5 #include "compat/stdint.h"
11 /** Numbering for (aligned) logarithmical bins.
12 Each number stands for an interval
13 [o*2^l,(o+1)*2^l), where l is the layer and o
15 Bin numbers in the tail111 encoding: meaningless
16 bits in the tail are set to 0111...11, while the
17 head denotes the offset. Thus, 1101 is the bin
18 at layer 1, offset 3 (i.e. fourth). */
21 static const uint64_t NONE;
22 static const uint64_t ALL;
23 static const uint32_t NONE32;
24 static const uint32_t ALL32;
26 bin64_t() : v(NONE) {}
27 bin64_t(const bin64_t&b) : v(b.v) {}
28 bin64_t(const uint32_t val) ;
29 bin64_t(const uint64_t val) : v(val) {}
30 bin64_t(uint8_t layer, uint64_t offset) :
31 v( (offset<<(layer+1)) | ((1ULL<<layer)-1) ) {}
32 operator uint64_t () const { return v; }
33 uint32_t to32() const ;
34 bool operator == (bin64_t& b) const { return v==b.v; }
36 static bin64_t none () { return NONE; }
37 static bin64_t all () { return ALL; }
39 uint64_t tail_bits () const {
43 uint64_t tail_bit () const {
44 return (tail_bits()+1)>>1;
47 bin64_t sibling () const {
48 // if (v==ALL) return NONE;
49 return bin64_t(v^(tail_bit()<<1));
54 uint64_t tail = ((v^(v+1))+1)>>1;
55 if (tail>0xffffffffULL) {
59 // courtesy of Sean Eron Anderson
60 // http://graphics.stanford.edu/~seander/bithacks.html
61 static const int DeBRUIJN[32] = {
62 0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
63 31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9
65 r += DeBRUIJN[((uint32_t)(tail*0x077CB531U))>>27];
69 uint64_t base_offset () const {
70 return (v&~(tail_bits()))>>1;
73 uint64_t offset () const {
74 return v >> (layer()+1);
77 bin64_t to (bool right) const {
80 uint64_t tb = tail_bit()>>1;
86 bin64_t left () const {
90 bin64_t right () const {
94 bool within (bin64_t maybe_asc) {
95 if (maybe_asc==bin64_t::NONE)
97 uint64_t short_tail = maybe_asc.tail_bits();
98 if (tail_bits()>short_tail)
100 return (v&~short_tail) == (maybe_asc.v&~short_tail) ;
103 /** Left or right, depending whether the destination is. */
104 bin64_t towards (bin64_t dest) const {
105 if (!dest.within(*this))
107 if (dest.within(left()))
113 bin64_t twisted (uint64_t mask) const {
114 return bin64_t( v ^ ((mask<<1)&~tail_bits()) );
117 bin64_t parent () const {
118 uint64_t tbs = tail_bits(), ntbs = (tbs+1)|tbs;
119 return bin64_t( (v&~ntbs) | tbs );
122 bool is_left () const {
123 uint64_t tb = tail_bit();
126 bool is_right() const { return !is_left(); }
128 bin64_t left_foot () const {
131 return bin64_t(0,base_offset());
134 /** Whether layer is 0. */
135 bool is_base () const {
139 /** Depth-first in-order binary tree traversal. */
140 bin64_t next_dfsio (uint8_t floor);
142 bin64_t width () const {
143 return (tail_bits()+1)>>1;
146 const char* str () const;
148 /** The array must have 64 cells, as it is the max
149 number of peaks possible +1 (and there are no reason
150 to assume there will be less in any given case. */
151 static int peaks (uint64_t length, bin64_t* peaks) ;
162 0 10 100 110 1000 1010 1100 1110
169 once we have peak hashes, this struture is more natural than bin-v1