core/crypto: Documentation cleanups

core/crypto/legacy/md5/md5.odin

@@ -1,3 +1,13 @@
+/*
+package md5 implements the MD5 hash algorithm.
+
+WARNING: The MD5 algorithm is known to be insecure and should only be
+used for interoperating with legacy applications.
+
+See:
+- https://eprint.iacr.org/2005/075
+- https://datatracker.ietf.org/doc/html/rfc1321
+*/
 package md5
 
 /*
@@ -6,16 +16,26 @@ package md5
 
     List of contributors:
         zhibog, dotbmp:  Initial implementation.
-
-    Implementation of the MD5 hashing algorithm, as defined in RFC 1321 <https://datatracker.ietf.org/doc/html/rfc1321>
 */
 
 import "core:encoding/endian"
 import "core:math/bits"
 import "core:mem"
 
+// DIGEST_SIZE is the MD5 digest size.
 DIGEST_SIZE :: 16
 
+// Context is a MD5 instance.
+Context :: struct {
+	data:    [BLOCK_SIZE]byte,
+	state:   [4]u32,
+	bitlen:  u64,
+	datalen: u32,
+
+	is_initialized: bool,
+}
+
+// init initializes a Context.
 init :: proc(ctx: ^Context) {
 	ctx.state[0] = 0x67452301
 	ctx.state[1] = 0xefcdab89
@@ -28,6 +48,7 @@ init :: proc(ctx: ^Context) {
 	ctx.is_initialized = true
 }
 
+// update adds more data to the Context.
 update :: proc(ctx: ^Context, data: []byte) {
 	assert(ctx.is_initialized)
 
@@ -42,6 +63,11 @@ update :: proc(ctx: ^Context, data: []byte) {
 	}
 }
 
+// final finalizes the Context, writes the digest to hash, and calls
+// reset on the Context.
+//
+// Iff finalize_clone is set, final will work on a copy of the Context,
+// which is useful for for calculating rolling digests.
 final :: proc(ctx: ^Context, hash: []byte, finalize_clone: bool = false) {
 	assert(ctx.is_initialized)
 
@@ -86,10 +112,13 @@ final :: proc(ctx: ^Context, hash: []byte, finalize_clone: bool = false) {
 	}
 }
 
+// clone clones the Context other into ctx.
 clone :: proc(ctx, other: ^$T) {
 	ctx^ = other^
 }
 
+// reset sanitizes the Context.  The Context must be re-initialized to
+// be used again.
 reset :: proc(ctx: ^$T) {
 	if !ctx.is_initialized {
 		return
@@ -102,17 +131,9 @@ reset :: proc(ctx: ^$T) {
     MD5 implementation
 */
 
+@(private)
 BLOCK_SIZE :: 64
 
-Context :: struct {
-	data:    [BLOCK_SIZE]byte,
-	state:   [4]u32,
-	bitlen:  u64,
-	datalen: u32,
-
-	is_initialized: bool,
-}
-
 /*
     @note(zh): F, G, H and I, as mentioned in the RFC, have been inlined into FF, GG, HH
     and II respectively, instead of declaring them separately.