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/* bufhelp.h - Some buffer manipulation helpers
* Copyright (C) 2012 Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
*
* This file is part of Libgcrypt.
*
* Libgcrypt 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 2.1 of
* the License, or (at your option) any later version.
*
* Libgcrypt 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#ifndef G10_BUFHELP_H
#define G10_BUFHELP_H
#include <config.h>
#ifdef HAVE_STDINT_H
# include <stdint.h> /* uintptr_t */
#elif defined(HAVE_INTTYPES_H)
# include <inttypes.h>
#else
/* In this case, uintptr_t is provided by config.h. */
#endif
#include "bithelp.h"
#if defined(__i386__) || defined(__x86_64__) || \
defined(__powerpc__) || defined(__powerpc64__) || \
(defined(__arm__) && defined(__ARM_FEATURE_UNALIGNED)) || \
defined(__aarch64__)
/* These architectures are able of unaligned memory accesses and can
handle those fast.
*/
# define BUFHELP_FAST_UNALIGNED_ACCESS 1
#endif
/* Optimized function for small buffer copying */
static inline void
buf_cpy(void *_dst, const void *_src, size_t len)
{
#if __GNUC__ >= 4 && (defined(__x86_64__) || defined(__i386__))
/* For AMD64 and i386, memcpy is faster. */
memcpy(_dst, _src, len);
#else
byte *dst = _dst;
const byte *src = _src;
uintptr_t *ldst;
const uintptr_t *lsrc;
#ifndef BUFHELP_FAST_UNALIGNED_ACCESS
const unsigned int longmask = sizeof(uintptr_t) - 1;
/* Skip fast processing if buffers are unaligned. */
if (((uintptr_t)dst | (uintptr_t)src) & longmask)
goto do_bytes;
#endif
ldst = (uintptr_t *)(void *)dst;
lsrc = (const uintptr_t *)(const void *)src;
for (; len >= sizeof(uintptr_t); len -= sizeof(uintptr_t))
*ldst++ = *lsrc++;
dst = (byte *)ldst;
src = (const byte *)lsrc;
#ifndef BUFHELP_FAST_UNALIGNED_ACCESS
do_bytes:
#endif
/* Handle tail. */
for (; len; len--)
*dst++ = *src++;
#endif /*__GNUC__ >= 4 && (__x86_64__ || __i386__)*/
}
/* Optimized function for buffer xoring */
static inline void
buf_xor(void *_dst, const void *_src1, const void *_src2, size_t len)
{
byte *dst = _dst;
const byte *src1 = _src1;
const byte *src2 = _src2;
uintptr_t *ldst;
const uintptr_t *lsrc1, *lsrc2;
#ifndef BUFHELP_FAST_UNALIGNED_ACCESS
const unsigned int longmask = sizeof(uintptr_t) - 1;
/* Skip fast processing if buffers are unaligned. */
if (((uintptr_t)dst | (uintptr_t)src1 | (uintptr_t)src2) & longmask)
goto do_bytes;
#endif
ldst = (uintptr_t *)(void *)dst;
lsrc1 = (const uintptr_t *)(const void *)src1;
lsrc2 = (const uintptr_t *)(const void *)src2;
for (; len >= sizeof(uintptr_t); len -= sizeof(uintptr_t))
*ldst++ = *lsrc1++ ^ *lsrc2++;
dst = (byte *)ldst;
src1 = (const byte *)lsrc1;
src2 = (const byte *)lsrc2;
#ifndef BUFHELP_FAST_UNALIGNED_ACCESS
do_bytes:
#endif
/* Handle tail. */
for (; len; len--)
*dst++ = *src1++ ^ *src2++;
}
/* Optimized function for buffer xoring with two destination buffers. Used
mainly by CFB mode encryption. */
static inline void
buf_xor_2dst(void *_dst1, void *_dst2, const void *_src, size_t len)
{
byte *dst1 = _dst1;
byte *dst2 = _dst2;
const byte *src = _src;
uintptr_t *ldst1, *ldst2;
const uintptr_t *lsrc;
#ifndef BUFHELP_FAST_UNALIGNED_ACCESS
const unsigned int longmask = sizeof(uintptr_t) - 1;
/* Skip fast processing if buffers are unaligned. */
if (((uintptr_t)src | (uintptr_t)dst1 | (uintptr_t)dst2) & longmask)
goto do_bytes;
#endif
ldst1 = (uintptr_t *)(void *)dst1;
ldst2 = (uintptr_t *)(void *)dst2;
lsrc = (const uintptr_t *)(const void *)src;
for (; len >= sizeof(uintptr_t); len -= sizeof(uintptr_t))
*ldst1++ = (*ldst2++ ^= *lsrc++);
dst1 = (byte *)ldst1;
dst2 = (byte *)ldst2;
src = (const byte *)lsrc;
#ifndef BUFHELP_FAST_UNALIGNED_ACCESS
do_bytes:
#endif
/* Handle tail. */
for (; len; len--)
*dst1++ = (*dst2++ ^= *src++);
}
/* Optimized function for combined buffer xoring and copying. Used by mainly
CBC mode decryption. */
static inline void
buf_xor_n_copy_2(void *_dst_xor, const void *_src_xor, void *_srcdst_cpy,
const void *_src_cpy, size_t len)
{
byte *dst_xor = _dst_xor;
byte *srcdst_cpy = _srcdst_cpy;
const byte *src_xor = _src_xor;
const byte *src_cpy = _src_cpy;
byte temp;
uintptr_t *ldst_xor, *lsrcdst_cpy;
const uintptr_t *lsrc_cpy, *lsrc_xor;
uintptr_t ltemp;
#ifndef BUFHELP_FAST_UNALIGNED_ACCESS
const unsigned int longmask = sizeof(uintptr_t) - 1;
/* Skip fast processing if buffers are unaligned. */
if (((uintptr_t)src_cpy | (uintptr_t)src_xor | (uintptr_t)dst_xor |
(uintptr_t)srcdst_cpy) & longmask)
goto do_bytes;
#endif
ldst_xor = (uintptr_t *)(void *)dst_xor;
lsrc_xor = (const uintptr_t *)(void *)src_xor;
lsrcdst_cpy = (uintptr_t *)(void *)srcdst_cpy;
lsrc_cpy = (const uintptr_t *)(const void *)src_cpy;
for (; len >= sizeof(uintptr_t); len -= sizeof(uintptr_t))
{
ltemp = *lsrc_cpy++;
*ldst_xor++ = *lsrcdst_cpy ^ *lsrc_xor++;
*lsrcdst_cpy++ = ltemp;
}
dst_xor = (byte *)ldst_xor;
src_xor = (const byte *)lsrc_xor;
srcdst_cpy = (byte *)lsrcdst_cpy;
src_cpy = (const byte *)lsrc_cpy;
#ifndef BUFHELP_FAST_UNALIGNED_ACCESS
do_bytes:
#endif
/* Handle tail. */
for (; len; len--)
{
temp = *src_cpy++;
*dst_xor++ = *srcdst_cpy ^ *src_xor++;
*srcdst_cpy++ = temp;
}
}
/* Optimized function for combined buffer xoring and copying. Used by mainly
CFB mode decryption. */
static inline void
buf_xor_n_copy(void *_dst_xor, void *_srcdst_cpy, const void *_src, size_t len)
{
buf_xor_n_copy_2(_dst_xor, _src, _srcdst_cpy, _src, len);
}
/* Constant-time compare of two buffers. Returns 1 if buffers are equal,
and 0 if buffers differ. */
static inline int
buf_eq_const(const void *_a, const void *_b, size_t len)
{
const byte *a = _a;
const byte *b = _b;
size_t diff, i;
/* Constant-time compare. */
for (i = 0, diff = 0; i < len; i++)
diff -= !!(a[i] - b[i]);
return !diff;
}
#ifndef BUFHELP_FAST_UNALIGNED_ACCESS
/* Functions for loading and storing unaligned u32 values of different
endianness. */
static inline u32 buf_get_be32(const void *_buf)
{
const byte *in = _buf;
return ((u32)in[0] << 24) | ((u32)in[1] << 16) | \
((u32)in[2] << 8) | (u32)in[3];
}
static inline u32 buf_get_le32(const void *_buf)
{
const byte *in = _buf;
return ((u32)in[3] << 24) | ((u32)in[2] << 16) | \
((u32)in[1] << 8) | (u32)in[0];
}
static inline void buf_put_be32(void *_buf, u32 val)
{
byte *out = _buf;
out[0] = val >> 24;
out[1] = val >> 16;
out[2] = val >> 8;
out[3] = val;
}
static inline void buf_put_le32(void *_buf, u32 val)
{
byte *out = _buf;
out[3] = val >> 24;
out[2] = val >> 16;
out[1] = val >> 8;
out[0] = val;
}
#ifdef HAVE_U64_TYPEDEF
/* Functions for loading and storing unaligned u64 values of different
endianness. */
static inline u64 buf_get_be64(const void *_buf)
{
const byte *in = _buf;
return ((u64)in[0] << 56) | ((u64)in[1] << 48) | \
((u64)in[2] << 40) | ((u64)in[3] << 32) | \
((u64)in[4] << 24) | ((u64)in[5] << 16) | \
((u64)in[6] << 8) | (u64)in[7];
}
static inline u64 buf_get_le64(const void *_buf)
{
const byte *in = _buf;
return ((u64)in[7] << 56) | ((u64)in[6] << 48) | \
((u64)in[5] << 40) | ((u64)in[4] << 32) | \
((u64)in[3] << 24) | ((u64)in[2] << 16) | \
((u64)in[1] << 8) | (u64)in[0];
}
static inline void buf_put_be64(void *_buf, u64 val)
{
byte *out = _buf;
out[0] = val >> 56;
out[1] = val >> 48;
out[2] = val >> 40;
out[3] = val >> 32;
out[4] = val >> 24;
out[5] = val >> 16;
out[6] = val >> 8;
out[7] = val;
}
static inline void buf_put_le64(void *_buf, u64 val)
{
byte *out = _buf;
out[7] = val >> 56;
out[6] = val >> 48;
out[5] = val >> 40;
out[4] = val >> 32;
out[3] = val >> 24;
out[2] = val >> 16;
out[1] = val >> 8;
out[0] = val;
}
#endif /*HAVE_U64_TYPEDEF*/
#else /*BUFHELP_FAST_UNALIGNED_ACCESS*/
/* Functions for loading and storing unaligned u32 values of different
endianness. */
static inline u32 buf_get_be32(const void *_buf)
{
return be_bswap32(*(const u32 *)_buf);
}
static inline u32 buf_get_le32(const void *_buf)
{
return le_bswap32(*(const u32 *)_buf);
}
static inline void buf_put_be32(void *_buf, u32 val)
{
u32 *out = _buf;
*out = be_bswap32(val);
}
static inline void buf_put_le32(void *_buf, u32 val)
{
u32 *out = _buf;
*out = le_bswap32(val);
}
#ifdef HAVE_U64_TYPEDEF
/* Functions for loading and storing unaligned u64 values of different
endianness. */
static inline u64 buf_get_be64(const void *_buf)
{
return be_bswap64(*(const u64 *)_buf);
}
static inline u64 buf_get_le64(const void *_buf)
{
return le_bswap64(*(const u64 *)_buf);
}
static inline void buf_put_be64(void *_buf, u64 val)
{
u64 *out = _buf;
*out = be_bswap64(val);
}
static inline void buf_put_le64(void *_buf, u64 val)
{
u64 *out = _buf;
*out = le_bswap64(val);
}
#endif /*HAVE_U64_TYPEDEF*/
#endif /*BUFHELP_FAST_UNALIGNED_ACCESS*/
#endif /*G10_BITHELP_H*/

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