
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135

use std::{
    ffi::{c_char, CString},
    mem::MaybeUninit,
};

pub mod brotli;
pub mod bzip2;
pub mod deflate;
pub mod gzip;
pub mod lz4;
pub mod snappy;
pub mod zstd;

#[no_mangle]
pub extern "C" fn snappy_raw_decompress_into(
    input: *const u8,
    input_len: usize,
    output: *mut u8,
    output_len: usize,
    error: &mut *mut c_char,
) -> isize {
    let input_slice = unsafe { std::slice::from_raw_parts(input, input_len) };
    let mut output_slice = unsafe { std::slice::from_raw_parts_mut(output, output_len) };
    match snappy::raw::decompress(input_slice, &mut output_slice) {
        Ok(size) => size as _,
        Err(err) => {
            let err_msg = CString::new(err.to_string()).unwrap();
            *error = err_msg.into_raw();
            -1
        }
    }
}

#[no_mangle]
pub extern "C" fn snappy_raw_max_compressed_len(input_len: usize) -> usize {
    snap::raw::max_compress_len(input_len)
}

#[no_mangle]
pub extern "C" fn snappy_raw_compress_into(
    input: *const u8,
    input_len: usize,
    output: *mut u8,
    output_len: usize,
    error: &mut *mut c_char,
) -> isize {
    let input_slice = unsafe { std::slice::from_raw_parts(input, input_len) };
    let mut output_slice = unsafe { std::slice::from_raw_parts_mut(output, output_len) };
    match snappy::raw::compress(&input_slice, &mut output_slice) {
        Ok(size) => size as _,
        Err(err) => {
            let err_msg = CString::new(err.to_string()).unwrap();
            *error = err_msg.into_raw();
            -1
        }
    }
}

#[no_mangle]
pub extern "C" fn free_string(ptr: *mut c_char) {
    let _ = unsafe { CString::from_raw(ptr) };
}

#[cfg(test)]
mod tests {

    use std::io::Cursor;

    // Default testing data
    fn gen_data() -> Vec<u8> {
        (0..1000000)
            .map(|_| b"oh what a beautiful morning, oh what a beautiful day!!".to_vec())
            .flat_map(|v| v)
            .collect()
    }

    // Single test generation
    macro_rules! round_trip {
        ($name:ident($compress_output:ident -> $decompress_output:ident), variant=$variant:ident, compressed_len=$compressed_len:literal, $(level=$level:tt)?) => {
            #[test]
            fn $name() {
                let data = gen_data();

                let mut compressed = Vec::new();

                let compressed_size = if stringify!($decompress_output) == "Slice" {
                        compressed = (0..data.len()).map(|_| 0).collect::<Vec<u8>>();
                        let mut cursor = Cursor::new(compressed.as_mut_slice());
                        crate::$variant::compress(&mut Cursor::new(data.as_slice()), &mut cursor $(, $level)?).unwrap()
                    } else {
                        crate::$variant::compress(&mut Cursor::new(data.as_slice()), &mut Cursor::new(&mut compressed) $(, $level)?).unwrap()
                    };

                assert_eq!(compressed_size, $compressed_len);
                compressed.truncate(compressed_size);

                let mut decompressed = Vec::new();

                let decompressed_size = if stringify!($decompress_output) == "Slice" {
                        decompressed = (0..data.len()).map(|_| 0).collect::<Vec<u8>>();
                        let mut cursor = Cursor::new(decompressed.as_mut_slice());
                        crate::$variant::decompress(&mut Cursor::new(&compressed), &mut cursor).unwrap()
                    } else {
                        crate::$variant::decompress(&mut Cursor::new(&compressed), &mut decompressed).unwrap()
                    };
                assert_eq!(decompressed_size, data.len());
                if &decompressed[..decompressed_size] != &data {
                    panic!("Decompressed and original data do not match! :-(")
                }
            }
        }
    }

    // macro to generate each variation of Output::* roundtrip.
    macro_rules! test_variant {
        ($variant:ident, compressed_len=$compressed_len:literal, $(level=$level:tt)?) => {
         #[cfg(test)]
         mod $variant {
            use super::*;
            round_trip!(roundtrip_compress_via_slice_decompress_via_slice(Slice -> Slice), variant=$variant, compressed_len=$compressed_len, $(level=$level)? );
            round_trip!(roundtrip_compress_via_slice_decompress_via_vector(Slice -> Vector), variant=$variant, compressed_len=$compressed_len, $(level=$level)? );
            round_trip!(roundtrip_compress_via_vector_decompress_via_slice(Vector -> Slice), variant=$variant, compressed_len=$compressed_len, $(level=$level)? );
            round_trip!(roundtrip_compress_via_vector_decompress_via_vector(Vector -> Vector), variant=$variant, compressed_len=$compressed_len, $(level=$level)? );
         }
        }
    }

    test_variant!(snappy, compressed_len = 2572398,);
    test_variant!(gzip, compressed_len = 157192, level = None);
    test_variant!(brotli, compressed_len = 128, level = None);
    test_variant!(bzip2, compressed_len = 14207, level = None);
    test_variant!(deflate, compressed_len = 157174, level = None);
    test_variant!(zstd, compressed_len = 4990, level = None);
    test_variant!(lz4, compressed_len = 303278, level = None);
}