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prometheus/vendor/github.com/ugorji/go/codec/noop.go

214 lines
6.5 KiB

// Copyright (c) 2012-2015 Ugorji Nwoke. All rights reserved.
// Use of this source code is governed by a MIT license found in the LICENSE file.
package codec
import (
"math/rand"
"time"
)
// NoopHandle returns a no-op handle. It basically does nothing.
// It is only useful for benchmarking, as it gives an idea of the
// overhead from the codec framework.
//
// LIBRARY USERS: *** DO NOT USE ***
func NoopHandle(slen int) *noopHandle {
h := noopHandle{}
h.rand = rand.New(rand.NewSource(time.Now().UnixNano()))
h.B = make([][]byte, slen)
h.S = make([]string, slen)
for i := 0; i < len(h.S); i++ {
b := make([]byte, i+1)
for j := 0; j < len(b); j++ {
b[j] = 'a' + byte(i)
}
h.B[i] = b
h.S[i] = string(b)
}
return &h
}
// noopHandle does nothing.
// It is used to simulate the overhead of the codec framework.
type noopHandle struct {
BasicHandle
binaryEncodingType
noopDrv // noopDrv is unexported here, so we can get a copy of it when needed.
}
type noopDrv struct {
d *Decoder
e *Encoder
i int
S []string
B [][]byte
mks []bool // stack. if map (true), else if array (false)
mk bool // top of stack. what container are we on? map or array?
ct valueType // last response for IsContainerType.
cb int // counter for ContainerType
rand *rand.Rand
}
func (h *noopDrv) r(v int) int { return h.rand.Intn(v) }
func (h *noopDrv) m(v int) int { h.i++; return h.i % v }
func (h *noopDrv) newEncDriver(e *Encoder) encDriver { h.e = e; return h }
func (h *noopDrv) newDecDriver(d *Decoder) decDriver { h.d = d; return h }
func (h *noopDrv) reset() {}
func (h *noopDrv) uncacheRead() {}
// --- encDriver
// stack functions (for map and array)
func (h *noopDrv) start(b bool) {
// println("start", len(h.mks)+1)
h.mks = append(h.mks, b)
h.mk = b
}
func (h *noopDrv) end() {
// println("end: ", len(h.mks)-1)
h.mks = h.mks[:len(h.mks)-1]
if len(h.mks) > 0 {
h.mk = h.mks[len(h.mks)-1]
} else {
h.mk = false
}
}
func (h *noopDrv) EncodeBuiltin(rt uintptr, v interface{}) {}
func (h *noopDrv) EncodeNil() {}
func (h *noopDrv) EncodeInt(i int64) {}
func (h *noopDrv) EncodeUint(i uint64) {}
func (h *noopDrv) EncodeBool(b bool) {}
func (h *noopDrv) EncodeFloat32(f float32) {}
func (h *noopDrv) EncodeFloat64(f float64) {}
func (h *noopDrv) EncodeRawExt(re *RawExt, e *Encoder) {}
func (h *noopDrv) EncodeArrayStart(length int) { h.start(true) }
func (h *noopDrv) EncodeMapStart(length int) { h.start(false) }
func (h *noopDrv) EncodeEnd() { h.end() }
func (h *noopDrv) EncodeString(c charEncoding, v string) {}
func (h *noopDrv) EncodeSymbol(v string) {}
func (h *noopDrv) EncodeStringBytes(c charEncoding, v []byte) {}
func (h *noopDrv) EncodeExt(rv interface{}, xtag uint64, ext Ext, e *Encoder) {}
// ---- decDriver
func (h *noopDrv) initReadNext() {}
func (h *noopDrv) CheckBreak() bool { return false }
func (h *noopDrv) IsBuiltinType(rt uintptr) bool { return false }
func (h *noopDrv) DecodeBuiltin(rt uintptr, v interface{}) {}
func (h *noopDrv) DecodeInt(bitsize uint8) (i int64) { return int64(h.m(15)) }
func (h *noopDrv) DecodeUint(bitsize uint8) (ui uint64) { return uint64(h.m(35)) }
func (h *noopDrv) DecodeFloat(chkOverflow32 bool) (f float64) { return float64(h.m(95)) }
func (h *noopDrv) DecodeBool() (b bool) { return h.m(2) == 0 }
func (h *noopDrv) DecodeString() (s string) { return h.S[h.m(8)] }
// func (h *noopDrv) DecodeStringAsBytes(bs []byte) []byte { return h.DecodeBytes(bs) }
func (h *noopDrv) DecodeBytes(bs []byte, isstring, zerocopy bool) []byte { return h.B[h.m(len(h.B))] }
func (h *noopDrv) ReadEnd() { h.end() }
// toggle map/slice
func (h *noopDrv) ReadMapStart() int { h.start(true); return h.m(10) }
func (h *noopDrv) ReadArrayStart() int { h.start(false); return h.m(10) }
func (h *noopDrv) ContainerType() (vt valueType) {
// return h.m(2) == 0
// handle kStruct, which will bomb is it calls this and doesn't get back a map or array.
// consequently, if the return value is not map or array, reset it to one of them based on h.m(7) % 2
// for kstruct: at least one out of every 2 times, return one of valueTypeMap or Array (else kstruct bombs)
// however, every 10th time it is called, we just return something else.
var vals = [...]valueType{valueTypeArray, valueTypeMap}
// ------------ TAKE ------------
// if h.cb%2 == 0 {
// if h.ct == valueTypeMap || h.ct == valueTypeArray {
// } else {
// h.ct = vals[h.m(2)]
// }
// } else if h.cb%5 == 0 {
// h.ct = valueType(h.m(8))
// } else {
// h.ct = vals[h.m(2)]
// }
// ------------ TAKE ------------
// if h.cb%16 == 0 {
// h.ct = valueType(h.cb % 8)
// } else {
// h.ct = vals[h.cb%2]
// }
h.ct = vals[h.cb%2]
h.cb++
return h.ct
// if h.ct == valueTypeNil || h.ct == valueTypeString || h.ct == valueTypeBytes {
// return h.ct
// }
// return valueTypeUnset
// TODO: may need to tweak this so it works.
// if h.ct == valueTypeMap && vt == valueTypeArray || h.ct == valueTypeArray && vt == valueTypeMap {
// h.cb = !h.cb
// h.ct = vt
// return h.cb
// }
// // go in a loop and check it.
// h.ct = vt
// h.cb = h.m(7) == 0
// return h.cb
}
func (h *noopDrv) TryDecodeAsNil() bool {
if h.mk {
return false
} else {
return h.m(8) == 0
}
}
func (h *noopDrv) DecodeExt(rv interface{}, xtag uint64, ext Ext) uint64 {
return 0
}
func (h *noopDrv) DecodeNaked() {
// use h.r (random) not h.m() because h.m() could cause the same value to be given.
var sk int
if h.mk {
// if mapkey, do not support values of nil OR bytes, array, map or rawext
sk = h.r(7) + 1
} else {
sk = h.r(12)
}
n := &h.d.n
switch sk {
case 0:
n.v = valueTypeNil
case 1:
n.v, n.b = valueTypeBool, false
case 2:
n.v, n.b = valueTypeBool, true
case 3:
n.v, n.i = valueTypeInt, h.DecodeInt(64)
case 4:
n.v, n.u = valueTypeUint, h.DecodeUint(64)
case 5:
n.v, n.f = valueTypeFloat, h.DecodeFloat(true)
case 6:
n.v, n.f = valueTypeFloat, h.DecodeFloat(false)
case 7:
n.v, n.s = valueTypeString, h.DecodeString()
case 8:
n.v, n.l = valueTypeBytes, h.B[h.m(len(h.B))]
case 9:
n.v = valueTypeArray
case 10:
n.v = valueTypeMap
default:
n.v = valueTypeExt
n.u = h.DecodeUint(64)
n.l = h.B[h.m(len(h.B))]
}
h.ct = n.v
return
}