Change license to ISC and reorganise

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

28 files changed, 832 insertions, 1649 deletions

diff --git a/.gitignore b/.gitignore
index 2159246..6851f37 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,4 @@
 _/
-/bin/
-/obj/
 \#*\#
 .*
 !.git*
@@ -19,4 +17,3 @@ _/
 *.ps
 *.dvi
 *.test
-
diff --git a/COPYING b/COPYING
deleted file mode 100644
index d7b0ce5..0000000
--- a/COPYING
+++ /dev/null
@@ -1,17 +0,0 @@
-libsha2 – SHA-2-family hashing library
-
-Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
-
-This library is free software: you can redistribute it and/or modify
-it under the terms of the GNU Affero General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-(at your option) any later version.
-
-This library is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU Affero General Public License for more details.
-
-You should have received a copy of the GNU Affero General Public License
-along with this library.  If not, see <http://www.gnu.org/licenses/>.
-
diff --git a/LICENSE b/LICENSE
index dba13ed..e2e53aa 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,661 +1,15 @@
-                    GNU AFFERO GENERAL PUBLIC LICENSE
-                       Version 3, 19 November 2007
+ISC License
 
- Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
- Everyone is permitted to copy and distribute verbatim copies
- of this license document, but changing it is not allowed.
+© 2015, 2019 Mattias Andrée <maandree@kth.se>
 
-                            Preamble
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
 
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-Program specifies that a certain numbered version of the GNU Affero General
-Public License "or any later version" applies to it, you have the
-option of following the terms and conditions either of that numbered
-version or of any later version published by the Free Software
-Foundation.  If the Program does not specify a version number of the
-GNU Affero General Public License, you may choose any version ever published
-by the Free Software Foundation.
-
-  If the Program specifies that a proxy can decide which future
-versions of the GNU Affero General Public License can be used, that proxy's
-public statement of acceptance of a version permanently authorizes you
-to choose that version for the Program.
-
-  Later license versions may give you additional or different
-permissions.  However, no additional obligations are imposed on any
-author or copyright holder as a result of your choosing to follow a
-later version.
-
-  15. Disclaimer of Warranty.
-
-  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
-APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
-HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
-OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
-THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
-PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
-IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
-ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
-
-  16. Limitation of Liability.
-
-  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
-WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
-THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
-GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
-USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
-DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
-PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
-EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
-SUCH DAMAGES.
-
-  17. Interpretation of Sections 15 and 16.
-
-  If the disclaimer of warranty and limitation of liability provided
-above cannot be given local legal effect according to their terms,
-reviewing courts shall apply local law that most closely approximates
-an absolute waiver of all civil liability in connection with the
-Program, unless a warranty or assumption of liability accompanies a
-copy of the Program in return for a fee.
-
-                     END OF TERMS AND CONDITIONS
-
-            How to Apply These Terms to Your New Programs
-
-  If you develop a new program, and you want it to be of the greatest
-possible use to the public, the best way to achieve this is to make it
-free software which everyone can redistribute and change under these terms.
-
-  To do so, attach the following notices to the program.  It is safest
-to attach them to the start of each source file to most effectively
-state the exclusion of warranty; and each file should have at least
-the "copyright" line and a pointer to where the full notice is found.
-
-    <one line to give the program's name and a brief idea of what it does.>
-    Copyright (C) <year>  <name of author>
-
-    This program is free software: you can redistribute it and/or modify
-    it under the terms of the GNU Affero General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Affero General Public License for more details.
-
-    You should have received a copy of the GNU Affero General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-Also add information on how to contact you by electronic and paper mail.
-
-  If your software can interact with users remotely through a computer
-network, you should also make sure that it provides a way for users to
-get its source.  For example, if your program is a web application, its
-interface could display a "Source" link that leads users to an archive
-of the code.  There are many ways you could offer source, and different
-solutions will be better for different programs; see section 13 for the
-specific requirements.
-
-  You should also get your employer (if you work as a programmer) or school,
-if any, to sign a "copyright disclaimer" for the program, if necessary.
-For more information on this, and how to apply and follow the GNU AGPL, see
-<http://www.gnu.org/licenses/>.
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..566907e
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,55 @@
+.NONPOSIX:
+
+CONFIGFILE = config.mk
+
+LIB_MAJOR = 1
+LIB_MINOR = 0
+LIB_VERSION = $(LIB_MAJOR).$(LIB_MINOR)
+
+LIBEXT = so
+LIBFLAGS = -shared -Wl,-soname,libsha2.$(LIBEXT).$(LIB_MAJOR)
+
+include $(CONFIGFILE)
+
+
+HDR =\
+	libsha2.h\
+	common.h
+
+OBJ =\
+	algorithm_output_size.o\
+	behex_lower.o\
+	behex_upper.o\
+	digest.o\
+	state_initialise.o\
+	state_output_size.o\
+	sum_fd.o\
+	unhex.o\
+	update.o\
+
+
+all: libsha2.a libsha2.$(LIBEXT)
+$(OBJ): $(@:.o=.c) $(HDR)
+$(OBJ:.o=.lo): $(@:.lo=.c) $(HDR)
+
+.c.o:
+	$(CC) -c -o $@ $< $(CFLAGS)
+
+.c.lo:
+	$(CC) -fPIC -c -o $@ $< $(CFLAGS)
+
+libsha2.$(LIBEXT): $(OBJ)
+	$(CC) $(LIBFLAGS) -o $@ $(OBJ) $(LDFLAGS)
+
+libsha2.a: $(OBJ)
+	-rm -f -- $@
+	$(AR) rc $@ $?
+	$(AR) -s $@
+
+clean:
+	-rm -f -- *.o *.lo *.su *.a *.so
+
+.SUFFIXES:
+.SUFFIXES: .lo .o .c
+
+.PHONY: all check install uninstall clean
diff --git a/README b/README
index 392e533..4fedb6f 100644
--- a/README
+++ b/README
@@ -12,4 +12,3 @@ RATIONALE
 
 SEE ALSO
 	libkeccak(7), sha224sum(1), sha256sum(1), sha384sum(1), sha512sum(1)
-
diff --git a/algorithm_output_size.c b/algorithm_output_size.c
new file mode 100644
index 0000000..9089aa4
--- /dev/null
+++ b/algorithm_output_size.c
@@ -0,0 +1,24 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Get the output size of an algorithm
+ * 
+ * @parma   algorithm  The hashing algorithm
+ * @return             The number of bytes in the output, zero on error
+ */
+size_t
+libsha2_algorithm_output_size(enum libsha2_algorithm algorithm)
+{
+	switch (algorithm) {
+	case LIBSHA2_224:     return 28;
+	case LIBSHA2_256:     return 32;
+	case LIBSHA2_384:     return 48;
+	case LIBSHA2_512:     return 64;
+	case LIBSHA2_512_224: return 28;
+	case LIBSHA2_512_256: return 32;
+	default:
+		return errno = EINVAL, 0;
+	}
+}
diff --git a/behex_lower.c b/behex_lower.c
new file mode 100644
index 0000000..476bb18
--- /dev/null
+++ b/behex_lower.c
@@ -0,0 +1,20 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Convert a binary hashsum to lower case hexadecimal representation
+ * 
+ * @param  output   Output array, should have an allocation size of at least `2 * n + 1`
+ * @param  hashsum  The hashsum to convert
+ * @param  n        The size of `hashsum`
+ */
+void
+libsha2_behex_lower(char *restrict output, const char *restrict hashsum, size_t n)
+{
+	output[2 * n] = '\0';
+	while (n--) {
+		output[2 * n + 0] = "0123456789abcdef"[(hashsum[n] >> 4) & 15];
+		output[2 * n + 1] = "0123456789abcdef"[(hashsum[n] >> 0) & 15];
+	}
+}
diff --git a/behex_upper.c b/behex_upper.c
new file mode 100644
index 0000000..29e5f91
--- /dev/null
+++ b/behex_upper.c
@@ -0,0 +1,20 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Convert a binary hashsum to upper case hexadecimal representation
+ * 
+ * @param  output   Output array, should have an allocation size of at least `2 * n + 1`
+ * @param  hashsum  The hashsum to convert
+ * @param  n        The size of `hashsum`
+ */
+void
+libsha2_behex_upper(char *restrict output, const char *restrict hashsum, size_t n)
+{
+	output[2 * n] = '\0';
+	while (n--) {
+		output[2 * n + 0] = "0123456789ABCDEF"[(hashsum[n] >> 4) & 15];
+		output[2 * n + 1] = "0123456789ABCDEF"[(hashsum[n] >> 0) & 15];
+	}
+}
diff --git a/common.h b/common.h
new file mode 100644
index 0000000..746cf36
--- /dev/null
+++ b/common.h
@@ -0,0 +1,9 @@
+/* See LICENSE file for copyright and license details. */
+#include "libsha2.h"
+
+#include <sys/stat.h>
+#include <alloca.h>
+#include <errno.h>
+#include <stddef.h>
+#include <string.h>
+#include <unistd.h>
diff --git a/config.mk b/config.mk
new file mode 100644
index 0000000..c27a18b
--- /dev/null
+++ b/config.mk
@@ -0,0 +1,6 @@
+PREFIX = /usr
+MANPREFIX = $(PREFIX)/share/man
+
+CPPFLAGS = -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_XOPEN_SOURCE=700
+CFLAGS   = -std=c99 -Wall -Wextra -O3 $(CPPFLAGS)
+LDFLAGS  = -s
diff --git a/digest.c b/digest.c
new file mode 100644
index 0000000..8658388
--- /dev/null
+++ b/digest.c
@@ -0,0 +1,66 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Absorb the last part of the message and output a hash
+ * 
+ * @param  state    The hashing state
+ * @param  message  The message, in bits
+ * @param  msglen   The length of the message, zero if there is nothing more to absorb
+ * @param  output   The output buffer for the hash
+ */
+void
+libsha2_digest(struct libsha2_state *restrict state, const char *restrict message, size_t msglen, char *output)
+{
+	char *appendix;
+	size_t i, j, k, n;
+
+	if (msglen & ~7) {
+		libsha2_update(state, message, msglen & ~7);
+		message += msglen & ~7;
+		msglen &= 7;
+	}
+
+	k = 8 * state->chunk_size;
+	n = state->chunk_size + 8;
+	n = (k + (n % k)) % k;
+	n = n / 8 - 1;
+
+	appendix = state->appendix;
+	if (msglen) {
+		j = 7 - msglen;
+		*appendix = *message;
+		*appendix |= 1 << j;
+		*appendix &= ~((1 << j) - 1);
+	} else {
+		*appendix = (unsigned char)128;
+	}
+
+	k = state->message_size + msglen;
+	i = state->chunk_size / 8;
+	appendix += n + i - 1;
+	for (i = i < sizeof(size_t) ? i : sizeof(size_t); i--;)
+		*(appendix - i) = (unsigned char)((k >> (i * 8)) & 255);
+
+	n += state->chunk_size;
+	libsha2_update(state, state->appendix, n);
+
+	n = libsha2_algorithm_output_size(state->algorithm);
+	switch (state->algorithm) {
+	case LIBSHA2_224:
+	case LIBSHA2_256:
+		for (i = 0; i < 8; i++)
+			for (j = 0; j < (state->chunk_size / 16); j++)
+				if (k = (i + 1) * (state->chunk_size / 16) - j - 1, k < n)
+					output[k] = (char)((state->h.b32[i] >> (8 * j)) & 255);
+		break;
+
+	default:
+		for (i = 0; i < 8; i++)
+			for (j = 0; j < (state->chunk_size / 16); j++)
+				if (k = (i + 1) * (state->chunk_size / 16) - j - 1, k < n)
+					output[k] = (char)((state->h.b64[i] >> (8 * j)) & 255);
+		break;
+	}
+}
diff --git a/libsha2.h b/libsha2.h
new file mode 100644
index 0000000..5b37130
--- /dev/null
+++ b/libsha2.h
@@ -0,0 +1,268 @@
+/* See LICENSE file for copyright and license details. */
+#ifndef LIBSHA2_H
+#define LIBSHA2_H  1
+
+#include <stdint.h>
+#include <stddef.h>
+
+
+/**
+ * Algorithms supported by libsha2
+ */
+enum libsha2_algorithm {
+	/**
+	 * SHA-224, outputs 28 bytes
+	 */
+	LIBSHA2_224,
+
+	/**
+	 * SHA-256, outputs 32 bytes
+	 */
+	LIBSHA2_256,
+
+	/**
+	 * SHA-384, outputs 48 bytes
+	 */
+	LIBSHA2_384,
+
+	/**
+	 * SHA-512, outputs 64 bytes
+	 */
+	LIBSHA2_512,
+
+	/**
+	 * SHA-512/224, outputs 28 bytes
+	 */
+	LIBSHA2_512_224,
+
+	/**
+	 * SHA-512/256, outputs 32 bytes
+	 */
+	LIBSHA2_512_256
+};
+
+/**
+ * Data structure that describes the state of a hashing process
+ * 
+ * Data that could just as well be allocated (with `auto`) are
+ * allocated here so that is is easier to wipe the data without
+ * exposing two versions of each function: one to wipe data,
+ * and one not to wipe data to gain speed, now you can use use
+ * `explicit_bzero` (or `memset`) when you are done.
+ * 
+ * This data structure is flat (it contains dynamic pointers)
+ * and can be marshalled and unmarshalled naïvely, and does
+ * not need destroyed; however, if you when to marshall it
+ * using as little memory as possible, this are comments
+ * about data that does not need to be mashalled
+ */
+struct libsha2_state {
+	/**
+	 * The size of the message, as far as processed, in bits;
+	 */
+	size_t message_size;
+
+	/**
+	 * Round constants
+	 */
+	union {
+		/**
+		 * For 32-bit algorithms
+		 */
+		uint32_t b32[64];
+    
+		/**
+		 * For 64-bit algorithms
+		 */
+		uint64_t b64[80];
+	} k;
+
+	/**
+	 * Words
+	 * 
+	 * Does not need to be marshalled
+	 */
+	union {
+		/**
+		 * For 32-bit algorithms
+		 */
+		uint32_t b32[64];
+
+		/**
+		 * For 64-bit algorithms
+		 */
+		uint64_t b64[80];
+	} w;
+
+	/**
+	 * Hashing values
+	 */
+	union {
+		/**
+		 * For 32-bit algorithms
+		 */
+		uint32_t b32[8];
+
+		/**
+		 * For 64-bit algorithms
+		 */
+		uint64_t b64[8];
+	} h;
+
+	/**
+	 * Temporary hashing values
+	 * 
+	 * Does not need to be marshalled
+	 */
+	union {
+		/**
+		 * For 32-bit algorithms
+		 */
+		uint32_t b32[8];
+
+		/**
+		 * For 64-bit algorithms
+		 */
+		uint64_t b64[8];
+	} work_h;
+
+	/**
+	 * Space for chunks to process, limited
+	 * to 64 bytes on 32-bit algorithms
+	 */
+	unsigned char chunk[128];
+
+	/**
+	 * Space for storing the last bits and
+	 * the padding
+	 * 
+	 * Does not need to be marshalled
+	 */
+	char appendix[256];
+
+	/**
+	 * The size of the chunks, in bytes
+	 */
+	size_t chunk_size;
+
+	/**
+	 * The algorithm that is used
+	 */
+	enum libsha2_algorithm algorithm;
+
+	int __padding1;
+};
+
+
+/**
+ * Initialise a state
+ * 
+ * @parma   state      The state that should be initialised
+ * @parma   algorithm  The hashing algorithm
+ * @return             Zero on success, -1 on error
+ */
+#if defined(__GNUC__)
+__attribute__((__leaf__, __nothrow__, __nonnull__))
+#endif
+int libsha2_state_initialise(struct libsha2_state *restrict, enum libsha2_algorithm);
+
+/**
+ * Get the output size of the algorithm specified for a state
+ * 
+ * @parma   state  The state
+ * @return         The number of bytes in the output, zero on error
+ */
+#if defined(__GNUC__)
+__attribute__((__nothrow__, __nonnull__, __pure__))
+#endif
+size_t libsha2_state_output_size(const struct libsha2_state *restrict);
+
+/**
+ * Get the output size of an algorithm
+ * 
+ * @parma   algorithm  The hashing algorithm
+ * @return             The number of bytes in the output, zero on error
+ */
+#if defined(__GNUC__)
+__attribute__((__leaf__, __nothrow__, __const__))
+#endif
+size_t libsha2_algorithm_output_size(enum libsha2_algorithm);
+
+/**
+ * Absorb more of the message
+ * 
+ * @param  state    The hashing state
+ * @param  message  The message, in bits, must be equivalent to 0 modulus 8
+ * @param  msglen   The length of the message
+ */
+#if defined(__GNUC__)
+__attribute__((__nonnull__, __nothrow__))
+#endif
+void libsha2_update(struct libsha2_state *restrict, const char *restrict, size_t);
+
+/**
+ * Absorb the last part of the message and output a hash
+ * 
+ * @param  state    The hashing state
+ * @param  message  The message, in bits
+ * @param  msglen   The length of the message, zero if there is nothing more to absorb
+ * @param  output   The output buffer for the hash
+ */
+#if defined(__GNUC__)
+__attribute__((__nonnull__(1, 4), __nothrow__))
+#endif
+void libsha2_digest(struct libsha2_state *restrict, const char *restrict, size_t, char *);
+
+/**
+ * Calculate the checksum for a file,
+ * the content of the file is assumed non-sensitive
+ * 
+ * @param   fd         The file descriptor of the file
+ * @param   algorithm  The hashing algorithm
+ * @param   hashsum    Output buffer for the hash
+ * @return             Zero on success, -1 on error
+ */
+#if defined(__GNUC__)
+__attribute__((__nonnull__, __leaf__))
+#endif
+int libsha2_sum_fd(int, enum libsha2_algorithm, char *restrict);
+
+/**
+ * Convert a binary hashsum to lower case hexadecimal representation
+ * 
+ * @param  output   Output array, should have an allocation size of at least `2 * n + 1`
+ * @param  hashsum  The hashsum to convert
+ * @param  n        The size of `hashsum`
+ */
+#if defined(__GNUC__)
+__attribute__((__leaf__, __nonnull__, __nothrow__))
+#endif
+void libsha2_behex_lower(char *restrict, const char *restrict, size_t);
+
+/**
+ * Convert a binary hashsum to upper case hexadecimal representation
+ * 
+ * @param  output   Output array, should have an allocation size of at least `2 * n + 1`
+ * @param  hashsum  The hashsum to convert
+ * @param  n        The size of `hashsum`
+ */
+#if defined(__GNUC__)
+__attribute__((__leaf__, __nonnull__, __nothrow__))
+#endif
+void libsha2_behex_upper(char *restrict, const char *restrict, size_t);
+
+/**
+ * Convert a hexadecimal hashsum (both lower case, upper
+ * case and mixed is supported) to binary representation
+ * 
+ * @param  output   Output array, should have an allocation
+ *                  size of at least `strlen(hashsum) / 2`
+ * @param  hashsum  The hashsum to convert
+ */
+#if defined(__GNUC__)
+__attribute__((__leaf__, __nonnull__, __nothrow__))
+#endif
+void libsha2_unhex(char *restrict, const char *restrict);
+
+
+#endif
diff --git a/src/libsha2.h b/src/libsha2.h
deleted file mode 100644
index d6ebd2b..0000000
--- a/src/libsha2.h
+++ /dev/null
@@ -1,30 +0,0 @@
-/**
- * libsha2 – SHA-2-family hashing library
- * 
- * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
- * 
- * This library is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- * 
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- * 
- * You should have received a copy of the GNU Affero General Public License
- * along with this library.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef LIBSHA2_H
-#define LIBSHA2_H  1
-
-
-#include "libsha2/digest.h"
-#include "libsha2/state.h"
-#include "libsha2/hex.h"
-#include "libsha2/files.h"
-
-
-#endif
-
diff --git a/src/libsha2/digest.c b/src/libsha2/digest.c
deleted file mode 100644
index 6b4765e..0000000
--- a/src/libsha2/digest.c
+++ /dev/null
@@ -1,217 +0,0 @@
-/**
- * libsha2 – SHA-2-family hashing library
- * 
- * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
- * 
- * This library is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- * 
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- * 
- * You should have received a copy of the GNU Affero General Public License
- * along with this library.  If not, see <http://www.gnu.org/licenses/>.
- */
-#include "digest.h"
-#include <alloca.h>
-#include <string.h>
-
-
-
-/**
- * Unified implementation (what can unified without performance impact)
- * of the chunk processing for all SHA-2 functions
- * 
- * @param  A       Wordsize-dependent constant, take a look at the code
- * @param  B       Wordsize-dependent constant, take a look at the code
- * @param  C       Wordsize-dependent constant, take a look at the code
- * @param  D       Wordsize-dependent constant, take a look at the code
- * @param  E       Wordsize-dependent constant, take a look at the code
- * @param  F       Wordsize-dependent constant, take a look at the code
- * @param  G       Wordsize-dependent constant, take a look at the code
- * @param  H       Wordsize-dependent constant, take a look at the code
- * @param  I       Wordsize-dependent constant, take a look at the code
- * @param  J       Wordsize-dependent constant, take a look at the code
- * @param  K       Wordsize-dependent constant, take a look at the code
- * @param  L       Wordsize-dependent constant, take a look at the code
- * @param  WORD_T  `__typeof()` on any wordsize-dependent variable, with exact size
- * @param  k       Round constants
- * @param  w       Words
- * @param  h       Hash values
- * @param  work_h  Space for temporary hash values
- */
-#define SHA2_IMPLEMENTATION(A, B, C, D, E, F, G, H, I, J, K, L, WORD_T, k, w, h, work_h)	\
-  memcpy(work_h, h, sizeof(work_h));								\
-												\
-  memset(w, 0, 16 * sizeof(*(w)));								\
-  for (i = 0; i < 16; i++)									\
-    for (j = 0; j < sizeof(WORD_T); j++)							\
-      w[i] |= ((WORD_T)(state->chunk[(i + 1) * sizeof(WORD_T) - j - 1])) << (j << 3);		\
-												\
-  for (i = 16; i < sizeof(k) / sizeof(*(k)); i++)						\
-    {												\
-      w[i] = w[i - 16] + w[i - 7];								\
-      w[i] += ROTR(w[i - 15], A) ^ ROTR(w[i - 15], B) ^ (w[i - 15] >> (C));			\
-      w[i] += ROTR(w[i - 2], D) ^ ROTR(w[i - 2], E) ^ (w[i - 2] >> (F));			\
-    }												\
-												\
-  for (i = 0; i < sizeof(k) / sizeof(*(k)); i++)						\
-    {												\
-      s1 = (work_h[4] & work_h[5]) ^ (work_h[6] & ~(work_h[4]));				\
-      s1 += work_h[7] + k[i] + w[i];								\
-      s0 = (work_h[0] & work_h[1]) ^ (work_h[0] & work_h[2]) ^ (work_h[1] & work_h[2]);		\
-      s1 += ROTR(work_h[4], G) ^ ROTR(work_h[4], H) ^ ROTR(work_h[4], I);			\
-      s0 += ROTR(work_h[0], J) ^ ROTR(work_h[0], K) ^ ROTR(work_h[0], L);			\
-      												\
-      memmove(work_h + 1, work_h, 7 * sizeof(*(work_h)));					\
-      work_h[4] += s1;										\
-      work_h[0] = s1 + s0;									\
-    }												\
-												\
-  for (i = 0; i < 8; i++)									\
-    h[i] += work_h[i]
-
-
-
-/**
- * Process a chunk using SHA-256
- * 
- * @param  state  The hashing state
- */
-static __attribute__((nonnull, nothrow))
-void process256(libsha2_state_t* restrict state)
-{
-  uint32_t s0, s1;
-  size_t i, j;
-#define ROTR(X, N)  (((X) >> (N)) | ((X) << ((sizeof(uint32_t) * 8) - (N))))
-  SHA2_IMPLEMENTATION(7, 18, 3, 17, 19, 10, 6, 11, 25, 2, 13, 22, uint32_t,
-		      state->k.b32, state->w.b32, state->h.b32, state->work_h.b32);
-#undef ROTR
-}
-
-
-/**
- * Process a chunk using SHA-512
- * 
- * @param  state  The hashing state
- */
-static __attribute__((nonnull, nothrow))
-void process512(libsha2_state_t* restrict state)
-{
-  uint64_t s0, s1;
-  size_t i, j;
-#define ROTR(X, N)  (((X) >> (N)) | ((X) << ((sizeof(uint64_t) * 8) - (N))))
-  SHA2_IMPLEMENTATION(1, 8, 7, 19, 61, 6, 14, 18, 41, 28, 34, 39, uint64_t,
-		      state->k.b64, state->w.b64, state->h.b64, state->work_h.b64);
-#undef ROTR
-}
-
-
-/**
- * Absorb more of the message
- * 
- * @param  state    The hashing state
- * @param  message  The message, in bits, must be equivalent to 0 modulus 8
- * @param  msglen   The length of the message
- */
-void libsha2_update(libsha2_state_t* restrict state, const char* restrict message, size_t msglen)
-{
-  size_t n, off, mlen;
-  
-  msglen /= 8;
-  mlen = state->message_size / 8;
-  
-  while (msglen)
-    {
-      off = mlen % state->chunk_size;
-      n = state->chunk_size - off;
-      n = n < msglen ? n : msglen;
-      memcpy(state->chunk + off, message, n);
-      if (off + n == state->chunk_size)
-	switch (state->algorithm)
-	  {
-	  case LIBSHA2_224:
-	  case LIBSHA2_256:
-	    process256(state);
-	    break;
-	    
-	  default:
-	    process512(state);
-	    break;
-	  }
-      message += n, mlen += n, msglen -= n;
-    }
-  
-  state->message_size = mlen * 8;
-}
-
-
-/**
- * Absorb the last part of the message and output a hash
- * 
- * @param  state    The hashing state
- * @param  message  The message, in bits
- * @param  msglen   The length of the message, zero if there is nothing more to absorb
- * @param  output   The output buffer for the hash
- */
-void libsha2_digest(libsha2_state_t* restrict state, const char* restrict message, size_t msglen, char* output)
-{
-  char* appendix;
-  size_t i, j, k, n;
-  
-  if (msglen & ~7)
-    {
-      libsha2_update(state, message, msglen & ~7);
-      message += msglen & ~7;
-      msglen &= 7;
-    }
-  
-  k = 8 * state->chunk_size;
-  n = state->chunk_size + 8;
-  n = (k + (n % k)) % k;
-  n = n / 8 - 1;
-  
-  appendix = state->appendix;
-  if (msglen)
-    {
-      j = 7 - msglen;
-      *appendix = *message;
-      *appendix |= 1 << j;
-      *appendix &= ~((1 << j) - 1);
-    }
-  else
-    *appendix = (unsigned char)128;
-  
-  k = state->message_size + msglen;
-  i = state->chunk_size / 8;
-  appendix += n + i - 1;
-  for (i = i < sizeof(size_t) ? i : sizeof(size_t); i--;)
-    *(appendix - i) = (unsigned char)((k >> (i * 8)) & 255);
-  
-  n += state->chunk_size;
-  libsha2_update(state, state->appendix, n);
-  
-  n = libsha2_algorithm_output_size(state->algorithm);
-  switch (state->algorithm)
-    {
-    case LIBSHA2_224:
-    case LIBSHA2_256:
-      for (i = 0; i < 8; i++)
-	for (j = 0; j < (state->chunk_size / 16); j++)
-	  if (k = (i + 1) * (state->chunk_size / 16) - j - 1, k < n)
-	    output[k] = (char)((state->h.b32[i] >> (8 * j)) & 255);
-      break;
-      
-    default:
-      for (i = 0; i < 8; i++)
-	for (j = 0; j < (state->chunk_size / 16); j++)
-	  if (k = (i + 1) * (state->chunk_size / 16) - j - 1, k < n)
-	    output[k] = (char)((state->h.b64[i] >> (8 * j)) & 255);
-      break;
-    }
-}
-
diff --git a/src/libsha2/digest.h b/src/libsha2/digest.h
deleted file mode 100644
index be81f90..0000000
--- a/src/libsha2/digest.h
+++ /dev/null
@@ -1,50 +0,0 @@
-/**
- * libsha2 – SHA-2-family hashing library
- * 
- * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
- * 
- * This library is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- * 
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- * 
- * You should have received a copy of the GNU Affero General Public License
- * along with this library.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef LIBSHA2_DIGEST_H
-#define LIBSHA2_DIGEST_H  1
-
-
-#include "state.h"
-
-
-/**
- * Absorb more of the message
- * 
- * @param  state    The hashing state
- * @param  message  The message, in bits, must be equivalent to 0 modulus 8
- * @param  msglen   The length of the message
- */
-__attribute__((nonnull, nothrow))
-void libsha2_update(libsha2_state_t* restrict state, const char* restrict message, size_t msglen);
-
-/**
- * Absorb the last part of the message and output a hash
- * 
- * @param  state    The hashing state
- * @param  message  The message, in bits
- * @param  msglen   The length of the message, zero if there is nothing more to absorb
- * @param  output   The output buffer for the hash
- */
-__attribute__((nonnull(1, 4), nothrow))
-void libsha2_digest(libsha2_state_t* restrict state, const char* restrict message, size_t msglen, char* output);
-
-
-
-#endif
-
diff --git a/src/libsha2/files.c b/src/libsha2/files.c
deleted file mode 100644
index 903c592..0000000
--- a/src/libsha2/files.c
+++ /dev/null
@@ -1,72 +0,0 @@
-/**
- * libsha2 – SHA-2-family hashing library
- * 
- * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
- * 
- * This library is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- * 
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- * 
- * You should have received a copy of the GNU Affero General Public License
- * along with this library.  If not, see <http://www.gnu.org/licenses/>.
- */
-#include "files.h"
-#include "digest.h"
-#include <stddef.h>
-#include <unistd.h>
-#include <sys/stat.h>
-#include <alloca.h>
-#include <errno.h>
-
-
-
-/**
- * Calculate the checksum for a file,
- * the content of the file is assumed non-sensitive
- * 
- * @param   fd         The file descriptor of the file
- * @param   algorithm  The hashing algorithm
- * @param   hashsum    Output buffer for the hash
- * @return             Zero on success, -1 on error
- */
-int libsha2_sum_fd(int fd, libsha2_algorithm_t algorithm, char* restrict hashsum)
-{
-  libsha2_state_t state;
-  ssize_t got;
-  struct stat attr;
-  size_t blksize = 4096;
-  char* restrict chunk;
-  
-  if (libsha2_state_initialise(&state, algorithm) < 0)
-    return -1;
-  
-  if (fstat(fd, &attr) == 0)
-    if (attr.st_blksize > 0)
-      blksize = (size_t)(attr.st_blksize);
-  
-  chunk = alloca(blksize);
-  
-  for (;;)
-    {
-      got = read(fd, chunk, blksize);
-      if (got < 0)
-	{
-	  if (errno == EINTR)
-	    continue;
-	  return -1;
-	}
-      if (got == 0)
-	break;
-      libsha2_update(&state, chunk, (size_t)got);
-    }
-  
-  libsha2_digest(&state, NULL, 0, hashsum);
-  return 0;
-}
-
diff --git a/src/libsha2/files.h b/src/libsha2/files.h
deleted file mode 100644
index 2854cd7..0000000
--- a/src/libsha2/files.h
+++ /dev/null
@@ -1,40 +0,0 @@
-/**
- * libsha2 – SHA-2-family hashing library
- * 
- * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
- * 
- * This library is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- * 
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- * 
- * You should have received a copy of the GNU Affero General Public License
- * along with this library.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef LIBSHA2_FILES_H
-#define LIBSHA2_FILES_H  1
-
-
-#include "state.h"
-
-
-/**
- * Calculate the checksum for a file,
- * the content of the file is assumed non-sensitive
- * 
- * @param   fd         The file descriptor of the file
- * @param   algorithm  The hashing algorithm
- * @param   hashsum    Output buffer for the hash
- * @return             Zero on success, -1 on error
- */
-__attribute__((nonnull, leaf))
-int libsha2_sum_fd(int fd, libsha2_algorithm_t algorithm, char* restrict hashsum);
-
-
-#endif
-
diff --git a/src/libsha2/hex.c b/src/libsha2/hex.c
deleted file mode 100644
index 1f5c372..0000000
--- a/src/libsha2/hex.c
+++ /dev/null
@@ -1,81 +0,0 @@
-/**
- * libsha2 – SHA-2-family hashing library
- * 
- * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
- * 
- * This library is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- * 
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- * 
- * You should have received a copy of the GNU Affero General Public License
- * along with this library.  If not, see <http://www.gnu.org/licenses/>.
- */
-#include "hex.h"
-#include <string.h>
-
-
-
-/**
- * Convert a binary hashsum to lower case hexadecimal representation
- * 
- * @param  output   Output array, should have an allocation size of at least `2 * n + 1`
- * @param  hashsum  The hashsum to convert
- * @param  n        The size of `hashsum`
- */
-void libsha2_behex_lower(char* restrict output, const char* restrict hashsum, size_t n)
-{
-  output[2 * n] = '\0';
-  while (n--)
-    {
-      output[2 * n + 0] = "0123456789abcdef"[(hashsum[n] >> 4) & 15];
-      output[2 * n + 1] = "0123456789abcdef"[(hashsum[n] >> 0) & 15];
-    }
-}
-
-
-/**
- * Convert a binary hashsum to upper case hexadecimal representation
- * 
- * @param  output   Output array, should have an allocation size of at least `2 * n + 1`
- * @param  hashsum  The hashsum to convert
- * @param  n        The size of `hashsum`
- */
-void libsha2_behex_upper(char* restrict output, const char* restrict hashsum, size_t n)
-{
-  output[2 * n] = '\0';
-  while (n--)
-    {
-      output[2 * n + 0] = "0123456789ABCDEF"[(hashsum[n] >> 4) & 15];
-      output[2 * n + 1] = "0123456789ABCDEF"[(hashsum[n] >> 0) & 15];
-    }
-}
-
-
-/**
- * Convert a hexadecimal hashsum (both lower case, upper
- * case and mixed is supported) to binary representation
- * 
- * @param  output   Output array, should have an allocation size of at least `strlen(hashsum) / 2`
- * @param  hashsum  The hashsum to convert
- */
-void libsha2_unhex(char* restrict output, const char* restrict hashsum)
-{
-  size_t n = strlen(hashsum) / 2;
-  while (n--)
-    {
-      char a = hashsum[2 * n + 0];
-      char b = hashsum[2 * n + 1];
-      
-      a = (char)((a & 15) + (a > '9' ? 9 : 0));
-      b = (char)((b & 15) + (b > '9' ? 9 : 0));
-      
-      output[n] = (char)((a << 4) | b);
-    }
-}
-
diff --git a/src/libsha2/hex.h b/src/libsha2/hex.h
deleted file mode 100644
index d9581b0..0000000
--- a/src/libsha2/hex.h
+++ /dev/null
@@ -1,62 +0,0 @@
-/**
- * libsha2 – SHA-2-family hashing library
- * 
- * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
- * 
- * This library is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- * 
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- * 
- * You should have received a copy of the GNU Affero General Public License
- * along with this library.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef LIBSHA2_HEX_H
-#define LIBSHA2_HEX_H  1
-
-
-#include <stddef.h>
-
-
-
-/**
- * Convert a binary hashsum to lower case hexadecimal representation
- * 
- * @param  output   Output array, should have an allocation size of at least `2 * n + 1`
- * @param  hashsum  The hashsum to convert
- * @param  n        The size of `hashsum`
- */
-__attribute__((leaf, nonnull, nothrow))
-void libsha2_behex_lower(char* restrict output, const char* restrict hashsum, size_t n);
-
-
-/**
- * Convert a binary hashsum to upper case hexadecimal representation
- * 
- * @param  output   Output array, should have an allocation size of at least `2 * n + 1`
- * @param  hashsum  The hashsum to convert
- * @param  n        The size of `hashsum`
- */
-__attribute__((leaf, nonnull, nothrow))
-void libsha2_behex_upper(char* restrict output, const char* restrict hashsum, size_t n);
-
-
-/**
- * Convert a hexadecimal hashsum (both lower case, upper
- * case and mixed is supported) to binary representation
- * 
- * @param  output   Output array, should have an allocation size of at least `strlen(hashsum) / 2`
- * @param  hashsum  The hashsum to convert
- */
-__attribute__((leaf, nonnull, nothrow))
-void libsha2_unhex(char* restrict output, const char* restrict hashsum);
-
-
-
-#endif
-
diff --git a/src/libsha2/mac/hmac.c b/src/libsha2/mac/hmac.c
deleted file mode 100644
index 2ee883d..0000000
--- a/src/libsha2/mac/hmac.c
+++ /dev/null
@@ -1,21 +0,0 @@
-/**
- * libsha2 – SHA-2-family hashing library
- * 
- * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
- * 
- * This library is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- * 
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- * 
- * You should have received a copy of the GNU Affero General Public License
- * along with this library.  If not, see <http://www.gnu.org/licenses/>.
- */
-#include "hmac.h"
-
-
diff --git a/src/libsha2/mac/hmac.h b/src/libsha2/mac/hmac.h
deleted file mode 100644
index 745d610..0000000
--- a/src/libsha2/mac/hmac.h
+++ /dev/null
@@ -1,25 +0,0 @@
-/**
- * libsha2 – SHA-2-family hashing library
- * 
- * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
- * 
- * This library is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- * 
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- * 
- * You should have received a copy of the GNU Affero General Public License
- * along with this library.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef LIBSHA2_MAC_HMAC_H
-#define LIBSHA2_MAC_HMAC_H  1
-
-
-
-#endif
-
diff --git a/src/libsha2/state.c b/src/libsha2/state.c
deleted file mode 100644
index fb6b4fc..0000000
--- a/src/libsha2/state.c
+++ /dev/null
@@ -1,151 +0,0 @@
-/**
- * libsha2 – SHA-2-family hashing library
- * 
- * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
- * 
- * This library is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- * 
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- * 
- * You should have received a copy of the GNU Affero General Public License
- * along with this library.  If not, see <http://www.gnu.org/licenses/>.
- */
-#include "state.h"
-#include <string.h>
-#include <errno.h>
-
-
-
-/**
- * Round constants, SHA-256, should keep the 32 most significant bits of 64 first constants
- */
-static const uint64_t ROUND_CONSTANTS[] = {
-  0x428A2F98D728AE22ULL, 0x7137449123EF65CDULL, 0xB5C0FBCFEC4D3B2FULL, 0xE9B5DBA58189DBBCULL,
-  0x3956C25BF348B538ULL, 0x59F111F1B605D019ULL, 0x923F82A4AF194F9BULL, 0xAB1C5ED5DA6D8118ULL,
-  0xD807AA98A3030242ULL, 0x12835B0145706FBEULL, 0x243185BE4EE4B28CULL, 0x550C7DC3D5FFB4E2ULL,
-  0x72BE5D74F27B896FULL, 0x80DEB1FE3B1696B1ULL, 0x9BDC06A725C71235ULL, 0xC19BF174CF692694ULL,
-  0xE49B69C19EF14AD2ULL, 0xEFBE4786384F25E3ULL, 0x0FC19DC68B8CD5B5ULL, 0x240CA1CC77AC9C65ULL,
-  0x2DE92C6F592B0275ULL, 0x4A7484AA6EA6E483ULL, 0x5CB0A9DCBD41FBD4ULL, 0x76F988DA831153B5ULL,
-  0x983E5152EE66DFABULL, 0xA831C66D2DB43210ULL, 0xB00327C898FB213FULL, 0xBF597FC7BEEF0EE4ULL,
-  0xC6E00BF33DA88FC2ULL, 0xD5A79147930AA725ULL, 0x06CA6351E003826FULL, 0x142929670A0E6E70ULL,
-  0x27B70A8546D22FFCULL, 0x2E1B21385C26C926ULL, 0x4D2C6DFC5AC42AEDULL, 0x53380D139D95B3DFULL,
-  0x650A73548BAF63DEULL, 0x766A0ABB3C77B2A8ULL, 0x81C2C92E47EDAEE6ULL, 0x92722C851482353BULL,
-  0xA2BFE8A14CF10364ULL, 0xA81A664BBC423001ULL, 0xC24B8B70D0F89791ULL, 0xC76C51A30654BE30ULL,
-  0xD192E819D6EF5218ULL, 0xD69906245565A910ULL, 0xF40E35855771202AULL, 0x106AA07032BBD1B8ULL,
-  0x19A4C116B8D2D0C8ULL, 0x1E376C085141AB53ULL, 0x2748774CDF8EEB99ULL, 0x34B0BCB5E19B48A8ULL,
-  0x391C0CB3C5C95A63ULL, 0x4ED8AA4AE3418ACBULL, 0x5B9CCA4F7763E373ULL, 0x682E6FF3D6B2B8A3ULL,
-  0x748F82EE5DEFB2FCULL, 0x78A5636F43172F60ULL, 0x84C87814A1F0AB72ULL, 0x8CC702081A6439ECULL,
-  0x90BEFFFA23631E28ULL, 0xA4506CEBDE82BDE9ULL, 0xBEF9A3F7B2C67915ULL, 0xC67178F2E372532BULL,
-  0xCA273ECEEA26619CULL, 0xD186B8C721C0C207ULL, 0xEADA7DD6CDE0EB1EULL, 0xF57D4F7FEE6ED178ULL,
-  0x06F067AA72176FBAULL, 0x0A637DC5A2C898A6ULL, 0x113F9804BEF90DAEULL, 0x1B710B35131C471BULL,
-  0x28DB77F523047D84ULL, 0x32CAAB7B40C72493ULL, 0x3C9EBE0A15C9BEBCULL, 0x431D67C49C100D4CULL,
-  0x4CC5D4BECB3E42B6ULL, 0x597F299CFC657E2AULL, 0x5FCB6FAB3AD6FAECULL, 0x6C44198C4A475817ULL};
-
-
-
-/**
- * Initialise a state
- * 
- * @parma   state      The state that should be initialised
- * @parma   algorithm  The hashing algorithm
- * @return             Zero on success, -1 on error
- */
-int libsha2_state_initialise(libsha2_state_t* restrict state, libsha2_algorithm_t algorithm)
-{
-  static const uint32_t H_224[] = {
-    0xC1059ED8UL, 0x367CD507UL, 0x3070DD17UL, 0xF70E5939UL,
-    0xFFC00B31UL, 0x68581511UL, 0x64F98FA7UL, 0xBEFA4FA4UL};
-  static const uint32_t H_256[] = {
-    0x6A09E667UL, 0xBB67AE85UL, 0x3C6EF372UL, 0xA54FF53AUL,
-    0x510E527FUL, 0x9B05688CUL, 0x1F83D9ABUL, 0x5BE0CD19UL};
-  static const uint64_t H_384[] = {
-    0xCBBB9D5DC1059ED8ULL, 0x629A292A367CD507ULL, 0x9159015A3070DD17ULL, 0x152FECD8F70E5939ULL,
-    0x67332667FFC00B31ULL, 0x8EB44A8768581511ULL, 0xDB0C2E0D64F98FA7ULL, 0x47B5481DBEFA4FA4ULL};
-  static const uint64_t H_512[] = {
-    0x6A09E667F3BCC908ULL, 0xBB67AE8584CAA73BULL, 0x3C6EF372FE94F82BULL, 0xA54FF53A5F1D36F1ULL,
-    0x510E527FADE682D1ULL, 0x9B05688C2B3E6C1FULL, 0x1F83D9ABFB41BD6BULL, 0x5BE0CD19137E2179ULL};
-  static const uint64_t H_512_224[] = {
-    0x8C3D37C819544DA2ULL, 0x73E1996689DCD4D6ULL, 0x1DFAB7AE32FF9C82ULL, 0x679DD514582F9FCFULL,
-    0x0F6D2B697BD44DA8ULL, 0x77E36F7304C48942ULL, 0x3F9D85A86A1D36C8ULL, 0x1112E6AD91D692A1ULL};
-  static const uint64_t H_512_256[] = {
-    0x22312194FC2BF72CULL, 0x9F555FA3C84C64C2ULL, 0x2393B86B6F53B151ULL, 0x963877195940EABDULL,
-    0x96283EE2A88EFFE3ULL, 0xBE5E1E2553863992ULL, 0x2B0199FC2C85B8AAULL, 0x0EB72DDC81C52CA2ULL};
-  
-  size_t i;
-  
-  memset(state, 0, sizeof(*state));
-  state->message_size = 0;
-  state->algorithm = algorithm;
-  
-  /* Set initial hash values. */
-  switch (algorithm)
-    {
-    case LIBSHA2_224:      memcpy(state->h.b32, H_224,     sizeof(H_224));      break;
-    case LIBSHA2_256:      memcpy(state->h.b32, H_256,     sizeof(H_256));      break;
-    case LIBSHA2_384:      memcpy(state->h.b64, H_384,     sizeof(H_384));      break;
-    case LIBSHA2_512:      memcpy(state->h.b64, H_512,     sizeof(H_512));      break;
-    case LIBSHA2_512_224:  memcpy(state->h.b64, H_512_224, sizeof(H_512_224));  break;
-    case LIBSHA2_512_256:  memcpy(state->h.b64, H_512_256, sizeof(H_512_256));  break;
-    default:
-      return errno = EINVAL, -1;
-    }
-  
-  /* Set round constants, and chunk size. */
-  switch (algorithm)
-    {
-    case LIBSHA2_224:
-    case LIBSHA2_256:
-      for (i = 0; i < 64; i++)
-	state->k.b32[i] = (uint32_t)(ROUND_CONSTANTS[i] >> 32);
-      state->chunk_size = 64;
-      break;
-      
-    default:
-      memcpy(state->k.b64, ROUND_CONSTANTS, sizeof(ROUND_CONSTANTS));
-      state->chunk_size = 128;
-      break;
-    }
-  
-  return 0;
-}
-
-
-/**
- * Get the output size of the algorithm specified for a state
- * 
- * @parma   state  The state
- * @return         The number of bytes in the output, zero on error
- */
-size_t libsha2_state_output_size(const libsha2_state_t* restrict state)
-{
-  return libsha2_algorithm_output_size(state->algorithm);
-}
-
-
-/**
- * Get the output size of an algorithm
- * 
- * @parma   algorithm  The hashing algorithm
- * @return             The number of bytes in the output, zero on error
- */
-size_t libsha2_algorithm_output_size(libsha2_algorithm_t algorithm)
-{
-  switch (algorithm)
-    {
-    case LIBSHA2_224:     return 28;
-    case LIBSHA2_256:     return 32;
-    case LIBSHA2_384:     return 48;
-    case LIBSHA2_512:     return 64;
-    case LIBSHA2_512_224: return 28;
-    case LIBSHA2_512_256: return 32;
-    default:
-      return errno = EINVAL, 0;
-    }
-}
-
diff --git a/src/libsha2/state.h b/src/libsha2/state.h
deleted file mode 100644
index f081a64..0000000
--- a/src/libsha2/state.h
+++ /dev/null
@@ -1,221 +0,0 @@
-/**
- * libsha2 – SHA-2-family hashing library
- * 
- * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
- * 
- * This library is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- * 
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- * 
- * You should have received a copy of the GNU Affero General Public License
- * along with this library.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef LIBSHA2_STATE_H
-#define LIBSHA2_STATE_H  1
-
-
-#include <stdint.h>
-#include <stddef.h>
-
-
-
-/**
- * Algorithms supported by libsha2
- */
-typedef enum libsha2_algorithm
-  {
-    /**
-     * SHA-224, outputs 28 bytes
-     */
-    LIBSHA2_224 = 1,
-    
-    /**
-     * SHA-256, outputs 32 bytes
-     */
-    LIBSHA2_256 = 2,
-    
-    /**
-     * SHA-384, outputs 48 bytes
-     */
-    LIBSHA2_384 = 3,
-    
-    /**
-     * SHA-512, outputs 64 bytes
-     */
-    LIBSHA2_512 = 4,
-    
-    /**
-     * SHA-512/224, outputs 28 bytes
-     */
-    LIBSHA2_512_224 = 5,
-    
-    /**
-     * SHA-512/256, outputs 32 bytes
-     */
-    LIBSHA2_512_256 = 6
-    
-  } libsha2_algorithm_t;
-
-
-/**
- * Datastructure that describes the state of a hashing process
- * 
- * Data that could just as well be allocated (with `auto`) are
- * allocated here so that is is easier to wipe the data without
- * exposing two versions of each function: one to wipe data,
- * and one not to wipe data to gain speed, now you can use use
- * `explicit_bzero` (or `memset`) when you are done.
- * 
- * This datastructure is flat (it contains dynamic pointers)
- * and can be marshalled and unmarshalled naïvely, and does
- * not need destroyed; however, if you when to marshall it
- * using as little memory as possible, this are comments
- * about data that does not need to be mashalled
- */
-typedef struct libsha2_state
-{
-  /**
-   * The size of the message, as far as processed, in bits;
-   */
-  size_t message_size;
-  
-  /**
-   * Round constants
-   */
-  union
-  {
-    /**
-     * For 32-bit algorithms
-     */
-    uint32_t b32[64];
-    
-    /**
-     * For 64-bit algorithms
-     */
-    uint64_t b64[80];
-    
-  } k;
-  
-  /**
-   * Words
-   * 
-   * Does not need to be marshalled
-   */
-  union
-  {
-    /**
-     * For 32-bit algorithms
-     */
-    uint32_t b32[64];
-    
-    /**
-     * For 64-bit algorithms
-     */
-    uint64_t b64[80];
-    
-  } w;
-  
-  /**
-   * Hashing values
-   */
-  union
-  {
-    /**
-     * For 32-bit algorithms
-     */
-    uint32_t b32[8];
-    
-    /**
-     * For 64-bit algorithms
-     */
-    uint64_t b64[8];
-    
-  } h;
-  
-  /**
-   * Temporary hashing values
-   * 
-   * Does not need to be marshalled
-   */
-  union
-  {
-    /**
-     * For 32-bit algorithms
-     */
-    uint32_t b32[8];
-    
-    /**
-     * For 64-bit algorithms
-     */
-    uint64_t b64[8];
-    
-  } work_h;
-  
-  /**
-   * Space for chunks to process, limited
-   * to 64 bytes on 32-bit algorithms
-   */
-  unsigned char chunk[128];
-  
-  /**
-   * Space for storing the last bits and
-   * the padding
-   * 
-   * Does not need to be marshalled
-   */
-  char appendix[256];
-  
-  /**
-   * The size of the chunks, in bytes
-   */
-  size_t chunk_size;
-  
-  /**
-   * The algorithm that is used
-   */
-  libsha2_algorithm_t algorithm;
-  
-  int __padding1;
-  
-} libsha2_state_t;
-
-
-
-/**
- * Initialise a state
- * 
- * @parma   state      The state that should be initialised
- * @parma   algorithm  The hashing algorithm
- * @return             Zero on success, -1 on error
- */
-__attribute__((leaf, nothrow, nonnull))
-int libsha2_state_initialise(libsha2_state_t* restrict state, libsha2_algorithm_t algorithm);
-
-/**
- * Get the output size of the algorithm specified for a state
- * 
- * @parma   state  The state
- * @return         The number of bytes in the output, zero on error
- */
-__attribute__((nothrow, nonnull, pure))
-size_t libsha2_state_output_size(const libsha2_state_t* restrict state);
-
-/**
- * Get the output size of an algorithm
- * 
- * @parma   algorithm  The hashing algorithm
- * @return             The number of bytes in the output, zero on error
- */
-__attribute__((leaf, nothrow, const))
-size_t libsha2_algorithm_output_size(libsha2_algorithm_t algorithm);
-
-
-
-#endif
-
diff --git a/state_initialise.c b/state_initialise.c
new file mode 100644
index 0000000..ba6fee0
--- /dev/null
+++ b/state_initialise.c
@@ -0,0 +1,125 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Round constants, SHA-256, should keep the 32 most significant bits of 64 first constants
+ */
+static const uint64_t ROUND_CONSTANTS[] = {
+	0x428A2F98D728AE22ULL, 0x7137449123EF65CDULL, 0xB5C0FBCFEC4D3B2FULL, 0xE9B5DBA58189DBBCULL,
+	0x3956C25BF348B538ULL, 0x59F111F1B605D019ULL, 0x923F82A4AF194F9BULL, 0xAB1C5ED5DA6D8118ULL,
+	0xD807AA98A3030242ULL, 0x12835B0145706FBEULL, 0x243185BE4EE4B28CULL, 0x550C7DC3D5FFB4E2ULL,
+	0x72BE5D74F27B896FULL, 0x80DEB1FE3B1696B1ULL, 0x9BDC06A725C71235ULL, 0xC19BF174CF692694ULL,
+	0xE49B69C19EF14AD2ULL, 0xEFBE4786384F25E3ULL, 0x0FC19DC68B8CD5B5ULL, 0x240CA1CC77AC9C65ULL,
+	0x2DE92C6F592B0275ULL, 0x4A7484AA6EA6E483ULL, 0x5CB0A9DCBD41FBD4ULL, 0x76F988DA831153B5ULL,
+	0x983E5152EE66DFABULL, 0xA831C66D2DB43210ULL, 0xB00327C898FB213FULL, 0xBF597FC7BEEF0EE4ULL,
+	0xC6E00BF33DA88FC2ULL, 0xD5A79147930AA725ULL, 0x06CA6351E003826FULL, 0x142929670A0E6E70ULL,
+	0x27B70A8546D22FFCULL, 0x2E1B21385C26C926ULL, 0x4D2C6DFC5AC42AEDULL, 0x53380D139D95B3DFULL,
+	0x650A73548BAF63DEULL, 0x766A0ABB3C77B2A8ULL, 0x81C2C92E47EDAEE6ULL, 0x92722C851482353BULL,
+	0xA2BFE8A14CF10364ULL, 0xA81A664BBC423001ULL, 0xC24B8B70D0F89791ULL, 0xC76C51A30654BE30ULL,
+	0xD192E819D6EF5218ULL, 0xD69906245565A910ULL, 0xF40E35855771202AULL, 0x106AA07032BBD1B8ULL,
+	0x19A4C116B8D2D0C8ULL, 0x1E376C085141AB53ULL, 0x2748774CDF8EEB99ULL, 0x34B0BCB5E19B48A8ULL,
+	0x391C0CB3C5C95A63ULL, 0x4ED8AA4AE3418ACBULL, 0x5B9CCA4F7763E373ULL, 0x682E6FF3D6B2B8A3ULL,
+	0x748F82EE5DEFB2FCULL, 0x78A5636F43172F60ULL, 0x84C87814A1F0AB72ULL, 0x8CC702081A6439ECULL,
+	0x90BEFFFA23631E28ULL, 0xA4506CEBDE82BDE9ULL, 0xBEF9A3F7B2C67915ULL, 0xC67178F2E372532BULL,
+	0xCA273ECEEA26619CULL, 0xD186B8C721C0C207ULL, 0xEADA7DD6CDE0EB1EULL, 0xF57D4F7FEE6ED178ULL,
+	0x06F067AA72176FBAULL, 0x0A637DC5A2C898A6ULL, 0x113F9804BEF90DAEULL, 0x1B710B35131C471BULL,
+	0x28DB77F523047D84ULL, 0x32CAAB7B40C72493ULL, 0x3C9EBE0A15C9BEBCULL, 0x431D67C49C100D4CULL,
+	0x4CC5D4BECB3E42B6ULL, 0x597F299CFC657E2AULL, 0x5FCB6FAB3AD6FAECULL, 0x6C44198C4A475817ULL
+};
+
+
+/**
+ * Initial state for SHA224
+ */
+static const uint32_t H_224[] = {
+	0xC1059ED8UL, 0x367CD507UL, 0x3070DD17UL, 0xF70E5939UL,
+	0xFFC00B31UL, 0x68581511UL, 0x64F98FA7UL, 0xBEFA4FA4UL
+};
+
+/**
+ * Initial state for SHA256
+ */
+static const uint32_t H_256[] = {
+	0x6A09E667UL, 0xBB67AE85UL, 0x3C6EF372UL, 0xA54FF53AUL,
+	0x510E527FUL, 0x9B05688CUL, 0x1F83D9ABUL, 0x5BE0CD19UL
+};
+
+/**
+ * Initial state for SHA384
+ */
+static const uint64_t H_384[] = {
+	0xCBBB9D5DC1059ED8ULL, 0x629A292A367CD507ULL, 0x9159015A3070DD17ULL, 0x152FECD8F70E5939ULL,
+	0x67332667FFC00B31ULL, 0x8EB44A8768581511ULL, 0xDB0C2E0D64F98FA7ULL, 0x47B5481DBEFA4FA4ULL
+};
+
+/**
+ * Initial state for SHA512
+ */
+static const uint64_t H_512[] = {
+	0x6A09E667F3BCC908ULL, 0xBB67AE8584CAA73BULL, 0x3C6EF372FE94F82BULL, 0xA54FF53A5F1D36F1ULL,
+	0x510E527FADE682D1ULL, 0x9B05688C2B3E6C1FULL, 0x1F83D9ABFB41BD6BULL, 0x5BE0CD19137E2179ULL
+};
+
+/**
+ * Initial state for SHA512/224
+ */
+static const uint64_t H_512_224[] = {
+	0x8C3D37C819544DA2ULL, 0x73E1996689DCD4D6ULL, 0x1DFAB7AE32FF9C82ULL, 0x679DD514582F9FCFULL,
+	0x0F6D2B697BD44DA8ULL, 0x77E36F7304C48942ULL, 0x3F9D85A86A1D36C8ULL, 0x1112E6AD91D692A1ULL
+};
+
+/**
+ * Initial state for SHA512/256
+ */
+static const uint64_t H_512_256[] = {
+	0x22312194FC2BF72CULL, 0x9F555FA3C84C64C2ULL, 0x2393B86B6F53B151ULL, 0x963877195940EABDULL,
+	0x96283EE2A88EFFE3ULL, 0xBE5E1E2553863992ULL, 0x2B0199FC2C85B8AAULL, 0x0EB72DDC81C52CA2ULL
+};
+
+
+/**
+ * Initialise a state
+ * 
+ * @parma   state      The state that should be initialised
+ * @parma   algorithm  The hashing algorithm
+ * @return             Zero on success, -1 on error
+ */
+int
+libsha2_state_initialise(struct libsha2_state *restrict state, enum libsha2_algorithm algorithm)
+{
+	size_t i;
+
+	memset(state, 0, sizeof(*state));
+	state->message_size = 0;
+	state->algorithm = algorithm;
+
+	/* Set initial hash values. */
+	switch (algorithm) {
+	case LIBSHA2_224:     memcpy(state->h.b32, H_224,     sizeof(H_224));     break;
+	case LIBSHA2_256:     memcpy(state->h.b32, H_256,     sizeof(H_256));     break;
+	case LIBSHA2_384:     memcpy(state->h.b64, H_384,     sizeof(H_384));     break;
+	case LIBSHA2_512:     memcpy(state->h.b64, H_512,     sizeof(H_512));     break;
+	case LIBSHA2_512_224: memcpy(state->h.b64, H_512_224, sizeof(H_512_224)); break;
+	case LIBSHA2_512_256: memcpy(state->h.b64, H_512_256, sizeof(H_512_256)); break;
+	default:
+		return errno = EINVAL, -1;
+	}
+
+	/* Set round constants, and chunk size. */
+	switch (algorithm) {
+	case LIBSHA2_224:
+	case LIBSHA2_256:
+		for (i = 0; i < 64; i++)
+			state->k.b32[i] = (uint32_t)(ROUND_CONSTANTS[i] >> 32);
+		state->chunk_size = 64;
+		break;
+
+	default:
+		memcpy(state->k.b64, ROUND_CONSTANTS, sizeof(ROUND_CONSTANTS));
+		state->chunk_size = 128;
+		break;
+	}
+  
+	return 0;
+}
diff --git a/state_output_size.c b/state_output_size.c
new file mode 100644
index 0000000..d2cc5c1
--- /dev/null
+++ b/state_output_size.c
@@ -0,0 +1,15 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Get the output size of the algorithm specified for a state
+ * 
+ * @parma   state  The state
+ * @return         The number of bytes in the output, zero on error
+ */
+size_t
+libsha2_state_output_size(const struct libsha2_state *restrict state)
+{
+	return libsha2_algorithm_output_size(state->algorithm);
+}
diff --git a/sum_fd.c b/sum_fd.c
new file mode 100644
index 0000000..381a634
--- /dev/null
+++ b/sum_fd.c
@@ -0,0 +1,46 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Calculate the checksum for a file,
+ * the content of the file is assumed non-sensitive
+ * 
+ * @param   fd         The file descriptor of the file
+ * @param   algorithm  The hashing algorithm
+ * @param   hashsum    Output buffer for the hash
+ * @return             Zero on success, -1 on error
+ */
+int
+libsha2_sum_fd(int fd, enum libsha2_algorithm algorithm, char *restrict hashsum)
+{
+	struct libsha2_state state;
+	ssize_t r;
+	struct stat attr;
+	size_t blksize = 4096;
+	char *restrict chunk;
+
+	if (libsha2_state_initialise(&state, algorithm) < 0)
+		return -1;
+
+	if (fstat(fd, &attr) == 0 && attr.st_blksize > 0)
+		blksize = (size_t)(attr.st_blksize);
+
+	chunk = alloca(blksize);
+
+	for (;;) {
+		r = read(fd, chunk, blksize);
+		if (r <= 0) {
+			if (!r)
+				break;
+			if (errno == EINTR)
+				continue;
+			return -1;
+		}
+		libsha2_update(&state, chunk, (size_t)r);
+	}
+
+	libsha2_digest(&state, NULL, 0, hashsum);
+	return 0;
+}
+
diff --git a/unhex.c b/unhex.c
new file mode 100644
index 0000000..0dc231d
--- /dev/null
+++ b/unhex.c
@@ -0,0 +1,26 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Convert a hexadecimal hashsum (both lower case, upper
+ * case and mixed is supported) to binary representation
+ * 
+ * @param  output   Output array, should have an allocation
+ *                  size of at least `strlen(hashsum) / 2`
+ * @param  hashsum  The hashsum to convert
+ */
+void
+libsha2_unhex(char *restrict output, const char *restrict hashsum)
+{
+	size_t n = strlen(hashsum) / 2;
+	while (n--) {
+		char a = hashsum[2 * n + 0];
+		char b = hashsum[2 * n + 1];
+
+		a = (char)((a & 15) + (a > '9' ? 9 : 0));
+		b = (char)((b & 15) + (b > '9' ? 9 : 0));
+
+		output[n] = (char)((a << 4) | b);
+	}
+}
diff --git a/update.c b/update.c
new file mode 100644
index 0000000..26eceb8
--- /dev/null
+++ b/update.c
@@ -0,0 +1,140 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Unified implementation (what can unified without performance impact)
+ * of the chunk processing for all SHA-2 functions
+ * 
+ * @param  A       Wordsize-dependent constant, take a look at the code
+ * @param  B       Wordsize-dependent constant, take a look at the code
+ * @param  C       Wordsize-dependent constant, take a look at the code
+ * @param  D       Wordsize-dependent constant, take a look at the code
+ * @param  E       Wordsize-dependent constant, take a look at the code
+ * @param  F       Wordsize-dependent constant, take a look at the code
+ * @param  G       Wordsize-dependent constant, take a look at the code
+ * @param  H       Wordsize-dependent constant, take a look at the code
+ * @param  I       Wordsize-dependent constant, take a look at the code
+ * @param  J       Wordsize-dependent constant, take a look at the code
+ * @param  K       Wordsize-dependent constant, take a look at the code
+ * @param  L       Wordsize-dependent constant, take a look at the code
+ * @param  WORD_T  `__typeof()` on any wordsize-dependent variable, with exact size
+ * @param  k       Round constants
+ * @param  w       Words
+ * @param  h       Hash values
+ * @param  work_h  Space for temporary hash values
+ */
+#define SHA2_IMPLEMENTATION(A, B, C, D, E, F, G, H, I, J, K, L, WORD_T, k, w, h, work_h)\
+	memcpy(work_h, h, sizeof(work_h));\
+	\
+	memset(w, 0, 16 * sizeof(*(w)));\
+	for (i = 0; i < 16; i++)\
+		for (j = 0; j < sizeof(WORD_T); j++)\
+			w[i] |= ((WORD_T)(state->chunk[(i + 1) * sizeof(WORD_T) - j - 1])) << (j << 3);\
+	\
+	for (i = 16; i < sizeof(k) / sizeof(*(k)); i++)	{\
+		w[i] = w[i - 16] + w[i - 7];\
+		w[i] += ROTR(w[i - 15], A) ^ ROTR(w[i - 15], B) ^ (w[i - 15] >> (C));\
+		w[i] += ROTR(w[i - 2], D) ^ ROTR(w[i - 2], E) ^ (w[i - 2] >> (F));\
+	}\
+	\
+	for (i = 0; i < sizeof(k) / sizeof(*(k)); i++) {\
+		s1 = (work_h[4] & work_h[5]) ^ (work_h[6] & ~(work_h[4]));\
+		s1 += work_h[7] + k[i] + w[i];\
+		s0 = (work_h[0] & work_h[1]) ^ (work_h[0] & work_h[2]) ^ (work_h[1] & work_h[2]);\
+		s1 += ROTR(work_h[4], G) ^ ROTR(work_h[4], H) ^ ROTR(work_h[4], I);\
+		s0 += ROTR(work_h[0], J) ^ ROTR(work_h[0], K) ^ ROTR(work_h[0], L);\
+		\
+		memmove(work_h + 1, work_h, 7 * sizeof(*(work_h)));\
+		work_h[4] += s1;\
+		work_h[0] = s1 + s0;\
+	}\
+	\
+	for (i = 0; i < 8; i++)\
+		h[i] += work_h[i]
+
+
+/**
+ * Process a chunk using SHA-256
+ * 
+ * @param  state  The hashing state
+ */
+#if defined(__GNUC__)
+__attribute__((__nonnull__, __nothrow__))
+#endif
+static void
+process256(struct libsha2_state *restrict state)
+{
+	uint32_t s0, s1;
+	size_t i, j;
+#if defined(__GNUC__)
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wmemset-elt-size"
+#endif
+#define ROTR(X, N) (((X) >> (N)) | ((X) << ((sizeof(uint32_t) * 8) - (N))))
+	SHA2_IMPLEMENTATION(7, 18, 3, 17, 19, 10, 6, 11, 25, 2, 13, 22, uint32_t,
+	                    state->k.b32, state->w.b32, state->h.b32, state->work_h.b32);
+#undef ROTR
+#if defined(__GNUC__)
+# pragma GCC diagnostic pop
+#endif
+}
+
+
+/**
+ * Process a chunk using SHA-512
+ * 
+ * @param  state  The hashing state
+ */
+#if defined(__GNUC__)
+__attribute__((__nonnull__, __nothrow__))
+#endif
+static void
+process512(struct libsha2_state *restrict state)
+{
+	uint64_t s0, s1;
+	size_t i, j;
+#define ROTR(X, N) (((X) >> (N)) | ((X) << ((sizeof(uint64_t) * 8) - (N))))
+	SHA2_IMPLEMENTATION(1, 8, 7, 19, 61, 6, 14, 18, 41, 28, 34, 39, uint64_t,
+	                    state->k.b64, state->w.b64, state->h.b64, state->work_h.b64);
+#undef ROTR
+}
+
+
+/**
+ * Absorb more of the message
+ * 
+ * @param  state    The hashing state
+ * @param  message  The message, in bits, must be equivalent to 0 modulus 8
+ * @param  msglen   The length of the message
+ */
+void
+libsha2_update(struct libsha2_state *restrict state, const char *restrict message, size_t msglen)
+{
+	size_t n, off, mlen;
+
+	msglen /= 8;
+	mlen = state->message_size / 8;
+
+	while (msglen) {
+		off = mlen % state->chunk_size;
+		n = state->chunk_size - off;
+		n = n < msglen ? n : msglen;
+		memcpy(state->chunk + off, message, n);
+		if (off + n == state->chunk_size) {
+			switch (state->algorithm) {
+			case LIBSHA2_224:
+			case LIBSHA2_256:
+				process256(state);
+				break;
+
+			default:
+				process512(state);
+				break;
+			}
+		}
+		message += n, mlen += n, msglen -= n;
+	}
+
+	state->message_size = mlen * 8;
+}