s4-codec 0.8.3

S4 (Squished S3) — pluggable GPU/CPU compression codec layer (nvCOMP zstd / Bitcomp, CPU zstd).
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
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

// build.rs — emits cargo link metadata when the `nvcomp-gpu` feature is on,
// and compiles the nvCOMP HLIF C-ABI shim via nvcc + ar.
//
// Without `nvcomp-gpu` the crate builds on any machine (no CUDA needed).

use std::path::PathBuf;
use std::process::Command;

fn main() {
    println!("cargo:rerun-if-changed=build.rs");
    println!("cargo:rerun-if-env-changed=NVCOMP_HOME");
    println!("cargo:rerun-if-env-changed=CUDA_HOME");
    println!("cargo:rerun-if-env-changed=NVCC");
    println!("cargo:rerun-if-changed=src/cuda_kernels/nvcomp_hlif_shim.cpp");

    if std::env::var_os("CARGO_FEATURE_NVCOMP_GPU").is_none() {
        return;
    }

    // ---------- Link metadata for nvCOMP / CUDA ----------

    let nvcomp_home = std::env::var("NVCOMP_HOME").unwrap_or_else(|_| "/opt/nvcomp".to_string());
    let nvcomp_lib = format!("{nvcomp_home}/lib");
    println!("cargo:rustc-link-search=native={nvcomp_lib}");
    println!("cargo:rustc-link-lib=dylib=nvcomp");
    println!("cargo:rustc-link-arg=-Wl,-rpath,{nvcomp_lib}");

    let cuda_home = std::env::var("CUDA_HOME").unwrap_or_else(|_| "/usr/local/cuda".to_string());
    let cuda_lib_candidates = [
        format!("{cuda_home}/lib64"),
        format!("{cuda_home}/lib"),
        format!("{cuda_home}/targets/x86_64-linux/lib"),
        format!("{cuda_home}/lib64/stubs"),
        format!("{cuda_home}/targets/x86_64-linux/lib/stubs"),
    ];
    for path in &cuda_lib_candidates {
        if std::path::Path::new(path).is_dir() {
            println!("cargo:rustc-link-search=native={path}");
        }
    }
    println!("cargo:rustc-link-lib=dylib=cudart");
    println!("cargo:rustc-link-lib=dylib=cuda");

    // ---------- HLIF C-ABI shim (C++ → static lib via nvcc + ar) ----------

    let manifest_dir = PathBuf::from(
        std::env::var("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR unset under cargo"),
    );
    let out_dir = PathBuf::from(std::env::var("OUT_DIR").expect("OUT_DIR unset under cargo"));

    let nvcc = std::env::var("NVCC").ok().or_else(|| {
        let candidate = format!("{cuda_home}/bin/nvcc");
        if std::path::Path::new(&candidate).exists() {
            Some(candidate)
        } else if Command::new("nvcc").arg("--version").output().is_ok() {
            Some("nvcc".to_string())
        } else {
            None
        }
    });

    let nvcomp_include = format!("{nvcomp_home}/include");
    let shim_cpp = manifest_dir.join("src/cuda_kernels/nvcomp_hlif_shim.cpp");
    let shim_obj = out_dir.join("nvcomp_hlif_shim.o");
    let shim_lib = out_dir.join("libferro_nvcomp_hlif_shim.a");
    if let Some(nvcc_path) = nvcc.as_deref() {
        let status = Command::new(nvcc_path)
            .args([
                "-std=c++17",
                "-O3",
                "-arch=sm_89",
                "-Xcompiler",
                "-fPIC",
                "-c",
                "-I",
            ])
            .arg(&nvcomp_include)
            .arg(&shim_cpp)
            .arg("-o")
            .arg(&shim_obj)
            .status();
        match status {
            Ok(s) if s.success() => {
                let ar_status = Command::new("ar")
                    .arg("crs")
                    .arg(&shim_lib)
                    .arg(&shim_obj)
                    .status();
                match ar_status {
                    Ok(s) if s.success() => {
                        println!(
                            "cargo:warning=s4-codec: built HLIF shim ({}) via nvcc + ar",
                            shim_lib.display()
                        );
                        println!("cargo:rustc-link-search=native={}", out_dir.display());
                        println!("cargo:rustc-link-lib=static=ferro_nvcomp_hlif_shim");
                        println!("cargo:rustc-link-lib=dylib=stdc++");
                    }
                    Ok(s) => {
                        println!(
                            "cargo:warning=s4-codec: ar failed (exit {}) on {}; HLIF backend will not link",
                            s,
                            shim_lib.display()
                        );
                    }
                    Err(e) => {
                        println!(
                            "cargo:warning=s4-codec: ar spawn failed: {}; HLIF backend will not link",
                            e
                        );
                    }
                }
            }
            Ok(s) => {
                println!(
                    "cargo:warning=s4-codec: nvcc HLIF shim build failed (exit {}); HLIF backend disabled",
                    s
                );
            }
            Err(e) => {
                println!(
                    "cargo:warning=s4-codec: nvcc HLIF shim spawn failed: {}; HLIF backend disabled",
                    e
                );
            }
        }
    } else {
        println!(
            "cargo:warning=s4-codec: nvcc unavailable; HLIF shim not built. Backend will return BackendUnavailable at runtime."
        );
    }
}