lbcutil/base58/genalphabet.go
Josh Rickmar dca623d4ef Optimize base58 decoding.
This change introduces an autogenerated base58 digit table to remove
the need to find the index of a character in the modified base58
alphabet each time.  Additionally, it removes some unnecessary big
integer allocations to cut down on the GC churn.

Before:
BenchmarkBase58Encode         20          64998995 ns/op           0.08 MB/s
BenchmarkBase58Decode         50          35965928 ns/op           0.19 MB/s

Now:
BenchmarkBase58Encode         20          64644351 ns/op           0.08 MB/s
BenchmarkBase58Decode        200           7914748 ns/op           0.86 MB/s
2015-01-24 14:59:51 -05:00

79 lines
1.4 KiB
Go

// Copyright (c) 2015 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
//+build ignore
package main
import (
"bytes"
"io"
"log"
"os"
"strconv"
)
var (
start = []byte(`// Copyright (c) 2015 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
// AUTOGENERATED by genalphabet.go; do not edit.
package base58
const (
// alphabet is the modified base58 alphabet used by Bitcoin.
alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
alphabetIdx0 = '1'
)
var b58 = [256]byte{`)
end = []byte(`}`)
alphabet = []byte("123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz")
tab = []byte("\t")
invalid = []byte("255")
comma = []byte(",")
space = []byte(" ")
nl = []byte("\n")
)
func write(w io.Writer, b []byte) {
_, err := w.Write(b)
if err != nil {
log.Fatal(err)
}
}
func main() {
fi, err := os.Create("alphabet.go")
if err != nil {
log.Fatal(err)
}
defer fi.Close()
write(fi, start)
write(fi, nl)
for i := byte(0); i < 32; i++ {
write(fi, tab)
for j := byte(0); j < 8; j++ {
idx := bytes.IndexByte(alphabet, i*8+j)
if idx == -1 {
write(fi, invalid)
} else {
write(fi, strconv.AppendInt(nil, int64(idx), 10))
}
write(fi, comma)
if j != 7 {
write(fi, space)
}
}
write(fi, nl)
}
write(fi, end)
write(fi, nl)
}