diff options
Diffstat (limited to 'vendor/github.com/cespare/xxhash/v2/xxhash_unsafe.go')
-rw-r--r-- | vendor/github.com/cespare/xxhash/v2/xxhash_unsafe.go | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/vendor/github.com/cespare/xxhash/v2/xxhash_unsafe.go b/vendor/github.com/cespare/xxhash/v2/xxhash_unsafe.go new file mode 100644 index 000000000..53bf76efb --- /dev/null +++ b/vendor/github.com/cespare/xxhash/v2/xxhash_unsafe.go @@ -0,0 +1,46 @@ +// +build !appengine + +// This file encapsulates usage of unsafe. +// xxhash_safe.go contains the safe implementations. + +package xxhash + +import ( + "reflect" + "unsafe" +) + +// Notes: +// +// See https://groups.google.com/d/msg/golang-nuts/dcjzJy-bSpw/tcZYBzQqAQAJ +// for some discussion about these unsafe conversions. +// +// In the future it's possible that compiler optimizations will make these +// unsafe operations unnecessary: https://golang.org/issue/2205. +// +// Both of these wrapper functions still incur function call overhead since they +// will not be inlined. We could write Go/asm copies of Sum64 and Digest.Write +// for strings to squeeze out a bit more speed. Mid-stack inlining should +// eventually fix this. + +// Sum64String computes the 64-bit xxHash digest of s. +// It may be faster than Sum64([]byte(s)) by avoiding a copy. +func Sum64String(s string) uint64 { + var b []byte + bh := (*reflect.SliceHeader)(unsafe.Pointer(&b)) + bh.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data + bh.Len = len(s) + bh.Cap = len(s) + return Sum64(b) +} + +// WriteString adds more data to d. It always returns len(s), nil. +// It may be faster than Write([]byte(s)) by avoiding a copy. +func (d *Digest) WriteString(s string) (n int, err error) { + var b []byte + bh := (*reflect.SliceHeader)(unsafe.Pointer(&b)) + bh.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data + bh.Len = len(s) + bh.Cap = len(s) + return d.Write(b) +} |