crc-fast-rust: created no-std-compatibility feature branch; updated deps/feature flags. added hashbrown; swapped std->core; added feature-flags. added test/example. adjusted the benchmark to clear a handful of warnings.

Author: loadingalias

.gitignore

@@ -4,4 +4,8 @@
 .idea
 .DS_Store
 .git
-.vscode
+.vscode
+
+no_std.md
+NO_STD_STATUS.md
+AUDIT_REPORT.md

Cargo.lock

@@ -23,19 +23,26 @@ bench = true
 
 [dependencies]
 crc = "3"
-digest = {  version = "0.10", features = ["alloc"] }
+digest = { version = "0.10", features = ["alloc"] }
 
 # will be removed once Rust 1.89 is the minimum supported version
 rustversion = "1.0"
 
 # constrain indexmap (transitive) to a version compatible with Rust 1.81.0
 indexmap = { version = ">=2.11.0, <2.12.0", optional = true }
 
+# no_std support
+# spin is always required for no_std builds (feature detection synchronization)
+spin = { version = "0.10.0", default-features = false, features = ["once", "rwlock"] }
+# hashbrown is only needed when caching is enabled in no_std
+hashbrown = { version = "0.16.0", optional = true }
+
 [dev-dependencies]
 criterion = "0.7"
 cbindgen = "0.29"
 rand = "0.9"
 regex = "1.12"
+wasm-bindgen-test = "0.3"
 
 # lto=true has a big improvement in performance
 [profile.release]
@@ -62,12 +69,15 @@ required-features = ["cli"]
 [[bench]]
 name = "benchmark"
 harness = false
+required-features = ["std"]
 
 [features]
 default = ["std"]
-std = []
+std = ["alloc"]  # std implies alloc is available
 cli = ["std"]
-alloc = []
+alloc = []  # marker feature for heap allocation support
+cache = ["alloc", "hashbrown"]  # caching requires alloc + hashbrown HashMap
+ffi = ["std"]
 
 # the features below are deprecated, aren't in use, and will be removed in the next MAJOR version (v2)
 vpclmulqdq = [] # deprecated, VPCLMULQDQ stabilized in Rust 1.89.0
@@ -87,4 +97,4 @@ rustdoc-args = ["--cfg", "docsrs"]
 [[test]]
 name = "checksum_integration_tests"
 path = "tests/checksum_integration_tests.rs"
-required-features = ["cli"]
+required-features = ["cli"]

Cargo.toml

@@ -59,11 +59,8 @@ fn create_aligned_data(input: &[u8]) -> Vec<u8> {
     // Size of our target alignment structure
     let align_size = std::mem::size_of::<[[u64; 4]; 2]>(); // 64 bytes
 
-    // Create a vector with padding to ensure we can find a properly aligned position
-    let mut padded = Vec::with_capacity(input.len() + align_size);
-
-    // Fill with zeros initially to reach needed capacity
-    padded.resize(input.len() + align_size, 0);
+    // Create a zero-filled vector with padding to ensure we can find a properly aligned position
+    let mut padded = vec![0; input.len() + align_size];
 
     // Find the first address that satisfies our alignment
     let start_addr = padded.as_ptr() as usize;
@@ -87,7 +84,7 @@ fn bench_crc32(c: &mut Criterion) {
     );
 
     for (size_name, size) in SIZES {
-        let buf = create_aligned_data(&*random_data(*size));
+        let buf = create_aligned_data(&random_data(*size));
 
         let (part1, rest) = buf.split_at(buf.len() / 4);
         let (part2, rest) = rest.split_at(rest.len() / 3);
@@ -115,10 +112,10 @@ fn bench_crc32(c: &mut Criterion) {
                 b.iter(|| {
                     black_box({
                         let mut digest = crc_fast::Digest::new(*algorithm);
-                        digest.update(&part1);
-                        digest.update(&part2);
-                        digest.update(&part3);
-                        digest.update(&part4);
+                        digest.update(part1);
+                        digest.update(part2);
+                        digest.update(part3);
+                        digest.update(part4);
                         digest.finalize()
                     })
                 })
@@ -137,7 +134,7 @@ fn bench_crc64(c: &mut Criterion) {
     let mut group = c.benchmark_group("CRC-64");
 
     for (size_name, size) in SIZES {
-        let buf = create_aligned_data(&*random_data(*size));
+        let buf = create_aligned_data(&random_data(*size));
 
         let (part1, rest) = buf.split_at(buf.len() / 4);
         let (part2, rest) = rest.split_at(rest.len() / 3);
@@ -165,10 +162,10 @@ fn bench_crc64(c: &mut Criterion) {
                 b.iter(|| {
                     black_box({
                         let mut digest = crc_fast::Digest::new(*algorithm);
-                        digest.update(&part1);
-                        digest.update(&part2);
-                        digest.update(&part3);
-                        digest.update(&part4);
+                        digest.update(part1);
+                        digest.update(part2);
+                        digest.update(part3);
+                        digest.update(part4);
                         digest.finalize()
                     })
                 })