avutil: Add detailed Doxygen description to a few hashes

libavutil/crc.h

@@ -37,6 +37,10 @@
  * @ingroup lavu_hash
  * CRC (Cyclic Redundancy Check) hash function implementation.
  *
+ * This module supports numerous CRC polynomials, in addition to the most
+ * widely used CRC-32-IEEE. See @ref AVCRCId for a list of available
+ * polynomials.
+ *
  * @{
  */
 

libavutil/sha.h

@@ -37,6 +37,14 @@
  * @ingroup lavu_hash
  * SHA-1 and SHA-256 (Secure Hash Algorithm) hash function implementations.
  *
+ * This module supports the following SHA hash functions:
+ *
+ * - SHA-1: 160 bits
+ * - SHA-224: 224 bits, as a variant of SHA-2
+ * - SHA-256: 256 bits, as a variant of SHA-2
+ *
+ * @see For SHA-384, SHA-512, and variants thereof, see @ref lavu_sha512.
+ *
  * @{
  */
 

libavutil/sha512.h

@@ -38,6 +38,15 @@
  * @ingroup lavu_hash
  * SHA-512 (Secure Hash Algorithm) hash function implementations.
  *
+ * This module supports the following SHA-2 hash functions:
+ *
+ * - SHA-512/224: 224 bits
+ * - SHA-512/256: 256 bits
+ * - SHA-384: 384 bits
+ * - SHA-512: 512 bits
+ *
+ * @see For SHA-1, SHA-256, and variants thereof, see @ref lavu_sha.
+ *
  * @{
  */