diff options
author | Steve Manuel <nilslice@gmail.com> | 2016-10-19 13:50:05 -0700 |
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committer | Steve Manuel <nilslice@gmail.com> | 2016-10-19 13:50:05 -0700 |
commit | ea078f9b4221332b9f63cc4e178aa814eec06e4f (patch) | |
tree | a90da6f77f265ce63c82da73f502f324bfb89ebc /cmd/ponzu/vendor/github.com/boltdb/bolt/page.go | |
parent | ea8ea4c22662aa082181a6c456ec56acf2bd777c (diff) |
vendoring all the dependencies into vendor directory prior to build step, which still vendors ponzu core code
Diffstat (limited to 'cmd/ponzu/vendor/github.com/boltdb/bolt/page.go')
-rw-r--r-- | cmd/ponzu/vendor/github.com/boltdb/bolt/page.go | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/cmd/ponzu/vendor/github.com/boltdb/bolt/page.go b/cmd/ponzu/vendor/github.com/boltdb/bolt/page.go new file mode 100644 index 0000000..7651a6b --- /dev/null +++ b/cmd/ponzu/vendor/github.com/boltdb/bolt/page.go @@ -0,0 +1,178 @@ +package bolt + +import ( + "fmt" + "os" + "sort" + "unsafe" +) + +const pageHeaderSize = int(unsafe.Offsetof(((*page)(nil)).ptr)) + +const minKeysPerPage = 2 + +const branchPageElementSize = int(unsafe.Sizeof(branchPageElement{})) +const leafPageElementSize = int(unsafe.Sizeof(leafPageElement{})) + +const ( + branchPageFlag = 0x01 + leafPageFlag = 0x02 + metaPageFlag = 0x04 + freelistPageFlag = 0x10 +) + +const ( + bucketLeafFlag = 0x01 +) + +type pgid uint64 + +type page struct { + id pgid + flags uint16 + count uint16 + overflow uint32 + ptr uintptr +} + +// typ returns a human readable page type string used for debugging. +func (p *page) typ() string { + if (p.flags & branchPageFlag) != 0 { + return "branch" + } else if (p.flags & leafPageFlag) != 0 { + return "leaf" + } else if (p.flags & metaPageFlag) != 0 { + return "meta" + } else if (p.flags & freelistPageFlag) != 0 { + return "freelist" + } + return fmt.Sprintf("unknown<%02x>", p.flags) +} + +// meta returns a pointer to the metadata section of the page. +func (p *page) meta() *meta { + return (*meta)(unsafe.Pointer(&p.ptr)) +} + +// leafPageElement retrieves the leaf node by index +func (p *page) leafPageElement(index uint16) *leafPageElement { + n := &((*[0x7FFFFFF]leafPageElement)(unsafe.Pointer(&p.ptr)))[index] + return n +} + +// leafPageElements retrieves a list of leaf nodes. +func (p *page) leafPageElements() []leafPageElement { + if p.count == 0 { + return nil + } + return ((*[0x7FFFFFF]leafPageElement)(unsafe.Pointer(&p.ptr)))[:] +} + +// branchPageElement retrieves the branch node by index +func (p *page) branchPageElement(index uint16) *branchPageElement { + return &((*[0x7FFFFFF]branchPageElement)(unsafe.Pointer(&p.ptr)))[index] +} + +// branchPageElements retrieves a list of branch nodes. +func (p *page) branchPageElements() []branchPageElement { + if p.count == 0 { + return nil + } + return ((*[0x7FFFFFF]branchPageElement)(unsafe.Pointer(&p.ptr)))[:] +} + +// dump writes n bytes of the page to STDERR as hex output. +func (p *page) hexdump(n int) { + buf := (*[maxAllocSize]byte)(unsafe.Pointer(p))[:n] + fmt.Fprintf(os.Stderr, "%x\n", buf) +} + +type pages []*page + +func (s pages) Len() int { return len(s) } +func (s pages) Swap(i, j int) { s[i], s[j] = s[j], s[i] } +func (s pages) Less(i, j int) bool { return s[i].id < s[j].id } + +// branchPageElement represents a node on a branch page. +type branchPageElement struct { + pos uint32 + ksize uint32 + pgid pgid +} + +// key returns a byte slice of the node key. +func (n *branchPageElement) key() []byte { + buf := (*[maxAllocSize]byte)(unsafe.Pointer(n)) + return (*[maxAllocSize]byte)(unsafe.Pointer(&buf[n.pos]))[:n.ksize] +} + +// leafPageElement represents a node on a leaf page. +type leafPageElement struct { + flags uint32 + pos uint32 + ksize uint32 + vsize uint32 +} + +// key returns a byte slice of the node key. +func (n *leafPageElement) key() []byte { + buf := (*[maxAllocSize]byte)(unsafe.Pointer(n)) + return (*[maxAllocSize]byte)(unsafe.Pointer(&buf[n.pos]))[:n.ksize:n.ksize] +} + +// value returns a byte slice of the node value. +func (n *leafPageElement) value() []byte { + buf := (*[maxAllocSize]byte)(unsafe.Pointer(n)) + return (*[maxAllocSize]byte)(unsafe.Pointer(&buf[n.pos+n.ksize]))[:n.vsize:n.vsize] +} + +// PageInfo represents human readable information about a page. +type PageInfo struct { + ID int + Type string + Count int + OverflowCount int +} + +type pgids []pgid + +func (s pgids) Len() int { return len(s) } +func (s pgids) Swap(i, j int) { s[i], s[j] = s[j], s[i] } +func (s pgids) Less(i, j int) bool { return s[i] < s[j] } + +// merge returns the sorted union of a and b. +func (a pgids) merge(b pgids) pgids { + // Return the opposite slice if one is nil. + if len(a) == 0 { + return b + } else if len(b) == 0 { + return a + } + + // Create a list to hold all elements from both lists. + merged := make(pgids, 0, len(a)+len(b)) + + // Assign lead to the slice with a lower starting value, follow to the higher value. + lead, follow := a, b + if b[0] < a[0] { + lead, follow = b, a + } + + // Continue while there are elements in the lead. + for len(lead) > 0 { + // Merge largest prefix of lead that is ahead of follow[0]. + n := sort.Search(len(lead), func(i int) bool { return lead[i] > follow[0] }) + merged = append(merged, lead[:n]...) + if n >= len(lead) { + break + } + + // Swap lead and follow. + lead, follow = follow, lead[n:] + } + + // Append what's left in follow. + merged = append(merged, follow...) + + return merged +} |