tidwall cfc65a13f6 Refactor repository and build scripts
This commit includes updates that affects the build, testing, and
deployment of Tile38.

- The root level build.sh has been broken up into multiple scripts
  and placed in the "scripts" directory.

- The vendor directory has been updated to follow the Go modules
  rules, thus `make` should work on isolated environments. Also
  some vendored packages may have been updated to a later
  version, if needed.

- The Makefile has been updated to allow for making single
  binaries such as `make tile38-server`. There is some scaffolding
  during the build process, so from now on all binaries should be
  made using make. For example, to run a development version of
  the tile38-cli binary, do this:
     make tile38-cli && ./tile38-cli
  not this:
     go run cmd/tile38-cli/main.go

- Travis.CI docker push script has been updated to address a
  change to Docker's JSON repo meta output, which in turn fixes
  a bug where new Tile38 versions were not being properly pushed
  to Docker
2019-11-18 10:33:15 -07:00

45 lines
1.0 KiB
Go

package geohash
// encoding encapsulates an encoding defined by a given base32 alphabet.
type encoding struct {
encode string
decode [256]byte
}
// newEncoding constructs a new encoding defined by the given alphabet,
// which must be a 32-byte string.
func newEncoding(encoder string) *encoding {
e := new(encoding)
e.encode = encoder
for i := 0; i < len(e.decode); i++ {
e.decode[i] = 0xff
}
for i := 0; i < len(encoder); i++ {
e.decode[encoder[i]] = byte(i)
}
return e
}
// Decode string into bits of a 64-bit word. The string s may be at most 12
// characters.
func (e *encoding) Decode(s string) uint64 {
x := uint64(0)
for i := 0; i < len(s); i++ {
x = (x << 5) | uint64(e.decode[s[i]])
}
return x
}
// Encode bits of 64-bit word into a string.
func (e *encoding) Encode(x uint64) string {
b := [12]byte{}
for i := 0; i < 12; i++ {
b[11-i] = e.encode[x&0x1f]
x >>= 5
}
return string(b[:])
}
// Base32Encoding with the Geohash alphabet.
var base32encoding = newEncoding("0123456789bcdefghjkmnpqrstuvwxyz")