1 files changed, 37 insertions, 0 deletions
diff --git a/src/crc.rs b/src/crc.rs
new file mode 100644
index 0000000..f24da02
--- /dev/null
+++ b/src/crc.rs
@@ -0,0 +1,37 @@
+const CRC_TABLE: [u32; 256] = make_crc_table();
+
+const fn make_crc_table() -> [u32; 256]
+{
+	let mut table =  [0u32; 256];
+	let mut c: u32;
+	let mut k: i32;
+	let mut n: u32 = 0;
+	while n < 256
+	{
+		c = n;
+		k = 0;
+		while k < 8
+		{
+			if c & 1 == 1
+			{
+				c = 0xedb88320 ^ (c >> 1);
+			}
+			else
+			{
+				c = c >> 1;
+			}
+			k += 1;
+		}
+		table[n as usize] = c;
+		n += 1;
+	}
+	table
+}
+
+pub fn update_crc(curr_crc: &mut u32, buff: &[u8]) -> ()
+{
+	for x in buff
+	{
+		*curr_crc = CRC_TABLE[((*curr_crc as u8 ^ x) & 0xff) as usize] ^ (*curr_crc >> 8);
+	}
+}