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// Copyright 2023 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package abi
import (
"unsafe"
)
// Map constants common to several packages
// runtime/runtime-gdb.py:MapTypePrinter contains its own copy
const (
// Number of bits in the group.slot count.
SwissMapGroupSlotsBits = 3
// Number of slots in a group.
SwissMapGroupSlots = 1 << SwissMapGroupSlotsBits // 8
// Maximum key or elem size to keep inline (instead of mallocing per element).
// Must fit in a uint8.
SwissMapMaxKeyBytes = 128
SwissMapMaxElemBytes = 128
ctrlEmpty = 0b10000000
bitsetLSB = 0x0101010101010101
// Value of control word with all empty slots.
SwissMapCtrlEmpty = bitsetLSB * uint64(ctrlEmpty)
)
type SwissMapType struct {
Type
Key *Type
Elem *Type
Group *Type // internal type representing a slot group
// function for hashing keys (ptr to key, seed) -> hash
Hasher func(unsafe.Pointer, uintptr) uintptr
GroupSize uintptr // == Group.Size_
SlotSize uintptr // size of key/elem slot
ElemOff uintptr // offset of elem in key/elem slot
Flags uint32
}
// Flag values
const (
SwissMapNeedKeyUpdate = 1 << iota
SwissMapHashMightPanic
SwissMapIndirectKey
SwissMapIndirectElem
)
func (mt *SwissMapType) NeedKeyUpdate() bool { // true if we need to update key on an overwrite
return mt.Flags&SwissMapNeedKeyUpdate != 0
}
func (mt *SwissMapType) HashMightPanic() bool { // true if hash function might panic
return mt.Flags&SwissMapHashMightPanic != 0
}
func (mt *SwissMapType) IndirectKey() bool { // store ptr to key instead of key itself
return mt.Flags&SwissMapIndirectKey != 0
}
func (mt *SwissMapType) IndirectElem() bool { // store ptr to elem instead of elem itself
return mt.Flags&SwissMapIndirectElem != 0
}
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