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gitea/vendor/github.com/ugorji/go/codec/helper_internal.go
Thomas Boerger b6a95a8cb3 Integrate public as bindata optionally (#293)
* Dropped unused codekit config

* Integrated dynamic and static bindata for public

* Ignore public bindata

* Add a general generate make task

* Integrated flexible public assets into web command

* Updated vendoring, added all missiong govendor deps

* Made the linter happy with the bindata and dynamic code

* Moved public bindata definition to modules directory

* Ignoring the new bindata path now

* Updated to the new public modules import path

* Updated public bindata command and drop the new prefix
2016-11-30 00:26:36 +08:00

243 lines
5.9 KiB
Go

// 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
// All non-std package dependencies live in this file,
// so porting to different environment is easy (just update functions).
import (
"errors"
"fmt"
"math"
"reflect"
)
func panicValToErr(panicVal interface{}, err *error) {
if panicVal == nil {
return
}
// case nil
switch xerr := panicVal.(type) {
case error:
*err = xerr
case string:
*err = errors.New(xerr)
default:
*err = fmt.Errorf("%v", panicVal)
}
return
}
func hIsEmptyValue(v reflect.Value, deref, checkStruct bool) bool {
switch v.Kind() {
case reflect.Invalid:
return true
case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
return v.Len() == 0
case reflect.Bool:
return !v.Bool()
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return v.Int() == 0
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return v.Uint() == 0
case reflect.Float32, reflect.Float64:
return v.Float() == 0
case reflect.Interface, reflect.Ptr:
if deref {
if v.IsNil() {
return true
}
return hIsEmptyValue(v.Elem(), deref, checkStruct)
} else {
return v.IsNil()
}
case reflect.Struct:
if !checkStruct {
return false
}
// return true if all fields are empty. else return false.
// we cannot use equality check, because some fields may be maps/slices/etc
// and consequently the structs are not comparable.
// return v.Interface() == reflect.Zero(v.Type()).Interface()
for i, n := 0, v.NumField(); i < n; i++ {
if !hIsEmptyValue(v.Field(i), deref, checkStruct) {
return false
}
}
return true
}
return false
}
func isEmptyValue(v reflect.Value) bool {
return hIsEmptyValue(v, derefForIsEmptyValue, checkStructForEmptyValue)
}
func pruneSignExt(v []byte, pos bool) (n int) {
if len(v) < 2 {
} else if pos && v[0] == 0 {
for ; v[n] == 0 && n+1 < len(v) && (v[n+1]&(1<<7) == 0); n++ {
}
} else if !pos && v[0] == 0xff {
for ; v[n] == 0xff && n+1 < len(v) && (v[n+1]&(1<<7) != 0); n++ {
}
}
return
}
func implementsIntf(typ, iTyp reflect.Type) (success bool, indir int8) {
if typ == nil {
return
}
rt := typ
// The type might be a pointer and we need to keep
// dereferencing to the base type until we find an implementation.
for {
if rt.Implements(iTyp) {
return true, indir
}
if p := rt; p.Kind() == reflect.Ptr {
indir++
if indir >= math.MaxInt8 { // insane number of indirections
return false, 0
}
rt = p.Elem()
continue
}
break
}
// No luck yet, but if this is a base type (non-pointer), the pointer might satisfy.
if typ.Kind() != reflect.Ptr {
// Not a pointer, but does the pointer work?
if reflect.PtrTo(typ).Implements(iTyp) {
return true, -1
}
}
return false, 0
}
// validate that this function is correct ...
// culled from OGRE (Object-Oriented Graphics Rendering Engine)
// function: halfToFloatI (http://stderr.org/doc/ogre-doc/api/OgreBitwise_8h-source.html)
func halfFloatToFloatBits(yy uint16) (d uint32) {
y := uint32(yy)
s := (y >> 15) & 0x01
e := (y >> 10) & 0x1f
m := y & 0x03ff
if e == 0 {
if m == 0 { // plu or minus 0
return s << 31
} else { // Denormalized number -- renormalize it
for (m & 0x00000400) == 0 {
m <<= 1
e -= 1
}
e += 1
const zz uint32 = 0x0400
m &= ^zz
}
} else if e == 31 {
if m == 0 { // Inf
return (s << 31) | 0x7f800000
} else { // NaN
return (s << 31) | 0x7f800000 | (m << 13)
}
}
e = e + (127 - 15)
m = m << 13
return (s << 31) | (e << 23) | m
}
// GrowCap will return a new capacity for a slice, given the following:
// - oldCap: current capacity
// - unit: in-memory size of an element
// - num: number of elements to add
func growCap(oldCap, unit, num int) (newCap int) {
// appendslice logic (if cap < 1024, *2, else *1.25):
// leads to many copy calls, especially when copying bytes.
// bytes.Buffer model (2*cap + n): much better for bytes.
// smarter way is to take the byte-size of the appended element(type) into account
// maintain 3 thresholds:
// t1: if cap <= t1, newcap = 2x
// t2: if cap <= t2, newcap = 1.75x
// t3: if cap <= t3, newcap = 1.5x
// else newcap = 1.25x
//
// t1, t2, t3 >= 1024 always.
// i.e. if unit size >= 16, then always do 2x or 1.25x (ie t1, t2, t3 are all same)
//
// With this, appending for bytes increase by:
// 100% up to 4K
// 75% up to 8K
// 50% up to 16K
// 25% beyond that
// unit can be 0 e.g. for struct{}{}; handle that appropriately
var t1, t2, t3 int // thresholds
if unit <= 1 {
t1, t2, t3 = 4*1024, 8*1024, 16*1024
} else if unit < 16 {
t3 = 16 / unit * 1024
t1 = t3 * 1 / 4
t2 = t3 * 2 / 4
} else {
t1, t2, t3 = 1024, 1024, 1024
}
var x int // temporary variable
// x is multiplier here: one of 5, 6, 7 or 8; incr of 25%, 50%, 75% or 100% respectively
if oldCap <= t1 { // [0,t1]
x = 8
} else if oldCap > t3 { // (t3,infinity]
x = 5
} else if oldCap <= t2 { // (t1,t2]
x = 7
} else { // (t2,t3]
x = 6
}
newCap = x * oldCap / 4
if num > 0 {
newCap += num
}
// ensure newCap is a multiple of 64 (if it is > 64) or 16.
if newCap > 64 {
if x = newCap % 64; x != 0 {
x = newCap / 64
newCap = 64 * (x + 1)
}
} else {
if x = newCap % 16; x != 0 {
x = newCap / 16
newCap = 16 * (x + 1)
}
}
return
}
func expandSliceValue(s reflect.Value, num int) reflect.Value {
if num <= 0 {
return s
}
l0 := s.Len()
l1 := l0 + num // new slice length
if l1 < l0 {
panic("ExpandSlice: slice overflow")
}
c0 := s.Cap()
if l1 <= c0 {
return s.Slice(0, l1)
}
st := s.Type()
c1 := growCap(c0, int(st.Elem().Size()), num)
s2 := reflect.MakeSlice(st, l1, c1)
// println("expandslicevalue: cap-old: ", c0, ", cap-new: ", c1, ", len-new: ", l1)
reflect.Copy(s2, s)
return s2
}