435c0d9fc8
This PR switches the Nomad repository from using govendor to Go modules for managing dependencies. Aspects of the Nomad workflow remain pretty much the same. The usual Makefile targets should continue to work as they always did. The API submodule simply defers to the parent Nomad version on the repository, keeping the semantics of API versioning that currently exists.
47 lines
1.4 KiB
Go
47 lines
1.4 KiB
Go
// +build !appengine
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// This file encapsulates usage of unsafe.
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// xxhash_safe.go contains the safe implementations.
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package xxhash
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import (
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"reflect"
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"unsafe"
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)
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// Notes:
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//
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// See https://groups.google.com/d/msg/golang-nuts/dcjzJy-bSpw/tcZYBzQqAQAJ
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// for some discussion about these unsafe conversions.
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//
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// In the future it's possible that compiler optimizations will make these
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// unsafe operations unnecessary: https://golang.org/issue/2205.
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//
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// Both of these wrapper functions still incur function call overhead since they
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// will not be inlined. We could write Go/asm copies of Sum64 and Digest.Write
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// for strings to squeeze out a bit more speed. Mid-stack inlining should
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// eventually fix this.
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// Sum64String computes the 64-bit xxHash digest of s.
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// It may be faster than Sum64([]byte(s)) by avoiding a copy.
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func Sum64String(s string) uint64 {
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var b []byte
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bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
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bh.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
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bh.Len = len(s)
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bh.Cap = len(s)
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return Sum64(b)
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}
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// WriteString adds more data to d. It always returns len(s), nil.
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// It may be faster than Write([]byte(s)) by avoiding a copy.
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func (d *Digest) WriteString(s string) (n int, err error) {
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var b []byte
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bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
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bh.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
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bh.Len = len(s)
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bh.Cap = len(s)
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return d.Write(b)
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}
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