158 lines
3.3 KiB
Go
158 lines
3.3 KiB
Go
package tsdb
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import (
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"encoding/binary"
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"hash"
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"unsafe"
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)
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// enbuf is a helper type to populate a byte slice with various types.
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type encbuf struct {
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b []byte
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c [binary.MaxVarintLen64]byte
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}
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func (e *encbuf) reset() { e.b = e.b[:0] }
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func (e *encbuf) get() []byte { return e.b }
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func (e *encbuf) len() int { return len(e.b) }
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func (e *encbuf) putString(s string) { e.b = append(e.b, s...) }
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func (e *encbuf) putBytes(b []byte) { e.b = append(e.b, b...) }
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func (e *encbuf) putByte(c byte) { e.b = append(e.b, c) }
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func (e *encbuf) putBE32int(x int) { e.putBE32(uint32(x)) }
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func (e *encbuf) putBE64int(x int) { e.putBE64(uint64(x)) }
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func (e *encbuf) putUvarint32(x uint32) { e.putUvarint64(uint64(x)) }
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func (e *encbuf) putUvarint(x int) { e.putUvarint64(uint64(x)) }
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func (e *encbuf) putBE32(x uint32) {
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binary.BigEndian.PutUint32(e.c[:], x)
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e.b = append(e.b, e.c[:4]...)
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}
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func (e *encbuf) putBE64(x uint64) {
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binary.BigEndian.PutUint64(e.c[:], x)
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e.b = append(e.b, e.c[:8]...)
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}
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func (e *encbuf) putUvarint64(x uint64) {
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n := binary.PutUvarint(e.c[:], x)
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e.b = append(e.b, e.c[:n]...)
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}
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func (e *encbuf) putVarint64(x int64) {
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n := binary.PutVarint(e.c[:], x)
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e.b = append(e.b, e.c[:n]...)
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}
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// putVarintStr writes a string to the buffer prefixed by its varint length (in bytes!).
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func (e *encbuf) putUvarintStr(s string) {
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b := *(*[]byte)(unsafe.Pointer(&s))
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e.putUvarint(len(b))
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e.putString(s)
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}
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// putHash appends a hash over the buffers current contents to the buffer.
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func (e *encbuf) putHash(h hash.Hash) {
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h.Reset()
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_, err := h.Write(e.b)
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if err != nil {
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panic(err) // The CRC32 implementation does not error
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}
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e.b = h.Sum(e.b)
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}
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// decbuf provides safe methods to extract data from a byte slice. It does all
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// necessary bounds checking and advancing of the byte slice.
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// Several datums can be extracted without checking for errors. However, before using
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// any datum, the err() method must be checked.
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type decbuf struct {
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b []byte
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e error
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}
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func (d *decbuf) uvarint() int { return int(d.uvarint64()) }
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func (d *decbuf) be32int() int { return int(d.be32()) }
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func (d *decbuf) uvarintStr() string {
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l := d.uvarint64()
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if d.e != nil {
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return ""
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}
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if len(d.b) < int(l) {
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d.e = errInvalidSize
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return ""
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}
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s := yoloString(d.b[:l])
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d.b = d.b[l:]
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return s
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}
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func (d *decbuf) varint64() int64 {
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if d.e != nil {
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return 0
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}
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x, n := binary.Varint(d.b)
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if n < 1 {
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d.e = errInvalidSize
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return 0
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}
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d.b = d.b[n:]
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return x
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}
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func (d *decbuf) uvarint64() uint64 {
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if d.e != nil {
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return 0
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}
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x, n := binary.Uvarint(d.b)
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if n < 1 {
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d.e = errInvalidSize
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return 0
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}
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d.b = d.b[n:]
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return x
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}
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func (d *decbuf) be64() uint64 {
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if d.e != nil {
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return 0
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}
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if len(d.b) < 4 {
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d.e = errInvalidSize
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return 0
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}
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x := binary.BigEndian.Uint64(d.b)
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d.b = d.b[8:]
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return x
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}
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func (d *decbuf) be32() uint32 {
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if d.e != nil {
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return 0
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}
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if len(d.b) < 4 {
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d.e = errInvalidSize
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return 0
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}
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x := binary.BigEndian.Uint32(d.b)
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d.b = d.b[4:]
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return x
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}
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func (d *decbuf) decbuf(l int) decbuf {
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if d.e != nil {
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return decbuf{e: d.e}
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}
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if l > len(d.b) {
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return decbuf{e: errInvalidSize}
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}
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r := decbuf{b: d.b[:l]}
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d.b = d.b[l:]
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return r
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}
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func (d *decbuf) err() error { return d.e }
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func (d *decbuf) len() int { return len(d.b) }
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func (d *decbuf) get() []byte { return d.b }
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