/src/CMake/Utilities/cmlibrhash/librhash/byte_order.c

Source
/* byte_order.c - byte order related platform dependent routines,
 *
 * Copyright (c) 2008, Aleksey Kravchenko <rhash.admin@gmail.com>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted.
 *
 * 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.
 */
#include "byte_order.h"

#ifndef rhash_ctz

#  if _MSC_VER >= 1300 && (_M_IX86 || _M_AMD64 || _M_IA64) /* if MSVC++ >= 2002 on x86/x64 */
#  include <intrin.h>
#  pragma intrinsic(_BitScanForward)

/**
 * Returns index of the trailing bit of x.
 *
 * @param x the number to process
 * @return zero-based index of the trailing bit
 */
unsigned rhash_ctz(unsigned x)
{
  unsigned long index;
  unsigned char isNonzero = _BitScanForward(&index, x); /* MSVC intrinsic */
  return (isNonzero ? (unsigned)index : 0);
}
#  else /* _MSC_VER >= 1300... */

/**
 * Returns index of the trailing bit of a 32-bit number.
 * This is a plain C equivalent for GCC __builtin_ctz() bit scan.
 *
 * @param x the number to process
 * @return zero-based index of the trailing bit
 */
unsigned rhash_ctz(unsigned x)
{
  /* array for conversion to bit position */
  static unsigned char bit_pos[32] =  {
    0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
    31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9
  };

  /* The De Bruijn bit-scan was devised in 1997, according to Donald Knuth
   * by Martin Lauter. The constant 0x077CB531UL is a De Bruijn sequence,
   * which produces a unique pattern of bits into the high 5 bits for each
   * possible bit position that it is multiplied against.
   * See http://graphics.stanford.edu/~seander/bithacks.html
   * and http://chessprogramming.wikispaces.com/BitScan */
  return (unsigned)bit_pos[((uint32_t)((x & -x) * 0x077CB531U)) >> 27];
}
#  endif /* _MSC_VER >= 1300... */
#endif /* rhash_ctz */

/**
 * Copy a memory block with simultaneous exchanging byte order.
 * The byte order is changed from little-endian 32-bit integers
 * to big-endian (or vice-versa).
 *
 * @param to the pointer where to copy memory block
 * @param index the index to start writing from
 * @param from  the source block to copy
 * @param length length of the memory block
 */
void rhash_swap_copy_str_to_u32(void* to, int index, const void* from, size_t length)
{
  /* if all pointers and length are 32-bits aligned */
  if ( 0 == (( (uintptr_t)to | (uintptr_t)from | (uintptr_t)index | length ) & 3) ) {
    /* copy memory as 32-bit words */
    const uint32_t* src = (const uint32_t*)from;
    const uint32_t* end = (const uint32_t*)((const char*)src + length);
    uint32_t* dst = (uint32_t*)((char*)to + index);
    for (; src < end; dst++, src++)
      *dst = bswap_32(*src);
  } else {
    const char* src = (const char*)from;
    for (length += index; (size_t)index < length; index++)
      ((char*)to)[index ^ 3] = *(src++);
  }
}

/**
 * Copy a memory block with changed byte order.
 * The byte order is changed from little-endian 64-bit integers
 * to big-endian (or vice-versa).
 *
 * @param to     the pointer where to copy memory block
 * @param index  the index to start writing from
 * @param from   the source block to copy
 * @param length length of the memory block
 */
void rhash_swap_copy_str_to_u64(void* to, int index, const void* from, size_t length)
{
  /* if all pointers and length are 64-bits aligned */
  if ( 0 == (( (uintptr_t)to | (uintptr_t)from | (uintptr_t)index | length ) & 7) ) {
    /* copy aligned memory block as 64-bit integers */
    const uint64_t* src = (const uint64_t*)from;
    const uint64_t* end = (const uint64_t*)((const char*)src + length);
    uint64_t* dst = (uint64_t*)((char*)to + index);
    while (src < end) *(dst++) = bswap_64( *(src++) );
  } else {
    const char* src = (const char*)from;
    for (length += index; (size_t)index < length; index++) ((char*)to)[index ^ 7] = *(src++);
  }
}

/**
 * Copy data from a sequence of 64-bit words to a binary string of given length,
 * while changing byte order.
 *
 * @param to     the binary string to receive data
 * @param from   the source sequence of 64-bit words
 * @param length the size in bytes of the data being copied
 */
void rhash_swap_copy_u64_to_str(void* to, const void* from, size_t length)
{
  /* if all pointers and length are 64-bits aligned */
  if ( 0 == (( (uintptr_t)to | (uintptr_t)from | length ) & 7) ) {
    /* copy aligned memory block as 64-bit integers */
    const uint64_t* src = (const uint64_t*)from;
    const uint64_t* end = (const uint64_t*)((const char*)src + length);
    uint64_t* dst = (uint64_t*)to;
    while (src < end) *(dst++) = bswap_64( *(src++) );
  } else {
    size_t index;
    char* dst = (char*)to;
    for (index = 0; index < length; index++) *(dst++) = ((char*)from)[index ^ 7];
  }
}

/**
 * Exchange byte order in the given array of 32-bit integers.
 *
 * @param arr    the array to process
 * @param length array length
 */
void rhash_u32_mem_swap(unsigned* arr, int length)
{
  unsigned* end = arr + length;
  for (; arr < end; arr++) {
    *arr = bswap_32(*arr);
  }
}

#ifdef HAS_INTEL_CPUID
#include <cpuid.h>

static uint64_t get_cpuid_features(void)
{
  uint32_t tmp, edx, ecx;
  if (__get_cpuid(1, &tmp, &tmp, &ecx, &edx))
    return ((((uint64_t)ecx) << 32) ^ edx);
  return 0;
}

int has_cpu_feature(unsigned feature_bit)
{
  static uint64_t features;
  const uint64_t feature = ((uint64_t)1) << feature_bit;
  if (!features)
    features = (get_cpuid_features() | 1);
  return !!(features & feature);
}
#endif

Coverage Report

Created: 2026-03-12 06:35

Line	Count	Source
1		/* byte_order.c - byte order related platform dependent routines,
2		*
3		* Copyright (c) 2008, Aleksey Kravchenko <rhash.admin@gmail.com>
4		*
5		* Permission to use, copy, modify, and/or distribute this software for any
6		* purpose with or without fee is hereby granted.
7		*
8		* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
9		* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
10		* AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
11		* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
12		* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
13		* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
14		* PERFORMANCE OF THIS SOFTWARE.
15		*/
16		#include "byte_order.h"
17
18		#ifndef rhash_ctz
19
20		# if _MSC_VER >= 1300 && (_M_IX86 \|\| _M_AMD64 \|\| _M_IA64) /* if MSVC++ >= 2002 on x86/x64 */
21		# include <intrin.h>
22		# pragma intrinsic(_BitScanForward)
23
24		/**
25		* Returns index of the trailing bit of x.
26		*
27		* @param x the number to process
28		* @return zero-based index of the trailing bit
29		*/
30		unsigned rhash_ctz(unsigned x)
31		{
32		unsigned long index;
33		unsigned char isNonzero = _BitScanForward(&index, x); /* MSVC intrinsic */
34		return (isNonzero ? (unsigned)index : 0);
35		}
36		# else /* _MSC_VER >= 1300... */
37
38		/**
39		* Returns index of the trailing bit of a 32-bit number.
40		* This is a plain C equivalent for GCC __builtin_ctz() bit scan.
41		*
42		* @param x the number to process
43		* @return zero-based index of the trailing bit
44		*/
45		unsigned rhash_ctz(unsigned x)
46		{
47		/* array for conversion to bit position */
48		static unsigned char bit_pos[32] = {
49		0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
50		31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9
51		};
52
53		/* The De Bruijn bit-scan was devised in 1997, according to Donald Knuth
54		* by Martin Lauter. The constant 0x077CB531UL is a De Bruijn sequence,
55		* which produces a unique pattern of bits into the high 5 bits for each
56		* possible bit position that it is multiplied against.
57		* See http://graphics.stanford.edu/~seander/bithacks.html
58		* and http://chessprogramming.wikispaces.com/BitScan */
59		return (unsigned)bit_pos[((uint32_t)((x & -x) * 0x077CB531U)) >> 27];
60		}
61		# endif /* _MSC_VER >= 1300... */
62		#endif /* rhash_ctz */
63
64		/**
65		* Copy a memory block with simultaneous exchanging byte order.
66		* The byte order is changed from little-endian 32-bit integers
67		* to big-endian (or vice-versa).
68		*
69		* @param to the pointer where to copy memory block
70		* @param index the index to start writing from
71		* @param from the source block to copy
72		* @param length length of the memory block
73		*/
74		void rhash_swap_copy_str_to_u32(void* to, int index, const void* from, size_t length)
75	0	{
76		/* if all pointers and length are 32-bits aligned */
77	0	if ( 0 == (( (uintptr_t)to \| (uintptr_t)from \| (uintptr_t)index \| length ) & 3) ) {
78		/* copy memory as 32-bit words */
79	0	const uint32_t* src = (const uint32_t*)from;
80	0	const uint32_t* end = (const uint32_t)((const char)src + length);
81	0	uint32_t* dst = (uint32_t)((char)to + index);
82	0	for (; src < end; dst++, src++)
83	0	dst = bswap_32(src);
84	0	} else {
85	0	const char* src = (const char*)from;
86	0	for (length += index; (size_t)index < length; index++)
87	0	((char)to)[index ^ 3] = (src++);
88	0	}
89	0	}
90
91		/**
92		* Copy a memory block with changed byte order.
93		* The byte order is changed from little-endian 64-bit integers
94		* to big-endian (or vice-versa).
95		*
96		* @param to the pointer where to copy memory block
97		* @param index the index to start writing from
98		* @param from the source block to copy
99		* @param length length of the memory block
100		*/
101		void rhash_swap_copy_str_to_u64(void* to, int index, const void* from, size_t length)
102	0	{
103		/* if all pointers and length are 64-bits aligned */
104	0	if ( 0 == (( (uintptr_t)to \| (uintptr_t)from \| (uintptr_t)index \| length ) & 7) ) {
105		/* copy aligned memory block as 64-bit integers */
106	0	const uint64_t* src = (const uint64_t*)from;
107	0	const uint64_t* end = (const uint64_t)((const char)src + length);
108	0	uint64_t* dst = (uint64_t)((char)to + index);
109	0	while (src < end) (dst++) = bswap_64( (src++) );
110	0	} else {
111	0	const char* src = (const char*)from;
112	0	for (length += index; (size_t)index < length; index++) ((char)to)[index ^ 7] = (src++);
113	0	}
114	0	}
115
116		/**
117		* Copy data from a sequence of 64-bit words to a binary string of given length,
118		* while changing byte order.
119		*
120		* @param to the binary string to receive data
121		* @param from the source sequence of 64-bit words
122		* @param length the size in bytes of the data being copied
123		*/
124		void rhash_swap_copy_u64_to_str(void* to, const void* from, size_t length)
125	0	{
126		/* if all pointers and length are 64-bits aligned */
127	0	if ( 0 == (( (uintptr_t)to \| (uintptr_t)from \| length ) & 7) ) {
128		/* copy aligned memory block as 64-bit integers */
129	0	const uint64_t* src = (const uint64_t*)from;
130	0	const uint64_t* end = (const uint64_t)((const char)src + length);
131	0	uint64_t* dst = (uint64_t*)to;
132	0	while (src < end) (dst++) = bswap_64( (src++) );
133	0	} else {
134	0	size_t index;
135	0	char* dst = (char*)to;
136	0	for (index = 0; index < length; index++) (dst++) = ((char)from)[index ^ 7];
137	0	}
138	0	}
139
140		/**
141		* Exchange byte order in the given array of 32-bit integers.
142		*
143		* @param arr the array to process
144		* @param length array length
145		*/
146		void rhash_u32_mem_swap(unsigned* arr, int length)
147	0	{
148	0	unsigned* end = arr + length;
149	0	for (; arr < end; arr++) {
150	0	arr = bswap_32(arr);
151	0	}
152	0	}
153
154		#ifdef HAS_INTEL_CPUID
155		#include <cpuid.h>
156
157		static uint64_t get_cpuid_features(void)
158		{
159		uint32_t tmp, edx, ecx;
160		if (__get_cpuid(1, &tmp, &tmp, &ecx, &edx))
161		return ((((uint64_t)ecx) << 32) ^ edx);
162		return 0;
163		}
164
165		int has_cpu_feature(unsigned feature_bit)
166		{
167		static uint64_t features;
168		const uint64_t feature = ((uint64_t)1) << feature_bit;
169		if (!features)
170		features = (get_cpuid_features() \| 1);
171		return !!(features & feature);
172		}
173		#endif