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Comparing libecb/ecb.h (file contents):
Revision 1.194 by root, Tue Jun 22 00:10:16 2021 UTC vs.
Revision 1.209 by root, Fri Mar 25 15:23:14 2022 UTC

… …
40 40
41#ifndef ECB_H 41#ifndef ECB_H
42#define ECB_H 42#define ECB_H
43 43
44/* 16 bits major, 16 bits minor */ 44/* 16 bits major, 16 bits minor */
45#define ECB_VERSION 0x00010009 45#define ECB_VERSION 0x0001000c
46 46
47#include <string.h> /* for memcpy */ 47#include <string.h> /* for memcpy */
48 48
49#if defined (_WIN32) && !defined (__MINGW32__) 49#if defined (_WIN32) && !defined (__MINGW32__)
50 typedef signed char int8_t; 50 typedef signed char int8_t;
… …
454/* count trailing zero bits and count # of one bits */ 454/* count trailing zero bits and count # of one bits */
455#if ECB_GCC_VERSION(3,4) \ 455#if ECB_GCC_VERSION(3,4) \
456 || (ECB_CLANG_BUILTIN(__builtin_clz) && ECB_CLANG_BUILTIN(__builtin_clzll) \ 456 || (ECB_CLANG_BUILTIN(__builtin_clz) && ECB_CLANG_BUILTIN(__builtin_clzll) \
457 && ECB_CLANG_BUILTIN(__builtin_ctz) && ECB_CLANG_BUILTIN(__builtin_ctzll) \ 457 && ECB_CLANG_BUILTIN(__builtin_ctz) && ECB_CLANG_BUILTIN(__builtin_ctzll) \
458 && ECB_CLANG_BUILTIN(__builtin_popcount)) 458 && ECB_CLANG_BUILTIN(__builtin_popcount))
459 /* we assume int == 32 bit, long == 32 or 64 bit and long long == 64 bit */
460 #define ecb_ld32(x) (__builtin_clz (x) ^ 31)
461 #define ecb_ld64(x) (__builtin_clzll (x) ^ 63)
462 #define ecb_ctz32(x) __builtin_ctz (x) 459 #define ecb_ctz32(x) __builtin_ctz (x)
460 #define ecb_ctz64(x) (__SIZEOF_LONG__ == 64 ? __builtin_ctzl (x) : __builtin_ctzll (x))
463 #define ecb_ctz64(x) __builtin_ctzll (x) 461 #define ecb_clz32(x) __builtin_clz (x)
462 #define ecb_clz64(x) (__SIZEOF_LONG__ == 64 ? __builtin_clzl (x) : __builtin_clzll (x))
463 #define ecb_ld32(x) (ecb_clz32 (x) ^ 31)
464 #define ecb_ld64(x) (ecb_clz64 (x) ^ 63)
464 #define ecb_popcount32(x) __builtin_popcount (x) 465 #define ecb_popcount32(x) __builtin_popcount (x)
465 /* no popcountll */ 466 /* ecb_popcount64 is more difficult, see below */
466#else 467#else
467 ecb_function_ ecb_const int ecb_ctz32 (uint32_t x); 468 ecb_function_ ecb_const int ecb_ctz32 (uint32_t x);
468 ecb_function_ ecb_const int 469 ecb_function_ ecb_const int
469 ecb_ctz32 (uint32_t x) 470 ecb_ctz32 (uint32_t x)
470 { 471 {
471#if 1400 <= _MSC_VER && (_M_IX86 || _M_X64 || _M_IA64 || _M_ARM) 472#if 1400 <= _MSC_VER && (_M_IX86 || _M_X64 || _M_IA64 || _M_ARM)
472 unsigned long r; 473 unsigned long r;
473 _BitScanForward (&r, x); 474 _BitScanForward (&r, x);
474 return (int)r; 475 return (int)r;
475#else 476#else
476 int r = 0; 477 int r;
477 478
478 x &= ~x + 1; /* this isolates the lowest bit */ 479 x &= ~x + 1; /* this isolates the lowest bit */
479 480
480#if ECB_branchless_on_i386 481 #if 1
482 /* David Seal's algorithm, Message-ID: <32975@armltd.uucp> from 1994 */
483 /* This happens to return 32 for x == 0, but the API does not support this */
484
485 /* -0 marks unused entries */
486 static unsigned char table[64] =
487 {
488 32, 0, 1, 12, 2, 6, -0, 13, 3, -0, 7, -0, -0, -0, -0, 14,
489 10, 4, -0, -0, 8, -0, -0, 25, -0, -0, -0, -0, -0, 21, 27, 15,
490 31, 11, 5, -0, -0, -0, -0, -0, 9, -0, -0, 24, -0, -0, 20, 26,
491 30, -0, -0, -0, -0, 23, -0, 19, 29, -0, 22, 18, 28, 17, 16, -0
492 };
493
494 /* magic constant results in 33 unique values in the upper 6 bits */
495 x *= 0x0450fbafU; /* == 17 * 65 * 65535 */
496
497 r = table [x >> 26];
498 #elif 0 /* branchless on i386, typically */
499 r = 0;
481 r += !!(x & 0xaaaaaaaa) << 0; 500 r += !!(x & 0xaaaaaaaa) << 0;
482 r += !!(x & 0xcccccccc) << 1; 501 r += !!(x & 0xcccccccc) << 1;
483 r += !!(x & 0xf0f0f0f0) << 2; 502 r += !!(x & 0xf0f0f0f0) << 2;
484 r += !!(x & 0xff00ff00) << 3; 503 r += !!(x & 0xff00ff00) << 3;
485 r += !!(x & 0xffff0000) << 4; 504 r += !!(x & 0xffff0000) << 4;
486#else 505 #else /* branchless on modern compilers, typically */
506 r = 0;
487 if (x & 0xaaaaaaaa) r += 1; 507 if (x & 0xaaaaaaaa) r += 1;
488 if (x & 0xcccccccc) r += 2; 508 if (x & 0xcccccccc) r += 2;
489 if (x & 0xf0f0f0f0) r += 4; 509 if (x & 0xf0f0f0f0) r += 4;
490 if (x & 0xff00ff00) r += 8; 510 if (x & 0xff00ff00) r += 8;
491 if (x & 0xffff0000) r += 16; 511 if (x & 0xffff0000) r += 16;
… …
507 int shift = x & 0xffffffff ? 0 : 32; 527 int shift = x & 0xffffffff ? 0 : 32;
508 return ecb_ctz32 (x >> shift) + shift; 528 return ecb_ctz32 (x >> shift) + shift;
509#endif 529#endif
510 } 530 }
511 531
532 ecb_function_ ecb_const int ecb_clz32 (uint32_t x);
533 ecb_function_ ecb_const int
534 ecb_clz32 (uint32_t x)
535 {
536#if 1400 <= _MSC_VER && (_M_IX86 || _M_X64 || _M_IA64 || _M_ARM)
537 unsigned long r;
538 _BitScanReverse (&r, x);
539 return (int)r;
540#else
541
542 /* Robert Harley's algorithm from comp.arch 1996-12-07 */
543 /* This happens to return 32 for x == 0, but the API does not support this */
544
545 /* -0 marks unused table elements */
546 static unsigned char table[64] =
547 {
548 32, 31, -0, 16, -0, 30, 3, -0, 15, -0, -0, -0, 29, 10, 2, -0,
549 -0, -0, 12, 14, 21, -0, 19, -0, -0, 28, -0, 25, -0, 9, 1, -0,
550 17, -0, 4, -0, -0, -0, 11, -0, 13, 22, 20, -0, 26, -0, -0, 18,
551 5, -0, -0, 23, -0, 27, -0, 6, -0, 24, 7, -0, 8, -0, 0, -0
552 };
553
554 /* propagate leftmost 1 bit to the right */
555 x |= x >> 1;
556 x |= x >> 2;
557 x |= x >> 4;
558 x |= x >> 8;
559 x |= x >> 16;
560
561 /* magic constant results in 33 unique values in the upper 6 bits */
562 x *= 0x06EB14F9U; /* == 7 * 255 * 255 * 255 */
563
564 return table [x >> 26];
565#endif
566 }
567
568 ecb_function_ ecb_const int ecb_clz64 (uint64_t x);
569 ecb_function_ ecb_const int
570 ecb_clz64 (uint64_t x)
571 {
572#if 1400 <= _MSC_VER && (_M_X64 || _M_IA64 || _M_ARM)
573 unsigned long r;
574 _BitScanReverse64 (&r, x);
575 return (int)r;
576#else
577 uint32_t l = x >> 32;
578 int shift = l ? 0 : 32;
579 return ecb_clz32 (l ? l : x) + shift;
580#endif
581 }
582
512 ecb_function_ ecb_const int ecb_popcount32 (uint32_t x); 583 ecb_function_ ecb_const int ecb_popcount32 (uint32_t x);
513 ecb_function_ ecb_const int 584 ecb_function_ ecb_const int
514 ecb_popcount32 (uint32_t x) 585 ecb_popcount32 (uint32_t x)
515 { 586 {
516 x -= (x >> 1) & 0x55555555; 587 x -= (x >> 1) & 0x55555555;
… …
591 x = ( x >> 16 ) | ( x << 16); 662 x = ( x >> 16 ) | ( x << 16);
592 663
593 return x; 664 return x;
594} 665}
595 666
596/* popcount64 is only available on 64 bit cpus as gcc builtin */
597/* so for this version we are lazy */
598ecb_function_ ecb_const int ecb_popcount64 (uint64_t x); 667ecb_function_ ecb_const int ecb_popcount64 (uint64_t x);
599ecb_function_ ecb_const int 668ecb_function_ ecb_const int
600ecb_popcount64 (uint64_t x) 669ecb_popcount64 (uint64_t x)
601{ 670{
671 /* popcount64 is only available on 64 bit cpus as gcc builtin. */
672 /* also, gcc/clang make this surprisingly difficult to use */
673#if (__SIZEOF_LONG__ == 8) && (ECB_GCC_VERSION(3,4) || ECB_CLANG_BUILTIN (__builtin_popcountl))
674 return __builtin_popcountl (x);
675#else
602 return ecb_popcount32 (x) + ecb_popcount32 (x >> 32); 676 return ecb_popcount32 (x) + ecb_popcount32 (x >> 32);
677#endif
603} 678}
604 679
605ecb_inline ecb_const uint8_t ecb_rotl8 (uint8_t x, unsigned int count); 680ecb_inline ecb_const uint8_t ecb_rotl8 (uint8_t x, unsigned int count);
606ecb_inline ecb_const uint8_t ecb_rotr8 (uint8_t x, unsigned int count); 681ecb_inline ecb_const uint8_t ecb_rotr8 (uint8_t x, unsigned int count);
607ecb_inline ecb_const uint16_t ecb_rotl16 (uint16_t x, unsigned int count); 682ecb_inline ecb_const uint16_t ecb_rotl16 (uint16_t x, unsigned int count);
… …
609ecb_inline ecb_const uint32_t ecb_rotl32 (uint32_t x, unsigned int count); 684ecb_inline ecb_const uint32_t ecb_rotl32 (uint32_t x, unsigned int count);
610ecb_inline ecb_const uint32_t ecb_rotr32 (uint32_t x, unsigned int count); 685ecb_inline ecb_const uint32_t ecb_rotr32 (uint32_t x, unsigned int count);
611ecb_inline ecb_const uint64_t ecb_rotl64 (uint64_t x, unsigned int count); 686ecb_inline ecb_const uint64_t ecb_rotl64 (uint64_t x, unsigned int count);
612ecb_inline ecb_const uint64_t ecb_rotr64 (uint64_t x, unsigned int count); 687ecb_inline ecb_const uint64_t ecb_rotr64 (uint64_t x, unsigned int count);
613 688
614ecb_inline ecb_const uint8_t ecb_rotl8 (uint8_t x, unsigned int count) { return (x >> ( 8 - count)) | (x << count); } 689ecb_inline ecb_const uint8_t ecb_rotl8 (uint8_t x, unsigned int count) { return (x >> (-count & 7)) | (x << (count & 7)); }
615ecb_inline ecb_const uint8_t ecb_rotr8 (uint8_t x, unsigned int count) { return (x << ( 8 - count)) | (x >> count); } 690ecb_inline ecb_const uint8_t ecb_rotr8 (uint8_t x, unsigned int count) { return (x << (-count & 7)) | (x >> (count & 7)); }
616ecb_inline ecb_const uint16_t ecb_rotl16 (uint16_t x, unsigned int count) { return (x >> (16 - count)) | (x << count); } 691ecb_inline ecb_const uint16_t ecb_rotl16 (uint16_t x, unsigned int count) { return (x >> (-count & 15)) | (x << (count & 15)); }
617ecb_inline ecb_const uint16_t ecb_rotr16 (uint16_t x, unsigned int count) { return (x << (16 - count)) | (x >> count); } 692ecb_inline ecb_const uint16_t ecb_rotr16 (uint16_t x, unsigned int count) { return (x << (-count & 15)) | (x >> (count & 15)); }
618ecb_inline ecb_const uint32_t ecb_rotl32 (uint32_t x, unsigned int count) { return (x >> (32 - count)) | (x << count); } 693ecb_inline ecb_const uint32_t ecb_rotl32 (uint32_t x, unsigned int count) { return (x >> (-count & 31)) | (x << (count & 31)); }
619ecb_inline ecb_const uint32_t ecb_rotr32 (uint32_t x, unsigned int count) { return (x << (32 - count)) | (x >> count); } 694ecb_inline ecb_const uint32_t ecb_rotr32 (uint32_t x, unsigned int count) { return (x << (-count & 31)) | (x >> (count & 31)); }
620ecb_inline ecb_const uint64_t ecb_rotl64 (uint64_t x, unsigned int count) { return (x >> (64 - count)) | (x << count); } 695ecb_inline ecb_const uint64_t ecb_rotl64 (uint64_t x, unsigned int count) { return (x >> (-count & 63)) | (x << (count & 63)); }
621ecb_inline ecb_const uint64_t ecb_rotr64 (uint64_t x, unsigned int count) { return (x << (64 - count)) | (x >> count); } 696ecb_inline ecb_const uint64_t ecb_rotr64 (uint64_t x, unsigned int count) { return (x << (-count & 63)) | (x >> (count & 63)); }
622 697
623#if ECB_CPP 698#if ECB_CPP
624 699
625inline uint8_t ecb_ctz (uint8_t v) { return ecb_ctz32 (v); } 700inline uint8_t ecb_ctz (uint8_t v) { return ecb_ctz32 (v); }
626inline uint16_t ecb_ctz (uint16_t v) { return ecb_ctz32 (v); } 701inline uint16_t ecb_ctz (uint16_t v) { return ecb_ctz32 (v); }
… …
774ecb_inline void ecb_poke_u64_u (void *ptr, uint64_t v) { memcpy (ptr, &v, sizeof (v)); } 849ecb_inline void ecb_poke_u64_u (void *ptr, uint64_t v) { memcpy (ptr, &v, sizeof (v)); }
775 850
776ecb_inline void ecb_poke_be_u16_u (void *ptr, uint_fast16_t v) { ecb_poke_u16_u (ptr, ecb_host_to_be_u16 (v)); } 851ecb_inline void ecb_poke_be_u16_u (void *ptr, uint_fast16_t v) { ecb_poke_u16_u (ptr, ecb_host_to_be_u16 (v)); }
777ecb_inline void ecb_poke_be_u32_u (void *ptr, uint_fast32_t v) { ecb_poke_u32_u (ptr, ecb_host_to_be_u32 (v)); } 852ecb_inline void ecb_poke_be_u32_u (void *ptr, uint_fast32_t v) { ecb_poke_u32_u (ptr, ecb_host_to_be_u32 (v)); }
778ecb_inline void ecb_poke_be_u64_u (void *ptr, uint_fast64_t v) { ecb_poke_u64_u (ptr, ecb_host_to_be_u64 (v)); } 853ecb_inline void ecb_poke_be_u64_u (void *ptr, uint_fast64_t v) { ecb_poke_u64_u (ptr, ecb_host_to_be_u64 (v)); }
779 854
780ecb_inline void ecb_poke_le_u16_u (void *ptr, uint_fast16_t v) { ecb_poke_u16_u (ptr, ecb_host_to_le_u16 (v)); } 855ecb_inline void ecb_poke_le_u16_u (void *ptr, uint_fast16_t v) { ecb_poke_u16_u (ptr, ecb_host_to_le_u16 (v)); }
781ecb_inline void ecb_poke_le_u32_u (void *ptr, uint_fast32_t v) { ecb_poke_u32_u (ptr, ecb_host_to_le_u32 (v)); } 856ecb_inline void ecb_poke_le_u32_u (void *ptr, uint_fast32_t v) { ecb_poke_u32_u (ptr, ecb_host_to_le_u32 (v)); }
782ecb_inline void ecb_poke_le_u64_u (void *ptr, uint_fast64_t v) { ecb_poke_u64_u (ptr, ecb_host_to_le_u64 (v)); } 857ecb_inline void ecb_poke_le_u64_u (void *ptr, uint_fast64_t v) { ecb_poke_u64_u (ptr, ecb_host_to_le_u64 (v)); }
783 858
784#if ECB_CPP 859#if ECB_CPP
… …
805template<typename T> inline void ecb_poke_u (void *ptr, T v) { memcpy (ptr, &v, sizeof (v)); } 880template<typename T> inline void ecb_poke_u (void *ptr, T v) { memcpy (ptr, &v, sizeof (v)); }
806template<typename T> inline void ecb_poke_be_u (void *ptr, T v) { return ecb_poke_u<T> (ptr, ecb_host_to_be (v)); } 881template<typename T> inline void ecb_poke_be_u (void *ptr, T v) { return ecb_poke_u<T> (ptr, ecb_host_to_be (v)); }
807template<typename T> inline void ecb_poke_le_u (void *ptr, T v) { return ecb_poke_u<T> (ptr, ecb_host_to_le (v)); } 882template<typename T> inline void ecb_poke_le_u (void *ptr, T v) { return ecb_poke_u<T> (ptr, ecb_host_to_le (v)); }
808 883
809#endif 884#endif
885
886/*****************************************************************************/
887/* pointer/integer hashing */
888
889/* based on hash by Chris Wellons, https://nullprogram.com/blog/2018/07/31/ */
890ecb_function_ uint32_t ecb_mix32 (uint32_t v);
891ecb_function_ uint32_t ecb_mix32 (uint32_t v)
892{
893 v ^= v >> 16; v *= 0x7feb352dU;
894 v ^= v >> 15; v *= 0x846ca68bU;
895 v ^= v >> 16;
896 return v;
897}
898
899ecb_function_ uint32_t ecb_unmix32 (uint32_t v);
900ecb_function_ uint32_t ecb_unmix32 (uint32_t v)
901{
902 v ^= v >> 16 ; v *= 0x43021123U;
903 v ^= v >> 15 ^ v >> 30; v *= 0x1d69e2a5U;
904 v ^= v >> 16 ;
905 return v;
906}
907
908/* based on splitmix64, by Sebastiona Vigna, https://prng.di.unimi.it/splitmix64.c */
909ecb_function_ uint64_t ecb_mix64 (uint64_t v);
910ecb_function_ uint64_t ecb_mix64 (uint64_t v)
911{
912 v ^= v >> 30; v *= 0xbf58476d1ce4e5b9U;
913 v ^= v >> 27; v *= 0x94d049bb133111ebU;
914 v ^= v >> 31;
915 return v;
916}
917
918ecb_function_ uint64_t ecb_unmix64 (uint64_t v);
919ecb_function_ uint64_t ecb_unmix64 (uint64_t v)
920{
921 v ^= v >> 31 ^ v >> 62; v *= 0x319642b2d24d8ec3U;
922 v ^= v >> 27 ^ v >> 54; v *= 0x96de1b173f119089U;
923 v ^= v >> 30 ^ v >> 60;
924 return v;
925}
926
927ecb_function_ uintptr_t ecb_ptrmix (void *p);
928ecb_function_ uintptr_t ecb_ptrmix (void *p)
929{
930 #if ECB_PTRSIZE <= 4
931 return ecb_mix32 ((uint32_t)p);
932 #else
933 return ecb_mix64 ((uint64_t)p);
934 #endif
935}
936
937ecb_function_ void *ecb_ptrunmix (uintptr_t v);
938ecb_function_ void *ecb_ptrunmix (uintptr_t v)
939{
940 #if ECB_PTRSIZE <= 4
941 return (void *)ecb_unmix32 (v);
942 #else
943 return (void *)ecb_unmix64 (v);
944 #endif
945}
946
947#if ECB_CPP
948
949template<typename T>
950inline uintptr_t ecb_ptrmix (T *p)
951{
952 return ecb_ptrmix (static_cast<void *>(p));
953}
954
955template<typename T>
956inline T *ecb_ptrunmix (uintptr_t v)
957{
958 return static_cast<T *>(ecb_ptrunmix (v));
959}
960
961#endif
962
963/*****************************************************************************/
964/* gray code */
965
966ecb_function_ uint_fast8_t ecb_gray8_encode (uint_fast8_t b) { return b ^ (b >> 1); }
967ecb_function_ uint_fast16_t ecb_gray16_encode (uint_fast16_t b) { return b ^ (b >> 1); }
968ecb_function_ uint_fast32_t ecb_gray32_encode (uint_fast32_t b) { return b ^ (b >> 1); }
969ecb_function_ uint_fast64_t ecb_gray64_encode (uint_fast64_t b) { return b ^ (b >> 1); }
970
971ecb_function_ uint8_t ecb_gray8_decode (uint8_t g)
972{
973 g ^= g >> 1;
974 g ^= g >> 2;
975 g ^= g >> 4;
976
977 return g;
978}
979
980ecb_function_ uint16_t ecb_gray16_decode (uint16_t g)
981{
982 g ^= g >> 1;
983 g ^= g >> 2;
984 g ^= g >> 4;
985 g ^= g >> 8;
986
987 return g;
988}
989
990ecb_function_ uint32_t ecb_gray32_decode (uint32_t g)
991{
992 g ^= g >> 1;
993 g ^= g >> 2;
994 g ^= g >> 4;
995 g ^= g >> 8;
996 g ^= g >> 16;
997
998 return g;
999}
1000
1001ecb_function_ uint64_t ecb_gray64_decode (uint64_t g)
1002{
1003 g ^= g >> 1;
1004 g ^= g >> 2;
1005 g ^= g >> 4;
1006 g ^= g >> 8;
1007 g ^= g >> 16;
1008 g ^= g >> 32;
1009
1010 return g;
1011}
1012
1013#if ECB_CPP
1014
1015ecb_function_ uint8_t ecb_gray_encode (uint8_t b) { return ecb_gray8_encode (b); }
1016ecb_function_ uint16_t ecb_gray_encode (uint16_t b) { return ecb_gray16_encode (b); }
1017ecb_function_ uint32_t ecb_gray_encode (uint32_t b) { return ecb_gray32_encode (b); }
1018ecb_function_ uint64_t ecb_gray_encode (uint64_t b) { return ecb_gray64_encode (b); }
1019
1020ecb_function_ uint8_t ecb_gray_decode (uint8_t g) { return ecb_gray8_decode (g); }
1021ecb_function_ uint16_t ecb_gray_decode (uint16_t g) { return ecb_gray16_decode (g); }
1022ecb_function_ uint32_t ecb_gray_decode (uint32_t g) { return ecb_gray32_decode (g); }
1023ecb_function_ uint64_t ecb_gray_decode (uint64_t g) { return ecb_gray64_decode (g); }
1024
1025#endif
1026
1027/*****************************************************************************/
1028/* 2d hilbert curves */
1029
1030/* algorithm from the book Hacker's Delight, modified to not */
1031/* run into undefined behaviour for n==16 */
1032static uint32_t
1033ecb_hilbert2d_index_to_coord32 (int n, uint32_t s)
1034{
1035 uint32_t comp, swap, cs, t, sr;
1036
1037 /* pad s on the left (unused) bits with 01 (no change groups) */
1038 s |= 0x55555555U << n << n;
1039 /* "s shift right" */
1040 sr = (s >> 1) & 0x55555555U;
1041 /* compute complement and swap info in two-bit groups */
1042 cs = ((s & 0x55555555U) + sr) ^ 0x55555555U;
1043
1044 /* parallel prefix xor op to propagate both complement
1045 * and swap info together from left to right (there is
1046 * no step "cs ^= cs >> 1", so in effect it computes
1047 * two independent parallel prefix operations on two
1048 * interleaved sets of sixteen bits).
1049 */
1050 cs ^= cs >> 2;
1051 cs ^= cs >> 4;
1052 cs ^= cs >> 8;
1053 cs ^= cs >> 16;
1054
1055 /* separate swap and complement bits */
1056 swap = cs & 0x55555555U;
1057 comp = (cs >> 1) & 0x55555555U;
1058
1059 /* calculate coordinates in odd and even bit positions */
1060 t = (s & swap) ^ comp;
1061 s = s ^ sr ^ t ^ (t << 1);
1062
1063 /* unpad/clear out any junk on the left */
1064 s = s & ((1 << n << n) - 1);
1065
1066 /* Now "unshuffle" to separate the x and y bits. */
1067 t = (s ^ (s >> 1)) & 0x22222222U; s ^= t ^ (t << 1);
1068 t = (s ^ (s >> 2)) & 0x0c0c0c0cU; s ^= t ^ (t << 2);
1069 t = (s ^ (s >> 4)) & 0x00f000f0U; s ^= t ^ (t << 4);
1070 t = (s ^ (s >> 8)) & 0x0000ff00U; s ^= t ^ (t << 8);
1071
1072 /* now s contains two 16-bit coordinates */
1073 return s;
1074}
1075
1076/* 64 bit, a straightforward extension to the 32 bit case */
1077static uint64_t
1078ecb_hilbert2d_index_to_coord64 (int n, uint64_t s)
1079{
1080 uint64_t comp, swap, cs, t, sr;
1081
1082 /* pad s on the left (unused) bits with 01 (no change groups) */
1083 s |= 0x5555555555555555U << n << n;
1084 /* "s shift right" */
1085 sr = (s >> 1) & 0x5555555555555555U;
1086 /* compute complement and swap info in two-bit groups */
1087 cs = ((s & 0x5555555555555555U) + sr) ^ 0x5555555555555555U;
1088
1089 /* parallel prefix xor op to propagate both complement
1090 * and swap info together from left to right (there is
1091 * no step "cs ^= cs >> 1", so in effect it computes
1092 * two independent parallel prefix operations on two
1093 * interleaved sets of thirty-two bits).
1094 */
1095 cs ^= cs >> 2;
1096 cs ^= cs >> 4;
1097 cs ^= cs >> 8;
1098 cs ^= cs >> 16;
1099 cs ^= cs >> 32;
1100
1101 /* separate swap and complement bits */
1102 swap = cs & 0x5555555555555555U;
1103 comp = (cs >> 1) & 0x5555555555555555U;
1104
1105 /* calculate coordinates in odd and even bit positions */
1106 t = (s & swap) ^ comp;
1107 s = s ^ sr ^ t ^ (t << 1);
1108
1109 /* unpad/clear out any junk on the left */
1110 s = s & ((1 << n << n) - 1);
1111
1112 /* Now "unshuffle" to separate the x and y bits. */
1113 t = (s ^ (s >> 1)) & 0x2222222222222222U; s ^= t ^ (t << 1);
1114 t = (s ^ (s >> 2)) & 0x0c0c0c0c0c0c0c0cU; s ^= t ^ (t << 2);
1115 t = (s ^ (s >> 4)) & 0x00f000f000f000f0U; s ^= t ^ (t << 4);
1116 t = (s ^ (s >> 8)) & 0x0000ff000000ff00U; s ^= t ^ (t << 8);
1117 t = (s ^ (s >> 16)) & 0x00000000ffff0000U; s ^= t ^ (t << 16);
1118
1119 /* now s contains two 32-bit coordinates */
1120 return s;
1121}
1122
1123/* algorithm from the book Hacker's Delight, but a similar algorithm*/
1124/* is given in https://doi.org/10.1002/spe.4380160103 */
1125/* this has been slightly improved over the original version */
1126ecb_function_ uint32_t
1127ecb_hilbert2d_coord_to_index32 (int n, uint32_t xy)
1128{
1129 uint32_t row;
1130 uint32_t state = 0;
1131 uint32_t s = 0;
1132
1133 do
1134 {
1135 --n;
1136
1137 row = 4 * state
1138 | (2 & (xy >> n >> 15))
1139 | (1 & (xy >> n ));
1140
1141 /* these funky constants are lookup tables for two-bit values */
1142 s = (s << 2) | (0x361e9cb4U >> 2 * row) & 3;
1143 state = (0x8fe65831U >> 2 * row) & 3;
1144 }
1145 while (n > 0);
1146
1147 return s;
1148}
1149
1150/* 64 bit, essentially the same as 32 bit */
1151ecb_function_ uint64_t
1152ecb_hilbert2d_coord_to_index64 (int n, uint64_t xy)
1153{
1154 uint32_t row;
1155 uint32_t state = 0;
1156 uint64_t s = 0;
1157
1158 do
1159 {
1160 --n;
1161
1162 row = 4 * state
1163 | (2 & (xy >> n >> 31))
1164 | (1 & (xy >> n ));
1165
1166 /* these funky constants are lookup tables for two-bit values */
1167 s = (s << 2) | (0x361e9cb4U >> 2 * row) & 3;
1168 state = (0x8fe65831U >> 2 * row) & 3;
1169 }
1170 while (n > 0);
1171
1172 return s;
1173}
810 1174
811/*****************************************************************************/ 1175/*****************************************************************************/
812/* division */ 1176/* division */
813 1177
814#if ECB_GCC_VERSION(3,0) || ECB_C99 1178#if ECB_GCC_VERSION(3,0) || ECB_C99
… …
948} 1312}
949 1313
950/*******************************************************************************/ 1314/*******************************************************************************/
951/* fast integer to ascii */ 1315/* fast integer to ascii */
952 1316
1317/*
1318 * This code is pretty complicated because it is general. The idea behind it,
1319 * however, is pretty simple: first, the number is multiplied with a scaling
1320 * factor (2**bits / 10**(digits-1)) to convert the integer into a fixed-point
1321 * number with the first digit in the upper bits.
1322 * Then this digit is converted to text and masked out. The resulting number
1323 * is then multiplied by 10, by multiplying the fixed point representation
1324 * by 5 and shifting the (binary) decimal point one to the right, so a 4.28
1325 * format becomes 5.27, 6.26 and so on.
1326 * The rest involves only advancing the pointer if we already generated a
1327 * non-zero digit, so leading zeroes are overwritten.
1328 */
1329
953// simply return a mask with "bits" bits set 1330/* simply return a mask with "bits" bits set */
954#define ecb_i2a_mask(type,bits) ((((type)1) << (bits)) - 1) 1331#define ecb_i2a_mask(type,bits) ((((type)1) << (bits)) - 1)
955 1332
956// oputput a single digit. maskvalue is 10**digitidx 1333/* oputput a single digit. maskvalue is 10**digitidx */
957#define ecb_i2a_digit(type,bits,digitmask,maskvalue,digitidx) \ 1334#define ecb_i2a_digit(type,bits,digitmask,maskvalue,digitidx) \
958 if (digitmask >= maskvalue) /* constant, used to decide how many digits to generate */ \ 1335 if (digitmask >= maskvalue) /* constant, used to decide how many digits to generate */ \
959 { \ 1336 { \
960 char digit = x >> (bits - digitidx); /* calculate the topmost digit */ \ 1337 char digit = x >> (bits - digitidx); /* calculate the topmost digit */ \
961 *ptr = digit + '0'; /* output it */ \ 1338 *ptr = digit + '0'; /* output it */ \
962 nz = (digitmask == maskvalue) || nz || digit; /* first term == always output last digit */ \ 1339 nz = (digitmask == maskvalue) || nz || digit; /* first term == always output last digit */ \
963 ptr += nz; /* output digit only if non-zero digit seen */ \ 1340 ptr += nz; /* output digit only if non-zero digit seen */ \
964 x = (x & ecb_i2a_mask (type, bits - digitidx)) * 5; /* *10, but shift decimal point right */ \ 1341 x = (x & ecb_i2a_mask (type, bits - digitidx)) * 5; /* *10, but shift decimal point right */ \
965 } 1342 }
966 1343
967// convert integer to fixed point format and multiply out digits, highest first 1344/* convert integer to fixed point format and multiply out digits, highest first */
968// requires magic constants: max. digits and number of bits after the decimal point 1345/* requires magic constants: max. digits and number of bits after the decimal point */
969#define ecb_i2a_def(suffix,ptr,v,type,bits,digitmask,lz) \ 1346#define ecb_i2a_def(suffix,ptr,v,type,bits,digitmask,lz) \
970ecb_inline char *ecb_i2a_ ## suffix (char *ptr, uint32_t u) \ 1347ecb_inline char *ecb_i2a_ ## suffix (char *ptr, uint32_t u) \
971{ \ 1348{ \
972 char nz = lz; /* non-zero digit seen? */ \ 1349 char nz = lz; /* non-zero digit seen? */ \
973 /* convert to x.bits fixed-point */ \ 1350 /* convert to x.bits fixed-point */ \
… …
984 ecb_i2a_digit (type,bits,digitmask, 100000000, 8); \ 1361 ecb_i2a_digit (type,bits,digitmask, 100000000, 8); \
985 ecb_i2a_digit (type,bits,digitmask, 1000000000, 9); \ 1362 ecb_i2a_digit (type,bits,digitmask, 1000000000, 9); \
986 return ptr; \ 1363 return ptr; \
987} 1364}
988 1365
989// predefined versions of the above, for various digits 1366/* predefined versions of the above, for various digits */
990// ecb_i2a_xN = almost N digits, limit defined by macro 1367/* ecb_i2a_xN = almost N digits, limit defined by macro */
991// ecb_i2a_N = up to N digits, leading zeroes suppressed 1368/* ecb_i2a_N = up to N digits, leading zeroes suppressed */
992// ecb_i2a_0N = exactly N digits, including leading zeroes 1369/* ecb_i2a_0N = exactly N digits, including leading zeroes */
993 1370
994// non-leading-zero versions, limited range 1371/* non-leading-zero versions, limited range */
995#define ECB_I2A_MAX_X5 59074 // limit for ecb_i2a_x5 1372#define ECB_I2A_MAX_X5 59074 /* limit for ecb_i2a_x5 */
996#define ECB_I2A_MAX_X10 2932500665 // limit for ecb_i2a_x10 1373#define ECB_I2A_MAX_X10 2932500665 /* limit for ecb_i2a_x10 */
997ecb_i2a_def ( x5, ptr, v, uint32_t, 26, 10000, 0) 1374ecb_i2a_def ( x5, ptr, v, uint32_t, 26, 10000, 0)
998ecb_i2a_def (x10, ptr, v, uint64_t, 60, 1000000000, 0) 1375ecb_i2a_def (x10, ptr, v, uint64_t, 60, 1000000000, 0)
999 1376
1000// non-leading zero versions, all digits, 4 and 9 are optimal for 32/64 bit 1377/* non-leading zero versions, all digits, 4 and 9 are optimal for 32/64 bit */
1001ecb_i2a_def ( 2, ptr, v, uint32_t, 10, 10, 0) 1378ecb_i2a_def ( 2, ptr, v, uint32_t, 10, 10, 0)
1002ecb_i2a_def ( 3, ptr, v, uint32_t, 12, 100, 0) 1379ecb_i2a_def ( 3, ptr, v, uint32_t, 12, 100, 0)
1003ecb_i2a_def ( 4, ptr, v, uint32_t, 26, 1000, 0) 1380ecb_i2a_def ( 4, ptr, v, uint32_t, 26, 1000, 0)
1004ecb_i2a_def ( 5, ptr, v, uint64_t, 30, 10000, 0) 1381ecb_i2a_def ( 5, ptr, v, uint64_t, 30, 10000, 0)
1005ecb_i2a_def ( 6, ptr, v, uint64_t, 36, 100000, 0) 1382ecb_i2a_def ( 6, ptr, v, uint64_t, 36, 100000, 0)
1006ecb_i2a_def ( 7, ptr, v, uint64_t, 44, 1000000, 0) 1383ecb_i2a_def ( 7, ptr, v, uint64_t, 44, 1000000, 0)
1007ecb_i2a_def ( 8, ptr, v, uint64_t, 50, 10000000, 0) 1384ecb_i2a_def ( 8, ptr, v, uint64_t, 50, 10000000, 0)
1008ecb_i2a_def ( 9, ptr, v, uint64_t, 56, 100000000, 0) 1385ecb_i2a_def ( 9, ptr, v, uint64_t, 56, 100000000, 0)
1009 1386
1010// leading-zero versions, all digits, 04 and 09 are optimal for 32/64 bit 1387/* leading-zero versions, all digits, 04 and 09 are optimal for 32/64 bit */
1011ecb_i2a_def (02, ptr, v, uint32_t, 10, 10, 1) 1388ecb_i2a_def (02, ptr, v, uint32_t, 10, 10, 1)
1012ecb_i2a_def (03, ptr, v, uint32_t, 12, 100, 1) 1389ecb_i2a_def (03, ptr, v, uint32_t, 12, 100, 1)
1013ecb_i2a_def (04, ptr, v, uint32_t, 26, 1000, 1) 1390ecb_i2a_def (04, ptr, v, uint32_t, 26, 1000, 1)
1014ecb_i2a_def (05, ptr, v, uint64_t, 30, 10000, 1) 1391ecb_i2a_def (05, ptr, v, uint64_t, 30, 10000, 1)
1015ecb_i2a_def (06, ptr, v, uint64_t, 36, 100000, 1) 1392ecb_i2a_def (06, ptr, v, uint64_t, 36, 100000, 1)
… …
1027ecb_i2a_u32 (char *ptr, uint32_t u) 1404ecb_i2a_u32 (char *ptr, uint32_t u)
1028{ 1405{
1029 #if ECB_64BIT_NATIVE 1406 #if ECB_64BIT_NATIVE
1030 if (ecb_expect_true (u <= ECB_I2A_MAX_X10)) 1407 if (ecb_expect_true (u <= ECB_I2A_MAX_X10))
1031 ptr = ecb_i2a_x10 (ptr, u); 1408 ptr = ecb_i2a_x10 (ptr, u);
1032 else // x10 almost, but not fully, covers 32 bit 1409 else /* x10 almost, but not fully, covers 32 bit */
1033 { 1410 {
1034 uint32_t u1 = u % 1000000000; 1411 uint32_t u1 = u % 1000000000;
1035 uint32_t u2 = u / 1000000000; 1412 uint32_t u2 = u / 1000000000;
1036 1413
1037 *ptr++ = u2 + '0'; 1414 *ptr++ = u2 + '0';
… …
1069{ 1446{
1070 *ptr = '-'; ptr += v < 0; 1447 *ptr = '-'; ptr += v < 0;
1071 uint32_t u = v < 0 ? -(uint32_t)v : v; 1448 uint32_t u = v < 0 ? -(uint32_t)v : v;
1072 1449
1073 #if ECB_64BIT_NATIVE 1450 #if ECB_64BIT_NATIVE
1074 ptr = ecb_i2a_x10 (ptr, u); // x10 fully covers 31 bit 1451 ptr = ecb_i2a_x10 (ptr, u); /* x10 fully covers 31 bit */
1075 #else 1452 #else
1076 ptr = ecb_i2a_u32 (ptr, u); 1453 ptr = ecb_i2a_u32 (ptr, u);
1077 #endif 1454 #endif
1078 1455
1079 return ptr; 1456 return ptr;
… …
1142 uint64_t u1 = u % 1000000000; 1519 uint64_t u1 = u % 1000000000;
1143 uint64_t ua = u / 1000000000; 1520 uint64_t ua = u / 1000000000;
1144 uint64_t u2 = ua % 1000000000; 1521 uint64_t u2 = ua % 1000000000;
1145 uint64_t u3 = ua / 1000000000; 1522 uint64_t u3 = ua / 1000000000;
1146 1523
1147 // 2**31 is 19 digits, so the top is exactly one digit 1524 /* 2**31 is 19 digits, so the top is exactly one digit */
1148 *ptr++ = u3 + '0'; 1525 *ptr++ = u3 + '0';
1149 ptr = ecb_i2a_09 (ptr, u2); 1526 ptr = ecb_i2a_09 (ptr, u2);
1150 ptr = ecb_i2a_09 (ptr, u1); 1527 ptr = ecb_i2a_09 (ptr, u1);
1151 } 1528 }
1152 #else 1529 #else

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