From e20291d78e5118ef594f651cc60843e191476438 Mon Sep 17 00:00:00 2001
From: Paul Barker <paul@paulbarker.me.uk>
Date: Sat, 16 Jan 2016 17:25:14 +0000
Subject: [PATCH] Add crypt_generichash_blake2b_statebytes function

The function crypto_generichash_statebytes exists to dynamically determine the
size of a crypto_generichash_state struct. This is useful when using libsodium
from a language which can't use sizeof on C types. However, no equivalent
existed for the crypto_generichash_blake2b_state struct for users who want to
explicitly use the blake2b algorithm.

The function crypt_generichash_blake2b_statebytes is added to fill this gap.
---
 .../crypto_generichash/blake2/generichash_blake2_api.c     | 7 +++++++
 src/libsodium/include/sodium/crypto_generichash_blake2b.h  | 3 +++
 test/default/generichash3.c                                | 1 +
 3 files changed, 11 insertions(+)

diff --git a/src/libsodium/crypto_generichash/blake2/generichash_blake2_api.c b/src/libsodium/crypto_generichash/blake2/generichash_blake2_api.c
index b775921e..14f16e42 100644
--- a/src/libsodium/crypto_generichash/blake2/generichash_blake2_api.c
+++ b/src/libsodium/crypto_generichash/blake2/generichash_blake2_api.c
@@ -39,3 +39,10 @@ size_t
 crypto_generichash_blake2b_personalbytes(void) {
     return crypto_generichash_blake2b_PERSONALBYTES;
 }
+
+size_t
+crypto_generichash_blake2b_statebytes(void)
+{
+    return (sizeof(crypto_generichash_blake2b_state) + (size_t) 63U)
+        & ~(size_t) 63U;
+}
diff --git a/src/libsodium/include/sodium/crypto_generichash_blake2b.h b/src/libsodium/include/sodium/crypto_generichash_blake2b.h
index 1708813e..3998e1bd 100644
--- a/src/libsodium/include/sodium/crypto_generichash_blake2b.h
+++ b/src/libsodium/include/sodium/crypto_generichash_blake2b.h
@@ -67,6 +67,9 @@ size_t crypto_generichash_blake2b_saltbytes(void);
 SODIUM_EXPORT
 size_t crypto_generichash_blake2b_personalbytes(void);
 
+SODIUM_EXPORT
+size_t crypto_generichash_blake2b_statebytes(void);
+
 SODIUM_EXPORT
 int crypto_generichash_blake2b(unsigned char *out, size_t outlen,
                                const unsigned char *in,
diff --git a/test/default/generichash3.c b/test/default/generichash3.c
index e430b725..fa0045e2 100644
--- a/test/default/generichash3.c
+++ b/test/default/generichash3.c
@@ -20,6 +20,7 @@ main(void)
     size_t        i;
     size_t        j;
 
+    assert(crypto_generichash_blake2b_statebytes() >= sizeof st);
     for (h = 0; h < crypto_generichash_blake2b_KEYBYTES_MAX; ++h) {
         k[h] = (unsigned char) h;
     }