more vendoring

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/multihash/.gobuilder.yml

+---
+artifacts:
+  - LICENSE
+  - README.md
+  - install.dist.sh

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/multihash/LICENSE

+The MIT License (MIT)
+
+Copyright (c) 2014 Juan Batiz-Benet
+
+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.

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/multihash/README.md

+# multihash tool
+
+The `multihash` tool uses `go-multihash` to hash things much like `shasum`.
+
+Warning: this is a **multihash** tool! Its digests follow the [multihash](https://github.com/jbenet/multihash) format.
+
+### Install
+
+- From Source:
+    ```
+    go get github.com/jbenet/go-multihash/multihash
+    ```
+- Precompiled Binaries: https://gobuilder.me/github.com/jbenet/go-multihash/multihash
+
+### Usage
+
+```sh
+> multihash -h
+usage: ./multihash [options] [FILE]
+Print or check multihash checksums.
+With no FILE, or when FILE is -, read standard input.
+
+Options:
+  -a="sha2-256": one of: sha1, sha2-256, sha2-512, sha3 (shorthand)
+  -algorithm="sha2-256": one of: sha1, sha2-256, sha2-512, sha3
+  -c="": check checksum matches (shorthand)
+  -check="": check checksum matches
+  -e="base58": one of: raw, hex, base58, base64 (shorthand)
+  -encoding="base58": one of: raw, hex, base58, base64
+  -l=-1: checksums length in bits (truncate). -1 is default (shorthand)
+  -length=-1: checksums length in bits (truncate). -1 is default
+```
+
+### Examples
+
+#### Input
+
+```sh
+# from stdin
+> multihash < main.go
+QmRZxt2b1FVZPNqd8hsiykDL3TdBDeTSPX9Kv46HmX4Gx8
+
+# from file
+> ./multihash main.go
+QmRZxt2b1FVZPNqd8hsiykDL3TdBDeTSPX9Kv46HmX4Gx8
+
+# from stdin "filename"
+> multihash - < main.go
+QmRZxt2b1FVZPNqd8hsiykDL3TdBDeTSPX9Kv46HmX4Gx8
+```
+
+#### Algorithms
+
+```sh
+> multihash -a ?
+error: algorithm '?' not one of: sha1, sha2-256, sha2-512, sha3
+
+> multihash -a sha1 < main.go
+5drkbcqJUo6fZVvcZJeVEVWAgndvLm
+
+> multihash -a sha2-256 < main.go
+QmcK3s36goo9v2HYcfTrDKKwxaxmJJ59etodQQFYsL5T5N
+
+> multihash -a sha2-512 < main.go
+8VuDcW4CooyPQA8Cc4eYpwjhyDJZqu5m5ZMDFzWULYsVS8d119JaGeNWsZbZ2ZG2kPtbrMx31MidokCigaD65yUPAs
+
+> multihash -a sha3 < main.go
+8tWDCTfAX24DYmzNixTj2ARJkqwRG736VHx5aJppmqRjhW9QT1EuTgKUmu9Pmunzq292jzPKxb2VxSsTXmjFY1HD3B
+```
+
+#### Encodings
+
+```sh
+> multihash -e raw < main.go
+ Ϛ�����I�5  S��WG>���_��]g�����u
+
+> multihash -e hex < main.go
+1220cf9aa2b8a38b9b49d135095390059a57473e97aceb5fcae25d67a8b6feb58275
+
+> multihash -e base64 < main.go
+EiDPmqK4o4ubSdE1CVOQBZpXRz6XrOtfyuJdZ6i2/rWCdQ==
+
+> multihash -e base58 < main.go
+Qmf1QjEXDmqBm7RqHKqFGNUyhzUjnX7cmgKMrGzzPceZDQ
+```
+
+#### Digest Length
+
+```sh
+# we're outputing hex (good byte alignment) to show the codes changing
+# notice the multihash code (first 2 chars) differs!
+> multihash -e hex -a sha2-256 -l 256 < main.go
+1220cf9aa2b8a38b9b49d135095390059a57473e97aceb5fcae25d67a8b6feb58275
+> multihash -e hex -a sha2-512 -l 256 < main.go
+132047a4b6c629f5545f529b0ff461dc09119969f3593186277a1cc7a8ea3560a6f1
+> multihash -e hex -a sha3 -l 256 < main.go
+14206b9222a1a47939e665261bd2b5573e55e7988675223adde73c1011066ad66335
+
+# notice the multihash length (next 2 chars) differs!
+> multihash -e hex -a sha2-256 -l 256 < main.go
+1220cf9aa2b8a38b9b49d135095390059a57473e97aceb5fcae25d67a8b6feb58275
+> multihash -e hex -a sha2-256 -l 200 < main.go
+1219cf9aa2b8a38b9b49d135095390059a57473e97aceb5fcae25d
+```
+
+#### Verify Checksum
+
+```sh
+> multihash -c QmRZxt2b1FVZPNqd8hsiykDL3TdBDeTSPX9Kv46HmX4Gx8 < main.go
+OK checksums match (-q for no output)
+
+> multihash -c QmcKaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa < main.go
+error: computed checksum did not match (-q for no output)
+
+# works with other arguments too
+> multihash -e hex -l 128 -c "12102ffc284a1e82bf51e567c75b2ae6edb9" < main.go
+OK checksums match (-q for no output)
+```

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/multihash/install.dist.sh

+#!/bin/sh
+
+bin=multihash
+
+# this script is currently brain dead.
+# it merely tries two locations.
+# in the future maybe use value of $PATH.
+
+binpath=/usr/local/bin
+if [ -d "$binpath" ]; then
+  mv "$bin" "$binpath/$bin"
+  echo "installed $binpath/$bin"
+  exit 0
+fi
+
+binpath=/usr/bin
+if [ -d "$binpath" ]; then
+  mv "$bin" "$binpath/$bin"
+  echo "installed $binpath/$bin"
+  exit 0
+fi

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/multihash/main.go

+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"os"
+
+	mh "QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash"
+	mhopts "QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/opts"
+)
+
+var usage = `usage: %s [options] [FILE]
+Print or check multihash checksums.
+With no FILE, or when FILE is -, read standard input.
+
+Options:
+`
+
+// flags
+var opts *mhopts.Options
+var checkRaw string
+var checkMh mh.Multihash
+var inputFilename string
+var quiet bool
+
+func init() {
+	flag.Usage = func() {
+		fmt.Fprintf(os.Stderr, usage, os.Args[0])
+		flag.PrintDefaults()
+	}
+
+	opts = mhopts.SetupFlags(flag.CommandLine)
+
+	checkStr := "check checksum matches"
+	flag.StringVar(&checkRaw, "check", "", checkStr)
+	flag.StringVar(&checkRaw, "c", "", checkStr+" (shorthand)")
+
+	quietStr := "quiet output (no newline on checksum, no error text)"
+	flag.BoolVar(&quiet, "quiet", false, quietStr)
+	flag.BoolVar(&quiet, "q", false, quietStr+" (shorthand)")
+}
+
+func parseFlags(o *mhopts.Options) error {
+	flag.Parse()
+	if err := o.ParseError(); err != nil {
+		return err
+	}
+
+	if checkRaw != "" {
+		var err error
+		checkMh, err = mhopts.Decode(o.Encoding, checkRaw)
+		if err != nil {
+			return fmt.Errorf("fail to decode check '%s': %s", checkRaw, err)
+		}
+	}
+
+	return nil
+}
+
+func getInput() (io.ReadCloser, error) {
+	args := flag.Args()
+
+	switch {
+	case len(args) < 1:
+		inputFilename = "-"
+		return os.Stdin, nil
+	case args[0] == "-":
+		inputFilename = "-"
+		return os.Stdin, nil
+	default:
+		inputFilename = args[0]
+		f, err := os.Open(args[0])
+		if err != nil {
+			return nil, fmt.Errorf("failed to open '%s': %s", args[0], err)
+		}
+		return f, nil
+	}
+}
+func printHash(o *mhopts.Options, r io.Reader) error {
+	h, err := o.Multihash(r)
+	if err != nil {
+		return err
+	}
+
+	s, err := mhopts.Encode(o.Encoding, h)
+	if err != nil {
+		return err
+	}
+
+	if quiet {
+		fmt.Print(s)
+	} else {
+		fmt.Println(s)
+	}
+	return nil
+}
+
+func main() {
+	checkErr := func(err error) {
+		if err != nil {
+			die("error: ", err)
+		}
+	}
+
+	err := parseFlags(opts)
+	checkErr(err)
+
+	inp, err := getInput()
+	checkErr(err)
+
+	if checkMh != nil {
+		err = opts.Check(inp, checkMh)
+		checkErr(err)
+		if !quiet {
+			fmt.Println("OK checksums match (-q for no output)")
+		}
+	} else {
+		err = printHash(opts, inp)
+		checkErr(err)
+	}
+	inp.Close()
+}
+
+func die(v ...interface{}) {
+	if !quiet {
+		fmt.Fprint(os.Stderr, v...)
+		fmt.Fprint(os.Stderr, "\n")
+	}
+	// flag.Usage()
+	os.Exit(1)
+}

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/multihash_test.go

+package multihash
+
+import (
+	"bytes"
+	"encoding/hex"
+	"fmt"
+	"testing"
+)
+
+// maybe silly, but makes it so changing
+// the table accidentally has to happen twice.
+var tCodes = map[int]string{
+	0x11: "sha1",
+	0x12: "sha2-256",
+	0x13: "sha2-512",
+	0x14: "sha3",
+	0x40: "blake2b",
+	0x41: "blake2s",
+}
+
+type TestCase struct {
+	hex  string
+	code int
+	name string
+}
+
+var testCases = []TestCase{
+	TestCase{"0beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33", 0x11, "sha1"},
+	TestCase{"0beec7b5", 0x11, "sha1"},
+	TestCase{"2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae", 0x12, "sha2-256"},
+	TestCase{"2c26b46b", 0x12, "sha2-256"},
+	TestCase{"0beec7b5ea3f0fdbc9", 0x40, "blake2b"},
+}
+
+func (tc TestCase) Multihash() (Multihash, error) {
+	ob, err := hex.DecodeString(tc.hex)
+	if err != nil {
+		return nil, err
+	}
+
+	b := make([]byte, 2+len(ob))
+	b[0] = byte(uint8(tc.code))
+	b[1] = byte(uint8(len(ob)))
+	copy(b[2:], ob)
+	return Cast(b)
+}
+
+func TestEncode(t *testing.T) {
+	for _, tc := range testCases {
+		ob, err := hex.DecodeString(tc.hex)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		pre := make([]byte, 2)
+		pre[0] = byte(uint8(tc.code))
+		pre[1] = byte(uint8(len(ob)))
+		nb := append(pre, ob...)
+
+		encC, err := Encode(ob, tc.code)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		if !bytes.Equal(encC, nb) {
+			t.Error("encoded byte mismatch: ", encC, nb)
+		}
+
+		encN, err := EncodeName(ob, tc.name)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		if !bytes.Equal(encN, nb) {
+			t.Error("encoded byte mismatch: ", encN, nb)
+		}
+
+		h, err := tc.Multihash()
+		if err != nil {
+			t.Error(err)
+		}
+		if !bytes.Equal(h, nb) {
+			t.Error("Multihash func mismatch.")
+		}
+	}
+}
+
+func ExampleEncodeName() {
+	// ignores errors for simplicity - don't do that at home.
+	buf, _ := hex.DecodeString("0beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33")
+	mhbuf, _ := EncodeName(buf, "sha1")
+	mhhex := hex.EncodeToString(mhbuf)
+	fmt.Printf("hex: %v\n", mhhex)
+
+	// Output:
+	// hex: 11140beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33
+}
+
+func TestDecode(t *testing.T) {
+	for _, tc := range testCases {
+		ob, err := hex.DecodeString(tc.hex)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		pre := make([]byte, 2)
+		pre[0] = byte(uint8(tc.code))
+		pre[1] = byte(uint8(len(ob)))
+		nb := append(pre, ob...)
+
+		dec, err := Decode(nb)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		if dec.Code != tc.code {
+			t.Error("decoded code mismatch: ", dec.Code, tc.code)
+		}
+
+		if dec.Name != tc.name {
+			t.Error("decoded name mismatch: ", dec.Name, tc.name)
+		}
+
+		if dec.Length != len(ob) {
+			t.Error("decoded length mismatch: ", dec.Length, len(ob))
+		}
+
+		if !bytes.Equal(dec.Digest, ob) {
+			t.Error("decoded byte mismatch: ", dec.Digest, ob)
+		}
+	}
+}
+
+func TestTable(t *testing.T) {
+	for k, v := range tCodes {
+		if Codes[k] != v {
+			t.Error("Table mismatch: ", Codes[k], v)
+		}
+		if Names[v] != k {
+			t.Error("Table mismatch: ", Names[v], k)
+		}
+	}
+}
+
+func ExampleDecode() {
+	// ignores errors for simplicity - don't do that at home.
+	buf, _ := hex.DecodeString("0beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33")
+	mhbuf, _ := EncodeName(buf, "sha1")
+	o, _ := Decode(mhbuf)
+	mhhex := hex.EncodeToString(o.Digest)
+	fmt.Printf("obj: %v 0x%x %d %s\n", o.Name, o.Code, o.Length, mhhex)
+
+	// Output:
+	// obj: sha1 0x11 20 0beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33
+}
+
+func TestValidCode(t *testing.T) {
+	for i := 0; i < 0xff; i++ {
+		_, ok := tCodes[i]
+		b := AppCode(i) || ok
+
+		if ValidCode(i) != b {
+			t.Error("ValidCode incorrect for: ", i)
+		}
+	}
+}
+
+func TestAppCode(t *testing.T) {
+	for i := 0; i < 0xff; i++ {
+		b := i >= 0 && i < 0x10
+		if AppCode(i) != b {
+			t.Error("AppCode incorrect for: ", i)
+		}
+	}
+}
+
+func TestCast(t *testing.T) {
+	for _, tc := range testCases {
+		ob, err := hex.DecodeString(tc.hex)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		pre := make([]byte, 2)
+		pre[0] = byte(uint8(tc.code))
+		pre[1] = byte(uint8(len(ob)))
+		nb := append(pre, ob...)
+
+		if _, err := Cast(nb); err != nil {
+			t.Error(err)
+			continue
+		}
+
+		if _, err = Cast(ob); err == nil {
+			t.Error("cast failed to detect non-multihash")
+			continue
+		}
+	}
+}
+
+func TestHex(t *testing.T) {
+	for _, tc := range testCases {
+		ob, err := hex.DecodeString(tc.hex)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		pre := make([]byte, 2)
+		pre[0] = byte(uint8(tc.code))
+		pre[1] = byte(uint8(len(ob)))
+		nb := append(pre, ob...)
+
+		hs := hex.EncodeToString(nb)
+		mh, err := FromHexString(hs)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		if !bytes.Equal(mh, nb) {
+			t.Error("FromHexString failed", nb, mh)
+			continue
+		}
+
+		if mh.HexString() != hs {
+			t.Error("Multihash.HexString failed", hs, mh.HexString)
+			continue
+		}
+	}
+}
+
+func BenchmarkEncode(b *testing.B) {
+	tc := testCases[0]
+	ob, err := hex.DecodeString(tc.hex)
+	if err != nil {
+		b.Error(err)
+		return
+	}
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		Encode(ob, tc.code)
+	}
+}
+
+func BenchmarkDecode(b *testing.B) {
+	tc := testCases[0]
+	ob, err := hex.DecodeString(tc.hex)
+	if err != nil {
+		b.Error(err)
+		return
+	}
+
+	pre := make([]byte, 2)
+	pre[0] = byte(uint8(tc.code))
+	pre[1] = byte(uint8(len(ob)))
+	nb := append(pre, ob...)
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		Decode(nb)
+	}
+}

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/opts/README.md

+# mhopts - multihash options for writing commands
+
+`mhopts` is a small package that helps to write commands which
+may take multihash options. Check it out in action:
+
+- [multihash](../multihash)
+- [hashpipe](https://github.com/jbenet/go-hashpipe)
+
+Godoc: [https://godoc.org/github.com/jbenet/go-multihash/opts](https://godoc.org/github.com/jbenet/go-multihash/opts)

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/opts/coding.go

+package opts
+
+import (
+	"encoding/base64"
+	"encoding/hex"
+	"fmt"
+
+	base58 "QmNsoHoCVhgXcv1Yg45jtkMgimxorTAN36fV9AQMFXHHAQ/go-base58"
+	mh "QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash"
+)
+
+func Decode(encoding, digest string) (mh.Multihash, error) {
+	switch encoding {
+	case "raw":
+		return mh.Cast([]byte(digest))
+	case "hex":
+		return hex.DecodeString(digest)
+	case "base58":
+		return base58.Decode(digest), nil
+	case "base64":
+		return base64.StdEncoding.DecodeString(digest)
+	default:
+		return nil, fmt.Errorf("unknown encoding: %s", encoding)
+	}
+}
+
+func Encode(encoding string, hash mh.Multihash) (string, error) {
+	switch encoding {
+	case "raw":
+		return string(hash), nil
+	case "hex":
+		return hex.EncodeToString(hash), nil
+	case "base58":
+		return base58.Encode(hash), nil
+	case "base64":
+		return base64.StdEncoding.EncodeToString(hash), nil
+	default:
+		return "", fmt.Errorf("unknown encoding: %s", encoding)
+	}
+}

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/opts/opts.go

+// Package opts helps to write commands which may take multihash
+// options.
+package opts
+
+import (
+	"bytes"
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"strings"
+
+	mh "QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash"
+)
+
+// package errors
+var (
+	ErrMatch = errors.New("multihash checksums did not match")
+)
+
+// Options is a struct used to parse cli flags.
+type Options struct {
+	Encoding      string
+	Algorithm     string
+	AlgorithmCode int
+	Length        int
+
+	fs *flag.FlagSet
+}
+
+// FlagValues are the values the various option flags can take.
+var FlagValues = struct {
+	Encodings  []string
+	Algorithms []string
+}{
+	Encodings:  []string{"raw", "hex", "base58", "base64"},
+	Algorithms: []string{"sha1", "sha2-256", "sha2-512", "sha3"},
+}
+
+// SetupFlags adds multihash related options to given flagset.
+func SetupFlags(f *flag.FlagSet) *Options {
+	// TODO: add arg for adding opt prefix and/or overriding opts
+
+	o := new(Options)
+	algoStr := "one of: " + strings.Join(FlagValues.Algorithms, ", ")
+	f.StringVar(&o.Algorithm, "algorithm", "sha2-256", algoStr)
+	f.StringVar(&o.Algorithm, "a", "sha2-256", algoStr+" (shorthand)")
+
+	encStr := "one of: " + strings.Join(FlagValues.Encodings, ", ")
+	f.StringVar(&o.Encoding, "encoding", "base58", encStr)
+	f.StringVar(&o.Encoding, "e", "base58", encStr+" (shorthand)")
+
+	lengthStr := "checksums length in bits (truncate). -1 is default"
+	f.IntVar(&o.Length, "length", -1, lengthStr)
+	f.IntVar(&o.Length, "l", -1, lengthStr+" (shorthand)")
+	return o
+}
+
+// Parse parses the values of flags from given argument slice.
+// It is equivalent to flags.Parse(args)
+func (o *Options) Parse(args []string) error {
+	if err := o.fs.Parse(args); err != nil {
+		return err
+	}
+	return o.ParseError()
+}
+
+// ParseError checks the parsed options for errors.
+func (o *Options) ParseError() error {
+	if !strIn(o.Encoding, FlagValues.Encodings) {
+		return fmt.Errorf("encoding '%s' not %s", o.Encoding, FlagValues.Encodings)
+	}
+
+	if !strIn(o.Algorithm, FlagValues.Algorithms) {
+		return fmt.Errorf("algorithm '%s' not %s", o.Algorithm, FlagValues.Algorithms)
+	}
+
+	var found bool
+	o.AlgorithmCode, found = mh.Names[o.Algorithm]
+	if !found {
+		return fmt.Errorf("algorithm '%s' not found (lib error, pls report).", o.Algorithm)
+	}
+
+	if o.Length >= 0 {
+		if o.Length%8 != 0 {
+			return fmt.Errorf("length must be multiple of 8")
+		}
+		o.Length = o.Length / 8
+
+		if o.Length > mh.DefaultLengths[o.AlgorithmCode] {
+			o.Length = mh.DefaultLengths[o.AlgorithmCode]
+		}
+	}
+	return nil
+}
+
+// strIn checks wither string a is in set.
+func strIn(a string, set []string) bool {
+	for _, s := range set {
+		if s == a {
+			return true
+		}
+	}
+	return false
+}
+
+// Check reads all the data in r, calculates its multihash,
+// and checks it matches h1
+func (o *Options) Check(r io.Reader, h1 mh.Multihash) error {
+	h2, err := o.Multihash(r)
+	if err != nil {
+		return err
+	}
+
+	if !bytes.Equal(h1, h2) {
+		return fmt.Errorf("computed checksum did not match")
+	}
+
+	return nil
+}
+
+// Multihash reads all the data in r and calculates its multihash.
+func (o *Options) Multihash(r io.Reader) (mh.Multihash, error) {
+	b, err := ioutil.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+
+	return mh.Sum(b, o.AlgorithmCode, o.Length)
+}

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/package.json

+{
+  "name": "go-multihash",
+  "author": "whyrusleeping",
+  "version": "1.0.0",
+  "gxDependencies": [
+    {
+      "name": "go-base58",
+      "hash": "QmNsoHoCVhgXcv1Yg45jtkMgimxorTAN36fV9AQMFXHHAQ",
+      "version": "1.0.0"
+    },
+    {
+      "name": "crypto-sha3",
+      "hash": "QmY1q6BMPywiUXEKAjehsgmPaBeLHTzs3FNaptUsbmpngb",
+      "version": "1.0.0"
+    }
+  ],
+  "language": "go",
+  "gx": {
+    "dvcsimport": "github.com/jbenet/go-multihash"
+  }
+}
\ No newline at end of file

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/sum.go

+package multihash
+
+import (
+	"crypto/sha1"
+	"crypto/sha256"
+	"crypto/sha512"
+	"errors"
+	"fmt"
+
+	sha3 "QmY1q6BMPywiUXEKAjehsgmPaBeLHTzs3FNaptUsbmpngb/crypto-sha3"
+)
+
+var ErrSumNotSupported = errors.New("Function not implemented. Complain to lib maintainer.")
+
+func Sum(data []byte, code int, length int) (Multihash, error) {
+	m := Multihash{}
+	err := error(nil)
+	if !ValidCode(code) {
+		return m, fmt.Errorf("invalid multihash code %d", code)
+	}
+
+	var d []byte
+	switch code {
+	case SHA1:
+		d = sumSHA1(data)
+	case SHA2_256:
+		d = sumSHA256(data)
+	case SHA2_512:
+		d = sumSHA512(data)
+	case SHA3:
+		d, err = sumSHA3(data)
+	default:
+		return m, ErrSumNotSupported
+	}
+
+	if err != nil {
+		return m, err
+	}
+
+	if length < 0 {
+		var ok bool
+		length, ok = DefaultLengths[code]
+		if !ok {
+			return m, fmt.Errorf("no default length for code %d", code)
+		}
+	}
+
+	return Encode(d[0:length], code)
+}
+
+func sumSHA1(data []byte) []byte {
+	a := sha1.Sum(data)
+	return a[0:20]
+}
+
+func sumSHA256(data []byte) []byte {
+	a := sha256.Sum256(data)
+	return a[0:32]
+}
+
+func sumSHA512(data []byte) []byte {
+	a := sha512.Sum512(data)
+	return a[0:64]
+}
+
+func sumSHA3(data []byte) ([]byte, error) {
+	h := sha3.New512()
+	if _, err := h.Write(data); err != nil {
+		return nil, err
+	}
+	return h.Sum(nil), nil
+}

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/sum_test.go

+package multihash
+
+import (
+	"bytes"
+	"testing"
+)
+
+type SumTestCase struct {
+	code   int
+	length int
+	input  string
+	hex    string
+}
+
+var sumTestCases = []SumTestCase{
+	SumTestCase{SHA1, -1, "foo", "11140beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33"},
+	SumTestCase{SHA1, 10, "foo", "110a0beec7b5ea3f0fdbc95d"},
+	SumTestCase{SHA2_256, -1, "foo", "12202c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae"},
+	SumTestCase{SHA2_256, 16, "foo", "12102c26b46b68ffc68ff99b453c1d304134"},
+	SumTestCase{SHA2_512, -1, "foo", "1340f7fbba6e0636f890e56fbbf3283e524c6fa3204ae298382d624741d0dc6638326e282c41be5e4254d8820772c5518a2c5a8c0c7f7eda19594a7eb539453e1ed7"},
+	SumTestCase{SHA2_512, 32, "foo", "1320f7fbba6e0636f890e56fbbf3283e524c6fa3204ae298382d624741d0dc663832"},
+}
+
+func TestSum(t *testing.T) {
+
+	for _, tc := range sumTestCases {
+
+		m1, err := FromHexString(tc.hex)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		m2, err := Sum([]byte(tc.input), tc.code, tc.length)
+		if err != nil {
+			t.Error(tc.code, "sum failed.", err)
+			continue
+		}
+
+		if !bytes.Equal(m1, m2) {
+			t.Error(tc.code, "sum failed.", m1, m2)
+		}
+
+		s1 := m1.HexString()
+		if s1 != tc.hex {
+			t.Error("hex strings not the same")
+		}
+
+		s2 := m1.B58String()
+		m3, err := FromB58String(s2)
+		if err != nil {
+			t.Error("failed to decode b58")
+		} else if !bytes.Equal(m3, m1) {
+			t.Error("b58 failing bytes")
+		} else if s2 != m3.B58String() {
+			t.Error("b58 failing string")
+		}
+	}
+}
+
+func BenchmarkSum(b *testing.B) {
+	tc := sumTestCases[0]
+	for i := 0; i < b.N; i++ {
+		Sum([]byte(tc.input), tc.code, tc.length)
+	}
+}

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/test/.gitignore

+bin/multihash

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/test/Makefile

+BINS = bin/multihash
+MULTIHASH_ROOT = ../
+MULTIHASH_CMD = ../multihash
+
+all: deps
+
+deps: bins
+
+clean:
+	rm $(BINS)
+
+bins: $(BINS)
+
+bin/multihash: $(MULTIHASH_ROOT)/**/*.go
+	go build -o bin/multihash $(MULTIHASH_CMD)
+
+test: test_expensive
+
+test_expensive:
+	cd sharness && make TEST_EXPENSIVE=1
+
+test_cheap:
+	cd sharness && make
+
+.PHONY: all clean

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/test/sharness/.gitignore

+lib/sharness/
+test-results/
+trash directory.*.sh/

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/test/sharness/Makefile

+# Run tests
+#
+# Copyright (c) 2014 Christian Couder
+# MIT Licensed; see the LICENSE file in this repository.
+#
+
+# NOTE: run with TEST_VERBOSE=1 for verbose sharness tests.
+
+T = $(sort $(wildcard t[0-9][0-9][0-9][0-9]-*.sh))
+BINS = bin/multihash
+SHARNESS = lib/sharness/sharness.sh
+
+all: clean deps $(T) aggregate
+
+clean:
+	@echo "*** $@ ***"
+	-rm -rf test-results
+
+$(T):
+	@echo "*** $@ ***"
+	./$@
+
+aggregate:
+	@echo "*** $@ ***"
+	lib/test-aggregate-results.sh
+
+deps: $(SHARNESS) $(BINS)
+
+$(SHARNESS):
+	@echo "*** installing $@ ***"
+	lib/install-sharness.sh
+
+bin/%:
+	@echo "*** installing $@ ***"
+	cd .. && make $@
+
+.PHONY: all clean $(T) aggregate

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/test/sharness/lib/install-sharness.sh

+#!/bin/sh
+# install sharness.sh
+#
+# Copyright (c) 2014 Juan Batiz-Benet
+# MIT Licensed; see the LICENSE file in this repository.
+#
+
+# settings
+version=50229a79ba22b2f13ccd82451d86570fecbd194c
+urlprefix=https://github.com/mlafeldt/sharness.git
+clonedir=lib
+sharnessdir=sharness
+
+die() {
+  echo >&2 "$@"
+  exit 1
+}
+
+mkdir -p "$clonedir" || die "Could not create '$clonedir' directory"
+cd "$clonedir" || die "Could not cd into '$clonedir' directory"
+
+git clone "$urlprefix" || die "Could not clone '$urlprefix'"
+cd "$sharnessdir" || die "Could not cd into '$sharnessdir' directory"
+git checkout "$version" || die "Could not checkout '$version'"
+
+exit 0

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/test/sharness/lib/test-aggregate-results.sh

+#!/bin/sh
+#
+# Script to aggregate results using Sharness
+#
+# Copyright (c) 2014 Christian Couder
+# MIT Licensed; see the LICENSE file in this repository.
+#
+
+SHARNESS_AGGREGATE="lib/sharness/aggregate-results.sh"
+
+test -f "$SHARNESS_AGGREGATE" || {
+	echo >&2 "Cannot find: $SHARNESS_AGGREGATE"
+	echo >&2 "Please check Sharness installation."
+	exit 1
+}
+
+ls test-results/t*-*.sh.*.counts | "$SHARNESS_AGGREGATE"

vendor/QmdeauTdyf38KDQB4Cc4CurPWRRb5pej27NCXPA7kbPTJy/go-multihash/test/sharness/lib/test-lib.sh

+# Test framework for go-ipfs
+#
+# Copyright (c) 2014 Christian Couder
+# MIT Licensed; see the LICENSE file in this repository.
+#
+# We are using sharness (https://github.com/mlafeldt/sharness)
+# which was extracted from the Git test framework.
+
+# Use the multihash tool to test against
+
+# Add current directory to path, for multihash tool.
+PATH=$(pwd)/bin:${PATH}
+
+# Set sharness verbosity. we set the env var directly as
+# it's too late to pass in --verbose, and --verbose is harder
+# to pass through in some cases.
+test "$TEST_VERBOSE" = 1 && verbose=t
+
+# assert the `multihash` we're using is the right one.
+if test `which multihash` != $(pwd)/bin/multihash; then
+	echo >&2 "Cannot find the tests' local multihash tool."
+	echo >&2 "Please check test and multihash tool installation."
+	exit 1
+fi
+
+SHARNESS_LIB="lib/sharness/sharness.sh"
+
+. "$SHARNESS_LIB" || {
+	echo >&2 "Cannot source: $SHARNESS_LIB"
+	echo >&2 "Please check Sharness installation."
+	exit 1
+}
+
+# Please put go-multihash specific shell functions below
+
+for hashbin in sha1sum shasum; do
+	if type "$hashbin"; then
+		export SHASUMBIN="$hashbin" &&
+		test_set_prereq SHASUM &&
+		break
+	fi
+done
+