README
¶
gofarmhash
Port of Google's Farmhash version 1.0.0 to pure Go
For more on Farmhash see https://code.google.com/p/farmhash/
Farmhash is a successor to Cityhash (also from Google). Farmhash, like Cityhash before it, use ideas from Austin Appleby's MurmurHash.
Installation
To install run:
go get github.com/leemcloughlin/gofarmhash
Documentation
For documentation including examples please see:
http://godoc.org/github.com/leemcloughlin/gofarmhash
License
As this is just a fairly literal port of Google's code consider this under the same license (MIT license). For details see COPYING
Documentation
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Overview ¶
Farmhash is a successor to Cityhash (both from Google)
Original Copyright ¶
Copyright (c) 2014 Google, Inc.
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.
FarmHash, by Geoff Pike ¶
Conversion Notes ¶
Converted by Lee McLoughlin, LMMRTech ¶
Converted from the original C++ source code by building it (on a Ubuntu based system with an Intel CPU). Then copying the build command and editing it to generate the output of the C pre-processor stage. This showed a version of what code was required. I then copied code from the original files to convert to Go in order to preserve original comments.
Note: If you want to compare results between this Go library and the original then when building the C++ its important to build with -DFARMHASH_DEBUG=0 (or edit src/farmhash.cc and add a #define) otherwise the results are byte swapped for reasons I don't understand. Of course a byte swapped hash is still a hash.
To test I wrote a small program in C++ to generate both hashes and results from internal routines to add to the test routines here in the Go version. This ensures these func's work the same as the C++ versions.
To obey Go export rules some functions had their first character case changed.
TODO: Sort out all Public vs private names & rationalise my use of prefixes (cc, mk, na) that I use to avoid clashes.
TODO: Figure out how to hash incrementally to use with the Go standard hash package.
TODO: More testing!
Note: An earlier version was a more literal conversion and lots of functions passed a len parameter after every slice passed.
Note: I'm sure others have already converted farmhash to Go but I'm improving my Go skills and wanted the experience.
Index ¶
- Constants
- func FingerPrint32(s []byte) uint32
- func FingerPrint64(s []byte) uint64
- func Hash32(s []byte) uint32
- func Hash32WithSeed(s []byte, seed uint32) uint32
- func Hash64(s []byte) uint64
- func Hash64WithSeed(s []byte, seed uint64) uint64
- func Hash64WithSeeds(s []byte, seed0, seed1 uint64) uint64
- type Uint128
Examples ¶
Constants ¶
const (
Version = "1.0.0"
)
Variables ¶
This section is empty.
Functions ¶
func FingerPrint32 ¶
func FingerPrint64 ¶
func Hash32 ¶
Example ¶
str := "hello world"
bytes := []byte(str)
hash := Hash32(bytes)
fmt.Printf("Hash32(%s) is %x\n", str, hash)
Output:
func Hash32WithSeed ¶
func Hash64WithSeed ¶
func Hash64WithSeeds ¶
Types ¶
type Uint128 ¶
type Uint128 struct {
First, Second uint64
}
func CityHash128 ¶
func CityHash128WithSeed ¶
func CityMurmur ¶
A subroutine for CityHash128(). Returns a decent 128-bit hash for strings of any length representable in signed long. Based on City and Murmur.
Source Files