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| </pre><pre class="rust"><code><span class="kw">use </span>core::hash::Hasher; |
| |
| <span class="kw">pub use </span><span class="kw">crate</span>::util::make_table_crc32 <span class="kw">as </span>make_table; |
| <span class="kw">use </span><span class="kw">crate</span>::CalcType; |
| |
| <span class="kw">pub const </span>CASTAGNOLI: u32 = <span class="number">0x1EDC6F41</span>; |
| <span class="kw">pub const </span>CASTAGNOLI_TABLE: [u32; <span class="number">256</span>] = make_table(CASTAGNOLI, <span class="bool-val">true</span>); |
| <span class="kw">pub const </span>IEEE: u32 = <span class="number">0x04C11DB7</span>; |
| <span class="kw">pub const </span>IEEE_TABLE: [u32; <span class="number">256</span>] = make_table(IEEE, <span class="bool-val">true</span>); |
| <span class="kw">pub const </span>KOOPMAN: u32 = <span class="number">0x741B8CD7</span>; |
| <span class="kw">pub const </span>KOOPMAN_TABLE: [u32; <span class="number">256</span>] = make_table(KOOPMAN, <span class="bool-val">true</span>); |
| |
| <span class="doccomment">/// `Digest` struct for CRC calculation |
| /// - `table`: Calculation table generated from input parameters. |
| /// - `initial`: Initial value. |
| /// - `value`: Current value of the CRC calculation. |
| /// - `final_xor`: Final value to XOR with when calling `Digest::sum32()`. |
| /// - `calc`: Type of calculation. See its documentation for details. |
| </span><span class="kw">pub struct </span>Digest { |
| table: [u32; <span class="number">256</span>], |
| initial: u32, |
| value: u32, |
| final_xor: u32, |
| calc: CalcType, |
| } |
| |
| <span class="kw">pub trait </span>Hasher32 { |
| <span class="doccomment">/// Resets CRC calculation to `initial` value |
| </span><span class="kw">fn </span>reset(<span class="kw-2">&mut </span><span class="self">self</span>); |
| <span class="doccomment">/// Updates CRC calculation with input byte array `bytes` |
| </span><span class="kw">fn </span>write(<span class="kw-2">&mut </span><span class="self">self</span>, bytes: <span class="kw-2">&</span>[u8]); |
| <span class="doccomment">/// Returns checksum after being XOR'd with `final_xor` |
| </span><span class="kw">fn </span>sum32(<span class="kw-2">&</span><span class="self">self</span>) -> u32; |
| } |
| |
| <span class="doccomment">/// Updates input CRC value `value` using CRC table `table` with byte array `bytes`. |
| </span><span class="kw">pub fn </span>update(<span class="kw-2">mut </span>value: u32, table: <span class="kw-2">&</span>[u32; <span class="number">256</span>], bytes: <span class="kw-2">&</span>[u8], calc: <span class="kw-2">&</span>CalcType) -> u32 { |
| <span class="kw">match </span>calc { |
| CalcType::Normal => { |
| value = bytes.iter().fold(value, |acc, <span class="kw-2">&</span>x| { |
| (acc << <span class="number">8</span>) ^ (table[((u32::from(x)) ^ (acc >> <span class="number">24</span>)) <span class="kw">as </span>usize]) |
| }) |
| } |
| CalcType::Reverse => { |
| value = bytes.iter().fold(value, |acc, <span class="kw-2">&</span>x| { |
| (acc >> <span class="number">8</span>) ^ (table[((acc ^ (u32::from(x))) & <span class="number">0xFF</span>) <span class="kw">as </span>usize]) |
| }) |
| } |
| CalcType::Compat => { |
| value = !value; |
| value = bytes.iter().fold(value, |acc, <span class="kw-2">&</span>x| { |
| (acc >> <span class="number">8</span>) ^ (table[((acc ^ (u32::from(x))) & <span class="number">0xFF</span>) <span class="kw">as </span>usize]) |
| }); |
| value = !value; |
| } |
| } |
| |
| value |
| } |
| |
| <span class="doccomment">/// Generates a IEEE 32 bit CRC checksum (AKA CRC32). |
| </span><span class="kw">pub fn </span>checksum_ieee(bytes: <span class="kw-2">&</span>[u8]) -> u32 { |
| update(<span class="number">0u32</span>, <span class="kw-2">&</span>IEEE_TABLE, bytes, <span class="kw-2">&</span>CalcType::Compat) |
| } |
| |
| <span class="doccomment">/// Generates a Castagnoli 32 bit CRC checksum (AKA CRC32-C). |
| </span><span class="kw">pub fn </span>checksum_castagnoli(bytes: <span class="kw-2">&</span>[u8]) -> u32 { |
| update(<span class="number">0u32</span>, <span class="kw-2">&</span>CASTAGNOLI_TABLE, bytes, <span class="kw-2">&</span>CalcType::Compat) |
| } |
| |
| <span class="doccomment">/// Generates a Koopman 32 bit CRC checksum (AKA CRC32-K). |
| </span><span class="kw">pub fn </span>checksum_koopman(bytes: <span class="kw-2">&</span>[u8]) -> u32 { |
| update(<span class="number">0u32</span>, <span class="kw-2">&</span>KOOPMAN_TABLE, bytes, <span class="kw-2">&</span>CalcType::Compat) |
| } |
| |
| <span class="kw">impl </span>Digest { |
| <span class="doccomment">/// Creates a new Digest from input polynomial. |
| /// |
| /// # Example |
| /// |
| /// ```rust |
| /// use crc::{crc32, Hasher32}; |
| /// let mut digest = crc32::Digest::new(crc32::IEEE); |
| /// digest.write(b"123456789"); |
| /// assert_eq!(digest.sum32(), 0xcbf43926);; |
| /// ``` |
| </span><span class="kw">pub const fn </span>new(poly: u32) -> Digest { |
| Digest { |
| table: make_table(poly, <span class="bool-val">true</span>), |
| initial: <span class="number">0u32</span>, |
| value: <span class="number">0u32</span>, |
| final_xor: <span class="number">0u32</span>, |
| calc: CalcType::Compat, |
| } |
| } |
| |
| <span class="doccomment">/// Creates a new Digest from input polynomial and initial value. |
| /// |
| /// # Example |
| /// |
| /// ```rust |
| /// use crc::{crc32, Hasher32}; |
| /// let mut digest = crc32::Digest::new_with_initial(crc32::IEEE, 0u32); |
| /// digest.write(b"123456789"); |
| /// assert_eq!(digest.sum32(), 0xcbf43926); |
| /// ``` |
| </span><span class="kw">pub const fn </span>new_with_initial(poly: u32, initial: u32) -> Digest { |
| Digest { |
| table: make_table(poly, <span class="bool-val">true</span>), |
| initial, |
| value: initial, |
| final_xor: <span class="number">0u32</span>, |
| calc: CalcType::Compat, |
| } |
| } |
| |
| <span class="doccomment">/// Creates a fully customized Digest from input parameters. |
| /// |
| /// # Example |
| /// |
| /// ```rust |
| /// use crc::{crc32, Hasher32}; |
| /// let mut digest = crc32::Digest::new_custom(crc32::IEEE, !0u32, !0u32, crc::CalcType::Reverse); |
| /// digest.write(b"123456789"); |
| /// assert_eq!(digest.sum32(), 0xcbf43926); |
| /// ``` |
| </span><span class="kw">pub fn </span>new_custom(poly: u32, initial: u32, final_xor: u32, calc: CalcType) -> Digest { |
| <span class="kw">let </span><span class="kw-2">mut </span>rfl: bool = <span class="bool-val">true</span>; |
| <span class="kw">if let </span>CalcType::Normal = calc { |
| rfl = <span class="bool-val">false</span>; |
| } |
| |
| Digest { |
| table: make_table(poly, rfl), |
| initial, |
| value: initial, |
| final_xor, |
| calc, |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>Hasher32 <span class="kw">for </span>Digest { |
| <span class="kw">fn </span>reset(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="self">self</span>.value = <span class="self">self</span>.initial; |
| } |
| |
| <span class="kw">fn </span>write(<span class="kw-2">&mut </span><span class="self">self</span>, bytes: <span class="kw-2">&</span>[u8]) { |
| <span class="self">self</span>.value = update(<span class="self">self</span>.value, <span class="kw-2">&</span><span class="self">self</span>.table, bytes, <span class="kw-2">&</span><span class="self">self</span>.calc); |
| } |
| |
| <span class="kw">fn </span>sum32(<span class="kw-2">&</span><span class="self">self</span>) -> u32 { |
| <span class="self">self</span>.value ^ <span class="self">self</span>.final_xor |
| } |
| } |
| |
| <span class="kw">impl </span>Hasher <span class="kw">for </span>Digest { |
| <span class="kw">fn </span>finish(<span class="kw-2">&</span><span class="self">self</span>) -> u64 { |
| u64::from(<span class="self">self</span>.sum32()) |
| } |
| |
| <span class="kw">fn </span>write(<span class="kw-2">&mut </span><span class="self">self</span>, bytes: <span class="kw-2">&</span>[u8]) { |
| Hasher32::write(<span class="self">self</span>, bytes); |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="crc" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
