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polarssl/library/alignment.h
Dave Rodgman 7f376fa6fc Improve documentation 
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
2023-01-20 14:04:48 +00:00

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/**
* \file alignment.h
*
* \brief Utility code for dealing with unaligned memory accesses
*/
/*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef MBEDTLS_LIBRARY_ALIGNMENT_H
#define MBEDTLS_LIBRARY_ALIGNMENT_H
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include "mbedtls/build_info.h"
/*
* Define MBEDTLS_EFFICIENT_UNALIGNED_ACCESS for architectures where unaligned memory
* accesses are known to be efficient.
*
* All functions defined here will behave correctly regardless, but might be less
* efficient when this is not defined.
*/
#if defined(__ARM_FEATURE_UNALIGNED) \
|| defined(__i386__) || defined(__amd64__) || defined(__x86_64__)
/*
* __ARM_FEATURE_UNALIGNED is defined where appropriate by armcc, gcc 7, clang 9
* (and later versions) for Arm v7 and later; all x86 platforms should have
* efficient unaligned access.
*/
#define MBEDTLS_EFFICIENT_UNALIGNED_ACCESS
#endif
/**
* Read the unsigned 16 bits integer from the given address, which need not
* be aligned.
*
* \param p pointer to 2 bytes of data
* \return Data at the given address
*/
inline uint16_t mbedtls_get_unaligned_uint16(const void *p)
{
uint16_t r;
memcpy(&r, p, sizeof(r));
return r;
}
/**
* Write the unsigned 16 bits integer to the given address, which need not
* be aligned.
*
* \param p pointer to 2 bytes of data
* \param x data to write
*/
inline void mbedtls_put_unaligned_uint16(void *p, uint16_t x)
{
memcpy(p, &x, sizeof(x));
}
/**
* Read the unsigned 32 bits integer from the given address, which need not
* be aligned.
*
* \param p pointer to 4 bytes of data
* \return Data at the given address
*/
inline uint32_t mbedtls_get_unaligned_uint32(const void *p)
{
uint32_t r;
memcpy(&r, p, sizeof(r));
return r;
}
/**
* Write the unsigned 32 bits integer to the given address, which need not
* be aligned.
*
* \param p pointer to 4 bytes of data
* \param x data to write
*/
inline void mbedtls_put_unaligned_uint32(void *p, uint32_t x)
{
memcpy(p, &x, sizeof(x));
}
/**
* Read the unsigned 64 bits integer from the given address, which need not
* be aligned.
*
* \param p pointer to 8 bytes of data
* \return Data at the given address
*/
inline uint64_t mbedtls_get_unaligned_uint64(const void *p)
{
uint64_t r;
memcpy(&r, p, sizeof(r));
return r;
}
/**
* Write the unsigned 64 bits integer to the given address, which need not
* be aligned.
*
* \param p pointer to 8 bytes of data
* \param x data to write
*/
inline void mbedtls_put_unaligned_uint64(void *p, uint64_t x)
{
memcpy(p, &x, sizeof(x));
}
/** Byte Reading Macros
*
* Given a multi-byte integer \p x, MBEDTLS_BYTE_n retrieves the n-th
* byte from x, where byte 0 is the least significant byte.
*/
#define MBEDTLS_BYTE_0(x) ((uint8_t) ((x) & 0xff))
#define MBEDTLS_BYTE_1(x) ((uint8_t) (((x) >> 8) & 0xff))
#define MBEDTLS_BYTE_2(x) ((uint8_t) (((x) >> 16) & 0xff))
#define MBEDTLS_BYTE_3(x) ((uint8_t) (((x) >> 24) & 0xff))
#define MBEDTLS_BYTE_4(x) ((uint8_t) (((x) >> 32) & 0xff))
#define MBEDTLS_BYTE_5(x) ((uint8_t) (((x) >> 40) & 0xff))
#define MBEDTLS_BYTE_6(x) ((uint8_t) (((x) >> 48) & 0xff))
#define MBEDTLS_BYTE_7(x) ((uint8_t) (((x) >> 56) & 0xff))
/*
* Detect GCC built-in byteswap routines
*/
#if defined(__GNUC__) && defined(__GNUC_PREREQ)
#if __GNUC_PREREQ(4, 8)
#define MBEDTLS_BSWAP16 __builtin_bswap16
#endif /* __GNUC_PREREQ(4,8) */
#if __GNUC_PREREQ(4, 3)
#define MBEDTLS_BSWAP32 __builtin_bswap32
#define MBEDTLS_BSWAP64 __builtin_bswap64
#endif /* __GNUC_PREREQ(4,3) */
#endif /* defined(__GNUC__) && defined(__GNUC_PREREQ) */
/*
* Detect Clang built-in byteswap routines
*/
#if defined(__clang__) && defined(__has_builtin)
#if __has_builtin(__builtin_bswap16)
#define MBEDTLS_BSWAP16 __builtin_bswap16
#endif /* __has_builtin(__builtin_bswap16) */
#if __has_builtin(__builtin_bswap32)
#define MBEDTLS_BSWAP32 __builtin_bswap32
#endif /* __has_builtin(__builtin_bswap32) */
#if __has_builtin(__builtin_bswap64)
#define MBEDTLS_BSWAP64 __builtin_bswap64
#endif /* __has_builtin(__builtin_bswap64) */
#endif /* defined(__clang__) && defined(__has_builtin) */
/*
* Detect MSVC built-in byteswap routines
*/
#if defined(_MSC_VER)
#define MBEDTLS_BSWAP16 _byteswap_ushort
#define MBEDTLS_BSWAP32 _byteswap_ulong
#define MBEDTLS_BSWAP64 _byteswap_uint64
#endif /* defined(_MSC_VER) */
/* Detect armcc built-in byteswap routine */
#if defined(__ARMCC_VERSION) && (__ARMCC_VERSION >= 410000)
#define MBEDTLS_BSWAP32 __rev
#endif
/*
* Where compiler built-ins are not present, fall back to C code that the
* compiler may be able to detect and transform into the relevant bswap or
* similar instruction.
*/
#if !defined(MBEDTLS_BSWAP16)
static inline uint16_t mbedtls_bswap16(uint16_t x)
{
return
(x & 0x00ff) << 8 |
(x & 0xff00) >> 8;
}
#define MBEDTLS_BSWAP16 mbedtls_bswap16
#endif /* !defined(MBEDTLS_BSWAP16) */
#if !defined(MBEDTLS_BSWAP32)
static inline uint32_t mbedtls_bswap32(uint32_t x)
{
return
(x & 0x000000ff) << 24 |
(x & 0x0000ff00) << 8 |
(x & 0x00ff0000) >> 8 |
(x & 0xff000000) >> 24;
}
#define MBEDTLS_BSWAP32 mbedtls_bswap32
#endif /* !defined(MBEDTLS_BSWAP32) */
#if !defined(MBEDTLS_BSWAP64)
static inline uint64_t mbedtls_bswap64(uint64_t x)
{
return
(x & 0x00000000000000ff) << 56 |
(x & 0x000000000000ff00) << 40 |
(x & 0x0000000000ff0000) << 24 |
(x & 0x00000000ff000000) << 8 |
(x & 0x000000ff00000000) >> 8 |
(x & 0x0000ff0000000000) >> 24 |
(x & 0x00ff000000000000) >> 40 |
(x & 0xff00000000000000) >> 56;
}
#define MBEDTLS_BSWAP64 mbedtls_bswap64
#endif /* !defined(MBEDTLS_BSWAP64) */
#if !defined(__BYTE_ORDER__)
static const uint16_t mbedtls_byte_order_detector = { 0x100 };
#define MBEDTLS_IS_BIG_ENDIAN (*((unsigned char *) (&mbedtls_byte_order_detector)) == 0x01)
#else
#define MBEDTLS_IS_BIG_ENDIAN ((__BYTE_ORDER__) == (__ORDER_BIG_ENDIAN__))
#endif /* !defined(__BYTE_ORDER__) */
/**
* Get the unsigned 32 bits integer corresponding to four bytes in
* big-endian order (MSB first).
*
* \param data Base address of the memory to get the four bytes from.
* \param offset Offset from \p data of the first and most significant
* byte of the four bytes to build the 32 bits unsigned
* integer from.
*/
#define MBEDTLS_GET_UINT32_BE(data, offset) \
((MBEDTLS_IS_BIG_ENDIAN) \
? mbedtls_get_unaligned_uint32((data) + (offset)) \
: MBEDTLS_BSWAP32(mbedtls_get_unaligned_uint32((data) + (offset))) \
)
/**
* Put in memory a 32 bits unsigned integer in big-endian order.
*
* \param n 32 bits unsigned integer to put in memory.
* \param data Base address of the memory where to put the 32
* bits unsigned integer in.
* \param offset Offset from \p data where to put the most significant
* byte of the 32 bits unsigned integer \p n.
*/
#define MBEDTLS_PUT_UINT32_BE(n, data, offset) \
{ \
if (MBEDTLS_IS_BIG_ENDIAN) \
{ \
mbedtls_put_unaligned_uint32((data) + (offset), (uint32_t) (n)); \
} \
else \
{ \
mbedtls_put_unaligned_uint32((data) + (offset), MBEDTLS_BSWAP32((uint32_t) (n))); \
} \
}
/**
* Get the unsigned 32 bits integer corresponding to four bytes in
* little-endian order (LSB first).
*
* \param data Base address of the memory to get the four bytes from.
* \param offset Offset from \p data of the first and least significant
* byte of the four bytes to build the 32 bits unsigned
* integer from.
*/
#define MBEDTLS_GET_UINT32_LE(data, offset) \
((MBEDTLS_IS_BIG_ENDIAN) \
? MBEDTLS_BSWAP32(mbedtls_get_unaligned_uint32((data) + (offset))) \
: mbedtls_get_unaligned_uint32((data) + (offset)) \
)
/**
* Put in memory a 32 bits unsigned integer in little-endian order.
*
* \param n 32 bits unsigned integer to put in memory.
* \param data Base address of the memory where to put the 32
* bits unsigned integer in.
* \param offset Offset from \p data where to put the least significant
* byte of the 32 bits unsigned integer \p n.
*/
#define MBEDTLS_PUT_UINT32_LE(n, data, offset) \
{ \
if (MBEDTLS_IS_BIG_ENDIAN) \
{ \
mbedtls_put_unaligned_uint32((data) + (offset), MBEDTLS_BSWAP32((uint32_t) (n))); \
} \
else \
{ \
mbedtls_put_unaligned_uint32((data) + (offset), ((uint32_t) (n))); \
} \
}
/**
* Get the unsigned 16 bits integer corresponding to two bytes in
* little-endian order (LSB first).
*
* \param data Base address of the memory to get the two bytes from.
* \param offset Offset from \p data of the first and least significant
* byte of the two bytes to build the 16 bits unsigned
* integer from.
*/
#define MBEDTLS_GET_UINT16_LE(data, offset) \
((MBEDTLS_IS_BIG_ENDIAN) \
? MBEDTLS_BSWAP16(mbedtls_get_unaligned_uint16((data) + (offset))) \
: mbedtls_get_unaligned_uint16((data) + (offset)) \
)
/**
* Put in memory a 16 bits unsigned integer in little-endian order.
*
* \param n 16 bits unsigned integer to put in memory.
* \param data Base address of the memory where to put the 16
* bits unsigned integer in.
* \param offset Offset from \p data where to put the least significant
* byte of the 16 bits unsigned integer \p n.
*/
#define MBEDTLS_PUT_UINT16_LE(n, data, offset) \
{ \
if (MBEDTLS_IS_BIG_ENDIAN) \
{ \
mbedtls_put_unaligned_uint16((data) + (offset), MBEDTLS_BSWAP16((uint16_t) (n))); \
} \
else \
{ \
mbedtls_put_unaligned_uint16((data) + (offset), (uint16_t) (n)); \
} \
}
/**
* Get the unsigned 16 bits integer corresponding to two bytes in
* big-endian order (MSB first).
*
* \param data Base address of the memory to get the two bytes from.
* \param offset Offset from \p data of the first and most significant
* byte of the two bytes to build the 16 bits unsigned
* integer from.
*/
#define MBEDTLS_GET_UINT16_BE(data, offset) \
((MBEDTLS_IS_BIG_ENDIAN) \
? mbedtls_get_unaligned_uint16((data) + (offset)) \
: MBEDTLS_BSWAP16(mbedtls_get_unaligned_uint16((data) + (offset))) \
)
/**
* Put in memory a 16 bits unsigned integer in big-endian order.
*
* \param n 16 bits unsigned integer to put in memory.
* \param data Base address of the memory where to put the 16
* bits unsigned integer in.
* \param offset Offset from \p data where to put the most significant
* byte of the 16 bits unsigned integer \p n.
*/
#define MBEDTLS_PUT_UINT16_BE(n, data, offset) \
{ \
if (MBEDTLS_IS_BIG_ENDIAN) \
{ \
mbedtls_put_unaligned_uint16((data) + (offset), (uint16_t) (n)); \
} \
else \
{ \
mbedtls_put_unaligned_uint16((data) + (offset), MBEDTLS_BSWAP16((uint16_t) (n))); \
} \
}
/**
* Get the unsigned 24 bits integer corresponding to three bytes in
* big-endian order (MSB first).
*
* \param data Base address of the memory to get the three bytes from.
* \param offset Offset from \p data of the first and most significant
* byte of the three bytes to build the 24 bits unsigned
* integer from.
*/
#define MBEDTLS_GET_UINT24_BE(data, offset) \
( \
((uint32_t) (data)[(offset)] << 16) \
| ((uint32_t) (data)[(offset) + 1] << 8) \
| ((uint32_t) (data)[(offset) + 2]) \
)
/**
* Put in memory a 24 bits unsigned integer in big-endian order.
*
* \param n 24 bits unsigned integer to put in memory.
* \param data Base address of the memory where to put the 24
* bits unsigned integer in.
* \param offset Offset from \p data where to put the most significant
* byte of the 24 bits unsigned integer \p n.
*/
#define MBEDTLS_PUT_UINT24_BE(n, data, offset) \
{ \
(data)[(offset)] = MBEDTLS_BYTE_2(n); \
(data)[(offset) + 1] = MBEDTLS_BYTE_1(n); \
(data)[(offset) + 2] = MBEDTLS_BYTE_0(n); \
}
/**
* Get the unsigned 24 bits integer corresponding to three bytes in
* little-endian order (LSB first).
*
* \param data Base address of the memory to get the three bytes from.
* \param offset Offset from \p data of the first and least significant
* byte of the three bytes to build the 24 bits unsigned
* integer from.
*/
#define MBEDTLS_GET_UINT24_LE(data, offset) \
( \
((uint32_t) (data)[(offset)]) \
| ((uint32_t) (data)[(offset) + 1] << 8) \
| ((uint32_t) (data)[(offset) + 2] << 16) \
)
/**
* Put in memory a 24 bits unsigned integer in little-endian order.
*
* \param n 24 bits unsigned integer to put in memory.
* \param data Base address of the memory where to put the 24
* bits unsigned integer in.
* \param offset Offset from \p data where to put the least significant
* byte of the 24 bits unsigned integer \p n.
*/
#define MBEDTLS_PUT_UINT24_LE(n, data, offset) \
{ \
(data)[(offset)] = MBEDTLS_BYTE_0(n); \
(data)[(offset) + 1] = MBEDTLS_BYTE_1(n); \
(data)[(offset) + 2] = MBEDTLS_BYTE_2(n); \
}
/**
* Get the unsigned 64 bits integer corresponding to eight bytes in
* big-endian order (MSB first).
*
* \param data Base address of the memory to get the eight bytes from.
* \param offset Offset from \p data of the first and most significant
* byte of the eight bytes to build the 64 bits unsigned
* integer from.
*/
#define MBEDTLS_GET_UINT64_BE(data, offset) \
((MBEDTLS_IS_BIG_ENDIAN) \
? mbedtls_get_unaligned_uint64((data) + (offset)) \
: MBEDTLS_BSWAP64(mbedtls_get_unaligned_uint64((data) + (offset))) \
)
/**
* Put in memory a 64 bits unsigned integer in big-endian order.
*
* \param n 64 bits unsigned integer to put in memory.
* \param data Base address of the memory where to put the 64
* bits unsigned integer in.
* \param offset Offset from \p data where to put the most significant
* byte of the 64 bits unsigned integer \p n.
*/
#define MBEDTLS_PUT_UINT64_BE(n, data, offset) \
{ \
if (MBEDTLS_IS_BIG_ENDIAN) \
{ \
mbedtls_put_unaligned_uint64((data) + (offset), (uint64_t) (n)); \
} \
else \
{ \
mbedtls_put_unaligned_uint64((data) + (offset), MBEDTLS_BSWAP64((uint64_t) (n))); \
} \
}
/**
* Get the unsigned 64 bits integer corresponding to eight bytes in
* little-endian order (LSB first).
*
* \param data Base address of the memory to get the eight bytes from.
* \param offset Offset from \p data of the first and least significant
* byte of the eight bytes to build the 64 bits unsigned
* integer from.
*/
#define MBEDTLS_GET_UINT64_LE(data, offset) \
((MBEDTLS_IS_BIG_ENDIAN) \
? MBEDTLS_BSWAP64(mbedtls_get_unaligned_uint64((data) + (offset))) \
: mbedtls_get_unaligned_uint64((data) + (offset)) \
)
/**
* Put in memory a 64 bits unsigned integer in little-endian order.
*
* \param n 64 bits unsigned integer to put in memory.
* \param data Base address of the memory where to put the 64
* bits unsigned integer in.
* \param offset Offset from \p data where to put the least significant
* byte of the 64 bits unsigned integer \p n.
*/
#define MBEDTLS_PUT_UINT64_LE(n, data, offset) \
{ \
if (MBEDTLS_IS_BIG_ENDIAN) \
{ \
mbedtls_put_unaligned_uint64((data) + (offset), MBEDTLS_BSWAP64((uint64_t) (n))); \
} \
else \
{ \
mbedtls_put_unaligned_uint64((data) + (offset), (uint64_t) (n)); \
} \
}
#endif /* MBEDTLS_LIBRARY_ALIGNMENT_H */
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