From 42e65ffe5f2659d998ff0a7e5ebea2573c23a86f Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Thu, 16 Aug 2012 16:38:31 +0200
Subject: crypto: Add more generic hash interface

---
 lib/crypto/doc/src/crypto.xml | 51 +++++++++++++++++++++++++++++++++++++++++++
 lib/crypto/src/crypto.erl     | 33 ++++++++++++++++++++++++++--
 2 files changed, 82 insertions(+), 2 deletions(-)

diff --git a/lib/crypto/doc/src/crypto.xml b/lib/crypto/doc/src/crypto.xml
index 36f8bc6deb..0d78dbc426 100644
--- a/lib/crypto/doc/src/crypto.xml
+++ b/lib/crypto/doc/src/crypto.xml
@@ -255,6 +255,57 @@ Mpint() = <![CDATA[<<ByteLen:32/integer-big, Bytes:ByteLen/binary>>]]>
           the computed <c>SHA</c> message digest.</p>
       </desc>
     </func>
+    <func>
+      <name>hash(Type, Data) -> Digest</name>
+      <fsummary></fsummary>
+      <type>
+	<v>Type = md4 | md5 | sha | sha224 | sha256 | sha384 | sha512</v>
+	<v>Data = iodata()</v>
+	<v>Digest = binary()</v>
+      </type>
+      <desc>
+        <p>Computes a message digest of type <c>Type</c> from <c>Data</c>.</p>
+      </desc>
+    </func>
+    <func>
+      <name>hash_init(Type) -> Context</name>
+      <fsummary></fsummary>
+      <type>
+	<v>Type = md4 | md5 | sha | sha224 | sha256 | sha384 | sha512</v>
+      </type>
+      <desc>
+        <p>Initializes the context for streaming hash operations. <c>Type</c> determines
+        which digest to use. The returned context should be used as argument
+	to <seealso marker="#hash_update/2">hash_update</seealso>.</p>
+      </desc>
+    </func>
+    <func>
+      <name>hash_update(Context, Data) -> NewContext</name>
+      <fsummary></fsummary>
+      <type>
+	<v>Data = iodata()</v>
+      </type>
+      <desc>
+        <p>Updates the digest represented by <c>Context</c> using the given <c>Data</c>. <c>Context</c>
+        must have been generated using <seealso marker="#hash_init/1">hash_init</seealso>
+	or a previous call to this function. <c>Data</c> can be any length. <c>NewContext</c>
+        must be passed into the next call to <c>hash_update</c>
+	or <seealso marker="#hash_final/1">hash_final</seealso>.</p>
+      </desc>
+    </func>
+    <func>
+      <name>hash_final(Context) -> Digest</name>
+      <fsummary></fsummary>
+      <type>
+	<v>Digest = binary()</v>
+      </type>
+      <desc>
+        <p>Finalizes the hash operation referenced by <c>Context</c> returned
+	from a previous call to <seealso marker="#hash_update/2">hash_update</seealso>.
+	The size of <c>Digest</c> is determined by the type of hash
+	function used to generate it.</p>
+      </desc>
+    </func>
     <func>
       <name>md5_mac(Key, Data) -> Mac</name>
       <fsummary>Compute an <c>MD5 MAC</c>message authentification code</fsummary>
diff --git a/lib/crypto/src/crypto.erl b/lib/crypto/src/crypto.erl
index a07e7a30b4..63043888b9 100644
--- a/lib/crypto/src/crypto.erl
+++ b/lib/crypto/src/crypto.erl
@@ -22,7 +22,7 @@
 -module(crypto).
 
 -export([start/0, stop/0, info/0, info_lib/0, version/0]).
--export([hash/2]).
+-export([hash/2, hash_init/1, hash_update/2, hash_final/1]).
 -export([md4/1, md4_init/0, md4_update/2, md4_final/1]).
 -export([md5/1, md5_init/0, md5_update/2, md5_final/1]).
 -export([sha/1, sha_init/0, sha_update/2, sha_final/1]).
@@ -194,11 +194,40 @@ version() -> ?CRYPTO_VSN.
 hash(md5, Data)    -> md5(Data);
 hash(md4, Data)    -> md4(Data);
 hash(sha, Data)    -> sha(Data);
-hash(sha1, Data)   -> sha(Data);
+hash(sha224, Data) -> sha224(Data);
 hash(sha256, Data) -> sha256(Data);
 hash(sha384, Data) -> sha384(Data);
 hash(sha512, Data) -> sha512(Data).
 
+-spec hash_init('md5'|'md4'|'sha'|'sha224'|'sha256'|'sha384'|'sha512') -> any().
+
+hash_init(md5) -> {md5, md5_init()};
+hash_init(md4) -> {md4, md4_init()};
+hash_init(sha) -> {sha, sha_init()};
+hash_init(sha224) -> {sha224, sha224_init()};
+hash_init(sha256) -> {sha256, sha256_init()};
+hash_init(sha384) -> {sha384, sha384_init()};
+hash_init(sha512) -> {sha512, sha512_init()}.
+
+-spec hash_update(_, iodata()) -> any().
+
+hash_update({md5,Context}, Data) -> {md5, md5_update(Context,Data)};
+hash_update({md4,Context}, Data) -> {md4, md4_update(Context,Data)};
+hash_update({sha,Context}, Data) -> {sha, sha_update(Context,Data)};
+hash_update({sha224,Context}, Data) -> {sha224, sha224_update(Context,Data)};
+hash_update({sha256,Context}, Data) -> {sha256, sha256_update(Context,Data)};
+hash_update({sha384,Context}, Data) -> {sha384, sha384_update(Context,Data)};
+hash_update({sha512,Context}, Data) -> {sha512, sha512_update(Context,Data)}.
+
+-spec hash_final(_) -> binary().
+
+hash_final({md5,Context}) -> md5_final(Context);
+hash_final({md4,Context}) -> md4_final(Context);
+hash_final({sha,Context}) -> sha_final(Context);
+hash_final({sha224,Context}) -> sha224_final(Context);
+hash_final({sha256,Context}) -> sha256_final(Context);
+hash_final({sha384,Context}) -> sha384_final(Context);
+hash_final({sha512,Context}) -> sha512_final(Context).
 
 %%
 %%  MD5
-- 
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