streaming

commit 2e101735bcb571463fd083fff12c7c8b294422aa
parent e7e2b86dca1304f64b739b15f24f474b5cffedeb
Author: blackfalcon <blackfalcon.ru@gmail.com>
Date:   Sat,  1 Jun 2024 03:59:57 -0300

scte35: use updateCRC

Diffstat:
M
scte35/crc_32.go
 | 
11
+++++------
M
scte35/splice.go
 | 
2
+-

2 files changed, 6 insertions(+), 7 deletions(-)
diff --git a/scte35/crc_32.go b/scte35/crc_32.go
@@ -41,11 +41,10 @@ func makeCRC32Table(poly uint32) crc32.Table {
 	return tab
 }
 
-// checksum calculates the checksum for the given bytes using tab.
-func checksum(b []byte, tab *crc32.Table) uint32 {
-	crc := int32(-1)
-	for i := range b {
-		crc = (crc << 8) ^ int32(tab[((crc>>24)^int32(b[i]))&0xFF])
+func updateCRC(val uint32, b []byte) uint32 {
+	crc := ^val
+	for _, v := range b {
+		crc = crctab[byte(crc>>24)^v] ^ (crc << 8)
 	}
-	return uint32(crc)
+	return ^crc
 }
diff --git a/scte35/splice.go b/scte35/splice.go
@@ -143,7 +143,7 @@ func Encode(splice *Splice) ([]byte, error) {
 	buf[1] |= byte(buflen >> 8)
 	buf[2] = byte(buflen)
 
-	crc := checksum(buf, &crctab)
+	crc := ^updateCRC(0, buf)
 	return binary.BigEndian.AppendUint32(buf, crc), nil
 }