Document SHA-1 functions and structures

Originally committed as revision 19385 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavutil/sha1.c

@@ -23,10 +23,11 @@
 #include "bswap.h"
 #include "sha1.h"
 
+/** hash context */
 typedef struct AVSHA1 {
-    uint64_t count;
+    uint64_t count;       ///< number of bytes in buffer
-    uint8_t buffer[64];
+    uint8_t buffer[64];   ///< 512-bit buffer of input values used in hash updating
-    uint32_t state[5];
+    uint32_t state[5];    ///< current hash value
 } AVSHA1;
 
 const int av_sha1_size = sizeof(AVSHA1);

libavutil/sha1.h

@@ -27,8 +27,28 @@ extern const int av_sha1_size;
 
 struct AVSHA1;
 
+/**
+ * Initializes SHA-1 hashing.
+ *
+ * @param context pointer to the function context (of size av_sha_size)
+ */
 void av_sha1_init(struct AVSHA1* context);
+
+/**
+ * Updates hash value.
+ *
+ * @param context hash function context
+ * @param data    input data to update hash with
+ * @param len     input data length
+ */
 void av_sha1_update(struct AVSHA1* context, const uint8_t* data, unsigned int len);
+
+/**
+ * Finishes hashing and output digest value.
+ *
+ * @param context hash function context
+ * @param digest  buffer where output digest value is stored
+ */
 void av_sha1_final(struct AVSHA1* context, uint8_t digest[20]);
 
 #endif /* AVUTIL_SHA1_H */