1 files changed, 93 insertions, 0 deletions
diff --git a/libhashsum_init_sha2_hasher.c b/libhashsum_init_sha2_hasher.c
new file mode 100644
index 0000000..ab64517
--- /dev/null
+++ b/libhashsum_init_sha2_hasher.c
@@ -0,0 +1,93 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+LIBHASHSUM_1_NONNULL_
+static size_t
+process(struct libhashsum_hasher *this, const void *data, size_t bytes)
+{
+	const uint8_t *m = data;
+	int i;
+	bytes -= bytes & (this->input_block_size - 1U);
+	if (bytes > SIZE_MAX >> 3) {
+		for (i = 0; i < 8; i++) {
+			libsha2_update(&this->state.sha2.s, m, bytes);
+			m = &m[bytes >> 3];
+		}
+	} else if (bytes) {
+		libsha2_update(&this->state.sha2.s, m, bytes << 3);
+	}
+	return bytes;
+}
+
+
+LIBHASHSUM_1_NONNULL_
+static int
+finalise_const(struct libhashsum_hasher *this, const void *data, size_t bytes, unsigned extra_bits)
+{
+	const uint8_t *m = data;
+	size_t r;
+
+	if (extra_bits > 7U) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	r = process(this, m, bytes);
+	m = &m[r];
+	bytes -= r;
+
+	libsha2_digest(&this->state.sha2.s, data, (bytes << 3) | extra_bits, this->state.sha2.sum);
+	memset(&this->state.sha2.s, 0, sizeof(this->state.sha2.s));
+	this->hash_output = this->state.sha2.sum;
+	return 0;
+}
+
+
+LIBHASHSUM_1_NONNULL_
+static int
+finalise(struct libhashsum_hasher *this, void *data, size_t bytes, unsigned extra_bits, size_t size)
+{
+	(void) size;
+	return finalise_const(this, data, bytes, extra_bits);
+}
+
+
+int
+libhashsum_init_sha2_hasher(struct libhashsum_hasher *this, unsigned algobits, size_t hashbits)
+{
+	enum libsha2_algorithm algo;
+
+	if (algobits == 32U && hashbits == 224U) {
+		this->algorithm = LIBHASHSUM_SHA_224;
+		algo = LIBSHA2_224;
+	} else if (algobits == 32U && hashbits == 256U) {
+		this->algorithm = LIBHASHSUM_SHA_256;
+		algo = LIBSHA2_256;
+	} else if (algobits == 64U && hashbits == 384U) {
+		this->algorithm = LIBHASHSUM_SHA_384;
+		algo = LIBSHA2_384;
+	} else if (algobits == 64U && hashbits == 512U) {
+		this->algorithm = LIBHASHSUM_SHA_512;
+		algo = LIBSHA2_512;
+	} else if (algobits == 64U && hashbits == 224U) {
+		this->algorithm = LIBHASHSUM_SHA_512_224;
+		algo = LIBSHA2_512_224;
+	} else if (algobits == 64U && hashbits == 256U) {
+		this->algorithm = LIBHASHSUM_SHA_512_256;
+		algo = LIBSHA2_512_256;
+	} else {
+		errno = EINVAL;
+		return -1;
+	}
+
+	this->input_block_size = (size_t)algobits << 1;
+	this->hash_size = hashbits >> 3;
+	this->hash_output = NULL;
+	this->supports_non_whole_bytes = 1;
+	this->process = &process;
+	this->finalise_const = &finalise_const;
+	this->finalise = &finalise;
+	libsha2_init(&this->state.sha2.s, algo);
+	return 0;
+}