| @@ -0,0 +1,174 @@ |
| 1 | +#include <u.h> |
| 2 | +#include <libc.h> |
| 3 | +#include "qp.h" |
| 4 | + |
| 5 | +typedef u16int Tbitmap; |
| 6 | +typedef struct Tbranch Tbranch; |
| 7 | +typedef struct Tleaf Tleaf; |
| 8 | + |
| 9 | +struct Tleaf { |
| 10 | + char *k; |
| 11 | + void *v; |
| 12 | +}; |
| 13 | + |
| 14 | +struct Tbranch { |
| 15 | + Trie *twigs; |
| 16 | + u64int x; |
| 17 | +}; |
| 18 | + |
| 19 | +union Trie { |
| 20 | + Tleaf leaf; |
| 21 | + Tbranch branch; |
| 22 | +}; |
| 23 | + |
| 24 | +#define x_flags(x) ((x)>>62) |
| 25 | +#define x_index(x) ((x)>>16 & ((1ULL<<46)-1ULL)) |
| 26 | +#define x_bitmap(x) ((x) & 0xffff) |
| 27 | + |
| 28 | +#define isbranch(t) (x_flags((t)->branch.x) != 0) |
| 29 | +#define hastwig(t, b) (x_bitmap((t)->branch.x) & (b)) |
| 30 | +#define twigoff(t, b) popcount(x_bitmap((t)->branch.x) & ((b)-1)) |
| 31 | +#define twig(t, i) (&(t)->branch.twigs[(i)]) |
| 32 | +#define twigoffmax(off, max, t, b) do{ off = twigoff(t, b); max = popcount(x_bitmap((t)->branch.x)); }while(0) |
| 33 | +#define nibbit(k, f) (1 << (((k) & (((f)-2) ^ 0x0f) & 0xff) >> ((2-(f))<<2))) |
| 34 | +#define twigbit(t, k, len) \ |
| 35 | + (x_index((t)->branch.x) >= (len) ? \ |
| 36 | + 1 : \ |
| 37 | + nibbit((u8int)(k)[x_index((t)->branch.x)], x_flags((t)->branch.x))) |
| 38 | + |
| 39 | +/* |
| 40 | +// need some speed? just say no. |
| 41 | +#define POPCNT BYTE $0xf3; BYTE $0x0f; BYTE $0xb8 |
| 42 | + |
| 43 | +TEXT popcount(SB),$0 |
| 44 | + MOVL b+0(FP), AX |
| 45 | + POPCNT |
| 46 | + RET |
| 47 | +*/ |
| 48 | +static u16int |
| 49 | +popcount(u16int b) |
| 50 | +{ |
| 51 | + b -= b>>1 & 0x5555; |
| 52 | + b = (b & 0x3333) + ((b>>2) & 0x3333); |
| 53 | + b = (b + (b>>4)) & 0x0f0f; |
| 54 | + b = (b + (b>>8)) & 0x00ff; |
| 55 | + return b; |
| 56 | +} |
| 57 | + |
| 58 | +int |
| 59 | +qpget(Trie *t, char *k, int len, char **pk, char **pv) |
| 60 | +{ |
| 61 | + Tbitmap b; |
| 62 | + |
| 63 | + assert(k != nil && pk != nil && pv != nil); |
| 64 | + |
| 65 | + for(; isbranch(t); t = twig(t, twigoff(t, b))){ |
| 66 | + b = twigbit(t, k, len); |
| 67 | + if(!hastwig(t, b)) |
| 68 | + return -1; |
| 69 | + } |
| 70 | + if(strncmp(k, t->leaf.k, len) != 0) |
| 71 | + return -1; |
| 72 | + *pk = t->leaf.k; |
| 73 | + *pv = t->leaf.v; |
| 74 | + |
| 75 | + return 0; |
| 76 | +} |
| 77 | + |
| 78 | +int |
| 79 | +qpnext(Trie *t, char **pk, int *plen, void **pv) |
| 80 | +{ |
| 81 | + Tbitmap b; |
| 82 | + uint s, m; |
| 83 | + |
| 84 | + assert(pk != nil && plen != nil && pv != nil); |
| 85 | + |
| 86 | + if(isbranch(t)){ |
| 87 | + b = twigbit(t, *pk, *plen); |
| 88 | + twigoffmax(s, m, t, b); |
| 89 | + for(; s < m; s++){ |
| 90 | + if(qpnext(twig(t, s), pk, plen, pv) == 0) |
| 91 | + return 0; |
| 92 | + } |
| 93 | + return -1; |
| 94 | + } |
| 95 | + |
| 96 | + if(*pk == nil){ |
| 97 | + *pk = t->leaf.k; |
| 98 | + *plen = strlen(*pk); |
| 99 | + *pv = t->leaf.v; |
| 100 | + return 0; |
| 101 | + } |
| 102 | + |
| 103 | + return -1; |
| 104 | +} |
| 105 | + |
| 106 | +Trie * |
| 107 | +qpset(Trie *t, char *k, int len, void *v) |
| 108 | +{ |
| 109 | + Trie *t0, t1, t2; |
| 110 | + uint i, s, m; |
| 111 | + u8int f; |
| 112 | + Tbitmap b, b1, b2; |
| 113 | + u8int k2; |
| 114 | + |
| 115 | + assert(k != nil && v != nil); |
| 116 | + if(len < 1) |
| 117 | + len = strlen(k); |
| 118 | + assert(len > 0); |
| 119 | + |
| 120 | + if(t == nil){ |
| 121 | + t = malloc(sizeof(*t)); |
| 122 | + t->leaf.k = k; |
| 123 | + t->leaf.v = v; |
| 124 | + return t; |
| 125 | + } |
| 126 | + |
| 127 | + t0 = t; |
| 128 | + for(; isbranch(t); t = twig(t, i)){ |
| 129 | + b = twigbit(t, k, len); |
| 130 | + i = hastwig(t, b) ? twigoff(t, b) : 0; |
| 131 | + } |
| 132 | + for(i = 0; i <= len && k[i] == t->leaf.k[i]; i++); |
| 133 | + if(i == len+1){ |
| 134 | + t->leaf.v = v; |
| 135 | + return t0; |
| 136 | + } |
| 137 | + |
| 138 | + k2 = (u8int)t->leaf.k[i]; |
| 139 | + f = (((u8int)k[i] ^ k2) & 0xf0) ? 1 : 2; |
| 140 | + b1 = nibbit(k[i], f); |
| 141 | + t1.leaf.k = k; |
| 142 | + t1.leaf.v = v; |
| 143 | + for(t = t0; isbranch(t); t = twig(t, twigoff(t, b))){ |
| 144 | + if(i == x_index(t->branch.x)){ |
| 145 | + if(f == x_flags(t->branch.x)) |
| 146 | + goto growbranch; |
| 147 | + if(f < x_flags(t->branch.x)) |
| 148 | + break; |
| 149 | + }else if(i < x_index(t->branch.x)){ |
| 150 | + break; |
| 151 | + } |
| 152 | + b = twigbit(t, k, len); |
| 153 | + assert(hastwig(t, b)); |
| 154 | + } |
| 155 | + |
| 156 | + t2 = *t; |
| 157 | + b2 = nibbit(k2, f); |
| 158 | + t->branch.twigs = malloc(sizeof(*t)*2); |
| 159 | + t->branch.x = (uvlong)f<<62 | (uvlong)i<<16 | b1 | b2; |
| 160 | + *twig(t, twigoff(t, b1)) = t1; |
| 161 | + *twig(t, twigoff(t, b2)) = t2; |
| 162 | + |
| 163 | + return t0; |
| 164 | + |
| 165 | +growbranch: |
| 166 | + assert(!hastwig(t, b1)); |
| 167 | + twigoffmax(s, m, t, b1); |
| 168 | + t->branch.twigs = realloc(t->branch.twigs, sizeof(*t)*(m+1)); |
| 169 | + memmove(t->branch.twigs+s+1, t->branch.twigs+s, sizeof(*t)*(m-s)); |
| 170 | + memmove(t->branch.twigs+s, &t1, sizeof(t1)); |
| 171 | + t->branch.x |= b1; |
| 172 | + |
| 173 | + return t0; |
| 174 | +} |