diff --git a/lib/dictBuilder/zdict.rs b/lib/dictBuilder/zdict.rs
index 12ad311b..e38db8be 100644
--- a/lib/dictBuilder/zdict.rs
+++ b/lib/dictBuilder/zdict.rs
@@ -90,7 +90,7 @@ pub unsafe extern "C" fn ZDICT_getDictID(
     if MEM_readLE32(dictBuffer) != ZSTD_MAGIC_DICTIONARY {
         return 0;
     }
-    MEM_readLE32((dictBuffer as *const core::ffi::c_char).add(4) as *const core::ffi::c_void)
+    MEM_readLE32(dictBuffer.byte_add(4))
 }
 
 #[cfg_attr(feature = "export-symbols", export_name = crate::prefix!(ZDICT_getDictHeaderSize))]
@@ -98,22 +98,22 @@ pub unsafe extern "C" fn ZDICT_getDictHeaderSize(
     dictBuffer: *const core::ffi::c_void,
     dictSize: size_t,
 ) -> size_t {
-    let mut headerSize: size_t = 0;
     if dictSize <= 8 || MEM_readLE32(dictBuffer) != ZSTD_MAGIC_DICTIONARY {
         return Error::dictionary_corrupted.to_error_code();
     }
-    let bs = malloc(::core::mem::size_of::<ZSTD_compressedBlockState_t>())
-        as *mut ZSTD_compressedBlockState_t;
-    let wksp = malloc(HUF_WORKSPACE_SIZE as size_t) as *mut u32;
-    if bs.is_null() || wksp.is_null() {
-        headerSize = Error::memory_allocation.to_error_code();
-    } else {
-        ZSTD_reset_compressedBlockState(bs);
-        headerSize = ZSTD_loadCEntropy(bs, wksp as *mut core::ffi::c_void, dictBuffer, dictSize);
-    }
-    free(bs as *mut core::ffi::c_void);
-    free(wksp as *mut core::ffi::c_void);
-    headerSize
+
+    // FIXME: in 1.92 we can use https://doc.rust-lang.org/std/boxed/struct.Box.html#method.new_zeroed
+    let mut bs = Box::<ZSTD_compressedBlockState_t>::new_uninit();
+    unsafe { ZSTD_reset_compressedBlockState(bs.as_mut_ptr()) };
+
+    let mut wksp = Box::<[u32]>::new_uninit_slice(HUF_WORKSPACE_SIZE as size_t / 4);
+
+    ZSTD_loadCEntropy(
+        bs.as_mut_ptr(),
+        wksp.as_mut_ptr() as *mut core::ffi::c_void,
+        dictBuffer,
+        dictSize,
+    )
 }
 
 unsafe fn ZDICT_count(
@@ -142,6 +142,7 @@ unsafe fn ZDICT_initDictItem(d: *mut dictItem) {
     (*d).length = 0;
     (*d).savings = -(1 as core::ffi::c_int) as u32;
 }
+
 const LLIMIT: core::ffi::c_int = 64;
 const MINMATCHLENGTH: core::ffi::c_int = 7;
 unsafe fn ZDICT_analyzePos(
@@ -715,15 +716,15 @@ unsafe fn ZDICT_trainBuffer_legacy(
     result
 }
 
-fn ZDICT_fillNoise(buffer: &mut [u8]) {
+fn fill_noise(buffer: &mut [u8]) {
     const prime1: u32 = 2654435761;
     const prime2: u32 = 2246822519;
 
     let mut acc = prime1;
 
-    for e in buffer.iter_mut() {
+    for v in buffer.iter_mut() {
         acc = acc.wrapping_mul(prime2);
-        *e = (acc >> 21) as u8;
+        *v = (acc >> 21) as u8;
     }
 }
 
@@ -1575,7 +1576,7 @@ pub unsafe extern "C" fn ZDICT_trainFromBuffer_legacy(
     }
     let mut new_buf = vec![0u8; sBuffSize.wrapping_add(NOISELENGTH as size_t)];
     core::ptr::copy_nonoverlapping(samplesBuffer.cast::<u8>(), new_buf.as_mut_ptr(), sBuffSize);
-    ZDICT_fillNoise(&mut new_buf[sBuffSize..]);
+    fill_noise(&mut new_buf[sBuffSize..]);
     ZDICT_trainFromBuffer_unsafe_legacy(
         dictBuffer,
         dictBufferCapacity,
@@ -1631,3 +1632,57 @@ pub unsafe extern "C" fn ZDICT_addEntropyTablesFromBuffer(
         params,
     )
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    const DICT: &[u8] = include_bytes!("../../test-libzstd-rs-sys/test-data/test-dict.dat");
+
+    #[test]
+    fn test_get_dict_header_size() {
+        let empty: &[u8] = &[];
+        let code = unsafe { ZDICT_getDictHeaderSize(empty.as_ptr().cast(), empty.len()) };
+        assert_eq!(
+            Error::from_error_code(code),
+            Some(Error::dictionary_corrupted)
+        );
+
+        let no_magic: &[u8] = &[0; 8];
+        let code = unsafe { ZDICT_getDictHeaderSize(no_magic.as_ptr().cast(), no_magic.len()) };
+        assert_eq!(
+            Error::from_error_code(code),
+            Some(Error::dictionary_corrupted)
+        );
+
+        let code = unsafe { ZDICT_getDictHeaderSize(DICT.as_ptr().cast(), DICT.len()) };
+        match Error::from_error_code(code) {
+            Some(err) => panic!("{:?}", err),
+            None => assert_eq!(code, 133),
+        }
+    }
+
+    #[test]
+    fn test_get_dict_id() {
+        let empty: &[u8] = &[];
+        let code = unsafe { ZDICT_getDictID(empty.as_ptr().cast(), empty.len()) };
+        assert_eq!(code, 0);
+
+        let no_magic: &[u8] = &[0; 8];
+        let code = unsafe { ZDICT_getDictID(no_magic.as_ptr().cast(), no_magic.len()) };
+        assert_eq!(code, 0);
+
+        let code = unsafe { ZDICT_getDictID(DICT.as_ptr().cast(), DICT.len()) };
+        assert_eq!(code, 1877512422);
+    }
+
+    #[test]
+    fn test_fill_noise() {
+        let mut buf = vec![0u8; 16];
+        fill_noise(&mut buf);
+        assert_eq!(
+            buf,
+            [226, 51, 247, 105, 221, 225, 137, 112, 5, 188, 15, 79, 183, 243, 110, 209]
+        );
+    }
+}
diff --git a/test-libzstd-rs-sys/test-data/test-dict.dat b/test-libzstd-rs-sys/test-data/test-dict.dat
new file mode 100644
index 00000000..cbff1eed
Binary files /dev/null and b/test-libzstd-rs-sys/test-data/test-dict.dat differ