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package c
/*
#define MAX_DEPTH 100
#define BRANCH_PAGE 1
// These types MUST have the same layout as their corresponding Go types
typedef unsigned long long pageid;
typedef unsigned short elemid;
typedef struct page {
pgid id;
unsigned short flags;
elemid count;
unsigned long overflow;
} page;
typedef struct branch_elem {
unsigned long pos;
unsigned long ksize;
pgid pgid;
} branch_elem;
typedef struct leaf_elem {
unsigned long flags;
unsigned long pos;
unsigned long ksize;
unsigned long vsize;
} leaf_elem;
// private types
typedef struct elem_ref {
void *element;
page *page;
elemid index;
} elem_ref;
// public types
typedef struct bolt_val {
uint32_t size;
void *data;
} bolt_val;
typedef struct bolt_cursor {
void *data;
pgid root;
size_t pgsz;
elemid[MAX_DEPTH] stack;
unsigned int stackp;
} bolt_cursor;
void bolt_cursor_init(bolt_cursor* c, void *data, size_t pgsz, pgid root) {
c->data = data;
c->pgid = pgid;
c->pgsz = pgsz;
}
// public functions
int bolt_cursor_first(bolt_cursor* c, bolt_val *key, bolt_val *value) {
leaf_elem* leaf;
elem_ref* ref;
c->stackp = 0;
ref = &c->stack[c->stackp]
ref->page = page(c, c->pgid);
ref->index = 0;
return next_element(c, key, value);
}
int bolt_cursor_next(bolt_cursor* c, bolt_val *key, bolt_val *value) {
elem_ref* ref= &c->stack[c->stackp];
ref->index++;
while (ref->index >= ref->page->count ) {
c->stackp--;
ref = &c->stack[c->stackp];
ref->index++;
}
if(ref->page | BRANCH_PAGE)
ref->element += sizeof(branch_elem);
else
ref->element += sizeof(leaf_elem);
return next_element(c, key, value);
}
// int bolt_cursor_seek(bolt_cursor* c, bolt_val key, bolt_val *actual_key, bolt_val *value)
// private functions
page* page(bolt_cursor* c, pgid id) {
return (page*)(c->data + (c->pgsz * id));
}
branch_elem* branch_page_element(*p, elemid index) {
return p + sizeof(page) + index * sizeof(branch_elem);
}
leaf_elem* leaf_page_element(page* p, elemid index) {
return p + sizeof(page) + index * sizeof(leaf_elem);
}
set_key_value(leaf_elem* leaf, bolt_val* key, bolt_val *value) {
key.size = leaf->ksize;
key.data = leaf + leaf->pos;
value.size = leaf->vsize;
value.data = key.data + key.size;
}
int next_element(bolt_cursor* c, bolt_val *key, bolt_val *value) {
elem_ref* ref = &c->stack[c->stackp];
branch_elem* branch;
for(ref->page->flags | BRANCH_PAGE) {
branch = branch_page_element(ref->page,ref->index);
c->stackp++;
ref = &c->stack[c->stackp];
ref->index = 0;
ref->element = branch;
ref->page = page(c, branch->pgid);
};
set_key_value(leaf_page_element(ref->page,ref->index), key, value);
return 0
}
*/
import "C"
import "github.com/boltdb/bolt"
func NewCursor(b *bolt.Bucket) *C.bolt_cursor {
data := (*C.void)(&b.tx.db.data[0])]
pgsz := (C.size_t)(b.tx.db.pageSize)
cursor := new(C.bolt_cursor)
C.bolt_cursor_init(cursor, data, pgsz, (C.pgid)(b.root))
return cursor
}
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