Mercurial > hg > octave-kai > gnulib-hg
changeset 17120:ac32fde6df85
hash-pjw-bare: new module
* lib/hash-pjw-bare.c: New file, very much like hash-pjw.c.
* lib/hash-pjw-bare.h: Likewise.
* modules/hash-pjw-bare: New file.
* MODULES.html.sh (Misc): Add it.
Copyright-paperwork-exempt: yes
author | Nikos Mavrogiannopoulos <nmav@gnutls.org> |
---|---|
date | Thu, 27 Sep 2012 08:42:07 +0200 |
parents | 973b259ceb42 |
children | 4e2101c3d42c |
files | ChangeLog MODULES.html.sh lib/hash-pjw-bare.c lib/hash-pjw-bare.h modules/hash-pjw-bare |
diffstat | 5 files changed, 97 insertions(+), 0 deletions(-) [+] |
line wrap: on
line diff
--- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +2012-10-02: Nikos Mavrogiannopoulos <nmav@gnutls.org> (tiny change) + + hash-pjw-bare: new module + * lib/hash-pjw-bare.c: New file, very much like hash-pjw.c. + * lib/hash-pjw-bare.h: Likewise. + * modules/hash-pjw-bare: New file. + * MODULES.html.sh (Misc): Add it. + 2012-10-02 Eric Blake <eblake@redhat.com> manywarnings: cater to more gcc infelicities
--- a/MODULES.html.sh +++ b/MODULES.html.sh @@ -2011,6 +2011,7 @@ func_module obstack-printf func_module obstack-printf-posix func_module hash-pjw + func_module hash-pjw-bare func_module hash func_module readline func_module readtokens
new file mode 100644 --- /dev/null +++ b/lib/hash-pjw-bare.c @@ -0,0 +1,42 @@ +/* hash-pjw-bare.c -- compute a hash value from a provided buffer. + + Copyright (C) 2012 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify it + under the terms of the GNU Lesser 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +#include <config.h> + +#include "hash-pjw-bare.h" + +#include <limits.h> + +#define SIZE_BITS (sizeof (size_t) * CHAR_BIT) + +/* Return a hash of the N bytes of X using the method described by + Bruno Haible in http://www.haible.de/bruno/hashfunc.html. + Note that while many hash functions reduce their result via modulo + to a 0..table_size-1 range, this function does not do that. */ + +size_t +hash_pjw_bare (const void *x, size_t n) +{ + const unsigned char *s = x; + size_t h = 0; + unsigned i; + + for (i = 0; i < n; i++) + h = s[i] + ((h << 9) | (h >> (SIZE_BITS - 9))); + + return h; +}
new file mode 100644 --- /dev/null +++ b/lib/hash-pjw-bare.h @@ -0,0 +1,24 @@ +/* hash-pjw-bare.h -- declaration for a simple hash function + Copyright (C) 2012 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify it + under the terms of the GNU Lesser 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +#include <stddef.h> + +/* Compute a hash code for a buffer starting at X and of size N, + and return the hash code. Note that unlike hash_pjw(), it does not + return it modulo a table size. + The result is platform dependent: it depends on the size of the 'size_t' + type and on the signedness of the 'char' type. */ +extern size_t hash_pjw_bare (const void *x, size_t n) _GL_ATTRIBUTE_PURE;
new file mode 100644 --- /dev/null +++ b/modules/hash-pjw-bare @@ -0,0 +1,22 @@ +Description: +Compute a hash value for a buffer of known size. + +Files: +lib/hash-pjw-bare.h +lib/hash-pjw-bare.c + +Depends-on: + +configure.ac: + +Makefile.am: +lib_SOURCES += hash-pjw-bare.h hash-pjw-bare.c + +Include: +"hash-pjw-bare.h" + +License: +LGPLv2+ + +Maintainer: +Jim Meyering