Add support for extended hash + add support for output hash to custom buffer when supported

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 35 insertions, 14 deletions

diff --git a/libhashsum_init_keccak__.c b/libhashsum_init_keccak__.c
index 03dd466..ee146bc 100644
--- a/libhashsum_init_keccak__.c
+++ b/libhashsum_init_keccak__.c
@@ -4,6 +4,26 @@
 
 
 LIBHASHSUM_1_NONNULL_
+static void
+stretch(struct libhashsum_hasher *this, int skip, void *buffer)
+{
+	if (skip) {
+		libkeccak_fast_squeeze(&this->state.keccak.s, 1);
+		return;
+	}
+
+	if (buffer)
+		this->hash_output = NULL;
+	else if (this->hash_size > sizeof(this->state.keccak.sum.buf))
+		this->hash_output = this->state.keccak.sum.dyn;
+	else
+		this->hash_output = this->state.keccak.sum.buf;
+
+	libkeccak_squeeze(&this->state.keccak.s, buffer ? buffer : this->hash_output);
+}
+
+
+LIBHASHSUM_1_NONNULL_
 static size_t
 process(struct libhashsum_hasher *this, const void *data, size_t bytes)
 {
@@ -29,15 +49,15 @@ finalise_const(struct libhashsum_hasher *this, const void *data, size_t bytes, u
 	m = &m[r];
 	bytes -= r;
 
-	if (this->hash_size > sizeof(this->state.keccak.sum.buf))
-		this->hash_output = this->state.keccak.sum.dyn;
-	else
-		this->hash_output = this->state.keccak.sum.buf;
+	if (!this->hash_output) {
+		if (this->hash_size > sizeof(this->state.keccak.sum.buf))
+			this->hash_output = this->state.keccak.sum.dyn;
+		else
+			this->hash_output = this->state.keccak.sum.buf;
+	}
 	libkeccak_digest(&this->state.keccak.s, m, bytes, extra_bits, this->state.keccak.suffix, this->hash_output);
 	libkeccak_state_wipe_message(&this->state.keccak.s);
-	libkeccak_state_fast_destroy(&this->state.keccak.s);
-	memset(&this->state.keccak.s, 0, sizeof(this->state.keccak.s));
-	this->state.keccak.s.M = NULL;
+	this->stretch = &stretch;
 	return 0;
 }
 
@@ -68,10 +88,12 @@ finalise(struct libhashsum_hasher *this, void *data, size_t bytes, unsigned extr
 		need += this->input_block_size;
 	}
 
-	if (this->hash_size > sizeof(this->state.keccak.sum.buf))
-		this->hash_output = this->state.keccak.sum.dyn;
-	else
-		this->hash_output = this->state.keccak.sum.buf;
+	if (!this->hash_output) {
+		if (this->hash_size > sizeof(this->state.keccak.sum.buf))
+			this->hash_output = this->state.keccak.sum.dyn;
+		else
+			this->hash_output = this->state.keccak.sum.buf;
+	}
 	if (size < need)
 		libkeccak_digest(&this->state.keccak.s, m, bytes, extra_bits, this->state.keccak.suffix,
 		                 this->state.keccak.squeezes > 1U ? NULL : this->hash_output);
@@ -90,9 +112,7 @@ finalise(struct libhashsum_hasher *this, void *data, size_t bytes, unsigned extr
 		libkeccak_squeeze(&this->state.keccak.s, this->hash_output);
 
 	libkeccak_state_wipe_message(&this->state.keccak.s);
-	libkeccak_state_fast_destroy(&this->state.keccak.s);
-	memset(&this->state.keccak.s, 0, sizeof(this->state.keccak.s));
-	this->state.keccak.s.M = NULL;
+	this->stretch = &stretch;
 	return 0;
 }
 
@@ -142,6 +162,7 @@ libhashsum_init_keccak__(struct libhashsum_hasher *this, size_t hashbits, void *
 	this->process = &process;
 	this->finalise_const = &finalise_const;
 	this->finalise = &finalise;
+	this->stretch = NULL;
 	this->destroy = &destroy;
 	return 0;
 }