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Diffstat (limited to 'src/int.h')
| -rw-r--r-- | src/int.h | 355 |
1 files changed, 0 insertions, 355 deletions
diff --git a/src/int.h b/src/int.h deleted file mode 100644 index 885933d..0000000 --- a/src/int.h +++ /dev/null @@ -1,355 +0,0 @@ -// Copyright © Tavian Barnes <tavianator@tavianator.com> -// SPDX-License-Identifier: 0BSD - -/** - * Bits & bytes. - */ - -#ifndef BFS_INT_H -#define BFS_INT_H - -#include "config.h" -#include <limits.h> -#include <stdint.h> - -#if __STDC_VERSION__ >= 202311L -# include <stdbit.h> -#endif - -// C23 polyfill: _WIDTH macros - -// The U*_MAX macros are of the form 2**n - 1, and we want to extract the n. -// One way would be *_WIDTH = popcount(*_MAX). Alternatively, we can use -// Hallvard B. Furuseth's technique from [1], which is shorter. -// -// [1]: https://groups.google.com/g/comp.lang.c/c/NfedEFBFJ0k - -// Let mask be of the form 2**m - 1, e.g. 0b111, and let n range over -// [0b0, 0b1, 0b11, 0b111, 0b1111, ...]. Then we have -// -// n % 0b111 -// == [0b0, 0b1, 0b11, 0b0, 0b1, 0b11, ...] -// n / (n % 0b111 + 1) -// == [0b0 (x3), 0b111 (x3), 0b111111 (x3), ...] -// n / (n % 0b111 + 1) / 0b111 -// == [0b0 (x3), 0b1 (x3), 0b1001 (x3), 0b1001001 (x3), ...] -// n / (n % 0b111 + 1) / 0b111 % 0b111 -// == [0 (x3), 1 (x3), 2 (x3), ...] -// == UMAX_CHUNK(n, 0b111) -#define UMAX_CHUNK(n, mask) (n / (n % mask + 1) / mask % mask) - -// 8 * UMAX_CHUNK(n, 255) gives [0 (x8), 8 (x8), 16 (x8), ...]. To that we add -// [0, 1, 2, ..., 6, 7, 0, 1, ...], which we get from a linear interpolation on -// n % 255: -// -// n % 255 -// == [0, 1, 3, 7, 15, 31, 63, 127, 0, ...] -// 86 / (n % 255 + 12) -// == [7, 6, 5, 4, 3, 2, 1, 0, 7, ...] -#define UMAX_INTERP(n) (7 - 86 / (n % 255 + 12)) - -#define UMAX_WIDTH(n) (8 * UMAX_CHUNK(n, 255) + UMAX_INTERP(n)) - -#ifndef CHAR_WIDTH -# define CHAR_WIDTH CHAR_BIT -#endif -#ifndef UCHAR_WIDTH -# define UCHAR_WIDTH CHAR_WIDTH -#endif -#ifndef SCHAR_WIDTH -# define SCHAR_WIDTH CHAR_WIDTH -#endif -#ifndef USHRT_WIDTH -# define USHRT_WIDTH UMAX_WIDTH(USHRT_MAX) -#endif -#ifndef SHRT_WIDTH -# define SHRT_WIDTH USHRT_WIDTH -#endif -#ifndef UINT_WIDTH -# define UINT_WIDTH UMAX_WIDTH(UINT_MAX) -#endif -#ifndef INT_WIDTH -# define INT_WIDTH UINT_WIDTH -#endif -#ifndef ULONG_WIDTH -# define ULONG_WIDTH UMAX_WIDTH(ULONG_MAX) -#endif -#ifndef LONG_WIDTH -# define LONG_WIDTH ULONG_WIDTH -#endif -#ifndef ULLONG_WIDTH -# define ULLONG_WIDTH UMAX_WIDTH(ULLONG_MAX) -#endif -#ifndef LLONG_WIDTH -# define LLONG_WIDTH ULLONG_WIDTH -#endif -#ifndef SIZE_WIDTH -# define SIZE_WIDTH UMAX_WIDTH(SIZE_MAX) -#endif -#ifndef PTRDIFF_WIDTH -# define PTRDIFF_WIDTH (UMAX_WIDTH(PTRDIFF_MAX) + 1) -#endif -#ifndef UINTPTR_WIDTH -# define UINTPTR_WIDTH UMAX_WIDTH(UINTPTR_MAX) -#endif -#ifndef INTPTR_WIDTH -# define INTPTR_WIDTH UINTPTR_WIDTH -#endif -#ifndef UINTMAX_WIDTH -# define UINTMAX_WIDTH UMAX_WIDTH(UINTMAX_MAX) -#endif -#ifndef INTMAX_WIDTH -# define INTMAX_WIDTH UINTMAX_WIDTH -#endif - -// C23 polyfill: byte order - -#ifdef __STDC_ENDIAN_LITTLE__ -# define ENDIAN_LITTLE __STDC_ENDIAN_LITTLE__ -#elif defined(__ORDER_LITTLE_ENDIAN__) -# define ENDIAN_LITTLE __ORDER_LITTLE_ENDIAN__ -#else -# define ENDIAN_LITTLE 1234 -#endif - -#ifdef __STDC_ENDIAN_BIG__ -# define ENDIAN_BIG __STDC_ENDIAN_BIG__ -#elif defined(__ORDER_BIG_ENDIAN__) -# define ENDIAN_BIG __ORDER_BIG_ENDIAN__ -#else -# define ENDIAN_BIG 4321 -#endif - -#ifdef __STDC_ENDIAN_NATIVE__ -# define ENDIAN_NATIVE __STDC_ENDIAN_NATIVE__ -#elif defined(__ORDER_NATIVE_ENDIAN__) -# define ENDIAN_NATIVE __ORDER_NATIVE_ENDIAN__ -#else -# define ENDIAN_NATIVE 0 -#endif - -#if __STDC_VERSION__ >= 202311L -# define bswap16 stdc_memreverse8u16 -# define bswap32 stdc_memreverse8u32 -# define bswap64 stdc_memreverse8u64 -#elif __GNUC__ -# define bswap16 __builtin_bswap16 -# define bswap32 __builtin_bswap32 -# define bswap64 __builtin_bswap64 -#else - -static inline uint16_t bswap16(uint16_t n) { - return (n << 8) | (n >> 8); -} - -static inline uint32_t bswap32(uint32_t n) { - return ((uint32_t)bswap16(n) << 16) | bswap16(n >> 16); -} - -static inline uint64_t bswap64(uint64_t n) { - return ((uint64_t)bswap32(n) << 32) | bswap32(n >> 32); -} - -#endif - -static inline uint8_t bswap8(uint8_t n) { - return n; -} - -/** - * Reverse the byte order of an integer. - */ -#define bswap(n) \ - _Generic((n), \ - uint8_t: bswap8, \ - uint16_t: bswap16, \ - uint32_t: bswap32, \ - uint64_t: bswap64)(n) - -// Define an overload for each unsigned type -#define UINT_OVERLOADS(macro) \ - macro(unsigned char, _uc, UCHAR_WIDTH) \ - macro(unsigned short, _us, USHRT_WIDTH) \ - macro(unsigned int, _ui, UINT_WIDTH) \ - macro(unsigned long, _ul, ULONG_WIDTH) \ - macro(unsigned long long, _ull, ULLONG_WIDTH) - -// Select an overload based on an unsigned integer type -#define UINT_SELECT(n, name) \ - _Generic((n), \ - char: name##_uc, \ - signed char: name##_uc, \ - unsigned char: name##_uc, \ - signed short: name##_us, \ - unsigned short: name##_us, \ - signed int: name##_ui, \ - unsigned int: name##_ui, \ - signed long: name##_ul, \ - unsigned long: name##_ul, \ - signed long long: name##_ull, \ - unsigned long long: name##_ull) - -// C23 polyfill: bit utilities - -#if __STDC_VERSION__ >= 202311L -# define count_ones stdc_count_ones -# define count_zeros stdc_count_zeros -# define rotate_left stdc_rotate_left -# define rotate_right stdc_rotate_right -# define leading_zeros stdc_leading_zeros -# define leading_ones stdc_leading_ones -# define trailing_zeros stdc_trailing_zeros -# define trailing_ones stdc_trailing_ones -# define first_leading_zero stdc_first_leading_zero -# define first_leading_one stdc_first_leading_one -# define first_trailing_zero stdc_first_trailing_zero -# define first_trailing_one stdc_first_trailing_one -# define has_single_bit stdc_has_single_bit -# define bit_width stdc_bit_width -# define bit_ceil stdc_bit_ceil -# define bit_floor stdc_bit_floor -#else - -#if __GNUC__ - -// GCC provides builtins for unsigned {int,long,long long}, so promote char/short -#define UINT_BUILTIN_uc(name) __builtin_##name -#define UINT_BUILTIN_us(name) __builtin_##name -#define UINT_BUILTIN_ui(name) __builtin_##name -#define UINT_BUILTIN_ul(name) __builtin_##name##l -#define UINT_BUILTIN_ull(name) __builtin_##name##ll -#define UINT_BUILTIN(name, suffix) UINT_BUILTIN##suffix(name) - -#define BUILTIN_WIDTH_uc UINT_WIDTH -#define BUILTIN_WIDTH_us UINT_WIDTH -#define BUILTIN_WIDTH_ui UINT_WIDTH -#define BUILTIN_WIDTH_ul ULONG_WIDTH -#define BUILTIN_WIDTH_ull ULLONG_WIDTH -#define BUILTIN_WIDTH(suffix) BUILTIN_WIDTH##suffix - -#define COUNT_ONES(type, suffix, width) \ - static inline int count_ones##suffix(type n) { \ - return UINT_BUILTIN(popcount, suffix)(n); \ - } - -#define LEADING_ZEROS(type, suffix, width) \ - static inline int leading_zeros##suffix(type n) { \ - return n \ - ? UINT_BUILTIN(clz, suffix)(n) - (BUILTIN_WIDTH(suffix) - width) \ - : width; \ - } - -#define TRAILING_ZEROS(type, suffix, width) \ - static inline int trailing_zeros##suffix(type n) { \ - return n ? UINT_BUILTIN(ctz, suffix)(n) : width; \ - } - -#define FIRST_TRAILING_ONE(type, suffix, width) \ - static inline int first_trailing_one##suffix(type n) { \ - return UINT_BUILTIN(ffs, suffix)(n); \ - } - -#else // !__GNUC__ - -#define COUNT_ONES(type, suffix, width) \ - static inline int count_ones##suffix(type n) { \ - int ret; \ - for (ret = 0; n; ++ret) { \ - n &= n - 1; \ - } \ - return ret; \ - } - -#define LEADING_ZEROS(type, suffix, width) \ - static inline int leading_zeros##suffix(type n) { \ - type bit = (type)1 << (width - 1); \ - int ret; \ - for (ret = 0; bit && !(n & bit); ++ret, bit >>= 1); \ - return ret; \ - } - -#define TRAILING_ZEROS(type, suffix, width) \ - static inline int trailing_zeros##suffix(type n) { \ - type bit = 1; \ - int ret; \ - for (ret = 0; bit && !(n & bit); ++ret, bit <<= 1); \ - return ret; \ - } - -#define FIRST_TRAILING_ONE(type, suffix, width) \ - static inline int first_trailing_one##suffix(type n) { \ - return n ? trailing_zeros##suffix(n) + 1 : 0; \ - } - -#endif // !__GNUC__ - -UINT_OVERLOADS(COUNT_ONES) -UINT_OVERLOADS(LEADING_ZEROS) -UINT_OVERLOADS(TRAILING_ZEROS) -UINT_OVERLOADS(FIRST_TRAILING_ONE) - -#define ROTATE_LEFT(type, suffix, width) \ - static inline type rotate_left##suffix(type n, int c) { \ - return (n << c) | (n >> ((width - c) % width)); \ - } - -#define ROTATE_RIGHT(type, suffix, width) \ - static inline type rotate_right##suffix(type n, int c) { \ - return (n >> c) | (n << ((width - c) % width)); \ - } - -#define FIRST_LEADING_ONE(type, suffix, width) \ - static inline int first_leading_one##suffix(type n) { \ - return width - leading_zeros##suffix(n); \ - } - -#define HAS_SINGLE_BIT(type, suffix, width) \ - static inline bool has_single_bit##suffix(type n) { \ - return n && !(n & (n - 1)); \ - } - -UINT_OVERLOADS(ROTATE_LEFT) -UINT_OVERLOADS(ROTATE_RIGHT) -UINT_OVERLOADS(FIRST_LEADING_ONE) -UINT_OVERLOADS(HAS_SINGLE_BIT) - -#define count_ones(n) UINT_SELECT(n, count_ones)(n) -#define count_zeros(n) UINT_SELECT(n, count_ones)(~(n)) - -#define rotate_left(n, c) UINT_SELECT(n, rotate_left)(n, c) -#define rotate_right(n, c) UINT_SELECT(n, rotate_right)(n, c) - -#define leading_zeros(n) UINT_SELECT(n, leading_zeros)(n) -#define leading_ones(n) UINT_SELECT(n, leading_zeros)(~(n)) - -#define trailing_zeros(n) UINT_SELECT(n, trailing_zeros)(n) -#define trailing_ones(n) UINT_SELECT(n, trailing_zeros)(~(n)) - -#define first_leading_one(n) UINT_SELECT(n, first_leading_one)(n) -#define first_leading_zero(n) UINT_SELECT(n, first_leading_one)(~(n)) - -#define first_trailing_one(n) UINT_SELECT(n, first_trailing_one)(n) -#define first_trailing_zero(n) UINT_SELECT(n, first_trailing_one)(~(n)) - -#define has_single_bit(n) UINT_SELECT(n, has_single_bit)(n) - -#define BIT_FLOOR(type, suffix, width) \ - static inline type bit_floor##suffix(type n) { \ - return n ? (type)1 << (first_leading_one##suffix(n) - 1) : 0; \ - } - -#define BIT_CEIL(type, suffix, width) \ - static inline type bit_ceil##suffix(type n) { \ - return (type)1 << first_leading_one##suffix(n - !!n); \ - } - -UINT_OVERLOADS(BIT_FLOOR) -UINT_OVERLOADS(BIT_CEIL) - -#define bit_width(n) first_leading_one(n) -#define bit_floor(n) UINT_SELECT(n, bit_floor)(n) -#define bit_ceil(n) UINT_SELECT(n, bit_ceil)(n) - -#endif // __STDC_VERSION__ < 202311L - -#endif // BFS_INT_H |