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Cleanup wordcodec

pull/1782/head
Ethan Frey 8 years ago
parent
commit
e20cdfcbae
2 changed files with 35 additions and 21 deletions
  1. +28
    -18
      keys/wordcodec.go
  2. +7
    -3
      keys/wordcodec_test.go

+ 28
- 18
keys/wordcodec.go View File

@ -1,7 +1,6 @@
package keys
import (
"fmt"
"io/ioutil"
"math/big"
"os"
@ -31,15 +30,7 @@ func NewCodec(words []string) (codec WordCodec, err error) {
return codec, errors.Errorf("Bank must have %d words, found %d", BankSize, len(words))
}
b := map[string]int{}
for i, w := range words {
if _, ok := b[w]; ok {
return codec, errors.Errorf("Duplicate word in list: %s", w)
}
b[w] = i
}
return WordCodec{words, b}, nil
return WordCodec{words: words}, nil
}
func LoadCodec(bank string) (codec WordCodec, err error) {
@ -111,7 +102,6 @@ func (c WordCodec) BytesToWords(data []byte) (words []string, err error) {
rem := nRem.Int64()
words = append(words, c.words[rem])
}
fmt.Println(words)
return words, nil
}
@ -128,25 +118,45 @@ func (c WordCodec) WordsToBytes(words []string) ([]byte, error) {
// since we output words based on the remainder, the first word has the lowest
// value... we must load them in reverse order
for i := 1; i <= l; i++ {
w := words[l-i]
rem, ok := c.bytes[w]
if !ok {
return nil, errors.Errorf("Unrecognized word: %s", w)
rem, err := c.GetIndex(words[l-i])
if err != nil {
return nil, err
}
nRem := big.NewInt(int64(rem))
nData.Mul(nData, n2048)
nData.Add(nData, nRem)
fmt.Printf("+%d: %v\n", rem, nData)
}
// we copy into a slice of the expected size, so it is not shorter if there
// are lots of leading 0s
dataBytes := nData.Bytes()
fmt.Printf("%#v\n", dataBytes)
outLen, _ := bytelenFromWords(len(words))
output := make([]byte, outLen)
copy(output[outLen-len(dataBytes):], dataBytes)
fmt.Printf("%#v\n", output)
return output, nil
}
// GetIndex finds the index of the words to create bytes
// Generates a map the first time it is loaded, to avoid needless
// computation when list is not used.
func (c WordCodec) GetIndex(word string) (int, error) {
// generate the first time
if c.bytes == nil {
b := map[string]int{}
for i, w := range c.words {
if _, ok := b[w]; ok {
return -1, errors.Errorf("Duplicate word in list: %s", w)
}
b[w] = i
}
c.bytes = b
}
// get the index, or an error
rem, ok := c.bytes[word]
if !ok {
return -1, errors.Errorf("Unrecognized word: %s", word)
}
return rem, nil
}

+ 7
- 3
keys/wordcodec_test.go View File

@ -54,12 +54,16 @@ func TestEncodeDecode(t *testing.T) {
require.Nil(err, "%+v", err)
cases := [][]byte{
// {7, 8, 9}, // TODO: 3 words -> 3 or 4 bytes
// {12, 54, 99, 11}, // TODO: 3 words -> 3 or 4 bytes
{1, 2, 3, 4, 5}, // normal
// {7, 8, 9}, // TODO: 3 words -> 3 or 4 bytes
{12, 54, 99, 11}, // TODO: 3 words -> 3 or 4 bytes
{0, 54, 99, 11}, // TODO: 3 words -> 3 or 4 bytes, detect leading 0
{1, 2, 3, 4, 5}, // normal
// {0, 0, 0, 0, 122, 23, 82, 195}, // leading 0s (8 chars, unclear)
{0, 0, 0, 0, 5, 22, 123, 55, 22}, // leading 0s (9 chars, clear)
{22, 44, 55, 1, 13, 0, 0, 0, 0}, // trailing 0s (9 chars, clear)
{0, 5, 253, 2, 0}, // leading and trailing zeros
{255, 196, 172, 234, 192, 255}, // big numbers
// {255, 196, 172, 1, 234, 192, 255}, // big numbers, two length choices
// others?
}


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