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vendor: add kcp-go package

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fatedier
2017-06-04 20:07:03 +08:00
parent 80ba931326
commit 84341b7fcc
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24
vendor/github.com/klauspost/cpuid/.gitignore generated vendored Normal file
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# Compiled Object files, Static and Dynamic libs (Shared Objects)
*.o
*.a
*.so
# Folders
_obj
_test
# Architecture specific extensions/prefixes
*.[568vq]
[568vq].out
*.cgo1.go
*.cgo2.c
_cgo_defun.c
_cgo_gotypes.go
_cgo_export.*
_testmain.go
*.exe
*.test
*.prof

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language: go
go:
- 1.3
- 1.4
- 1.5
- 1.6
- tip

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The MIT License (MIT)
Copyright (c) 2015 Klaus Post
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

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# cpuid
Package cpuid provides information about the CPU running the current program.
CPU features are detected on startup, and kept for fast access through the life of the application.
Currently x86 / x64 (AMD64) is supported, and no external C (cgo) code is used, which should make the library very easy to use.
You can access the CPU information by accessing the shared CPU variable of the cpuid library.
Package home: https://github.com/klauspost/cpuid
[![GoDoc][1]][2] [![Build Status][3]][4]
[1]: https://godoc.org/github.com/klauspost/cpuid?status.svg
[2]: https://godoc.org/github.com/klauspost/cpuid
[3]: https://travis-ci.org/klauspost/cpuid.svg
[4]: https://travis-ci.org/klauspost/cpuid
# features
## CPU Instructions
* **CMOV** (i686 CMOV)
* **NX** (NX (No-Execute) bit)
* **AMD3DNOW** (AMD 3DNOW)
* **AMD3DNOWEXT** (AMD 3DNowExt)
* **MMX** (standard MMX)
* **MMXEXT** (SSE integer functions or AMD MMX ext)
* **SSE** (SSE functions)
* **SSE2** (P4 SSE functions)
* **SSE3** (Prescott SSE3 functions)
* **SSSE3** (Conroe SSSE3 functions)
* **SSE4** (Penryn SSE4.1 functions)
* **SSE4A** (AMD Barcelona microarchitecture SSE4a instructions)
* **SSE42** (Nehalem SSE4.2 functions)
* **AVX** (AVX functions)
* **AVX2** (AVX2 functions)
* **FMA3** (Intel FMA 3)
* **FMA4** (Bulldozer FMA4 functions)
* **XOP** (Bulldozer XOP functions)
* **F16C** (Half-precision floating-point conversion)
* **BMI1** (Bit Manipulation Instruction Set 1)
* **BMI2** (Bit Manipulation Instruction Set 2)
* **TBM** (AMD Trailing Bit Manipulation)
* **LZCNT** (LZCNT instruction)
* **POPCNT** (POPCNT instruction)
* **AESNI** (Advanced Encryption Standard New Instructions)
* **CLMUL** (Carry-less Multiplication)
* **HTT** (Hyperthreading (enabled))
* **HLE** (Hardware Lock Elision)
* **RTM** (Restricted Transactional Memory)
* **RDRAND** (RDRAND instruction is available)
* **RDSEED** (RDSEED instruction is available)
* **ADX** (Intel ADX (Multi-Precision Add-Carry Instruction Extensions))
* **SHA** (Intel SHA Extensions)
* **AVX512F** (AVX-512 Foundation)
* **AVX512DQ** (AVX-512 Doubleword and Quadword Instructions)
* **AVX512IFMA** (AVX-512 Integer Fused Multiply-Add Instructions)
* **AVX512PF** (AVX-512 Prefetch Instructions)
* **AVX512ER** (AVX-512 Exponential and Reciprocal Instructions)
* **AVX512CD** (AVX-512 Conflict Detection Instructions)
* **AVX512BW** (AVX-512 Byte and Word Instructions)
* **AVX512VL** (AVX-512 Vector Length Extensions)
* **AVX512VBMI** (AVX-512 Vector Bit Manipulation Instructions)
* **MPX** (Intel MPX (Memory Protection Extensions))
* **ERMS** (Enhanced REP MOVSB/STOSB)
* **RDTSCP** (RDTSCP Instruction)
* **CX16** (CMPXCHG16B Instruction)
* **SGX** (Software Guard Extensions, with activation details)
## Performance
* **RDTSCP()** Returns current cycle count. Can be used for benchmarking.
* **SSE2SLOW** (SSE2 is supported, but usually not faster)
* **SSE3SLOW** (SSE3 is supported, but usually not faster)
* **ATOM** (Atom processor, some SSSE3 instructions are slower)
* **Cache line** (Probable size of a cache line).
* **L1, L2, L3 Cache size** on newer Intel/AMD CPUs.
## Cpu Vendor/VM
* **Intel**
* **AMD**
* **VIA**
* **Transmeta**
* **NSC**
* **KVM** (Kernel-based Virtual Machine)
* **MSVM** (Microsoft Hyper-V or Windows Virtual PC)
* **VMware**
* **XenHVM**
# installing
```go get github.com/klauspost/cpuid```
# example
```Go
package main
import (
"fmt"
"github.com/klauspost/cpuid"
)
func main() {
// Print basic CPU information:
fmt.Println("Name:", cpuid.CPU.BrandName)
fmt.Println("PhysicalCores:", cpuid.CPU.PhysicalCores)
fmt.Println("ThreadsPerCore:", cpuid.CPU.ThreadsPerCore)
fmt.Println("LogicalCores:", cpuid.CPU.LogicalCores)
fmt.Println("Family", cpuid.CPU.Family, "Model:", cpuid.CPU.Model)
fmt.Println("Features:", cpuid.CPU.Features)
fmt.Println("Cacheline bytes:", cpuid.CPU.CacheLine)
fmt.Println("L1 Data Cache:", cpuid.CPU.Cache.L1D, "bytes")
fmt.Println("L1 Instruction Cache:", cpuid.CPU.Cache.L1D, "bytes")
fmt.Println("L2 Cache:", cpuid.CPU.Cache.L2, "bytes")
fmt.Println("L3 Cache:", cpuid.CPU.Cache.L3, "bytes")
// Test if we have a specific feature:
if cpuid.CPU.SSE() {
fmt.Println("We have Streaming SIMD Extensions")
}
}
```
Sample output:
```
>go run main.go
Name: Intel(R) Core(TM) i5-2540M CPU @ 2.60GHz
PhysicalCores: 2
ThreadsPerCore: 2
LogicalCores: 4
Family 6 Model: 42
Features: CMOV,MMX,MMXEXT,SSE,SSE2,SSE3,SSSE3,SSE4.1,SSE4.2,AVX,AESNI,CLMUL
Cacheline bytes: 64
We have Streaming SIMD Extensions
```
# private package
In the "private" folder you can find an autogenerated version of the library you can include in your own packages.
For this purpose all exports are removed, and functions and constants are lowercased.
This is not a recommended way of using the library, but provided for convenience, if it is difficult for you to use external packages.
# license
This code is published under an MIT license. See LICENSE file for more information.

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// Copyright (c) 2015 Klaus Post, released under MIT License. See LICENSE file.
// +build 386,!gccgo
// func asmCpuid(op uint32) (eax, ebx, ecx, edx uint32)
TEXT ·asmCpuid(SB), 7, $0
XORL CX, CX
MOVL op+0(FP), AX
CPUID
MOVL AX, eax+4(FP)
MOVL BX, ebx+8(FP)
MOVL CX, ecx+12(FP)
MOVL DX, edx+16(FP)
RET
// func asmCpuidex(op, op2 uint32) (eax, ebx, ecx, edx uint32)
TEXT ·asmCpuidex(SB), 7, $0
MOVL op+0(FP), AX
MOVL op2+4(FP), CX
CPUID
MOVL AX, eax+8(FP)
MOVL BX, ebx+12(FP)
MOVL CX, ecx+16(FP)
MOVL DX, edx+20(FP)
RET
// func xgetbv(index uint32) (eax, edx uint32)
TEXT ·asmXgetbv(SB), 7, $0
MOVL index+0(FP), CX
BYTE $0x0f; BYTE $0x01; BYTE $0xd0 // XGETBV
MOVL AX, eax+4(FP)
MOVL DX, edx+8(FP)
RET
// func asmRdtscpAsm() (eax, ebx, ecx, edx uint32)
TEXT ·asmRdtscpAsm(SB), 7, $0
BYTE $0x0F; BYTE $0x01; BYTE $0xF9 // RDTSCP
MOVL AX, eax+0(FP)
MOVL BX, ebx+4(FP)
MOVL CX, ecx+8(FP)
MOVL DX, edx+12(FP)
RET

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// Copyright (c) 2015 Klaus Post, released under MIT License. See LICENSE file.
//+build amd64,!gccgo
// func asmCpuid(op uint32) (eax, ebx, ecx, edx uint32)
TEXT ·asmCpuid(SB), 7, $0
XORQ CX, CX
MOVL op+0(FP), AX
CPUID
MOVL AX, eax+8(FP)
MOVL BX, ebx+12(FP)
MOVL CX, ecx+16(FP)
MOVL DX, edx+20(FP)
RET
// func asmCpuidex(op, op2 uint32) (eax, ebx, ecx, edx uint32)
TEXT ·asmCpuidex(SB), 7, $0
MOVL op+0(FP), AX
MOVL op2+4(FP), CX
CPUID
MOVL AX, eax+8(FP)
MOVL BX, ebx+12(FP)
MOVL CX, ecx+16(FP)
MOVL DX, edx+20(FP)
RET
// func asmXgetbv(index uint32) (eax, edx uint32)
TEXT ·asmXgetbv(SB), 7, $0
MOVL index+0(FP), CX
BYTE $0x0f; BYTE $0x01; BYTE $0xd0 // XGETBV
MOVL AX, eax+8(FP)
MOVL DX, edx+12(FP)
RET
// func asmRdtscpAsm() (eax, ebx, ecx, edx uint32)
TEXT ·asmRdtscpAsm(SB), 7, $0
BYTE $0x0F; BYTE $0x01; BYTE $0xF9 // RDTSCP
MOVL AX, eax+0(FP)
MOVL BX, ebx+4(FP)
MOVL CX, ecx+8(FP)
MOVL DX, edx+12(FP)
RET

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// Copyright (c) 2015 Klaus Post, released under MIT License. See LICENSE file.
// +build 386,!gccgo amd64,!gccgo
package cpuid
func asmCpuid(op uint32) (eax, ebx, ecx, edx uint32)
func asmCpuidex(op, op2 uint32) (eax, ebx, ecx, edx uint32)
func asmXgetbv(index uint32) (eax, edx uint32)
func asmRdtscpAsm() (eax, ebx, ecx, edx uint32)
func initCPU() {
cpuid = asmCpuid
cpuidex = asmCpuidex
xgetbv = asmXgetbv
rdtscpAsm = asmRdtscpAsm
}

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// Copyright (c) 2015 Klaus Post, released under MIT License. See LICENSE file.
// +build !amd64,!386 gccgo
package cpuid
func initCPU() {
cpuid = func(op uint32) (eax, ebx, ecx, edx uint32) {
return 0, 0, 0, 0
}
cpuidex = func(op, op2 uint32) (eax, ebx, ecx, edx uint32) {
return 0, 0, 0, 0
}
xgetbv = func(index uint32) (eax, edx uint32) {
return 0, 0
}
rdtscpAsm = func() (eax, ebx, ecx, edx uint32) {
return 0, 0, 0, 0
}
}

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vendor/github.com/klauspost/cpuid/generate.go generated vendored Normal file
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package cpuid
//go:generate go run private-gen.go

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vendor/github.com/klauspost/cpuid/private-gen.go generated vendored Normal file
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// +build ignore
package main
import (
"bytes"
"fmt"
"go/ast"
"go/parser"
"go/printer"
"go/token"
"io"
"io/ioutil"
"log"
"os"
"reflect"
"strings"
"unicode"
"unicode/utf8"
)
var inFiles = []string{"cpuid.go", "cpuid_test.go"}
var copyFiles = []string{"cpuid_amd64.s", "cpuid_386.s", "detect_ref.go", "detect_intel.go"}
var fileSet = token.NewFileSet()
var reWrites = []rewrite{
initRewrite("CPUInfo -> cpuInfo"),
initRewrite("Vendor -> vendor"),
initRewrite("Flags -> flags"),
initRewrite("Detect -> detect"),
initRewrite("CPU -> cpu"),
}
var excludeNames = map[string]bool{"string": true, "join": true, "trim": true,
// cpuid_test.go
"t": true, "println": true, "logf": true, "log": true, "fatalf": true, "fatal": true,
}
var excludePrefixes = []string{"test", "benchmark"}
func main() {
Package := "private"
parserMode := parser.ParseComments
exported := make(map[string]rewrite)
for _, file := range inFiles {
in, err := os.Open(file)
if err != nil {
log.Fatalf("opening input", err)
}
src, err := ioutil.ReadAll(in)
if err != nil {
log.Fatalf("reading input", err)
}
astfile, err := parser.ParseFile(fileSet, file, src, parserMode)
if err != nil {
log.Fatalf("parsing input", err)
}
for _, rw := range reWrites {
astfile = rw(astfile)
}
// Inspect the AST and print all identifiers and literals.
var startDecl token.Pos
var endDecl token.Pos
ast.Inspect(astfile, func(n ast.Node) bool {
var s string
switch x := n.(type) {
case *ast.Ident:
if x.IsExported() {
t := strings.ToLower(x.Name)
for _, pre := range excludePrefixes {
if strings.HasPrefix(t, pre) {
return true
}
}
if excludeNames[t] != true {
//if x.Pos() > startDecl && x.Pos() < endDecl {
exported[x.Name] = initRewrite(x.Name + " -> " + t)
}
}
case *ast.GenDecl:
if x.Tok == token.CONST && x.Lparen > 0 {
startDecl = x.Lparen
endDecl = x.Rparen
// fmt.Printf("Decl:%s -> %s\n", fileSet.Position(startDecl), fileSet.Position(endDecl))
}
}
if s != "" {
fmt.Printf("%s:\t%s\n", fileSet.Position(n.Pos()), s)
}
return true
})
for _, rw := range exported {
astfile = rw(astfile)
}
var buf bytes.Buffer
printer.Fprint(&buf, fileSet, astfile)
// Remove package documentation and insert information
s := buf.String()
ind := strings.Index(buf.String(), "\npackage cpuid")
s = s[ind:]
s = "// Generated, DO NOT EDIT,\n" +
"// but copy it to your own project and rename the package.\n" +
"// See more at http://github.com/klauspost/cpuid\n" +
s
outputName := Package + string(os.PathSeparator) + file
err = ioutil.WriteFile(outputName, []byte(s), 0644)
if err != nil {
log.Fatalf("writing output: %s", err)
}
log.Println("Generated", outputName)
}
for _, file := range copyFiles {
dst := ""
if strings.HasPrefix(file, "cpuid") {
dst = Package + string(os.PathSeparator) + file
} else {
dst = Package + string(os.PathSeparator) + "cpuid_" + file
}
err := copyFile(file, dst)
if err != nil {
log.Fatalf("copying file: %s", err)
}
log.Println("Copied", dst)
}
}
// CopyFile copies a file from src to dst. If src and dst files exist, and are
// the same, then return success. Copy the file contents from src to dst.
func copyFile(src, dst string) (err error) {
sfi, err := os.Stat(src)
if err != nil {
return
}
if !sfi.Mode().IsRegular() {
// cannot copy non-regular files (e.g., directories,
// symlinks, devices, etc.)
return fmt.Errorf("CopyFile: non-regular source file %s (%q)", sfi.Name(), sfi.Mode().String())
}
dfi, err := os.Stat(dst)
if err != nil {
if !os.IsNotExist(err) {
return
}
} else {
if !(dfi.Mode().IsRegular()) {
return fmt.Errorf("CopyFile: non-regular destination file %s (%q)", dfi.Name(), dfi.Mode().String())
}
if os.SameFile(sfi, dfi) {
return
}
}
err = copyFileContents(src, dst)
return
}
// copyFileContents copies the contents of the file named src to the file named
// by dst. The file will be created if it does not already exist. If the
// destination file exists, all it's contents will be replaced by the contents
// of the source file.
func copyFileContents(src, dst string) (err error) {
in, err := os.Open(src)
if err != nil {
return
}
defer in.Close()
out, err := os.Create(dst)
if err != nil {
return
}
defer func() {
cerr := out.Close()
if err == nil {
err = cerr
}
}()
if _, err = io.Copy(out, in); err != nil {
return
}
err = out.Sync()
return
}
type rewrite func(*ast.File) *ast.File
// Mostly copied from gofmt
func initRewrite(rewriteRule string) rewrite {
f := strings.Split(rewriteRule, "->")
if len(f) != 2 {
fmt.Fprintf(os.Stderr, "rewrite rule must be of the form 'pattern -> replacement'\n")
os.Exit(2)
}
pattern := parseExpr(f[0], "pattern")
replace := parseExpr(f[1], "replacement")
return func(p *ast.File) *ast.File { return rewriteFile(pattern, replace, p) }
}
// parseExpr parses s as an expression.
// It might make sense to expand this to allow statement patterns,
// but there are problems with preserving formatting and also
// with what a wildcard for a statement looks like.
func parseExpr(s, what string) ast.Expr {
x, err := parser.ParseExpr(s)
if err != nil {
fmt.Fprintf(os.Stderr, "parsing %s %s at %s\n", what, s, err)
os.Exit(2)
}
return x
}
// Keep this function for debugging.
/*
func dump(msg string, val reflect.Value) {
fmt.Printf("%s:\n", msg)
ast.Print(fileSet, val.Interface())
fmt.Println()
}
*/
// rewriteFile applies the rewrite rule 'pattern -> replace' to an entire file.
func rewriteFile(pattern, replace ast.Expr, p *ast.File) *ast.File {
cmap := ast.NewCommentMap(fileSet, p, p.Comments)
m := make(map[string]reflect.Value)
pat := reflect.ValueOf(pattern)
repl := reflect.ValueOf(replace)
var rewriteVal func(val reflect.Value) reflect.Value
rewriteVal = func(val reflect.Value) reflect.Value {
// don't bother if val is invalid to start with
if !val.IsValid() {
return reflect.Value{}
}
for k := range m {
delete(m, k)
}
val = apply(rewriteVal, val)
if match(m, pat, val) {
val = subst(m, repl, reflect.ValueOf(val.Interface().(ast.Node).Pos()))
}
return val
}
r := apply(rewriteVal, reflect.ValueOf(p)).Interface().(*ast.File)
r.Comments = cmap.Filter(r).Comments() // recreate comments list
return r
}
// set is a wrapper for x.Set(y); it protects the caller from panics if x cannot be changed to y.
func set(x, y reflect.Value) {
// don't bother if x cannot be set or y is invalid
if !x.CanSet() || !y.IsValid() {
return
}
defer func() {
if x := recover(); x != nil {
if s, ok := x.(string); ok &&
(strings.Contains(s, "type mismatch") || strings.Contains(s, "not assignable")) {
// x cannot be set to y - ignore this rewrite
return
}
panic(x)
}
}()
x.Set(y)
}
// Values/types for special cases.
var (
objectPtrNil = reflect.ValueOf((*ast.Object)(nil))
scopePtrNil = reflect.ValueOf((*ast.Scope)(nil))
identType = reflect.TypeOf((*ast.Ident)(nil))
objectPtrType = reflect.TypeOf((*ast.Object)(nil))
positionType = reflect.TypeOf(token.NoPos)
callExprType = reflect.TypeOf((*ast.CallExpr)(nil))
scopePtrType = reflect.TypeOf((*ast.Scope)(nil))
)
// apply replaces each AST field x in val with f(x), returning val.
// To avoid extra conversions, f operates on the reflect.Value form.
func apply(f func(reflect.Value) reflect.Value, val reflect.Value) reflect.Value {
if !val.IsValid() {
return reflect.Value{}
}
// *ast.Objects introduce cycles and are likely incorrect after
// rewrite; don't follow them but replace with nil instead
if val.Type() == objectPtrType {
return objectPtrNil
}
// similarly for scopes: they are likely incorrect after a rewrite;
// replace them with nil
if val.Type() == scopePtrType {
return scopePtrNil
}
switch v := reflect.Indirect(val); v.Kind() {
case reflect.Slice:
for i := 0; i < v.Len(); i++ {
e := v.Index(i)
set(e, f(e))
}
case reflect.Struct:
for i := 0; i < v.NumField(); i++ {
e := v.Field(i)
set(e, f(e))
}
case reflect.Interface:
e := v.Elem()
set(v, f(e))
}
return val
}
func isWildcard(s string) bool {
rune, size := utf8.DecodeRuneInString(s)
return size == len(s) && unicode.IsLower(rune)
}
// match returns true if pattern matches val,
// recording wildcard submatches in m.
// If m == nil, match checks whether pattern == val.
func match(m map[string]reflect.Value, pattern, val reflect.Value) bool {
// Wildcard matches any expression. If it appears multiple
// times in the pattern, it must match the same expression
// each time.
if m != nil && pattern.IsValid() && pattern.Type() == identType {
name := pattern.Interface().(*ast.Ident).Name
if isWildcard(name) && val.IsValid() {
// wildcards only match valid (non-nil) expressions.
if _, ok := val.Interface().(ast.Expr); ok && !val.IsNil() {
if old, ok := m[name]; ok {
return match(nil, old, val)
}
m[name] = val
return true
}
}
}
// Otherwise, pattern and val must match recursively.
if !pattern.IsValid() || !val.IsValid() {
return !pattern.IsValid() && !val.IsValid()
}
if pattern.Type() != val.Type() {
return false
}
// Special cases.
switch pattern.Type() {
case identType:
// For identifiers, only the names need to match
// (and none of the other *ast.Object information).
// This is a common case, handle it all here instead
// of recursing down any further via reflection.
p := pattern.Interface().(*ast.Ident)
v := val.Interface().(*ast.Ident)
return p == nil && v == nil || p != nil && v != nil && p.Name == v.Name
case objectPtrType, positionType:
// object pointers and token positions always match
return true
case callExprType:
// For calls, the Ellipsis fields (token.Position) must
// match since that is how f(x) and f(x...) are different.
// Check them here but fall through for the remaining fields.
p := pattern.Interface().(*ast.CallExpr)
v := val.Interface().(*ast.CallExpr)
if p.Ellipsis.IsValid() != v.Ellipsis.IsValid() {
return false
}
}
p := reflect.Indirect(pattern)
v := reflect.Indirect(val)
if !p.IsValid() || !v.IsValid() {
return !p.IsValid() && !v.IsValid()
}
switch p.Kind() {
case reflect.Slice:
if p.Len() != v.Len() {
return false
}
for i := 0; i < p.Len(); i++ {
if !match(m, p.Index(i), v.Index(i)) {
return false
}
}
return true
case reflect.Struct:
for i := 0; i < p.NumField(); i++ {
if !match(m, p.Field(i), v.Field(i)) {
return false
}
}
return true
case reflect.Interface:
return match(m, p.Elem(), v.Elem())
}
// Handle token integers, etc.
return p.Interface() == v.Interface()
}
// subst returns a copy of pattern with values from m substituted in place
// of wildcards and pos used as the position of tokens from the pattern.
// if m == nil, subst returns a copy of pattern and doesn't change the line
// number information.
func subst(m map[string]reflect.Value, pattern reflect.Value, pos reflect.Value) reflect.Value {
if !pattern.IsValid() {
return reflect.Value{}
}
// Wildcard gets replaced with map value.
if m != nil && pattern.Type() == identType {
name := pattern.Interface().(*ast.Ident).Name
if isWildcard(name) {
if old, ok := m[name]; ok {
return subst(nil, old, reflect.Value{})
}
}
}
if pos.IsValid() && pattern.Type() == positionType {
// use new position only if old position was valid in the first place
if old := pattern.Interface().(token.Pos); !old.IsValid() {
return pattern
}
return pos
}
// Otherwise copy.
switch p := pattern; p.Kind() {
case reflect.Slice:
v := reflect.MakeSlice(p.Type(), p.Len(), p.Len())
for i := 0; i < p.Len(); i++ {
v.Index(i).Set(subst(m, p.Index(i), pos))
}
return v
case reflect.Struct:
v := reflect.New(p.Type()).Elem()
for i := 0; i < p.NumField(); i++ {
v.Field(i).Set(subst(m, p.Field(i), pos))
}
return v
case reflect.Ptr:
v := reflect.New(p.Type()).Elem()
if elem := p.Elem(); elem.IsValid() {
v.Set(subst(m, elem, pos).Addr())
}
return v
case reflect.Interface:
v := reflect.New(p.Type()).Elem()
if elem := p.Elem(); elem.IsValid() {
v.Set(subst(m, elem, pos))
}
return v
}
return pattern
}

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vendor/github.com/klauspost/reedsolomon/.gitignore generated vendored Normal file
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# Compiled Object files, Static and Dynamic libs (Shared Objects)
*.o
*.a
*.so
# Folders
_obj
_test
# Architecture specific extensions/prefixes
*.[568vq]
[568vq].out
*.cgo1.go
*.cgo2.c
_cgo_defun.c
_cgo_gotypes.go
_cgo_export.*
_testmain.go
*.exe
*.test
*.prof

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language: go
sudo: false
os:
- linux
- osx
go:
- 1.5
- 1.6
- 1.7
- 1.8
- master
install:
- go get ./...
script:
- go vet ./...
- go test -v -cpu=1,2,4 .
- go test -v -cpu=1,2,4 -short -race .
- go test -tags=noasm -v -cpu=1,2,4 -short -race .
- go build examples/simple-decoder.go
- go build examples/simple-encoder.go
- go build examples/stream-decoder.go
- go build examples/stream-encoder.go
- diff <(gofmt -d .) <("")
matrix:
allow_failures:
- go: 'master'
fast_finish: true

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The MIT License (MIT)
Copyright (c) 2015 Klaus Post
Copyright (c) 2015 Backblaze
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

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# Reed-Solomon
[![GoDoc][1]][2] [![Build Status][3]][4]
[1]: https://godoc.org/github.com/klauspost/reedsolomon?status.svg
[2]: https://godoc.org/github.com/klauspost/reedsolomon
[3]: https://travis-ci.org/klauspost/reedsolomon.svg?branch=master
[4]: https://travis-ci.org/klauspost/reedsolomon
Reed-Solomon Erasure Coding in Go, with speeds exceeding 1GB/s/cpu core implemented in pure Go.
This is a golang port of the [JavaReedSolomon](https://github.com/Backblaze/JavaReedSolomon) library released by [Backblaze](http://backblaze.com), with some additional optimizations.
For an introduction on erasure coding, see the post on the [Backblaze blog](https://www.backblaze.com/blog/reed-solomon/).
Package home: https://github.com/klauspost/reedsolomon
Godoc: https://godoc.org/github.com/klauspost/reedsolomon
# Installation
To get the package use the standard:
```bash
go get github.com/klauspost/reedsolomon
```
# Usage
This section assumes you know the basics of Reed-Solomon encoding. A good start is this [Backblaze blog post](https://www.backblaze.com/blog/reed-solomon/).
This package performs the calculation of the parity sets. The usage is therefore relatively simple.
First of all, you need to choose your distribution of data and parity shards. A 'good' distribution is very subjective, and will depend a lot on your usage scenario. A good starting point is above 5 and below 257 data shards (the maximum supported number), and the number of parity shards to be 2 or above, and below the number of data shards.
To create an encoder with 10 data shards (where your data goes) and 3 parity shards (calculated):
```Go
enc, err := reedsolomon.New(10, 3)
```
This encoder will work for all parity sets with this distribution of data and parity shards. The error will only be set if you specify 0 or negative values in any of the parameters, or if you specify more than 256 data shards.
The you send and receive data is a simple slice of byte slices; `[][]byte`. In the example above, the top slice must have a length of 13.
```Go
data := make([][]byte, 13)
```
You should then fill the 10 first slices with *equally sized* data, and create parity shards that will be populated with parity data. In this case we create the data in memory, but you could for instance also use [mmap](https://github.com/edsrzf/mmap-go) to map files.
```Go
// Create all shards, size them at 50000 each
for i := range input {
data[i] := make([]byte, 50000)
}
// Fill some data into the data shards
for i, in := range data[:10] {
for j:= range in {
in[j] = byte((i+j)&0xff)
}
}
```
To populate the parity shards, you simply call `Encode()` with your data.
```Go
err = enc.Encode(data)
```
The only cases where you should get an error is, if the data shards aren't of equal size. The last 3 shards now contain parity data. You can verify this by calling `Verify()`:
```Go
ok, err = enc.Verify(data)
```
The final (and important) part is to be able to reconstruct missing shards. For this to work, you need to know which parts of your data is missing. The encoder *does not know which parts are invalid*, so if data corruption is a likely scenario, you need to implement a hash check for each shard. If a byte has changed in your set, and you don't know which it is, there is no way to reconstruct the data set.
To indicate missing data, you set the shard to nil before calling `Reconstruct()`:
```Go
// Delete two data shards
data[3] = nil
data[7] = nil
// Reconstruct the missing shards
err := enc.Reconstruct(data)
```
The missing data and parity shards will be recreated. If more than 3 shards are missing, the reconstruction will fail.
So to sum up reconstruction:
* The number of data/parity shards must match the numbers used for encoding.
* The order of shards must be the same as used when encoding.
* You may only supply data you know is valid.
* Invalid shards should be set to nil.
For complete examples of an encoder and decoder see the [examples folder](https://github.com/klauspost/reedsolomon/tree/master/examples).
# Splitting/Joining Data
You might have a large slice of data. To help you split this, there are some helper functions that can split and join a single byte slice.
```Go
bigfile, _ := ioutil.Readfile("myfile.data")
// Split the file
split, err := enc.Split(bigfile)
```
This will split the file into the number of data shards set when creating the encoder and create empty parity shards.
An important thing to note is that you have to *keep track of the exact input size*. If the size of the input isn't divisible by the number of data shards, extra zeros will be inserted in the last shard.
To join a data set, use the `Join()` function, which will join the shards and write it to the `io.Writer` you supply:
```Go
// Join a data set and write it to io.Discard.
err = enc.Join(io.Discard, data, len(bigfile))
```
# Streaming/Merging
It might seem like a limitation that all data should be in memory, but an important property is that *as long as the number of data/parity shards are the same, you can merge/split data sets*, and they will remain valid as a separate set.
```Go
// Split the data set of 50000 elements into two of 25000
splitA := make([][]byte, 13)
splitB := make([][]byte, 13)
// Merge into a 100000 element set
merged := make([][]byte, 13)
for i := range data {
splitA[i] = data[i][:25000]
splitB[i] = data[i][25000:]
// Concencate it to itself
merged[i] = append(make([]byte, 0, len(data[i])*2), data[i]...)
merged[i] = append(merged[i], data[i]...)
}
// Each part should still verify as ok.
ok, err := enc.Verify(splitA)
if ok && err == nil {
log.Println("splitA ok")
}
ok, err = enc.Verify(splitB)
if ok && err == nil {
log.Println("splitB ok")
}
ok, err = enc.Verify(merge)
if ok && err == nil {
log.Println("merge ok")
}
```
This means that if you have a data set that may not fit into memory, you can split processing into smaller blocks. For the best throughput, don't use too small blocks.
This also means that you can divide big input up into smaller blocks, and do reconstruction on parts of your data. This doesn't give the same flexibility of a higher number of data shards, but it will be much more performant.
# Streaming API
There has been added support for a streaming API, to help perform fully streaming operations, which enables you to do the same operations, but on streams. To use the stream API, use [`NewStream`](https://godoc.org/github.com/klauspost/reedsolomon#NewStream) function to create the encoding/decoding interfaces. You can use [`NewStreamC`](https://godoc.org/github.com/klauspost/reedsolomon#NewStreamC) to ready an interface that reads/writes concurrently from the streams.
Input is delivered as `[]io.Reader`, output as `[]io.Writer`, and functionality corresponds to the in-memory API. Each stream must supply the same amount of data, similar to how each slice must be similar size with the in-memory API.
If an error occurs in relation to a stream, a [`StreamReadError`](https://godoc.org/github.com/klauspost/reedsolomon#StreamReadError) or [`StreamWriteError`](https://godoc.org/github.com/klauspost/reedsolomon#StreamWriteError) will help you determine which stream was the offender.
There is no buffering or timeouts/retry specified. If you want to add that, you need to add it to the Reader/Writer.
For complete examples of a streaming encoder and decoder see the [examples folder](https://github.com/klauspost/reedsolomon/tree/master/examples).
#Advanced Options
You can modify internal options which affects how jobs are split between and processed by goroutines.
To create options, use the WithXXX functions. You can supply options to `New`, `NewStream` and `NewStreamC`. If no Options are supplied, default options are used.
Example of how to supply options:
```Go
enc, err := reedsolomon.New(10, 3, WithMaxGoroutines(25))
```
# Performance
Performance depends mainly on the number of parity shards. In rough terms, doubling the number of parity shards will double the encoding time.
Here are the throughput numbers with some different selections of data and parity shards. For reference each shard is 1MB random data, and 2 CPU cores are used for encoding.
| Data | Parity | Parity | MB/s | SSSE3 MB/s | SSSE3 Speed | Rel. Speed |
|------|--------|--------|--------|-------------|-------------|------------|
| 5 | 2 | 40% | 576,11 | 2599,2 | 451% | 100,00% |
| 10 | 2 | 20% | 587,73 | 3100,28 | 528% | 102,02% |
| 10 | 4 | 40% | 298,38 | 2470,97 | 828% | 51,79% |
| 50 | 20 | 40% | 59,81 | 713,28 | 1193% | 10,38% |
If `runtime.GOMAXPROCS()` is set to a value higher than 1, the encoder will use multiple goroutines to perform the calculations in `Verify`, `Encode` and `Reconstruct`.
Example of performance scaling on Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz - 4 physical cores, 8 logical cores. The example uses 10 blocks with 16MB data each and 4 parity blocks.
| Threads | MB/s | Speed |
|---------|---------|-------|
| 1 | 1355,11 | 100% |
| 2 | 2339,78 | 172% |
| 4 | 3179,33 | 235% |
| 8 | 4346,18 | 321% |
# asm2plan9s
[asm2plan9s](https://github.com/fwessels/asm2plan9s) is used for assembling the AVX2 instructions into their BYTE/WORD/LONG equivalents.
# Links
* [Backblaze Open Sources Reed-Solomon Erasure Coding Source Code](https://www.backblaze.com/blog/reed-solomon/).
* [JavaReedSolomon](https://github.com/Backblaze/JavaReedSolomon). Compatible java library by Backblaze.
* [reedsolomon-c](https://github.com/jannson/reedsolomon-c). C version, compatible with output from this package.
* [Reed-Solomon Erasure Coding in Haskell](https://github.com/NicolasT/reedsolomon). Haskell port of the package with similar performance.
* [go-erasure](https://github.com/somethingnew2-0/go-erasure). A similar library using cgo, slower in my tests.
* [rsraid](https://github.com/goayame/rsraid). A similar library written in Go. Slower, but supports more shards.
* [Screaming Fast Galois Field Arithmetic](http://www.snia.org/sites/default/files2/SDC2013/presentations/NewThinking/EthanMiller_Screaming_Fast_Galois_Field%20Arithmetic_SIMD%20Instructions.pdf). Basis for SSE3 optimizations.
# License
This code, as the original [JavaReedSolomon](https://github.com/Backblaze/JavaReedSolomon) is published under an MIT license. See LICENSE file for more information.

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os: Visual Studio 2015
platform: x64
clone_folder: c:\gopath\src\github.com\klauspost\reedsolomon
# environment variables
environment:
GOPATH: c:\gopath
install:
- echo %PATH%
- echo %GOPATH%
- go version
- go env
- go get -d ./...
build_script:
- go test -v -cpu=2 ./...
- go test -cpu=1,2,4 -short -race ./...

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vendor/github.com/klauspost/reedsolomon/galois_amd64.go generated vendored Normal file
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//+build !noasm
//+build !appengine
// Copyright 2015, Klaus Post, see LICENSE for details.
package reedsolomon
//go:noescape
func galMulSSSE3(low, high, in, out []byte)
//go:noescape
func galMulSSSE3Xor(low, high, in, out []byte)
//go:noescape
func galMulAVX2Xor(low, high, in, out []byte)
//go:noescape
func galMulAVX2(low, high, in, out []byte)
// This is what the assembler rountes does in blocks of 16 bytes:
/*
func galMulSSSE3(low, high, in, out []byte) {
for n, input := range in {
l := input & 0xf
h := input >> 4
out[n] = low[l] ^ high[h]
}
}
func galMulSSSE3Xor(low, high, in, out []byte) {
for n, input := range in {
l := input & 0xf
h := input >> 4
out[n] ^= low[l] ^ high[h]
}
}
*/
func galMulSlice(c byte, in, out []byte, ssse3, avx2 bool) {
var done int
if avx2 {
galMulAVX2(mulTableLow[c][:], mulTableHigh[c][:], in, out)
done = (len(in) >> 5) << 5
} else if ssse3 {
galMulSSSE3(mulTableLow[c][:], mulTableHigh[c][:], in, out)
done = (len(in) >> 4) << 4
}
remain := len(in) - done
if remain > 0 {
mt := mulTable[c]
for i := done; i < len(in); i++ {
out[i] = mt[in[i]]
}
}
}
func galMulSliceXor(c byte, in, out []byte, ssse3, avx2 bool) {
var done int
if avx2 {
galMulAVX2Xor(mulTableLow[c][:], mulTableHigh[c][:], in, out)
done = (len(in) >> 5) << 5
} else if ssse3 {
galMulSSSE3Xor(mulTableLow[c][:], mulTableHigh[c][:], in, out)
done = (len(in) >> 4) << 4
}
remain := len(in) - done
if remain > 0 {
mt := mulTable[c]
for i := done; i < len(in); i++ {
out[i] ^= mt[in[i]]
}
}
}

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//+build !noasm !appengine
// Copyright 2015, Klaus Post, see LICENSE for details.
// Based on http://www.snia.org/sites/default/files2/SDC2013/presentations/NewThinking/EthanMiller_Screaming_Fast_Galois_Field%20Arithmetic_SIMD%20Instructions.pdf
// and http://jerasure.org/jerasure/gf-complete/tree/master
// func galMulSSSE3Xor(low, high, in, out []byte)
TEXT ·galMulSSSE3Xor(SB), 7, $0
MOVQ low+0(FP), SI // SI: &low
MOVQ high+24(FP), DX // DX: &high
MOVOU (SI), X6 // X6 low
MOVOU (DX), X7 // X7: high
MOVQ $15, BX // BX: low mask
MOVQ BX, X8
PXOR X5, X5
MOVQ in+48(FP), SI // R11: &in
MOVQ in_len+56(FP), R9 // R9: len(in)
MOVQ out+72(FP), DX // DX: &out
PSHUFB X5, X8 // X8: lomask (unpacked)
SHRQ $4, R9 // len(in) / 16
CMPQ R9, $0
JEQ done_xor
loopback_xor:
MOVOU (SI), X0 // in[x]
MOVOU (DX), X4 // out[x]
MOVOU X0, X1 // in[x]
MOVOU X6, X2 // low copy
MOVOU X7, X3 // high copy
PSRLQ $4, X1 // X1: high input
PAND X8, X0 // X0: low input
PAND X8, X1 // X0: high input
PSHUFB X0, X2 // X2: mul low part
PSHUFB X1, X3 // X3: mul high part
PXOR X2, X3 // X3: Result
PXOR X4, X3 // X3: Result xor existing out
MOVOU X3, (DX) // Store
ADDQ $16, SI // in+=16
ADDQ $16, DX // out+=16
SUBQ $1, R9
JNZ loopback_xor
done_xor:
RET
// func galMulSSSE3(low, high, in, out []byte)
TEXT ·galMulSSSE3(SB), 7, $0
MOVQ low+0(FP), SI // SI: &low
MOVQ high+24(FP), DX // DX: &high
MOVOU (SI), X6 // X6 low
MOVOU (DX), X7 // X7: high
MOVQ $15, BX // BX: low mask
MOVQ BX, X8
PXOR X5, X5
MOVQ in+48(FP), SI // R11: &in
MOVQ in_len+56(FP), R9 // R9: len(in)
MOVQ out+72(FP), DX // DX: &out
PSHUFB X5, X8 // X8: lomask (unpacked)
SHRQ $4, R9 // len(in) / 16
CMPQ R9, $0
JEQ done
loopback:
MOVOU (SI), X0 // in[x]
MOVOU X0, X1 // in[x]
MOVOU X6, X2 // low copy
MOVOU X7, X3 // high copy
PSRLQ $4, X1 // X1: high input
PAND X8, X0 // X0: low input
PAND X8, X1 // X0: high input
PSHUFB X0, X2 // X2: mul low part
PSHUFB X1, X3 // X3: mul high part
PXOR X2, X3 // X3: Result
MOVOU X3, (DX) // Store
ADDQ $16, SI // in+=16
ADDQ $16, DX // out+=16
SUBQ $1, R9
JNZ loopback
done:
RET
// func galMulAVX2Xor(low, high, in, out []byte)
TEXT ·galMulAVX2Xor(SB), 7, $0
MOVQ low+0(FP), SI // SI: &low
MOVQ high+24(FP), DX // DX: &high
MOVQ $15, BX // BX: low mask
MOVQ BX, X5
MOVOU (SI), X6 // X6 low
MOVOU (DX), X7 // X7: high
MOVQ in_len+56(FP), R9 // R9: len(in)
LONG $0x384de3c4; WORD $0x01f6 // VINSERTI128 YMM6, YMM6, XMM6, 1 ; low
LONG $0x3845e3c4; WORD $0x01ff // VINSERTI128 YMM7, YMM7, XMM7, 1 ; high
LONG $0x787d62c4; BYTE $0xc5 // VPBROADCASTB YMM8, XMM5 ; X8: lomask (unpacked)
SHRQ $5, R9 // len(in) /32
MOVQ out+72(FP), DX // DX: &out
MOVQ in+48(FP), SI // R11: &in
TESTQ R9, R9
JZ done_xor_avx2
loopback_xor_avx2:
LONG $0x066ffec5 // VMOVDQU YMM0, [rsi]
LONG $0x226ffec5 // VMOVDQU YMM4, [rdx]
LONG $0xd073f5c5; BYTE $0x04 // VPSRLQ YMM1, YMM0, 4 ; X1: high input
LONG $0xdb7dc1c4; BYTE $0xc0 // VPAND YMM0, YMM0, YMM8 ; X0: low input
LONG $0xdb75c1c4; BYTE $0xc8 // VPAND YMM1, YMM1, YMM8 ; X1: high input
LONG $0x004de2c4; BYTE $0xd0 // VPSHUFB YMM2, YMM6, YMM0 ; X2: mul low part
LONG $0x0045e2c4; BYTE $0xd9 // VPSHUFB YMM3, YMM7, YMM1 ; X2: mul high part
LONG $0xdbefedc5 // VPXOR YMM3, YMM2, YMM3 ; X3: Result
LONG $0xe4efe5c5 // VPXOR YMM4, YMM3, YMM4 ; X4: Result
LONG $0x227ffec5 // VMOVDQU [rdx], YMM4
ADDQ $32, SI // in+=32
ADDQ $32, DX // out+=32
SUBQ $1, R9
JNZ loopback_xor_avx2
done_xor_avx2:
// VZEROUPPER
BYTE $0xc5; BYTE $0xf8; BYTE $0x77
RET
// func galMulAVX2(low, high, in, out []byte)
TEXT ·galMulAVX2(SB), 7, $0
MOVQ low+0(FP), SI // SI: &low
MOVQ high+24(FP), DX // DX: &high
MOVQ $15, BX // BX: low mask
MOVQ BX, X5
MOVOU (SI), X6 // X6 low
MOVOU (DX), X7 // X7: high
MOVQ in_len+56(FP), R9 // R9: len(in)
LONG $0x384de3c4; WORD $0x01f6 // VINSERTI128 YMM6, YMM6, XMM6, 1 ; low
LONG $0x3845e3c4; WORD $0x01ff // VINSERTI128 YMM7, YMM7, XMM7, 1 ; high
LONG $0x787d62c4; BYTE $0xc5 // VPBROADCASTB YMM8, XMM5 ; X8: lomask (unpacked)
SHRQ $5, R9 // len(in) /32
MOVQ out+72(FP), DX // DX: &out
MOVQ in+48(FP), SI // R11: &in
TESTQ R9, R9
JZ done_avx2
loopback_avx2:
LONG $0x066ffec5 // VMOVDQU YMM0, [rsi]
LONG $0xd073f5c5; BYTE $0x04 // VPSRLQ YMM1, YMM0, 4 ; X1: high input
LONG $0xdb7dc1c4; BYTE $0xc0 // VPAND YMM0, YMM0, YMM8 ; X0: low input
LONG $0xdb75c1c4; BYTE $0xc8 // VPAND YMM1, YMM1, YMM8 ; X1: high input
LONG $0x004de2c4; BYTE $0xd0 // VPSHUFB YMM2, YMM6, YMM0 ; X2: mul low part
LONG $0x0045e2c4; BYTE $0xd9 // VPSHUFB YMM3, YMM7, YMM1 ; X2: mul high part
LONG $0xe3efedc5 // VPXOR YMM4, YMM2, YMM3 ; X4: Result
LONG $0x227ffec5 // VMOVDQU [rdx], YMM4
ADDQ $32, SI // in+=32
ADDQ $32, DX // out+=32
SUBQ $1, R9
JNZ loopback_avx2
done_avx2:
BYTE $0xc5; BYTE $0xf8; BYTE $0x77 // VZEROUPPER
RET

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//+build !amd64 noasm appengine
// Copyright 2015, Klaus Post, see LICENSE for details.
package reedsolomon
func galMulSlice(c byte, in, out []byte, ssse3, avx2 bool) {
mt := mulTable[c]
for n, input := range in {
out[n] = mt[input]
}
}
func galMulSliceXor(c byte, in, out []byte, ssse3, avx2 bool) {
mt := mulTable[c]
for n, input := range in {
out[n] ^= mt[input]
}
}

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vendor/github.com/klauspost/reedsolomon/gentables.go generated vendored Normal file
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//+build ignore
package main
import (
"fmt"
)
var logTable = [fieldSize]int16{
-1, 0, 1, 25, 2, 50, 26, 198,
3, 223, 51, 238, 27, 104, 199, 75,
4, 100, 224, 14, 52, 141, 239, 129,
28, 193, 105, 248, 200, 8, 76, 113,
5, 138, 101, 47, 225, 36, 15, 33,
53, 147, 142, 218, 240, 18, 130, 69,
29, 181, 194, 125, 106, 39, 249, 185,
201, 154, 9, 120, 77, 228, 114, 166,
6, 191, 139, 98, 102, 221, 48, 253,
226, 152, 37, 179, 16, 145, 34, 136,
54, 208, 148, 206, 143, 150, 219, 189,
241, 210, 19, 92, 131, 56, 70, 64,
30, 66, 182, 163, 195, 72, 126, 110,
107, 58, 40, 84, 250, 133, 186, 61,
202, 94, 155, 159, 10, 21, 121, 43,
78, 212, 229, 172, 115, 243, 167, 87,
7, 112, 192, 247, 140, 128, 99, 13,
103, 74, 222, 237, 49, 197, 254, 24,
227, 165, 153, 119, 38, 184, 180, 124,
17, 68, 146, 217, 35, 32, 137, 46,
55, 63, 209, 91, 149, 188, 207, 205,
144, 135, 151, 178, 220, 252, 190, 97,
242, 86, 211, 171, 20, 42, 93, 158,
132, 60, 57, 83, 71, 109, 65, 162,
31, 45, 67, 216, 183, 123, 164, 118,
196, 23, 73, 236, 127, 12, 111, 246,
108, 161, 59, 82, 41, 157, 85, 170,
251, 96, 134, 177, 187, 204, 62, 90,
203, 89, 95, 176, 156, 169, 160, 81,
11, 245, 22, 235, 122, 117, 44, 215,
79, 174, 213, 233, 230, 231, 173, 232,
116, 214, 244, 234, 168, 80, 88, 175,
}
const (
// The number of elements in the field.
fieldSize = 256
// The polynomial used to generate the logarithm table.
//
// There are a number of polynomials that work to generate
// a Galois field of 256 elements. The choice is arbitrary,
// and we just use the first one.
//
// The possibilities are: 29, 43, 45, 77, 95, 99, 101, 105,
//* 113, 135, 141, 169, 195, 207, 231, and 245.
generatingPolynomial = 29
)
func main() {
t := generateExpTable()
fmt.Printf("var expTable = %#v\n", t)
//t2 := generateMulTableSplit(t)
//fmt.Printf("var mulTable = %#v\n", t2)
low, high := generateMulTableHalf(t)
fmt.Printf("var mulTableLow = %#v\n", low)
fmt.Printf("var mulTableHigh = %#v\n", high)
}
/**
* Generates the inverse log table.
*/
func generateExpTable() []byte {
result := make([]byte, fieldSize*2-2)
for i := 1; i < fieldSize; i++ {
log := logTable[i]
result[log] = byte(i)
result[log+fieldSize-1] = byte(i)
}
return result
}
func generateMulTable(expTable []byte) []byte {
result := make([]byte, 256*256)
for v := range result {
a := byte(v & 0xff)
b := byte(v >> 8)
if a == 0 || b == 0 {
result[v] = 0
continue
}
logA := int(logTable[a])
logB := int(logTable[b])
result[v] = expTable[logA+logB]
}
return result
}
func generateMulTableSplit(expTable []byte) [256][256]byte {
var result [256][256]byte
for a := range result {
for b := range result[a] {
if a == 0 || b == 0 {
result[a][b] = 0
continue
}
logA := int(logTable[a])
logB := int(logTable[b])
result[a][b] = expTable[logA+logB]
}
}
return result
}
func generateMulTableHalf(expTable []byte) (low [256][16]byte, high [256][16]byte) {
for a := range low {
for b := range low {
result := 0
if !(a == 0 || b == 0) {
logA := int(logTable[a])
logB := int(logTable[b])
result = int(expTable[logA+logB])
}
if (b & 0xf) == b {
low[a][b] = byte(result)
}
if (b & 0xf0) == b {
high[a][b>>4] = byte(result)
}
}
}
return
}

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vendor/github.com/klauspost/reedsolomon/inversion_tree.go generated vendored Normal file
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/**
* A thread-safe tree which caches inverted matrices.
*
* Copyright 2016, Peter Collins
*/
package reedsolomon
import (
"errors"
"sync"
)
// The tree uses a Reader-Writer mutex to make it thread-safe
// when accessing cached matrices and inserting new ones.
type inversionTree struct {
mutex *sync.RWMutex
root inversionNode
}
type inversionNode struct {
matrix matrix
children []*inversionNode
}
// newInversionTree initializes a tree for storing inverted matrices.
// Note that the root node is the identity matrix as it implies
// there were no errors with the original data.
func newInversionTree(dataShards, parityShards int) inversionTree {
identity, _ := identityMatrix(dataShards)
root := inversionNode{
matrix: identity,
children: make([]*inversionNode, dataShards+parityShards),
}
return inversionTree{
mutex: &sync.RWMutex{},
root: root,
}
}
// GetInvertedMatrix returns the cached inverted matrix or nil if it
// is not found in the tree keyed on the indices of invalid rows.
func (t inversionTree) GetInvertedMatrix(invalidIndices []int) matrix {
// Lock the tree for reading before accessing the tree.
t.mutex.RLock()
defer t.mutex.RUnlock()
// If no invalid indices were give we should return the root
// identity matrix.
if len(invalidIndices) == 0 {
return t.root.matrix
}
// Recursively search for the inverted matrix in the tree, passing in
// 0 as the parent index as we start at the root of the tree.
return t.root.getInvertedMatrix(invalidIndices, 0)
}
// errAlreadySet is returned if the root node matrix is overwritten
var errAlreadySet = errors.New("the root node identity matrix is already set")
// InsertInvertedMatrix inserts a new inverted matrix into the tree
// keyed by the indices of invalid rows. The total number of shards
// is required for creating the proper length lists of child nodes for
// each node.
func (t inversionTree) InsertInvertedMatrix(invalidIndices []int, matrix matrix, shards int) error {
// If no invalid indices were given then we are done because the
// root node is already set with the identity matrix.
if len(invalidIndices) == 0 {
return errAlreadySet
}
if !matrix.IsSquare() {
return errNotSquare
}
// Lock the tree for writing and reading before accessing the tree.
t.mutex.Lock()
defer t.mutex.Unlock()
// Recursively create nodes for the inverted matrix in the tree until
// we reach the node to insert the matrix to. We start by passing in
// 0 as the parent index as we start at the root of the tree.
t.root.insertInvertedMatrix(invalidIndices, matrix, shards, 0)
return nil
}
func (n inversionNode) getInvertedMatrix(invalidIndices []int, parent int) matrix {
// Get the child node to search next from the list of children. The
// list of children starts relative to the parent index passed in
// because the indices of invalid rows is sorted (by default). As we
// search recursively, the first invalid index gets popped off the list,
// so when searching through the list of children, use that first invalid
// index to find the child node.
firstIndex := invalidIndices[0]
node := n.children[firstIndex-parent]
// If the child node doesn't exist in the list yet, fail fast by
// returning, so we can construct and insert the proper inverted matrix.
if node == nil {
return nil
}
// If there's more than one invalid index left in the list we should
// keep searching recursively.
if len(invalidIndices) > 1 {
// Search recursively on the child node by passing in the invalid indices
// with the first index popped off the front. Also the parent index to
// pass down is the first index plus one.
return node.getInvertedMatrix(invalidIndices[1:], firstIndex+1)
}
// If there aren't any more invalid indices to search, we've found our
// node. Return it, however keep in mind that the matrix could still be
// nil because intermediary nodes in the tree are created sometimes with
// their inversion matrices uninitialized.
return node.matrix
}
func (n inversionNode) insertInvertedMatrix(invalidIndices []int, matrix matrix, shards, parent int) {
// As above, get the child node to search next from the list of children.
// The list of children starts relative to the parent index passed in
// because the indices of invalid rows is sorted (by default). As we
// search recursively, the first invalid index gets popped off the list,
// so when searching through the list of children, use that first invalid
// index to find the child node.
firstIndex := invalidIndices[0]
node := n.children[firstIndex-parent]
// If the child node doesn't exist in the list yet, create a new
// node because we have the writer lock and add it to the list
// of children.
if node == nil {
// Make the length of the list of children equal to the number
// of shards minus the first invalid index because the list of
// invalid indices is sorted, so only this length of errors
// are possible in the tree.
node = &inversionNode{
children: make([]*inversionNode, shards-firstIndex),
}
// Insert the new node into the tree at the first index relative
// to the parent index that was given in this recursive call.
n.children[firstIndex-parent] = node
}
// If there's more than one invalid index left in the list we should
// keep searching recursively in order to find the node to add our
// matrix.
if len(invalidIndices) > 1 {
// As above, search recursively on the child node by passing in
// the invalid indices with the first index popped off the front.
// Also the total number of shards and parent index are passed down
// which is equal to the first index plus one.
node.insertInvertedMatrix(invalidIndices[1:], matrix, shards, firstIndex+1)
} else {
// If there aren't any more invalid indices to search, we've found our
// node. Cache the inverted matrix in this node.
node.matrix = matrix
}
}

279
vendor/github.com/klauspost/reedsolomon/matrix.go generated vendored Normal file
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/**
* Matrix Algebra over an 8-bit Galois Field
*
* Copyright 2015, Klaus Post
* Copyright 2015, Backblaze, Inc.
*/
package reedsolomon
import (
"errors"
"fmt"
"strconv"
"strings"
)
// byte[row][col]
type matrix [][]byte
// newMatrix returns a matrix of zeros.
func newMatrix(rows, cols int) (matrix, error) {
if rows <= 0 {
return nil, errInvalidRowSize
}
if cols <= 0 {
return nil, errInvalidColSize
}
m := matrix(make([][]byte, rows))
for i := range m {
m[i] = make([]byte, cols)
}
return m, nil
}
// NewMatrixData initializes a matrix with the given row-major data.
// Note that data is not copied from input.
func newMatrixData(data [][]byte) (matrix, error) {
m := matrix(data)
err := m.Check()
if err != nil {
return nil, err
}
return m, nil
}
// IdentityMatrix returns an identity matrix of the given size.
func identityMatrix(size int) (matrix, error) {
m, err := newMatrix(size, size)
if err != nil {
return nil, err
}
for i := range m {
m[i][i] = 1
}
return m, nil
}
// errInvalidRowSize will be returned if attempting to create a matrix with negative or zero row number.
var errInvalidRowSize = errors.New("invalid row size")
// errInvalidColSize will be returned if attempting to create a matrix with negative or zero column number.
var errInvalidColSize = errors.New("invalid column size")
// errColSizeMismatch is returned if the size of matrix columns mismatch.
var errColSizeMismatch = errors.New("column size is not the same for all rows")
func (m matrix) Check() error {
rows := len(m)
if rows <= 0 {
return errInvalidRowSize
}
cols := len(m[0])
if cols <= 0 {
return errInvalidColSize
}
for _, col := range m {
if len(col) != cols {
return errColSizeMismatch
}
}
return nil
}
// String returns a human-readable string of the matrix contents.
//
// Example: [[1, 2], [3, 4]]
func (m matrix) String() string {
rowOut := make([]string, 0, len(m))
for _, row := range m {
colOut := make([]string, 0, len(row))
for _, col := range row {
colOut = append(colOut, strconv.Itoa(int(col)))
}
rowOut = append(rowOut, "["+strings.Join(colOut, ", ")+"]")
}
return "[" + strings.Join(rowOut, ", ") + "]"
}
// Multiply multiplies this matrix (the one on the left) by another
// matrix (the one on the right) and returns a new matrix with the result.
func (m matrix) Multiply(right matrix) (matrix, error) {
if len(m[0]) != len(right) {
return nil, fmt.Errorf("columns on left (%d) is different than rows on right (%d)", len(m[0]), len(right))
}
result, _ := newMatrix(len(m), len(right[0]))
for r, row := range result {
for c := range row {
var value byte
for i := range m[0] {
value ^= galMultiply(m[r][i], right[i][c])
}
result[r][c] = value
}
}
return result, nil
}
// Augment returns the concatenation of this matrix and the matrix on the right.
func (m matrix) Augment(right matrix) (matrix, error) {
if len(m) != len(right) {
return nil, errMatrixSize
}
result, _ := newMatrix(len(m), len(m[0])+len(right[0]))
for r, row := range m {
for c := range row {
result[r][c] = m[r][c]
}
cols := len(m[0])
for c := range right[0] {
result[r][cols+c] = right[r][c]
}
}
return result, nil
}
// errMatrixSize is returned if matrix dimensions are doesn't match.
var errMatrixSize = errors.New("matrix sizes does not match")
func (m matrix) SameSize(n matrix) error {
if len(m) != len(n) {
return errMatrixSize
}
for i := range m {
if len(m[i]) != len(n[i]) {
return errMatrixSize
}
}
return nil
}
// Returns a part of this matrix. Data is copied.
func (m matrix) SubMatrix(rmin, cmin, rmax, cmax int) (matrix, error) {
result, err := newMatrix(rmax-rmin, cmax-cmin)
if err != nil {
return nil, err
}
// OPTME: If used heavily, use copy function to copy slice
for r := rmin; r < rmax; r++ {
for c := cmin; c < cmax; c++ {
result[r-rmin][c-cmin] = m[r][c]
}
}
return result, nil
}
// SwapRows Exchanges two rows in the matrix.
func (m matrix) SwapRows(r1, r2 int) error {
if r1 < 0 || len(m) <= r1 || r2 < 0 || len(m) <= r2 {
return errInvalidRowSize
}
m[r2], m[r1] = m[r1], m[r2]
return nil
}
// IsSquare will return true if the matrix is square
// and nil if the matrix is square
func (m matrix) IsSquare() bool {
return len(m) == len(m[0])
}
// errSingular is returned if the matrix is singular and cannot be inversed
var errSingular = errors.New("matrix is singular")
// errNotSquare is returned if attempting to inverse a non-square matrix.
var errNotSquare = errors.New("only square matrices can be inverted")
// Invert returns the inverse of this matrix.
// Returns ErrSingular when the matrix is singular and doesn't have an inverse.
// The matrix must be square, otherwise ErrNotSquare is returned.
func (m matrix) Invert() (matrix, error) {
if !m.IsSquare() {
return nil, errNotSquare
}
size := len(m)
work, _ := identityMatrix(size)
work, _ = m.Augment(work)
err := work.gaussianElimination()
if err != nil {
return nil, err
}
return work.SubMatrix(0, size, size, size*2)
}
func (m matrix) gaussianElimination() error {
rows := len(m)
columns := len(m[0])
// Clear out the part below the main diagonal and scale the main
// diagonal to be 1.
for r := 0; r < rows; r++ {
// If the element on the diagonal is 0, find a row below
// that has a non-zero and swap them.
if m[r][r] == 0 {
for rowBelow := r + 1; rowBelow < rows; rowBelow++ {
if m[rowBelow][r] != 0 {
m.SwapRows(r, rowBelow)
break
}
}
}
// If we couldn't find one, the matrix is singular.
if m[r][r] == 0 {
return errSingular
}
// Scale to 1.
if m[r][r] != 1 {
scale := galDivide(1, m[r][r])
for c := 0; c < columns; c++ {
m[r][c] = galMultiply(m[r][c], scale)
}
}
// Make everything below the 1 be a 0 by subtracting
// a multiple of it. (Subtraction and addition are
// both exclusive or in the Galois field.)
for rowBelow := r + 1; rowBelow < rows; rowBelow++ {
if m[rowBelow][r] != 0 {
scale := m[rowBelow][r]
for c := 0; c < columns; c++ {
m[rowBelow][c] ^= galMultiply(scale, m[r][c])
}
}
}
}
// Now clear the part above the main diagonal.
for d := 0; d < rows; d++ {
for rowAbove := 0; rowAbove < d; rowAbove++ {
if m[rowAbove][d] != 0 {
scale := m[rowAbove][d]
for c := 0; c < columns; c++ {
m[rowAbove][c] ^= galMultiply(scale, m[d][c])
}
}
}
}
return nil
}
// Create a Vandermonde matrix, which is guaranteed to have the
// property that any subset of rows that forms a square matrix
// is invertible.
func vandermonde(rows, cols int) (matrix, error) {
result, err := newMatrix(rows, cols)
if err != nil {
return nil, err
}
for r, row := range result {
for c := range row {
result[r][c] = galExp(byte(r), c)
}
}
return result, nil
}

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vendor/github.com/klauspost/reedsolomon/options.go generated vendored Normal file
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package reedsolomon
import (
"runtime"
"github.com/klauspost/cpuid"
)
// Option allows to override processing parameters.
type Option func(*options)
type options struct {
maxGoroutines int
minSplitSize int
useAVX2, useSSSE3 bool
}
var defaultOptions = options{
maxGoroutines: 50,
minSplitSize: 512,
}
func init() {
if runtime.GOMAXPROCS(0) <= 1 {
defaultOptions.maxGoroutines = 1
}
// Detect CPU capabilities.
defaultOptions.useSSSE3 = cpuid.CPU.SSSE3()
defaultOptions.useAVX2 = cpuid.CPU.AVX2()
}
// WithMaxGoroutines is the maximum number of goroutines number for encoding & decoding.
// Jobs will be split into this many parts, unless each goroutine would have to process
// less than minSplitSize bytes (set with WithMinSplitSize).
// For the best speed, keep this well above the GOMAXPROCS number for more fine grained
// scheduling.
// If n <= 0, it is ignored.
func WithMaxGoroutines(n int) Option {
return func(o *options) {
if n > 0 {
o.maxGoroutines = n
}
}
}
// MinSplitSize Is the minimum encoding size in bytes per goroutine.
// See WithMaxGoroutines on how jobs are split.
// If n <= 0, it is ignored.
func WithMinSplitSize(n int) Option {
return func(o *options) {
if n > 0 {
o.minSplitSize = n
}
}
}
func withSSE3(enabled bool) Option {
return func(o *options) {
o.useSSSE3 = enabled
}
}
func withAVX2(enabled bool) Option {
return func(o *options) {
o.useAVX2 = enabled
}
}

596
vendor/github.com/klauspost/reedsolomon/reedsolomon.go generated vendored Normal file
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/**
* Reed-Solomon Coding over 8-bit values.
*
* Copyright 2015, Klaus Post
* Copyright 2015, Backblaze, Inc.
*/
// Package reedsolomon enables Erasure Coding in Go
//
// For usage and examples, see https://github.com/klauspost/reedsolomon
//
package reedsolomon
import (
"bytes"
"errors"
"io"
"sync"
)
// Encoder is an interface to encode Reed-Salomon parity sets for your data.
type Encoder interface {
// Encodes parity for a set of data shards.
// Input is 'shards' containing data shards followed by parity shards.
// The number of shards must match the number given to New().
// Each shard is a byte array, and they must all be the same size.
// The parity shards will always be overwritten and the data shards
// will remain the same, so it is safe for you to read from the
// data shards while this is running.
Encode(shards [][]byte) error
// Verify returns true if the parity shards contain correct data.
// The data is the same format as Encode. No data is modified, so
// you are allowed to read from data while this is running.
Verify(shards [][]byte) (bool, error)
// Reconstruct will recreate the missing shards if possible.
//
// Given a list of shards, some of which contain data, fills in the
// ones that don't have data.
//
// The length of the array must be equal to the total number of shards.
// You indicate that a shard is missing by setting it to nil.
//
// If there are too few shards to reconstruct the missing
// ones, ErrTooFewShards will be returned.
//
// The reconstructed shard set is complete, but integrity is not verified.
// Use the Verify function to check if data set is ok.
Reconstruct(shards [][]byte) error
// Split a data slice into the number of shards given to the encoder,
// and create empty parity shards.
//
// The data will be split into equally sized shards.
// If the data size isn't dividable by the number of shards,
// the last shard will contain extra zeros.
//
// There must be at least 1 byte otherwise ErrShortData will be
// returned.
//
// The data will not be copied, except for the last shard, so you
// should not modify the data of the input slice afterwards.
Split(data []byte) ([][]byte, error)
// Join the shards and write the data segment to dst.
//
// Only the data shards are considered.
// You must supply the exact output size you want.
// If there are to few shards given, ErrTooFewShards will be returned.
// If the total data size is less than outSize, ErrShortData will be returned.
Join(dst io.Writer, shards [][]byte, outSize int) error
}
// reedSolomon contains a matrix for a specific
// distribution of datashards and parity shards.
// Construct if using New()
type reedSolomon struct {
DataShards int // Number of data shards, should not be modified.
ParityShards int // Number of parity shards, should not be modified.
Shards int // Total number of shards. Calculated, and should not be modified.
m matrix
tree inversionTree
parity [][]byte
o options
}
// ErrInvShardNum will be returned by New, if you attempt to create
// an Encoder where either data or parity shards is zero or less.
var ErrInvShardNum = errors.New("cannot create Encoder with zero or less data/parity shards")
// ErrMaxShardNum will be returned by New, if you attempt to create
// an Encoder where data and parity shards cannot be bigger than
// Galois field GF(2^8) - 1.
var ErrMaxShardNum = errors.New("cannot create Encoder with 255 or more data+parity shards")
// New creates a new encoder and initializes it to
// the number of data shards and parity shards that
// you want to use. You can reuse this encoder.
// Note that the maximum number of data shards is 256.
// If no options are supplied, default options are used.
func New(dataShards, parityShards int, opts ...Option) (Encoder, error) {
r := reedSolomon{
DataShards: dataShards,
ParityShards: parityShards,
Shards: dataShards + parityShards,
o: defaultOptions,
}
for _, opt := range opts {
opt(&r.o)
}
if dataShards <= 0 || parityShards <= 0 {
return nil, ErrInvShardNum
}
if dataShards+parityShards > 255 {
return nil, ErrMaxShardNum
}
// Start with a Vandermonde matrix. This matrix would work,
// in theory, but doesn't have the property that the data
// shards are unchanged after encoding.
vm, err := vandermonde(r.Shards, dataShards)
if err != nil {
return nil, err
}
// Multiply by the inverse of the top square of the matrix.
// This will make the top square be the identity matrix, but
// preserve the property that any square subset of rows is
// invertible.
top, _ := vm.SubMatrix(0, 0, dataShards, dataShards)
top, _ = top.Invert()
r.m, _ = vm.Multiply(top)
// Inverted matrices are cached in a tree keyed by the indices
// of the invalid rows of the data to reconstruct.
// The inversion root node will have the identity matrix as
// its inversion matrix because it implies there are no errors
// with the original data.
r.tree = newInversionTree(dataShards, parityShards)
r.parity = make([][]byte, parityShards)
for i := range r.parity {
r.parity[i] = r.m[dataShards+i]
}
return &r, err
}
// ErrTooFewShards is returned if too few shards where given to
// Encode/Verify/Reconstruct. It will also be returned from Reconstruct
// if there were too few shards to reconstruct the missing data.
var ErrTooFewShards = errors.New("too few shards given")
// Encodes parity for a set of data shards.
// An array 'shards' containing data shards followed by parity shards.
// The number of shards must match the number given to New.
// Each shard is a byte array, and they must all be the same size.
// The parity shards will always be overwritten and the data shards
// will remain the same.
func (r reedSolomon) Encode(shards [][]byte) error {
if len(shards) != r.Shards {
return ErrTooFewShards
}
err := checkShards(shards, false)
if err != nil {
return err
}
// Get the slice of output buffers.
output := shards[r.DataShards:]
// Do the coding.
r.codeSomeShards(r.parity, shards[0:r.DataShards], output, r.ParityShards, len(shards[0]))
return nil
}
// Verify returns true if the parity shards contain the right data.
// The data is the same format as Encode. No data is modified.
func (r reedSolomon) Verify(shards [][]byte) (bool, error) {
if len(shards) != r.Shards {
return false, ErrTooFewShards
}
err := checkShards(shards, false)
if err != nil {
return false, err
}
// Slice of buffers being checked.
toCheck := shards[r.DataShards:]
// Do the checking.
return r.checkSomeShards(r.parity, shards[0:r.DataShards], toCheck, r.ParityShards, len(shards[0])), nil
}
// Multiplies a subset of rows from a coding matrix by a full set of
// input shards to produce some output shards.
// 'matrixRows' is The rows from the matrix to use.
// 'inputs' An array of byte arrays, each of which is one input shard.
// The number of inputs used is determined by the length of each matrix row.
// outputs Byte arrays where the computed shards are stored.
// The number of outputs computed, and the
// number of matrix rows used, is determined by
// outputCount, which is the number of outputs to compute.
func (r reedSolomon) codeSomeShards(matrixRows, inputs, outputs [][]byte, outputCount, byteCount int) {
if r.o.maxGoroutines > 1 && byteCount > r.o.minSplitSize {
r.codeSomeShardsP(matrixRows, inputs, outputs, outputCount, byteCount)
return
}
for c := 0; c < r.DataShards; c++ {
in := inputs[c]
for iRow := 0; iRow < outputCount; iRow++ {
if c == 0 {
galMulSlice(matrixRows[iRow][c], in, outputs[iRow], r.o.useSSSE3, r.o.useAVX2)
} else {
galMulSliceXor(matrixRows[iRow][c], in, outputs[iRow], r.o.useSSSE3, r.o.useAVX2)
}
}
}
}
// Perform the same as codeSomeShards, but split the workload into
// several goroutines.
func (r reedSolomon) codeSomeShardsP(matrixRows, inputs, outputs [][]byte, outputCount, byteCount int) {
var wg sync.WaitGroup
do := byteCount / r.o.maxGoroutines
if do < r.o.minSplitSize {
do = r.o.minSplitSize
}
start := 0
for start < byteCount {
if start+do > byteCount {
do = byteCount - start
}
wg.Add(1)
go func(start, stop int) {
for c := 0; c < r.DataShards; c++ {
in := inputs[c]
for iRow := 0; iRow < outputCount; iRow++ {
if c == 0 {
galMulSlice(matrixRows[iRow][c], in[start:stop], outputs[iRow][start:stop], r.o.useSSSE3, r.o.useAVX2)
} else {
galMulSliceXor(matrixRows[iRow][c], in[start:stop], outputs[iRow][start:stop], r.o.useSSSE3, r.o.useAVX2)
}
}
}
wg.Done()
}(start, start+do)
start += do
}
wg.Wait()
}
// checkSomeShards is mostly the same as codeSomeShards,
// except this will check values and return
// as soon as a difference is found.
func (r reedSolomon) checkSomeShards(matrixRows, inputs, toCheck [][]byte, outputCount, byteCount int) bool {
if r.o.maxGoroutines > 1 && byteCount > r.o.minSplitSize {
return r.checkSomeShardsP(matrixRows, inputs, toCheck, outputCount, byteCount)
}
outputs := make([][]byte, len(toCheck))
for i := range outputs {
outputs[i] = make([]byte, byteCount)
}
for c := 0; c < r.DataShards; c++ {
in := inputs[c]
for iRow := 0; iRow < outputCount; iRow++ {
galMulSliceXor(matrixRows[iRow][c], in, outputs[iRow], r.o.useSSSE3, r.o.useAVX2)
}
}
for i, calc := range outputs {
if !bytes.Equal(calc, toCheck[i]) {
return false
}
}
return true
}
func (r reedSolomon) checkSomeShardsP(matrixRows, inputs, toCheck [][]byte, outputCount, byteCount int) bool {
same := true
var mu sync.RWMutex // For above
var wg sync.WaitGroup
do := byteCount / r.o.maxGoroutines
if do < r.o.minSplitSize {
do = r.o.minSplitSize
}
start := 0
for start < byteCount {
if start+do > byteCount {
do = byteCount - start
}
wg.Add(1)
go func(start, do int) {
defer wg.Done()
outputs := make([][]byte, len(toCheck))
for i := range outputs {
outputs[i] = make([]byte, do)
}
for c := 0; c < r.DataShards; c++ {
mu.RLock()
if !same {
mu.RUnlock()
return
}
mu.RUnlock()
in := inputs[c][start : start+do]
for iRow := 0; iRow < outputCount; iRow++ {
galMulSliceXor(matrixRows[iRow][c], in, outputs[iRow], r.o.useSSSE3, r.o.useAVX2)
}
}
for i, calc := range outputs {
if !bytes.Equal(calc, toCheck[i][start:start+do]) {
mu.Lock()
same = false
mu.Unlock()
return
}
}
}(start, do)
start += do
}
wg.Wait()
return same
}
// ErrShardNoData will be returned if there are no shards,
// or if the length of all shards is zero.
var ErrShardNoData = errors.New("no shard data")
// ErrShardSize is returned if shard length isn't the same for all
// shards.
var ErrShardSize = errors.New("shard sizes does not match")
// checkShards will check if shards are the same size
// or 0, if allowed. An error is returned if this fails.
// An error is also returned if all shards are size 0.
func checkShards(shards [][]byte, nilok bool) error {
size := shardSize(shards)
if size == 0 {
return ErrShardNoData
}
for _, shard := range shards {
if len(shard) != size {
if len(shard) != 0 || !nilok {
return ErrShardSize
}
}
}
return nil
}
// shardSize return the size of a single shard.
// The first non-zero size is returned,
// or 0 if all shards are size 0.
func shardSize(shards [][]byte) int {
for _, shard := range shards {
if len(shard) != 0 {
return len(shard)
}
}
return 0
}
// Reconstruct will recreate the missing shards, if possible.
//
// Given a list of shards, some of which contain data, fills in the
// ones that don't have data.
//
// The length of the array must be equal to Shards.
// You indicate that a shard is missing by setting it to nil.
//
// If there are too few shards to reconstruct the missing
// ones, ErrTooFewShards will be returned.
//
// The reconstructed shard set is complete, but integrity is not verified.
// Use the Verify function to check if data set is ok.
func (r reedSolomon) Reconstruct(shards [][]byte) error {
if len(shards) != r.Shards {
return ErrTooFewShards
}
// Check arguments.
err := checkShards(shards, true)
if err != nil {
return err
}
shardSize := shardSize(shards)
// Quick check: are all of the shards present? If so, there's
// nothing to do.
numberPresent := 0
for i := 0; i < r.Shards; i++ {
if len(shards[i]) != 0 {
numberPresent++
}
}
if numberPresent == r.Shards {
// Cool. All of the shards data data. We don't
// need to do anything.
return nil
}
// More complete sanity check
if numberPresent < r.DataShards {
return ErrTooFewShards
}
// Pull out an array holding just the shards that
// correspond to the rows of the submatrix. These shards
// will be the input to the decoding process that re-creates
// the missing data shards.
//
// Also, create an array of indices of the valid rows we do have
// and the invalid rows we don't have up until we have enough valid rows.
subShards := make([][]byte, r.DataShards)
validIndices := make([]int, r.DataShards)
invalidIndices := make([]int, 0)
subMatrixRow := 0
for matrixRow := 0; matrixRow < r.Shards && subMatrixRow < r.DataShards; matrixRow++ {
if len(shards[matrixRow]) != 0 {
subShards[subMatrixRow] = shards[matrixRow]
validIndices[subMatrixRow] = matrixRow
subMatrixRow++
} else {
invalidIndices = append(invalidIndices, matrixRow)
}
}
// Attempt to get the cached inverted matrix out of the tree
// based on the indices of the invalid rows.
dataDecodeMatrix := r.tree.GetInvertedMatrix(invalidIndices)
// If the inverted matrix isn't cached in the tree yet we must
// construct it ourselves and insert it into the tree for the
// future. In this way the inversion tree is lazily loaded.
if dataDecodeMatrix == nil {
// Pull out the rows of the matrix that correspond to the
// shards that we have and build a square matrix. This
// matrix could be used to generate the shards that we have
// from the original data.
subMatrix, _ := newMatrix(r.DataShards, r.DataShards)
for subMatrixRow, validIndex := range validIndices {
for c := 0; c < r.DataShards; c++ {
subMatrix[subMatrixRow][c] = r.m[validIndex][c]
}
}
// Invert the matrix, so we can go from the encoded shards
// back to the original data. Then pull out the row that
// generates the shard that we want to decode. Note that
// since this matrix maps back to the original data, it can
// be used to create a data shard, but not a parity shard.
dataDecodeMatrix, err = subMatrix.Invert()
if err != nil {
return err
}
// Cache the inverted matrix in the tree for future use keyed on the
// indices of the invalid rows.
err = r.tree.InsertInvertedMatrix(invalidIndices, dataDecodeMatrix, r.Shards)
if err != nil {
return err
}
}
// Re-create any data shards that were missing.
//
// The input to the coding is all of the shards we actually
// have, and the output is the missing data shards. The computation
// is done using the special decode matrix we just built.
outputs := make([][]byte, r.ParityShards)
matrixRows := make([][]byte, r.ParityShards)
outputCount := 0
for iShard := 0; iShard < r.DataShards; iShard++ {
if len(shards[iShard]) == 0 {
shards[iShard] = make([]byte, shardSize)
outputs[outputCount] = shards[iShard]
matrixRows[outputCount] = dataDecodeMatrix[iShard]
outputCount++
}
}
r.codeSomeShards(matrixRows, subShards, outputs[:outputCount], outputCount, shardSize)
// Now that we have all of the data shards intact, we can
// compute any of the parity that is missing.
//
// The input to the coding is ALL of the data shards, including
// any that we just calculated. The output is whichever of the
// data shards were missing.
outputCount = 0
for iShard := r.DataShards; iShard < r.Shards; iShard++ {
if len(shards[iShard]) == 0 {
shards[iShard] = make([]byte, shardSize)
outputs[outputCount] = shards[iShard]
matrixRows[outputCount] = r.parity[iShard-r.DataShards]
outputCount++
}
}
r.codeSomeShards(matrixRows, shards[:r.DataShards], outputs[:outputCount], outputCount, shardSize)
return nil
}
// ErrShortData will be returned by Split(), if there isn't enough data
// to fill the number of shards.
var ErrShortData = errors.New("not enough data to fill the number of requested shards")
// Split a data slice into the number of shards given to the encoder,
// and create empty parity shards.
//
// The data will be split into equally sized shards.
// If the data size isn't divisible by the number of shards,
// the last shard will contain extra zeros.
//
// There must be at least 1 byte otherwise ErrShortData will be
// returned.
//
// The data will not be copied, except for the last shard, so you
// should not modify the data of the input slice afterwards.
func (r reedSolomon) Split(data []byte) ([][]byte, error) {
if len(data) == 0 {
return nil, ErrShortData
}
// Calculate number of bytes per shard.
perShard := (len(data) + r.DataShards - 1) / r.DataShards
// Pad data to r.Shards*perShard.
padding := make([]byte, (r.Shards*perShard)-len(data))
data = append(data, padding...)
// Split into equal-length shards.
dst := make([][]byte, r.Shards)
for i := range dst {
dst[i] = data[:perShard]
data = data[perShard:]
}
return dst, nil
}
// ErrReconstructRequired is returned if too few data shards are intact and a
// reconstruction is required before you can successfully join the shards.
var ErrReconstructRequired = errors.New("reconstruction required as one or more required data shards are nil")
// Join the shards and write the data segment to dst.
//
// Only the data shards are considered.
// You must supply the exact output size you want.
//
// If there are to few shards given, ErrTooFewShards will be returned.
// If the total data size is less than outSize, ErrShortData will be returned.
// If one or more required data shards are nil, ErrReconstructRequired will be returned.
func (r reedSolomon) Join(dst io.Writer, shards [][]byte, outSize int) error {
// Do we have enough shards?
if len(shards) < r.DataShards {
return ErrTooFewShards
}
shards = shards[:r.DataShards]
// Do we have enough data?
size := 0
for _, shard := range shards {
if shard == nil {
return ErrReconstructRequired
}
size += len(shard)
// Do we have enough data already?
if size >= outSize {
break
}
}
if size < outSize {
return ErrShortData
}
// Copy data to dst
write := outSize
for _, shard := range shards {
if write < len(shard) {
_, err := dst.Write(shard[:write])
return err
}
n, err := dst.Write(shard)
if err != nil {
return err
}
write -= n
}
return nil
}

575
vendor/github.com/klauspost/reedsolomon/streaming.go generated vendored Normal file
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@@ -0,0 +1,575 @@
/**
* Reed-Solomon Coding over 8-bit values.
*
* Copyright 2015, Klaus Post
* Copyright 2015, Backblaze, Inc.
*/
package reedsolomon
import (
"bytes"
"errors"
"fmt"
"io"
"sync"
)
// StreamEncoder is an interface to encode Reed-Salomon parity sets for your data.
// It provides a fully streaming interface, and processes data in blocks of up to 4MB.
//
// For small shard sizes, 10MB and below, it is recommended to use the in-memory interface,
// since the streaming interface has a start up overhead.
//
// For all operations, no readers and writers should not assume any order/size of
// individual reads/writes.
//
// For usage examples, see "stream-encoder.go" and "streamdecoder.go" in the examples
// folder.
type StreamEncoder interface {
// Encodes parity shards for a set of data shards.
//
// Input is 'shards' containing readers for data shards followed by parity shards
// io.Writer.
//
// The number of shards must match the number given to NewStream().
//
// Each reader must supply the same number of bytes.
//
// The parity shards will be written to the writer.
// The number of bytes written will match the input size.
//
// If a data stream returns an error, a StreamReadError type error
// will be returned. If a parity writer returns an error, a
// StreamWriteError will be returned.
Encode(data []io.Reader, parity []io.Writer) error
// Verify returns true if the parity shards contain correct data.
//
// The number of shards must match the number total data+parity shards
// given to NewStream().
//
// Each reader must supply the same number of bytes.
// If a shard stream returns an error, a StreamReadError type error
// will be returned.
Verify(shards []io.Reader) (bool, error)
// Reconstruct will recreate the missing shards if possible.
//
// Given a list of valid shards (to read) and invalid shards (to write)
//
// You indicate that a shard is missing by setting it to nil in the 'valid'
// slice and at the same time setting a non-nil writer in "fill".
// An index cannot contain both non-nil 'valid' and 'fill' entry.
// If both are provided 'ErrReconstructMismatch' is returned.
//
// If there are too few shards to reconstruct the missing
// ones, ErrTooFewShards will be returned.
//
// The reconstructed shard set is complete, but integrity is not verified.
// Use the Verify function to check if data set is ok.
Reconstruct(valid []io.Reader, fill []io.Writer) error
// Split a an input stream into the number of shards given to the encoder.
//
// The data will be split into equally sized shards.
// If the data size isn't dividable by the number of shards,
// the last shard will contain extra zeros.
//
// You must supply the total size of your input.
// 'ErrShortData' will be returned if it is unable to retrieve the
// number of bytes indicated.
Split(data io.Reader, dst []io.Writer, size int64) (err error)
// Join the shards and write the data segment to dst.
//
// Only the data shards are considered.
//
// You must supply the exact output size you want.
// If there are to few shards given, ErrTooFewShards will be returned.
// If the total data size is less than outSize, ErrShortData will be returned.
Join(dst io.Writer, shards []io.Reader, outSize int64) error
}
// StreamReadError is returned when a read error is encountered
// that relates to a supplied stream.
// This will allow you to find out which reader has failed.
type StreamReadError struct {
Err error // The error
Stream int // The stream number on which the error occurred
}
// Error returns the error as a string
func (s StreamReadError) Error() string {
return fmt.Sprintf("error reading stream %d: %s", s.Stream, s.Err)
}
// String returns the error as a string
func (s StreamReadError) String() string {
return s.Error()
}
// StreamWriteError is returned when a write error is encountered
// that relates to a supplied stream. This will allow you to
// find out which reader has failed.
type StreamWriteError struct {
Err error // The error
Stream int // The stream number on which the error occurred
}
// Error returns the error as a string
func (s StreamWriteError) Error() string {
return fmt.Sprintf("error writing stream %d: %s", s.Stream, s.Err)
}
// String returns the error as a string
func (s StreamWriteError) String() string {
return s.Error()
}
// rsStream contains a matrix for a specific
// distribution of datashards and parity shards.
// Construct if using NewStream()
type rsStream struct {
r *reedSolomon
bs int // Block size
// Shard reader
readShards func(dst [][]byte, in []io.Reader) error
// Shard writer
writeShards func(out []io.Writer, in [][]byte) error
creads bool
cwrites bool
}
// NewStream creates a new encoder and initializes it to
// the number of data shards and parity shards that
// you want to use. You can reuse this encoder.
// Note that the maximum number of data shards is 256.
func NewStream(dataShards, parityShards int, o ...Option) (StreamEncoder, error) {
enc, err := New(dataShards, parityShards, o...)
if err != nil {
return nil, err
}
rs := enc.(*reedSolomon)
r := rsStream{r: rs, bs: 4 << 20}
r.readShards = readShards
r.writeShards = writeShards
return &r, err
}
// NewStreamC creates a new encoder and initializes it to
// the number of data shards and parity shards given.
//
// This functions as 'NewStream', but allows you to enable CONCURRENT reads and writes.
func NewStreamC(dataShards, parityShards int, conReads, conWrites bool, o ...Option) (StreamEncoder, error) {
enc, err := New(dataShards, parityShards, o...)
if err != nil {
return nil, err
}
rs := enc.(*reedSolomon)
r := rsStream{r: rs, bs: 4 << 20}
r.readShards = readShards
r.writeShards = writeShards
if conReads {
r.readShards = cReadShards
}
if conWrites {
r.writeShards = cWriteShards
}
return &r, err
}
func createSlice(n, length int) [][]byte {
out := make([][]byte, n)
for i := range out {
out[i] = make([]byte, length)
}
return out
}
// Encodes parity shards for a set of data shards.
//
// Input is 'shards' containing readers for data shards followed by parity shards
// io.Writer.
//
// The number of shards must match the number given to NewStream().
//
// Each reader must supply the same number of bytes.
//
// The parity shards will be written to the writer.
// The number of bytes written will match the input size.
//
// If a data stream returns an error, a StreamReadError type error
// will be returned. If a parity writer returns an error, a
// StreamWriteError will be returned.
func (r rsStream) Encode(data []io.Reader, parity []io.Writer) error {
if len(data) != r.r.DataShards {
return ErrTooFewShards
}
if len(parity) != r.r.ParityShards {
return ErrTooFewShards
}
all := createSlice(r.r.Shards, r.bs)
in := all[:r.r.DataShards]
out := all[r.r.DataShards:]
read := 0
for {
err := r.readShards(in, data)
switch err {
case nil:
case io.EOF:
if read == 0 {
return ErrShardNoData
}
return nil
default:
return err
}
out = trimShards(out, shardSize(in))
read += shardSize(in)
err = r.r.Encode(all)
if err != nil {
return err
}
err = r.writeShards(parity, out)
if err != nil {
return err
}
}
}
// Trim the shards so they are all the same size
func trimShards(in [][]byte, size int) [][]byte {
for i := range in {
if in[i] != nil {
in[i] = in[i][0:size]
}
if len(in[i]) < size {
in[i] = nil
}
}
return in
}
func readShards(dst [][]byte, in []io.Reader) error {
if len(in) != len(dst) {
panic("internal error: in and dst size does not match")
}
size := -1
for i := range in {
if in[i] == nil {
dst[i] = nil
continue
}
n, err := io.ReadFull(in[i], dst[i])
// The error is EOF only if no bytes were read.
// If an EOF happens after reading some but not all the bytes,
// ReadFull returns ErrUnexpectedEOF.
switch err {
case io.ErrUnexpectedEOF, io.EOF:
if size < 0 {
size = n
} else if n != size {
// Shard sizes must match.
return ErrShardSize
}
dst[i] = dst[i][0:n]
case nil:
continue
default:
return StreamReadError{Err: err, Stream: i}
}
}
if size == 0 {
return io.EOF
}
return nil
}
func writeShards(out []io.Writer, in [][]byte) error {
if len(out) != len(in) {
panic("internal error: in and out size does not match")
}
for i := range in {
if out[i] == nil {
continue
}
n, err := out[i].Write(in[i])
if err != nil {
return StreamWriteError{Err: err, Stream: i}
}
//
if n != len(in[i]) {
return StreamWriteError{Err: io.ErrShortWrite, Stream: i}
}
}
return nil
}
type readResult struct {
n int
size int
err error
}
// cReadShards reads shards concurrently
func cReadShards(dst [][]byte, in []io.Reader) error {
if len(in) != len(dst) {
panic("internal error: in and dst size does not match")
}
var wg sync.WaitGroup
wg.Add(len(in))
res := make(chan readResult, len(in))
for i := range in {
if in[i] == nil {
dst[i] = nil
wg.Done()
continue
}
go func(i int) {
defer wg.Done()
n, err := io.ReadFull(in[i], dst[i])
// The error is EOF only if no bytes were read.
// If an EOF happens after reading some but not all the bytes,
// ReadFull returns ErrUnexpectedEOF.
res <- readResult{size: n, err: err, n: i}
}(i)
}
wg.Wait()
close(res)
size := -1
for r := range res {
switch r.err {
case io.ErrUnexpectedEOF, io.EOF:
if size < 0 {
size = r.size
} else if r.size != size {
// Shard sizes must match.
return ErrShardSize
}
dst[r.n] = dst[r.n][0:r.size]
case nil:
default:
return StreamReadError{Err: r.err, Stream: r.n}
}
}
if size == 0 {
return io.EOF
}
return nil
}
// cWriteShards writes shards concurrently
func cWriteShards(out []io.Writer, in [][]byte) error {
if len(out) != len(in) {
panic("internal error: in and out size does not match")
}
var errs = make(chan error, len(out))
var wg sync.WaitGroup
wg.Add(len(out))
for i := range in {
go func(i int) {
defer wg.Done()
if out[i] == nil {
errs <- nil
return
}
n, err := out[i].Write(in[i])
if err != nil {
errs <- StreamWriteError{Err: err, Stream: i}
return
}
if n != len(in[i]) {
errs <- StreamWriteError{Err: io.ErrShortWrite, Stream: i}
}
}(i)
}
wg.Wait()
close(errs)
for err := range errs {
if err != nil {
return err
}
}
return nil
}
// Verify returns true if the parity shards contain correct data.
//
// The number of shards must match the number total data+parity shards
// given to NewStream().
//
// Each reader must supply the same number of bytes.
// If a shard stream returns an error, a StreamReadError type error
// will be returned.
func (r rsStream) Verify(shards []io.Reader) (bool, error) {
if len(shards) != r.r.Shards {
return false, ErrTooFewShards
}
read := 0
all := createSlice(r.r.Shards, r.bs)
for {
err := r.readShards(all, shards)
if err == io.EOF {
if read == 0 {
return false, ErrShardNoData
}
return true, nil
}
if err != nil {
return false, err
}
read += shardSize(all)
ok, err := r.r.Verify(all)
if !ok || err != nil {
return ok, err
}
}
}
// ErrReconstructMismatch is returned by the StreamEncoder, if you supply
// "valid" and "fill" streams on the same index.
// Therefore it is impossible to see if you consider the shard valid
// or would like to have it reconstructed.
var ErrReconstructMismatch = errors.New("valid shards and fill shards are mutually exclusive")
// Reconstruct will recreate the missing shards if possible.
//
// Given a list of valid shards (to read) and invalid shards (to write)
//
// You indicate that a shard is missing by setting it to nil in the 'valid'
// slice and at the same time setting a non-nil writer in "fill".
// An index cannot contain both non-nil 'valid' and 'fill' entry.
//
// If there are too few shards to reconstruct the missing
// ones, ErrTooFewShards will be returned.
//
// The reconstructed shard set is complete, but integrity is not verified.
// Use the Verify function to check if data set is ok.
func (r rsStream) Reconstruct(valid []io.Reader, fill []io.Writer) error {
if len(valid) != r.r.Shards {
return ErrTooFewShards
}
if len(fill) != r.r.Shards {
return ErrTooFewShards
}
all := createSlice(r.r.Shards, r.bs)
for i := range valid {
if valid[i] != nil && fill[i] != nil {
return ErrReconstructMismatch
}
}
read := 0
for {
err := r.readShards(all, valid)
if err == io.EOF {
if read == 0 {
return ErrShardNoData
}
return nil
}
if err != nil {
return err
}
read += shardSize(all)
all = trimShards(all, shardSize(all))
err = r.r.Reconstruct(all)
if err != nil {
return err
}
err = r.writeShards(fill, all)
if err != nil {
return err
}
}
}
// Join the shards and write the data segment to dst.
//
// Only the data shards are considered.
//
// You must supply the exact output size you want.
// If there are to few shards given, ErrTooFewShards will be returned.
// If the total data size is less than outSize, ErrShortData will be returned.
func (r rsStream) Join(dst io.Writer, shards []io.Reader, outSize int64) error {
// Do we have enough shards?
if len(shards) < r.r.DataShards {
return ErrTooFewShards
}
// Trim off parity shards if any
shards = shards[:r.r.DataShards]
for i := range shards {
if shards[i] == nil {
return StreamReadError{Err: ErrShardNoData, Stream: i}
}
}
// Join all shards
src := io.MultiReader(shards...)
// Copy data to dst
n, err := io.CopyN(dst, src, outSize)
if err == io.EOF {
return ErrShortData
}
if err != nil {
return err
}
if n != outSize {
return ErrShortData
}
return nil
}
// Split a an input stream into the number of shards given to the encoder.
//
// The data will be split into equally sized shards.
// If the data size isn't dividable by the number of shards,
// the last shard will contain extra zeros.
//
// You must supply the total size of your input.
// 'ErrShortData' will be returned if it is unable to retrieve the
// number of bytes indicated.
func (r rsStream) Split(data io.Reader, dst []io.Writer, size int64) error {
if size == 0 {
return ErrShortData
}
if len(dst) != r.r.DataShards {
return ErrInvShardNum
}
for i := range dst {
if dst[i] == nil {
return StreamWriteError{Err: ErrShardNoData, Stream: i}
}
}
// Calculate number of bytes per shard.
perShard := (size + int64(r.r.DataShards) - 1) / int64(r.r.DataShards)
// Pad data to r.Shards*perShard.
padding := make([]byte, (int64(r.r.Shards)*perShard)-size)
data = io.MultiReader(data, bytes.NewBuffer(padding))
// Split into equal-length shards and copy.
for i := range dst {
n, err := io.CopyN(dst[i], data, perShard)
if err != io.EOF && err != nil {
return err
}
if n != perShard {
return ErrShortData
}
}
return nil
}