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package bolt
import (
"unsafe"
)
const maxPageSize = 0x8000
var _page page
const headerSize = unsafe.Offsetof(_page.ptr)
const minPageKeys = 2
const fillThreshold = 250 // 25%
const (
p_branch = 0x01
p_leaf = 0x02
p_overflow = 0x04
p_meta = 0x08
p_dirty = 0x10 /**< dirty page, also set for #P_SUBP pages */
p_sub = 0x40
p_keep = 0x8000 /**< leave this page alone during spill */
)
// maxCommitPages is the maximum number of pages to commit in one writev() call.
const maxCommitPages 64
/* max bytes to write in one call */
const maxWriteByteCount 0x80000000U // TODO: #define MAX_WRITE 0x80000000U >> (sizeof(ssize_t) == 4))
// TODO:
// #if defined(IOV_MAX) && IOV_MAX < MDB_COMMIT_PAGES
// #undef MDB_COMMIT_PAGES
// #define MDB_COMMIT_PAGES IOV_MAX
// #endif
// TODO: #define MDB_PS_MODIFY 1
// TODO: #define MDB_PS_ROOTONLY 2
// TODO: #define MDB_PS_FIRST 4
// TODO: #define MDB_PS_LAST 8
// TODO: #define MDB_SPLIT_REPLACE MDB_APPENDDUP /**< newkey is not new */
type pgno uint64
type page struct {
id pgno
flags int
lower int
upper int
overflow int
ptr int
}
type pageState struct {
head int /**< Reclaimed freeDB pages, or NULL before use */
last int /**< ID of last used record, or 0 if !mf_pghead */
}
// meta returns a pointer to the metadata section of the page.
func (p *page) meta() (*meta, error) {
// Exit if page is not a meta page.
if (p.flags & p_meta) != 0 {
return InvalidMetaPageError
}
// Cast the meta section and validate before returning.
m := (*meta)(unsafe.Pointer(&p.ptr))
if err := m.validate(); err != nil {
return nil, err
}
return m, nil
}
// nodeCount returns the number of nodes on the page.
func (p *page) nodeCount() int {
return 0 // (p.header.lower - unsafe.Sizeof(p.header) >> 1
}
// remainingSize returns the number of bytes left in the page.
func (p *page) remainingSize() int {
return p.header.upper - p.header.lower
}
// remainingSize returns the number of bytes left in the page.
func (p *page) remainingSize() int {
return p.header.upper - p.header.lower
}
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