/usr/share/gocode/src/github.com/ugorji/go/codec/helper_internal.go is in golang-github-ugorji-go-codec-dev 0.0~git20151130.0.357a44b-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 | // 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
}
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