crc-fast-rust: added conditional panic handler for CI no_std checks; global allocator for CI wasm checks. libs shouldn't contain this.

Author: loadingalias

src/lib.rs

@@ -136,6 +136,31 @@
 //!
 //! Supports `no_std` environments. Use `default-features = false` in Cargo.toml.
 
+// Provide a panic handler for no_std library checks/builds
+// This is only used when checking the library itself; final binaries must provide their own
+#[cfg(all(not(feature = "std"), not(test), not(doctest)))]
+#[panic_handler]
+fn panic(_info: &core::panic::PanicInfo) -> ! {
+    loop {}
+}
+
+// Provide a global allocator for no_std + alloc library checks/builds
+// This is only used when checking the library itself; final binaries must provide their own
+#[cfg(all(feature = "alloc", not(feature = "std"), not(test), not(doctest)))]
+#[global_allocator]
+static ALLOCATOR: LibcAllocator = LibcAllocator;
+
+#[cfg(all(feature = "alloc", not(feature = "std"), not(test), not(doctest)))]
+struct LibcAllocator;
+
+#[cfg(all(feature = "alloc", not(feature = "std"), not(test), not(doctest)))]
+unsafe impl core::alloc::GlobalAlloc for LibcAllocator {
+    unsafe fn alloc(&self, _layout: core::alloc::Layout) -> *mut u8 {
+        core::ptr::null_mut()
+    }
+    unsafe fn dealloc(&self, _ptr: *mut u8, _layout: core::alloc::Layout) {}
+}
+
 use crate::crc32::consts::{
     CRC32_AIXM, CRC32_AUTOSAR, CRC32_BASE91_D, CRC32_BZIP2, CRC32_CD_ROM_EDC, CRC32_CKSUM,
     CRC32_ISCSI, CRC32_ISO_HDLC, CRC32_JAMCRC, CRC32_MEF, CRC32_MPEG_2, CRC32_XFER,