mirror of
https://github.com/golang/go
synced 2024-10-07 05:21:22 -06:00
c007ce824d
Preparation was in CL 134570043. This CL contains only the effect of 'hg mv src/pkg/* src'. For more about the move, see golang.org/s/go14nopkg.
353 lines
8.8 KiB
Go
353 lines
8.8 KiB
Go
// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime
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import "unsafe"
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const (
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c0 = uintptr((8-ptrSize)/4*2860486313 + (ptrSize-4)/4*33054211828000289)
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c1 = uintptr((8-ptrSize)/4*3267000013 + (ptrSize-4)/4*23344194077549503)
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)
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// type algorithms - known to compiler
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const (
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alg_MEM = iota
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alg_MEM0
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alg_MEM8
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alg_MEM16
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alg_MEM32
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alg_MEM64
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alg_MEM128
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alg_NOEQ
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alg_NOEQ0
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alg_NOEQ8
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alg_NOEQ16
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alg_NOEQ32
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alg_NOEQ64
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alg_NOEQ128
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alg_STRING
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alg_INTER
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alg_NILINTER
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alg_SLICE
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alg_FLOAT32
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alg_FLOAT64
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alg_CPLX64
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alg_CPLX128
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alg_max
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)
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type typeAlg struct {
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// function for hashing objects of this type
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// (ptr to object, size, seed) -> hash
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hash func(unsafe.Pointer, uintptr, uintptr) uintptr
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// function for comparing objects of this type
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// (ptr to object A, ptr to object B, size) -> ==?
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equal func(unsafe.Pointer, unsafe.Pointer, uintptr) bool
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}
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var algarray = [alg_max]typeAlg{
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alg_MEM: {memhash, memequal},
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alg_MEM0: {memhash, memequal0},
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alg_MEM8: {memhash, memequal8},
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alg_MEM16: {memhash, memequal16},
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alg_MEM32: {memhash, memequal32},
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alg_MEM64: {memhash, memequal64},
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alg_MEM128: {memhash, memequal128},
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alg_NOEQ: {nil, nil},
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alg_NOEQ0: {nil, nil},
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alg_NOEQ8: {nil, nil},
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alg_NOEQ16: {nil, nil},
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alg_NOEQ32: {nil, nil},
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alg_NOEQ64: {nil, nil},
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alg_NOEQ128: {nil, nil},
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alg_STRING: {strhash, strequal},
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alg_INTER: {interhash, interequal},
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alg_NILINTER: {nilinterhash, nilinterequal},
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alg_SLICE: {nil, nil},
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alg_FLOAT32: {f32hash, f32equal},
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alg_FLOAT64: {f64hash, f64equal},
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alg_CPLX64: {c64hash, c64equal},
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alg_CPLX128: {c128hash, c128equal},
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}
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const nacl = GOOS == "nacl"
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var useAeshash bool
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// in asm_*.s
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func aeshash(p unsafe.Pointer, s, h uintptr) uintptr
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func aeshash32(p unsafe.Pointer, s, h uintptr) uintptr
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func aeshash64(p unsafe.Pointer, s, h uintptr) uintptr
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func aeshashstr(p unsafe.Pointer, s, h uintptr) uintptr
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func memhash(p unsafe.Pointer, s, h uintptr) uintptr {
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if !nacl && useAeshash {
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return aeshash(p, s, h)
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}
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h ^= c0
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for s > 0 {
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h = (h ^ uintptr(*(*byte)(p))) * c1
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p = add(p, 1)
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s--
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}
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return h
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}
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func strhash(a unsafe.Pointer, s, h uintptr) uintptr {
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return memhash((*stringStruct)(a).str, uintptr(len(*(*string)(a))), h)
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}
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// NOTE: Because NaN != NaN, a map can contain any
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// number of (mostly useless) entries keyed with NaNs.
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// To avoid long hash chains, we assign a random number
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// as the hash value for a NaN.
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func f32hash(p unsafe.Pointer, s, h uintptr) uintptr {
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f := *(*float32)(p)
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switch {
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case f == 0:
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return c1 * (c0 ^ h) // +0, -0
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case f != f:
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return c1 * (c0 ^ h ^ uintptr(fastrand1())) // any kind of NaN
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default:
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return memhash(p, 4, h)
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}
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}
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func f64hash(p unsafe.Pointer, s, h uintptr) uintptr {
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f := *(*float64)(p)
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switch {
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case f == 0:
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return c1 * (c0 ^ h) // +0, -0
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case f != f:
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return c1 * (c0 ^ h ^ uintptr(fastrand1())) // any kind of NaN
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default:
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return memhash(p, 8, h)
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}
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}
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func c64hash(p unsafe.Pointer, s, h uintptr) uintptr {
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x := (*[2]float32)(p)
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return f32hash(unsafe.Pointer(&x[1]), 4, f32hash(unsafe.Pointer(&x[0]), 4, h))
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}
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func c128hash(p unsafe.Pointer, s, h uintptr) uintptr {
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x := (*[2]float64)(p)
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return f64hash(unsafe.Pointer(&x[1]), 8, f64hash(unsafe.Pointer(&x[0]), 8, h))
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}
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func interhash(p unsafe.Pointer, s, h uintptr) uintptr {
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a := (*iface)(p)
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tab := a.tab
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if tab == nil {
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return h
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}
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t := tab._type
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fn := goalg(t.alg).hash
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if fn == nil {
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panic(errorString("hash of unhashable type " + *t._string))
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}
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if isDirectIface(t) {
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return c1 * fn(unsafe.Pointer(&a.data), uintptr(t.size), h^c0)
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} else {
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return c1 * fn(a.data, uintptr(t.size), h^c0)
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}
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}
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func nilinterhash(p unsafe.Pointer, s, h uintptr) uintptr {
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a := (*eface)(p)
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t := a._type
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if t == nil {
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return h
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}
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fn := goalg(t.alg).hash
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if fn == nil {
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panic(errorString("hash of unhashable type " + *t._string))
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}
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if isDirectIface(t) {
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return c1 * fn(unsafe.Pointer(&a.data), uintptr(t.size), h^c0)
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} else {
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return c1 * fn(a.data, uintptr(t.size), h^c0)
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}
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}
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func memequal(p, q unsafe.Pointer, size uintptr) bool {
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if p == q {
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return true
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}
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return memeq(p, q, size)
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}
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func memequal0(p, q unsafe.Pointer, size uintptr) bool {
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return true
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}
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func memequal8(p, q unsafe.Pointer, size uintptr) bool {
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return *(*int8)(p) == *(*int8)(q)
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}
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func memequal16(p, q unsafe.Pointer, size uintptr) bool {
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return *(*int16)(p) == *(*int16)(q)
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}
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func memequal32(p, q unsafe.Pointer, size uintptr) bool {
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return *(*int32)(p) == *(*int32)(q)
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}
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func memequal64(p, q unsafe.Pointer, size uintptr) bool {
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return *(*int64)(p) == *(*int64)(q)
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}
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func memequal128(p, q unsafe.Pointer, size uintptr) bool {
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return *(*[2]int64)(p) == *(*[2]int64)(q)
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}
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func f32equal(p, q unsafe.Pointer, size uintptr) bool {
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return *(*float32)(p) == *(*float32)(q)
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}
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func f64equal(p, q unsafe.Pointer, size uintptr) bool {
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return *(*float64)(p) == *(*float64)(q)
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}
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func c64equal(p, q unsafe.Pointer, size uintptr) bool {
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return *(*complex64)(p) == *(*complex64)(q)
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}
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func c128equal(p, q unsafe.Pointer, size uintptr) bool {
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return *(*complex128)(p) == *(*complex128)(q)
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}
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func strequal(p, q unsafe.Pointer, size uintptr) bool {
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return *(*string)(p) == *(*string)(q)
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}
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func interequal(p, q unsafe.Pointer, size uintptr) bool {
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return ifaceeq(*(*interface {
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f()
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})(p), *(*interface {
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f()
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})(q))
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}
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func nilinterequal(p, q unsafe.Pointer, size uintptr) bool {
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return efaceeq(*(*interface{})(p), *(*interface{})(q))
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}
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func efaceeq(p, q interface{}) bool {
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x := (*eface)(unsafe.Pointer(&p))
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y := (*eface)(unsafe.Pointer(&q))
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t := x._type
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if t != y._type {
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return false
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}
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if t == nil {
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return true
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}
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eq := goalg(t.alg).equal
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if eq == nil {
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panic(errorString("comparing uncomparable type " + *t._string))
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}
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if isDirectIface(t) {
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return eq(noescape(unsafe.Pointer(&x.data)), noescape(unsafe.Pointer(&y.data)), uintptr(t.size))
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}
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return eq(x.data, y.data, uintptr(t.size))
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}
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func ifaceeq(p, q interface {
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f()
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}) bool {
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x := (*iface)(unsafe.Pointer(&p))
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y := (*iface)(unsafe.Pointer(&q))
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xtab := x.tab
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if xtab != y.tab {
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return false
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}
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if xtab == nil {
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return true
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}
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t := xtab._type
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eq := goalg(t.alg).equal
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if eq == nil {
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panic(errorString("comparing uncomparable type " + *t._string))
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}
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if isDirectIface(t) {
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return eq(noescape(unsafe.Pointer(&x.data)), noescape(unsafe.Pointer(&y.data)), uintptr(t.size))
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}
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return eq(x.data, y.data, uintptr(t.size))
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}
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// Testing adapters for hash quality tests (see hash_test.go)
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func haveGoodHash() bool {
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return useAeshash
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}
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func stringHash(s string, seed uintptr) uintptr {
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return algarray[alg_STRING].hash(noescape(unsafe.Pointer(&s)), unsafe.Sizeof(s), seed)
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}
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func bytesHash(b []byte, seed uintptr) uintptr {
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s := (*sliceStruct)(unsafe.Pointer(&b))
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return algarray[alg_MEM].hash(s.array, uintptr(s.len), seed)
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}
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func int32Hash(i uint32, seed uintptr) uintptr {
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return algarray[alg_MEM32].hash(noescape(unsafe.Pointer(&i)), 4, seed)
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}
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func int64Hash(i uint64, seed uintptr) uintptr {
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return algarray[alg_MEM64].hash(noescape(unsafe.Pointer(&i)), 8, seed)
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}
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func efaceHash(i interface{}, seed uintptr) uintptr {
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return algarray[alg_NILINTER].hash(noescape(unsafe.Pointer(&i)), unsafe.Sizeof(i), seed)
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}
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func ifaceHash(i interface {
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F()
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}, seed uintptr) uintptr {
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return algarray[alg_INTER].hash(noescape(unsafe.Pointer(&i)), unsafe.Sizeof(i), seed)
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}
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// Testing adapter for memclr
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func memclrBytes(b []byte) {
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s := (*sliceStruct)(unsafe.Pointer(&b))
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memclr(s.array, uintptr(s.len))
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}
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// TODO(dvyukov): remove when Type is converted to Go and contains *typeAlg.
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func goalg(a unsafe.Pointer) *typeAlg {
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return (*typeAlg)(a)
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}
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// used in asm_{386,amd64}.s
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const hashRandomBytes = 32
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var aeskeysched [hashRandomBytes]byte
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//go:noescape
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func get_random_data(rnd *unsafe.Pointer, n *int32)
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func init() {
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if theGoos == "nacl" {
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return
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}
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// Install aes hash algorithm if we have the instructions we need
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if (cpuid_ecx&(1<<25)) != 0 && // aes (aesenc)
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(cpuid_ecx&(1<<9)) != 0 && // sse3 (pshufb)
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(cpuid_ecx&(1<<19)) != 0 { // sse4.1 (pinsr{d,q})
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useAeshash = true
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algarray[alg_MEM].hash = aeshash
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algarray[alg_MEM8].hash = aeshash
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algarray[alg_MEM16].hash = aeshash
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algarray[alg_MEM32].hash = aeshash32
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algarray[alg_MEM64].hash = aeshash64
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algarray[alg_MEM128].hash = aeshash
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algarray[alg_STRING].hash = aeshashstr
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// Initialize with random data so hash collisions will be hard to engineer.
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var rnd unsafe.Pointer
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var n int32
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get_random_data(&rnd, &n)
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if n > hashRandomBytes {
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n = hashRandomBytes
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}
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memmove(unsafe.Pointer(&aeskeysched[0]), rnd, uintptr(n))
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if n < hashRandomBytes {
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// Not very random, but better than nothing.
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for t := nanotime(); n < hashRandomBytes; n++ {
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aeskeysched[n] = byte(t >> uint(8*(n%8)))
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}
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}
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}
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}
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