index/myvarint.go

   1 // vim:ts=4:sw=4:noet
   2 package index
   3
   4 /*
   5 #cgo CFLAGS: -std=gnu99 -O3
   6 #include <stdlib.h>
   7 #include <stdio.h>
   8 #include <stdint.h>
   9
  10 static __attribute__((hot)) const uint32_t uvarint(const uint8_t *restrict*data) {
  11     uint32_t b, c, d;
  12     if ((b = *((*data)++)) < 0x80) {
  13         return b;
  14     } else if ((c = *((*data)++)) < 0x80) {
  15         return (uint32_t) (b & 0x7F)        |
  16                        (uint32_t) (c << 7);
  17     } else if ((d = *((*data)++)) < 0x80) {
  18                 return (uint32_t) (b & 0x7F)        |
  19                        (uint32_t)((c & 0x7F) << 7)  |
  20                            (uint32_t) (d << 14);
  21         } else {
  22                 return (uint32_t) (b & 0x7F)        |
  23                        (uint32_t)((c & 0x7F) << 7)  |
  24                            (uint32_t)((d & 0x7F) << 14) |
  25                            ((uint32_t)(*((*data)++)) << 21);
  26         }
  27 }
  28
  29 // NB: This is a fragile macro, beware! We cannot use the do { } while (0)
  30 // trick because we use continue in the macro.
  31 #define skip_unless_fileid_in(cntvar, lstvar) \
  32         while (cntvar && *lstvar < fileid) { \
  33                 cntvar--; \
  34                 lstvar++; \
  35         } \
  36         if (!cntvar || *lstvar != fileid) \
  37                 continue;
  38
  39 #define RESTRICT \
  40         if (restrict_list) { \
  41                 skip_unless_fileid_in(restrictcount, restrict_list); \
  42         }
  43
  44
  45 int cPostingList(const uint8_t *restrict list,
  46                  int count,
  47                  uint32_t *restrict result,
  48                  int restrictcount,
  49                  uint32_t *restrict restrict_list) {
  50         int oidx = 0;
  51         int fileid = ~0;
  52         while (count--) {
  53                 fileid += uvarint(&list);
  54                 RESTRICT;
  55                 result[oidx++] = fileid;
  56         }
  57         return oidx;
  58 }
  59
  60 int cPostingAnd(const uint8_t *restrict list,
  61                 int count,
  62                                 uint32_t *restrict file_id_list,
  63                                 int file_id_count,
  64                                 uint32_t *restrict result,
  65                                 int restrictcount,
  66                                 uint32_t *restrict restrict_list) {
  67         int oidx = 0;
  68         int fileid = ~0;
  69         while (count--) {
  70                 fileid += uvarint(&list);
  71                 RESTRICT;
  72                 skip_unless_fileid_in(file_id_count, file_id_list);
  73                 result[oidx++] = fileid;
  74         }
  75         return oidx;
  76 }
  77
  78 int cPostingOr(const uint8_t *restrict list,
  79                int count,
  80                            uint32_t *restrict file_id_list,
  81                            int file_id_count,
  82                            uint32_t *restrict result,
  83                            int restrictcount,
  84                            uint32_t *restrict restrict_list) {
  85         int fidx = 0;
  86         int oidx = 0;
  87         int fileid = ~0;
  88         while (count--) {
  89                 fileid += uvarint(&list);
  90                 RESTRICT;
  91                 while (fidx < file_id_count && file_id_list[fidx] < fileid)
  92                         result[oidx++] = file_id_list[fidx++];
  93                 result[oidx++] = fileid;
  94                 if (fidx < file_id_count && file_id_list[fidx] == fileid)
  95                         fidx++;
  96         }
  97         while (fidx < file_id_count)
  98                 result[oidx++] = file_id_list[fidx++];
  99         return oidx;
 100 }
 101
 102 int cPostingLast(const uint8_t *restrict list,
 103                  uint32_t count,
 104                  uint32_t fileid,
 105                  uint32_t *totalbytes) {
 106     const uint8_t *restrict start = list;
 107     while (count--) {
 108         fileid += uvarint(&list);
 109     }
 110     *totalbytes = (list - start);
 111     return fileid;
 112 }
 113
 114 */
 115 import "C"
 116
 117 func myPostingList(data []byte, count int, restrict []uint32) []uint32 {
 118         result := make([]uint32, count)
 119         if count == 0 {
 120                 return result
 121         }
 122         var restrictptr *C.uint32_t
 123         if len(restrict) > 0 {
 124                 restrictptr = (*C.uint32_t)(&restrict[0])
 125         }
 126         num := C.cPostingList((*C.uint8_t)(&data[0]),
 127                 C.int(count),
 128                 (*C.uint32_t)(&result[0]),
 129                 C.int(len(restrict)),
 130                 restrictptr)
 131         return result[0:int(num)]
 132 }
 133
 134 func myPostingAnd(data []byte, count int, list []uint32, restrict []uint32) []uint32 {
 135         // reverse enough space to hold it all, we truncate later
 136         result := make([]uint32, count)
 137         if count == 0 {
 138                 return result
 139         }
 140         var listptr, restrictptr *C.uint32_t
 141         if len(restrict) > 0 {
 142                 restrictptr = (*C.uint32_t)(&restrict[0])
 143         }
 144         if len(list) > 0 {
 145                 listptr = (*C.uint32_t)(&list[0])
 146         }
 147         num := C.cPostingAnd((*C.uint8_t)(&data[0]),
 148                 C.int(count),
 149                 listptr,
 150                 C.int(len(list)),
 151                 (*C.uint32_t)(&result[0]),
 152                 C.int(len(restrict)),
 153                 restrictptr)
 154         return result[0:int(num)]
 155 }
 156
 157 func myPostingOr(data []byte, count int, list []uint32, restrict []uint32) []uint32 {
 158         if len(list)+count == 0 {
 159                 return nil
 160         }
 161         // reverse enough space to hold it all, we truncate later
 162         result := make([]uint32, len(list)+count)
 163         var dataptr *C.uint8_t
 164         var listptr, restrictptr *C.uint32_t
 165         if count > 0 {
 166                 dataptr = (*C.uint8_t)(&data[0])
 167         }
 168         if len(restrict) > 0 {
 169                 restrictptr = (*C.uint32_t)(&restrict[0])
 170         }
 171         if len(list) > 0 {
 172                 listptr = (*C.uint32_t)(&list[0])
 173         }
 174         num := C.cPostingOr(dataptr,
 175                 C.int(count),
 176                 listptr,
 177                 C.int(len(list)),
 178                 (*C.uint32_t)(&result[0]),
 179                 C.int(len(restrict)),
 180                 restrictptr)
 181         return result[0:int(num)]
 182 }
 183
 184 func myPostingLast(data []byte, count uint32, fileid uint32) (int, uint32) {
 185         var dataptr *C.uint8_t
 186         if count > 0 {
 187                 dataptr = (*C.uint8_t)(&data[0])
 188         }
 189         var totalbytes uint32
 190         last := int(C.cPostingLast(dataptr,
 191                 C.uint32_t(count),
 192                 C.uint32_t(fileid),
 193                 (*C.uint32_t)(&totalbytes)))
 194         return last, totalbytes
 195 }